iommu/arm-smmu: Support DMA-API domains

[cascardo/linux.git] / drivers / iommu / arm-smmu-v3.c

/*
 * IOMMU API for ARM architected SMMUv3 implementations.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 2015 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 *
 * This driver is powered by bad coffee and bombay mix.
 */

#include <linux/delay.h>
#include <linux/dma-iommu.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>

#include "io-pgtable.h"

/* MMIO registers */
#define ARM_SMMU_IDR0                   0x0
#define IDR0_ST_LVL_SHIFT               27
#define IDR0_ST_LVL_MASK                0x3
#define IDR0_ST_LVL_2LVL                (1 << IDR0_ST_LVL_SHIFT)
#define IDR0_STALL_MODEL_SHIFT          24
#define IDR0_STALL_MODEL_MASK           0x3
#define IDR0_STALL_MODEL_STALL          (0 << IDR0_STALL_MODEL_SHIFT)
#define IDR0_STALL_MODEL_FORCE          (2 << IDR0_STALL_MODEL_SHIFT)
#define IDR0_TTENDIAN_SHIFT             21
#define IDR0_TTENDIAN_MASK              0x3
#define IDR0_TTENDIAN_LE                (2 << IDR0_TTENDIAN_SHIFT)
#define IDR0_TTENDIAN_BE                (3 << IDR0_TTENDIAN_SHIFT)
#define IDR0_TTENDIAN_MIXED             (0 << IDR0_TTENDIAN_SHIFT)
#define IDR0_CD2L                       (1 << 19)
#define IDR0_VMID16                     (1 << 18)
#define IDR0_PRI                        (1 << 16)
#define IDR0_SEV                        (1 << 14)
#define IDR0_MSI                        (1 << 13)
#define IDR0_ASID16                     (1 << 12)
#define IDR0_ATS                        (1 << 10)
#define IDR0_HYP                        (1 << 9)
#define IDR0_COHACC                     (1 << 4)
#define IDR0_TTF_SHIFT                  2
#define IDR0_TTF_MASK                   0x3
#define IDR0_TTF_AARCH64                (2 << IDR0_TTF_SHIFT)
#define IDR0_TTF_AARCH32_64             (3 << IDR0_TTF_SHIFT)
#define IDR0_S1P                        (1 << 1)
#define IDR0_S2P                        (1 << 0)

#define ARM_SMMU_IDR1                   0x4
#define IDR1_TABLES_PRESET              (1 << 30)
#define IDR1_QUEUES_PRESET              (1 << 29)
#define IDR1_REL                        (1 << 28)
#define IDR1_CMDQ_SHIFT                 21
#define IDR1_CMDQ_MASK                  0x1f
#define IDR1_EVTQ_SHIFT                 16
#define IDR1_EVTQ_MASK                  0x1f
#define IDR1_PRIQ_SHIFT                 11
#define IDR1_PRIQ_MASK                  0x1f
#define IDR1_SSID_SHIFT                 6
#define IDR1_SSID_MASK                  0x1f
#define IDR1_SID_SHIFT                  0
#define IDR1_SID_MASK                   0x3f

#define ARM_SMMU_IDR5                   0x14
#define IDR5_STALL_MAX_SHIFT            16
#define IDR5_STALL_MAX_MASK             0xffff
#define IDR5_GRAN64K                    (1 << 6)
#define IDR5_GRAN16K                    (1 << 5)
#define IDR5_GRAN4K                     (1 << 4)
#define IDR5_OAS_SHIFT                  0
#define IDR5_OAS_MASK                   0x7
#define IDR5_OAS_32_BIT                 (0 << IDR5_OAS_SHIFT)
#define IDR5_OAS_36_BIT                 (1 << IDR5_OAS_SHIFT)
#define IDR5_OAS_40_BIT                 (2 << IDR5_OAS_SHIFT)
#define IDR5_OAS_42_BIT                 (3 << IDR5_OAS_SHIFT)
#define IDR5_OAS_44_BIT                 (4 << IDR5_OAS_SHIFT)
#define IDR5_OAS_48_BIT                 (5 << IDR5_OAS_SHIFT)

#define ARM_SMMU_CR0                    0x20
#define CR0_CMDQEN                      (1 << 3)
#define CR0_EVTQEN                      (1 << 2)
#define CR0_PRIQEN                      (1 << 1)
#define CR0_SMMUEN                      (1 << 0)

#define ARM_SMMU_CR0ACK                 0x24

#define ARM_SMMU_CR1                    0x28
#define CR1_SH_NSH                      0
#define CR1_SH_OSH                      2
#define CR1_SH_ISH                      3
#define CR1_CACHE_NC                    0
#define CR1_CACHE_WB                    1
#define CR1_CACHE_WT                    2
#define CR1_TABLE_SH_SHIFT              10
#define CR1_TABLE_OC_SHIFT              8
#define CR1_TABLE_IC_SHIFT              6
#define CR1_QUEUE_SH_SHIFT              4
#define CR1_QUEUE_OC_SHIFT              2
#define CR1_QUEUE_IC_SHIFT              0

#define ARM_SMMU_CR2                    0x2c
#define CR2_PTM                         (1 << 2)
#define CR2_RECINVSID                   (1 << 1)
#define CR2_E2H                         (1 << 0)

#define ARM_SMMU_IRQ_CTRL               0x50
#define IRQ_CTRL_EVTQ_IRQEN             (1 << 2)
#define IRQ_CTRL_PRIQ_IRQEN             (1 << 1)
#define IRQ_CTRL_GERROR_IRQEN           (1 << 0)

#define ARM_SMMU_IRQ_CTRLACK            0x54

#define ARM_SMMU_GERROR                 0x60
#define GERROR_SFM_ERR                  (1 << 8)
#define GERROR_MSI_GERROR_ABT_ERR       (1 << 7)
#define GERROR_MSI_PRIQ_ABT_ERR         (1 << 6)
#define GERROR_MSI_EVTQ_ABT_ERR         (1 << 5)
#define GERROR_MSI_CMDQ_ABT_ERR         (1 << 4)
#define GERROR_PRIQ_ABT_ERR             (1 << 3)
#define GERROR_EVTQ_ABT_ERR             (1 << 2)
#define GERROR_CMDQ_ERR                 (1 << 0)
#define GERROR_ERR_MASK                 0xfd

#define ARM_SMMU_GERRORN                0x64

#define ARM_SMMU_GERROR_IRQ_CFG0        0x68
#define ARM_SMMU_GERROR_IRQ_CFG1        0x70
#define ARM_SMMU_GERROR_IRQ_CFG2        0x74

#define ARM_SMMU_STRTAB_BASE            0x80
#define STRTAB_BASE_RA                  (1UL << 62)
#define STRTAB_BASE_ADDR_SHIFT          6
#define STRTAB_BASE_ADDR_MASK           0x3ffffffffffUL

#define ARM_SMMU_STRTAB_BASE_CFG        0x88
#define STRTAB_BASE_CFG_LOG2SIZE_SHIFT  0
#define STRTAB_BASE_CFG_LOG2SIZE_MASK   0x3f
#define STRTAB_BASE_CFG_SPLIT_SHIFT     6
#define STRTAB_BASE_CFG_SPLIT_MASK      0x1f
#define STRTAB_BASE_CFG_FMT_SHIFT       16
#define STRTAB_BASE_CFG_FMT_MASK        0x3
#define STRTAB_BASE_CFG_FMT_LINEAR      (0 << STRTAB_BASE_CFG_FMT_SHIFT)
#define STRTAB_BASE_CFG_FMT_2LVL        (1 << STRTAB_BASE_CFG_FMT_SHIFT)

#define ARM_SMMU_CMDQ_BASE              0x90
#define ARM_SMMU_CMDQ_PROD              0x98
#define ARM_SMMU_CMDQ_CONS              0x9c

#define ARM_SMMU_EVTQ_BASE              0xa0
#define ARM_SMMU_EVTQ_PROD              0x100a8
#define ARM_SMMU_EVTQ_CONS              0x100ac
#define ARM_SMMU_EVTQ_IRQ_CFG0          0xb0
#define ARM_SMMU_EVTQ_IRQ_CFG1          0xb8
#define ARM_SMMU_EVTQ_IRQ_CFG2          0xbc

#define ARM_SMMU_PRIQ_BASE              0xc0
#define ARM_SMMU_PRIQ_PROD              0x100c8
#define ARM_SMMU_PRIQ_CONS              0x100cc
#define ARM_SMMU_PRIQ_IRQ_CFG0          0xd0
#define ARM_SMMU_PRIQ_IRQ_CFG1          0xd8
#define ARM_SMMU_PRIQ_IRQ_CFG2          0xdc

/* Common MSI config fields */
#define MSI_CFG0_ADDR_SHIFT             2
#define MSI_CFG0_ADDR_MASK              0x3fffffffffffUL
#define MSI_CFG2_SH_SHIFT               4
#define MSI_CFG2_SH_NSH                 (0UL << MSI_CFG2_SH_SHIFT)
#define MSI_CFG2_SH_OSH                 (2UL << MSI_CFG2_SH_SHIFT)
#define MSI_CFG2_SH_ISH                 (3UL << MSI_CFG2_SH_SHIFT)
#define MSI_CFG2_MEMATTR_SHIFT          0
#define MSI_CFG2_MEMATTR_DEVICE_nGnRE   (0x1 << MSI_CFG2_MEMATTR_SHIFT)

#define Q_IDX(q, p)                     ((p) & ((1 << (q)->max_n_shift) - 1))
#define Q_WRP(q, p)                     ((p) & (1 << (q)->max_n_shift))
#define Q_OVERFLOW_FLAG                 (1 << 31)
#define Q_OVF(q, p)                     ((p) & Q_OVERFLOW_FLAG)
#define Q_ENT(q, p)                     ((q)->base +                    \
                                         Q_IDX(q, p) * (q)->ent_dwords)

#define Q_BASE_RWA                      (1UL << 62)
#define Q_BASE_ADDR_SHIFT               5
#define Q_BASE_ADDR_MASK                0xfffffffffffUL
#define Q_BASE_LOG2SIZE_SHIFT           0
#define Q_BASE_LOG2SIZE_MASK            0x1fUL

/*
 * Stream table.
 *
 * Linear: Enough to cover 1 << IDR1.SIDSIZE entries
 * 2lvl: 128k L1 entries,
 *       256 lazy entries per table (each table covers a PCI bus)
 */
#define STRTAB_L1_SZ_SHIFT              20
#define STRTAB_SPLIT                    8

#define STRTAB_L1_DESC_DWORDS           1
#define STRTAB_L1_DESC_SPAN_SHIFT       0
#define STRTAB_L1_DESC_SPAN_MASK        0x1fUL
#define STRTAB_L1_DESC_L2PTR_SHIFT      6
#define STRTAB_L1_DESC_L2PTR_MASK       0x3ffffffffffUL

#define STRTAB_STE_DWORDS               8
#define STRTAB_STE_0_V                  (1UL << 0)
#define STRTAB_STE_0_CFG_SHIFT          1
#define STRTAB_STE_0_CFG_MASK           0x7UL
#define STRTAB_STE_0_CFG_ABORT          (0UL << STRTAB_STE_0_CFG_SHIFT)
#define STRTAB_STE_0_CFG_BYPASS         (4UL << STRTAB_STE_0_CFG_SHIFT)
#define STRTAB_STE_0_CFG_S1_TRANS       (5UL << STRTAB_STE_0_CFG_SHIFT)
#define STRTAB_STE_0_CFG_S2_TRANS       (6UL << STRTAB_STE_0_CFG_SHIFT)

#define STRTAB_STE_0_S1FMT_SHIFT        4
#define STRTAB_STE_0_S1FMT_LINEAR       (0UL << STRTAB_STE_0_S1FMT_SHIFT)
#define STRTAB_STE_0_S1CTXPTR_SHIFT     6
#define STRTAB_STE_0_S1CTXPTR_MASK      0x3ffffffffffUL
#define STRTAB_STE_0_S1CDMAX_SHIFT      59
#define STRTAB_STE_0_S1CDMAX_MASK       0x1fUL

#define STRTAB_STE_1_S1C_CACHE_NC       0UL
#define STRTAB_STE_1_S1C_CACHE_WBRA     1UL
#define STRTAB_STE_1_S1C_CACHE_WT       2UL
#define STRTAB_STE_1_S1C_CACHE_WB       3UL
#define STRTAB_STE_1_S1C_SH_NSH         0UL
#define STRTAB_STE_1_S1C_SH_OSH         2UL
#define STRTAB_STE_1_S1C_SH_ISH         3UL
#define STRTAB_STE_1_S1CIR_SHIFT        2
#define STRTAB_STE_1_S1COR_SHIFT        4
#define STRTAB_STE_1_S1CSH_SHIFT        6

#define STRTAB_STE_1_S1STALLD           (1UL << 27)

#define STRTAB_STE_1_EATS_ABT           0UL
#define STRTAB_STE_1_EATS_TRANS         1UL
#define STRTAB_STE_1_EATS_S1CHK         2UL
#define STRTAB_STE_1_EATS_SHIFT         28

#define STRTAB_STE_1_STRW_NSEL1         0UL
#define STRTAB_STE_1_STRW_EL2           2UL
#define STRTAB_STE_1_STRW_SHIFT         30

#define STRTAB_STE_1_SHCFG_INCOMING     1UL
#define STRTAB_STE_1_SHCFG_SHIFT        44

#define STRTAB_STE_2_S2VMID_SHIFT       0
#define STRTAB_STE_2_S2VMID_MASK        0xffffUL
#define STRTAB_STE_2_VTCR_SHIFT         32
#define STRTAB_STE_2_VTCR_MASK          0x7ffffUL
#define STRTAB_STE_2_S2AA64             (1UL << 51)
#define STRTAB_STE_2_S2ENDI             (1UL << 52)
#define STRTAB_STE_2_S2PTW              (1UL << 54)
#define STRTAB_STE_2_S2R                (1UL << 58)

#define STRTAB_STE_3_S2TTB_SHIFT        4
#define STRTAB_STE_3_S2TTB_MASK         0xfffffffffffUL

/* Context descriptor (stage-1 only) */
#define CTXDESC_CD_DWORDS               8
#define CTXDESC_CD_0_TCR_T0SZ_SHIFT     0
#define ARM64_TCR_T0SZ_SHIFT            0
#define ARM64_TCR_T0SZ_MASK             0x1fUL
#define CTXDESC_CD_0_TCR_TG0_SHIFT      6
#define ARM64_TCR_TG0_SHIFT             14
#define ARM64_TCR_TG0_MASK              0x3UL
#define CTXDESC_CD_0_TCR_IRGN0_SHIFT    8
#define ARM64_TCR_IRGN0_SHIFT           8
#define ARM64_TCR_IRGN0_MASK            0x3UL
#define CTXDESC_CD_0_TCR_ORGN0_SHIFT    10
#define ARM64_TCR_ORGN0_SHIFT           10
#define ARM64_TCR_ORGN0_MASK            0x3UL
#define CTXDESC_CD_0_TCR_SH0_SHIFT      12
#define ARM64_TCR_SH0_SHIFT             12
#define ARM64_TCR_SH0_MASK              0x3UL
#define CTXDESC_CD_0_TCR_EPD0_SHIFT     14
#define ARM64_TCR_EPD0_SHIFT            7
#define ARM64_TCR_EPD0_MASK             0x1UL
#define CTXDESC_CD_0_TCR_EPD1_SHIFT     30
#define ARM64_TCR_EPD1_SHIFT            23
#define ARM64_TCR_EPD1_MASK             0x1UL

#define CTXDESC_CD_0_ENDI               (1UL << 15)
#define CTXDESC_CD_0_V                  (1UL << 31)

#define CTXDESC_CD_0_TCR_IPS_SHIFT      32
#define ARM64_TCR_IPS_SHIFT             32
#define ARM64_TCR_IPS_MASK              0x7UL
#define CTXDESC_CD_0_TCR_TBI0_SHIFT     38
#define ARM64_TCR_TBI0_SHIFT            37
#define ARM64_TCR_TBI0_MASK             0x1UL

#define CTXDESC_CD_0_AA64               (1UL << 41)
#define CTXDESC_CD_0_R                  (1UL << 45)
#define CTXDESC_CD_0_A                  (1UL << 46)
#define CTXDESC_CD_0_ASET_SHIFT         47
#define CTXDESC_CD_0_ASET_SHARED        (0UL << CTXDESC_CD_0_ASET_SHIFT)
#define CTXDESC_CD_0_ASET_PRIVATE       (1UL << CTXDESC_CD_0_ASET_SHIFT)
#define CTXDESC_CD_0_ASID_SHIFT         48
#define CTXDESC_CD_0_ASID_MASK          0xffffUL

#define CTXDESC_CD_1_TTB0_SHIFT         4
#define CTXDESC_CD_1_TTB0_MASK          0xfffffffffffUL

#define CTXDESC_CD_3_MAIR_SHIFT         0

/* Convert between AArch64 (CPU) TCR format and SMMU CD format */
#define ARM_SMMU_TCR2CD(tcr, fld)                                       \
        (((tcr) >> ARM64_TCR_##fld##_SHIFT & ARM64_TCR_##fld##_MASK)    \
         << CTXDESC_CD_0_TCR_##fld##_SHIFT)

/* Command queue */
#define CMDQ_ENT_DWORDS                 2
#define CMDQ_MAX_SZ_SHIFT               8

#define CMDQ_ERR_SHIFT                  24
#define CMDQ_ERR_MASK                   0x7f
#define CMDQ_ERR_CERROR_NONE_IDX        0
#define CMDQ_ERR_CERROR_ILL_IDX         1
#define CMDQ_ERR_CERROR_ABT_IDX         2

#define CMDQ_0_OP_SHIFT                 0
#define CMDQ_0_OP_MASK                  0xffUL
#define CMDQ_0_SSV                      (1UL << 11)

#define CMDQ_PREFETCH_0_SID_SHIFT       32
#define CMDQ_PREFETCH_1_SIZE_SHIFT      0
#define CMDQ_PREFETCH_1_ADDR_MASK       ~0xfffUL

#define CMDQ_CFGI_0_SID_SHIFT           32
#define CMDQ_CFGI_0_SID_MASK            0xffffffffUL
#define CMDQ_CFGI_1_LEAF                (1UL << 0)
#define CMDQ_CFGI_1_RANGE_SHIFT         0
#define CMDQ_CFGI_1_RANGE_MASK          0x1fUL

#define CMDQ_TLBI_0_VMID_SHIFT          32
#define CMDQ_TLBI_0_ASID_SHIFT          48
#define CMDQ_TLBI_1_LEAF                (1UL << 0)
#define CMDQ_TLBI_1_VA_MASK             ~0xfffUL
#define CMDQ_TLBI_1_IPA_MASK            0xfffffffff000UL

#define CMDQ_PRI_0_SSID_SHIFT           12
#define CMDQ_PRI_0_SSID_MASK            0xfffffUL
#define CMDQ_PRI_0_SID_SHIFT            32
#define CMDQ_PRI_0_SID_MASK             0xffffffffUL
#define CMDQ_PRI_1_GRPID_SHIFT          0
#define CMDQ_PRI_1_GRPID_MASK           0x1ffUL
#define CMDQ_PRI_1_RESP_SHIFT           12
#define CMDQ_PRI_1_RESP_DENY            (0UL << CMDQ_PRI_1_RESP_SHIFT)
#define CMDQ_PRI_1_RESP_FAIL            (1UL << CMDQ_PRI_1_RESP_SHIFT)
#define CMDQ_PRI_1_RESP_SUCC            (2UL << CMDQ_PRI_1_RESP_SHIFT)

#define CMDQ_SYNC_0_CS_SHIFT            12
#define CMDQ_SYNC_0_CS_NONE             (0UL << CMDQ_SYNC_0_CS_SHIFT)
#define CMDQ_SYNC_0_CS_SEV              (2UL << CMDQ_SYNC_0_CS_SHIFT)

/* Event queue */
#define EVTQ_ENT_DWORDS                 4
#define EVTQ_MAX_SZ_SHIFT               7

#define EVTQ_0_ID_SHIFT                 0
#define EVTQ_0_ID_MASK                  0xffUL

/* PRI queue */
#define PRIQ_ENT_DWORDS                 2
#define PRIQ_MAX_SZ_SHIFT               8

#define PRIQ_0_SID_SHIFT                0
#define PRIQ_0_SID_MASK                 0xffffffffUL
#define PRIQ_0_SSID_SHIFT               32
#define PRIQ_0_SSID_MASK                0xfffffUL
#define PRIQ_0_PERM_PRIV                (1UL << 58)
#define PRIQ_0_PERM_EXEC                (1UL << 59)
#define PRIQ_0_PERM_READ                (1UL << 60)
#define PRIQ_0_PERM_WRITE               (1UL << 61)
#define PRIQ_0_PRG_LAST                 (1UL << 62)
#define PRIQ_0_SSID_V                   (1UL << 63)

#define PRIQ_1_PRG_IDX_SHIFT            0
#define PRIQ_1_PRG_IDX_MASK             0x1ffUL
#define PRIQ_1_ADDR_SHIFT               12
#define PRIQ_1_ADDR_MASK                0xfffffffffffffUL

/* High-level queue structures */
#define ARM_SMMU_POLL_TIMEOUT_US        100

static bool disable_bypass;
module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
MODULE_PARM_DESC(disable_bypass,
        "Disable bypass streams such that incoming transactions from devices that are not attached to an iommu domain will report an abort back to the device and will not be allowed to pass through the SMMU.");

enum pri_resp {
        PRI_RESP_DENY,
        PRI_RESP_FAIL,
        PRI_RESP_SUCC,
};

enum arm_smmu_msi_index {
        EVTQ_MSI_INDEX,
        GERROR_MSI_INDEX,
        PRIQ_MSI_INDEX,
        ARM_SMMU_MAX_MSIS,
};

static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
        [EVTQ_MSI_INDEX] = {
                ARM_SMMU_EVTQ_IRQ_CFG0,
                ARM_SMMU_EVTQ_IRQ_CFG1,
                ARM_SMMU_EVTQ_IRQ_CFG2,
        },
        [GERROR_MSI_INDEX] = {
                ARM_SMMU_GERROR_IRQ_CFG0,
                ARM_SMMU_GERROR_IRQ_CFG1,
                ARM_SMMU_GERROR_IRQ_CFG2,
        },
        [PRIQ_MSI_INDEX] = {
                ARM_SMMU_PRIQ_IRQ_CFG0,
                ARM_SMMU_PRIQ_IRQ_CFG1,
                ARM_SMMU_PRIQ_IRQ_CFG2,
        },
};

struct arm_smmu_cmdq_ent {
        /* Common fields */
        u8                              opcode;
        bool                            substream_valid;

        /* Command-specific fields */
        union {
                #define CMDQ_OP_PREFETCH_CFG    0x1
                struct {
                        u32                     sid;
                        u8                      size;
                        u64                     addr;
                } prefetch;

                #define CMDQ_OP_CFGI_STE        0x3
                #define CMDQ_OP_CFGI_ALL        0x4
                struct {
                        u32                     sid;
                        union {
                                bool            leaf;
                                u8              span;
                        };
                } cfgi;

                #define CMDQ_OP_TLBI_NH_ASID    0x11
                #define CMDQ_OP_TLBI_NH_VA      0x12
                #define CMDQ_OP_TLBI_EL2_ALL    0x20
                #define CMDQ_OP_TLBI_S12_VMALL  0x28
                #define CMDQ_OP_TLBI_S2_IPA     0x2a
                #define CMDQ_OP_TLBI_NSNH_ALL   0x30
                struct {
                        u16                     asid;
                        u16                     vmid;
                        bool                    leaf;
                        u64                     addr;
                } tlbi;

                #define CMDQ_OP_PRI_RESP        0x41
                struct {
                        u32                     sid;
                        u32                     ssid;
                        u16                     grpid;
                        enum pri_resp           resp;
                } pri;

                #define CMDQ_OP_CMD_SYNC        0x46
        };
};

struct arm_smmu_queue {
        int                             irq; /* Wired interrupt */

        __le64                          *base;
        dma_addr_t                      base_dma;
        u64                             q_base;

        size_t                          ent_dwords;
        u32                             max_n_shift;
        u32                             prod;
        u32                             cons;

        u32 __iomem                     *prod_reg;
        u32 __iomem                     *cons_reg;
};

struct arm_smmu_cmdq {
        struct arm_smmu_queue           q;
        spinlock_t                      lock;
};

struct arm_smmu_evtq {
        struct arm_smmu_queue           q;
        u32                             max_stalls;
};

struct arm_smmu_priq {
        struct arm_smmu_queue           q;
};

/* High-level stream table and context descriptor structures */
struct arm_smmu_strtab_l1_desc {
        u8                              span;

        __le64                          *l2ptr;
        dma_addr_t                      l2ptr_dma;
};

struct arm_smmu_s1_cfg {
        __le64                          *cdptr;
        dma_addr_t                      cdptr_dma;

        struct arm_smmu_ctx_desc {
                u16     asid;
                u64     ttbr;
                u64     tcr;
                u64     mair;
        }                               cd;
};

struct arm_smmu_s2_cfg {
        u16                             vmid;
        u64                             vttbr;
        u64                             vtcr;
};

struct arm_smmu_strtab_ent {
        bool                            valid;

        bool                            bypass; /* Overrides s1/s2 config */
        struct arm_smmu_s1_cfg          *s1_cfg;
        struct arm_smmu_s2_cfg          *s2_cfg;
};

struct arm_smmu_strtab_cfg {
        __le64                          *strtab;
        dma_addr_t                      strtab_dma;
        struct arm_smmu_strtab_l1_desc  *l1_desc;
        unsigned int                    num_l1_ents;

        u64                             strtab_base;
        u32                             strtab_base_cfg;
};

/* An SMMUv3 instance */
struct arm_smmu_device {
        struct device                   *dev;
        void __iomem                    *base;

#define ARM_SMMU_FEAT_2_LVL_STRTAB      (1 << 0)
#define ARM_SMMU_FEAT_2_LVL_CDTAB       (1 << 1)
#define ARM_SMMU_FEAT_TT_LE             (1 << 2)
#define ARM_SMMU_FEAT_TT_BE             (1 << 3)
#define ARM_SMMU_FEAT_PRI               (1 << 4)
#define ARM_SMMU_FEAT_ATS               (1 << 5)
#define ARM_SMMU_FEAT_SEV               (1 << 6)
#define ARM_SMMU_FEAT_MSI               (1 << 7)
#define ARM_SMMU_FEAT_COHERENCY         (1 << 8)
#define ARM_SMMU_FEAT_TRANS_S1          (1 << 9)
#define ARM_SMMU_FEAT_TRANS_S2          (1 << 10)
#define ARM_SMMU_FEAT_STALLS            (1 << 11)
#define ARM_SMMU_FEAT_HYP               (1 << 12)
        u32                             features;

#define ARM_SMMU_OPT_SKIP_PREFETCH      (1 << 0)
        u32                             options;

        struct arm_smmu_cmdq            cmdq;
        struct arm_smmu_evtq            evtq;
        struct arm_smmu_priq            priq;

        int                             gerr_irq;

        unsigned long                   ias; /* IPA */
        unsigned long                   oas; /* PA */

#define ARM_SMMU_MAX_ASIDS              (1 << 16)
        unsigned int                    asid_bits;
        DECLARE_BITMAP(asid_map, ARM_SMMU_MAX_ASIDS);

#define ARM_SMMU_MAX_VMIDS              (1 << 16)
        unsigned int                    vmid_bits;
        DECLARE_BITMAP(vmid_map, ARM_SMMU_MAX_VMIDS);

        unsigned int                    ssid_bits;
        unsigned int                    sid_bits;

        struct arm_smmu_strtab_cfg      strtab_cfg;
};

/* SMMU private data for an IOMMU group */
struct arm_smmu_group {
        struct arm_smmu_device          *smmu;
        struct arm_smmu_domain          *domain;
        int                             num_sids;
        u32                             *sids;
        struct arm_smmu_strtab_ent      ste;
};

/* SMMU private data for an IOMMU domain */
enum arm_smmu_domain_stage {
        ARM_SMMU_DOMAIN_S1 = 0,
        ARM_SMMU_DOMAIN_S2,
        ARM_SMMU_DOMAIN_NESTED,
};

struct arm_smmu_domain {
        struct arm_smmu_device          *smmu;
        struct mutex                    init_mutex; /* Protects smmu pointer */

        struct io_pgtable_ops           *pgtbl_ops;
        spinlock_t                      pgtbl_lock;

        enum arm_smmu_domain_stage      stage;
        union {
                struct arm_smmu_s1_cfg  s1_cfg;
                struct arm_smmu_s2_cfg  s2_cfg;
        };

        struct iommu_domain             domain;
};

struct arm_smmu_option_prop {
        u32 opt;
        const char *prop;
};

static struct arm_smmu_option_prop arm_smmu_options[] = {
        { ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
        { 0, NULL},
};

static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
{
        return container_of(dom, struct arm_smmu_domain, domain);
}

static void parse_driver_options(struct arm_smmu_device *smmu)
{
        int i = 0;

        do {
                if (of_property_read_bool(smmu->dev->of_node,
                                                arm_smmu_options[i].prop)) {
                        smmu->options |= arm_smmu_options[i].opt;
                        dev_notice(smmu->dev, "option %s\n",
                                arm_smmu_options[i].prop);
                }
        } while (arm_smmu_options[++i].opt);
}

/* Low-level queue manipulation functions */
static bool queue_full(struct arm_smmu_queue *q)
{
        return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
               Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
}

static bool queue_empty(struct arm_smmu_queue *q)
{
        return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
               Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
}

static void queue_sync_cons(struct arm_smmu_queue *q)
{
        q->cons = readl_relaxed(q->cons_reg);
}

static void queue_inc_cons(struct arm_smmu_queue *q)
{
        u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;

        q->cons = Q_OVF(q, q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
        writel(q->cons, q->cons_reg);
}

static int queue_sync_prod(struct arm_smmu_queue *q)
{
        int ret = 0;
        u32 prod = readl_relaxed(q->prod_reg);

        if (Q_OVF(q, prod) != Q_OVF(q, q->prod))
                ret = -EOVERFLOW;

        q->prod = prod;
        return ret;
}

static void queue_inc_prod(struct arm_smmu_queue *q)
{
        u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + 1;

        q->prod = Q_OVF(q, q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
        writel(q->prod, q->prod_reg);
}

static bool __queue_cons_before(struct arm_smmu_queue *q, u32 until)
{
        if (Q_WRP(q, q->cons) == Q_WRP(q, until))
                return Q_IDX(q, q->cons) < Q_IDX(q, until);

        return Q_IDX(q, q->cons) >= Q_IDX(q, until);
}

static int queue_poll_cons(struct arm_smmu_queue *q, u32 until, bool wfe)
{
        ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US);

        while (queue_sync_cons(q), __queue_cons_before(q, until)) {
                if (ktime_compare(ktime_get(), timeout) > 0)
                        return -ETIMEDOUT;

                if (wfe) {
                        wfe();
                } else {
                        cpu_relax();
                        udelay(1);
                }
        }

        return 0;
}

static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
{
        int i;

        for (i = 0; i < n_dwords; ++i)
                *dst++ = cpu_to_le64(*src++);
}

static int queue_insert_raw(struct arm_smmu_queue *q, u64 *ent)
{
        if (queue_full(q))
                return -ENOSPC;

        queue_write(Q_ENT(q, q->prod), ent, q->ent_dwords);
        queue_inc_prod(q);
        return 0;
}

static void queue_read(__le64 *dst, u64 *src, size_t n_dwords)
{
        int i;

        for (i = 0; i < n_dwords; ++i)
                *dst++ = le64_to_cpu(*src++);
}

static int queue_remove_raw(struct arm_smmu_queue *q, u64 *ent)
{
        if (queue_empty(q))
                return -EAGAIN;

        queue_read(ent, Q_ENT(q, q->cons), q->ent_dwords);
        queue_inc_cons(q);
        return 0;
}

/* High-level queue accessors */
static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
{
        memset(cmd, 0, CMDQ_ENT_DWORDS << 3);
        cmd[0] |= (ent->opcode & CMDQ_0_OP_MASK) << CMDQ_0_OP_SHIFT;

        switch (ent->opcode) {
        case CMDQ_OP_TLBI_EL2_ALL:
        case CMDQ_OP_TLBI_NSNH_ALL:
                break;
        case CMDQ_OP_PREFETCH_CFG:
                cmd[0] |= (u64)ent->prefetch.sid << CMDQ_PREFETCH_0_SID_SHIFT;
                cmd[1] |= ent->prefetch.size << CMDQ_PREFETCH_1_SIZE_SHIFT;
                cmd[1] |= ent->prefetch.addr & CMDQ_PREFETCH_1_ADDR_MASK;
                break;
        case CMDQ_OP_CFGI_STE:
                cmd[0] |= (u64)ent->cfgi.sid << CMDQ_CFGI_0_SID_SHIFT;
                cmd[1] |= ent->cfgi.leaf ? CMDQ_CFGI_1_LEAF : 0;
                break;
        case CMDQ_OP_CFGI_ALL:
                /* Cover the entire SID range */
                cmd[1] |= CMDQ_CFGI_1_RANGE_MASK << CMDQ_CFGI_1_RANGE_SHIFT;
                break;
        case CMDQ_OP_TLBI_NH_VA:
                cmd[0] |= (u64)ent->tlbi.asid << CMDQ_TLBI_0_ASID_SHIFT;
                cmd[1] |= ent->tlbi.leaf ? CMDQ_TLBI_1_LEAF : 0;
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_VA_MASK;
                break;
        case CMDQ_OP_TLBI_S2_IPA:
                cmd[0] |= (u64)ent->tlbi.vmid << CMDQ_TLBI_0_VMID_SHIFT;
                cmd[1] |= ent->tlbi.leaf ? CMDQ_TLBI_1_LEAF : 0;
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_IPA_MASK;
                break;
        case CMDQ_OP_TLBI_NH_ASID:
                cmd[0] |= (u64)ent->tlbi.asid << CMDQ_TLBI_0_ASID_SHIFT;
                /* Fallthrough */
        case CMDQ_OP_TLBI_S12_VMALL:
                cmd[0] |= (u64)ent->tlbi.vmid << CMDQ_TLBI_0_VMID_SHIFT;
                break;
        case CMDQ_OP_PRI_RESP:
                cmd[0] |= ent->substream_valid ? CMDQ_0_SSV : 0;
                cmd[0] |= ent->pri.ssid << CMDQ_PRI_0_SSID_SHIFT;
                cmd[0] |= (u64)ent->pri.sid << CMDQ_PRI_0_SID_SHIFT;
                cmd[1] |= ent->pri.grpid << CMDQ_PRI_1_GRPID_SHIFT;
                switch (ent->pri.resp) {
                case PRI_RESP_DENY:
                        cmd[1] |= CMDQ_PRI_1_RESP_DENY;
                        break;
                case PRI_RESP_FAIL:
                        cmd[1] |= CMDQ_PRI_1_RESP_FAIL;
                        break;
                case PRI_RESP_SUCC:
                        cmd[1] |= CMDQ_PRI_1_RESP_SUCC;
                        break;
                default:
                        return -EINVAL;
                }
                break;
        case CMDQ_OP_CMD_SYNC:
                cmd[0] |= CMDQ_SYNC_0_CS_SEV;
                break;
        default:
                return -ENOENT;
        }

        return 0;
}

static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
{
        static const char *cerror_str[] = {
                [CMDQ_ERR_CERROR_NONE_IDX]      = "No error",
                [CMDQ_ERR_CERROR_ILL_IDX]       = "Illegal command",
                [CMDQ_ERR_CERROR_ABT_IDX]       = "Abort on command fetch",
        };

        int i;
        u64 cmd[CMDQ_ENT_DWORDS];
        struct arm_smmu_queue *q = &smmu->cmdq.q;
        u32 cons = readl_relaxed(q->cons_reg);
        u32 idx = cons >> CMDQ_ERR_SHIFT & CMDQ_ERR_MASK;
        struct arm_smmu_cmdq_ent cmd_sync = {
                .opcode = CMDQ_OP_CMD_SYNC,
        };

        dev_err(smmu->dev, "CMDQ error (cons 0x%08x): %s\n", cons,
                idx < ARRAY_SIZE(cerror_str) ?  cerror_str[idx] : "Unknown");

        switch (idx) {
        case CMDQ_ERR_CERROR_ABT_IDX:
                dev_err(smmu->dev, "retrying command fetch\n");
        case CMDQ_ERR_CERROR_NONE_IDX:
                return;
        case CMDQ_ERR_CERROR_ILL_IDX:
                /* Fallthrough */
        default:
                break;
        }

        /*
         * We may have concurrent producers, so we need to be careful
         * not to touch any of the shadow cmdq state.
         */
        queue_read(cmd, Q_ENT(q, idx), q->ent_dwords);
        dev_err(smmu->dev, "skipping command in error state:\n");
        for (i = 0; i < ARRAY_SIZE(cmd); ++i)
                dev_err(smmu->dev, "\t0x%016llx\n", (unsigned long long)cmd[i]);

        /* Convert the erroneous command into a CMD_SYNC */
        if (arm_smmu_cmdq_build_cmd(cmd, &cmd_sync)) {
                dev_err(smmu->dev, "failed to convert to CMD_SYNC\n");
                return;
        }

        queue_write(cmd, Q_ENT(q, idx), q->ent_dwords);
}

static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
                                    struct arm_smmu_cmdq_ent *ent)
{
        u32 until;
        u64 cmd[CMDQ_ENT_DWORDS];
        bool wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV);
        struct arm_smmu_queue *q = &smmu->cmdq.q;

        if (arm_smmu_cmdq_build_cmd(cmd, ent)) {
                dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n",
                         ent->opcode);
                return;
        }

        spin_lock(&smmu->cmdq.lock);
        while (until = q->prod + 1, queue_insert_raw(q, cmd) == -ENOSPC) {
                /*
                 * Keep the queue locked, otherwise the producer could wrap
                 * twice and we could see a future consumer pointer that looks
                 * like it's behind us.
                 */
                if (queue_poll_cons(q, until, wfe))
                        dev_err_ratelimited(smmu->dev, "CMDQ timeout\n");
        }

        if (ent->opcode == CMDQ_OP_CMD_SYNC && queue_poll_cons(q, until, wfe))
                dev_err_ratelimited(smmu->dev, "CMD_SYNC timeout\n");
        spin_unlock(&smmu->cmdq.lock);
}

/* Context descriptor manipulation functions */
static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr)
{
        u64 val = 0;

        /* Repack the TCR. Just care about TTBR0 for now */
        val |= ARM_SMMU_TCR2CD(tcr, T0SZ);
        val |= ARM_SMMU_TCR2CD(tcr, TG0);
        val |= ARM_SMMU_TCR2CD(tcr, IRGN0);
        val |= ARM_SMMU_TCR2CD(tcr, ORGN0);
        val |= ARM_SMMU_TCR2CD(tcr, SH0);
        val |= ARM_SMMU_TCR2CD(tcr, EPD0);
        val |= ARM_SMMU_TCR2CD(tcr, EPD1);
        val |= ARM_SMMU_TCR2CD(tcr, IPS);
        val |= ARM_SMMU_TCR2CD(tcr, TBI0);

        return val;
}

static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
                                    struct arm_smmu_s1_cfg *cfg)
{
        u64 val;

        /*
         * We don't need to issue any invalidation here, as we'll invalidate
         * the STE when installing the new entry anyway.
         */
        val = arm_smmu_cpu_tcr_to_cd(cfg->cd.tcr) |
#ifdef __BIG_ENDIAN
              CTXDESC_CD_0_ENDI |
#endif
              CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET_PRIVATE |
              CTXDESC_CD_0_AA64 | (u64)cfg->cd.asid << CTXDESC_CD_0_ASID_SHIFT |
              CTXDESC_CD_0_V;
        cfg->cdptr[0] = cpu_to_le64(val);

        val = cfg->cd.ttbr & CTXDESC_CD_1_TTB0_MASK << CTXDESC_CD_1_TTB0_SHIFT;
        cfg->cdptr[1] = cpu_to_le64(val);

        cfg->cdptr[3] = cpu_to_le64(cfg->cd.mair << CTXDESC_CD_3_MAIR_SHIFT);
}

/* Stream table manipulation functions */
static void
arm_smmu_write_strtab_l1_desc(__le64 *dst, struct arm_smmu_strtab_l1_desc *desc)
{
        u64 val = 0;

        val |= (desc->span & STRTAB_L1_DESC_SPAN_MASK)
                << STRTAB_L1_DESC_SPAN_SHIFT;
        val |= desc->l2ptr_dma &
               STRTAB_L1_DESC_L2PTR_MASK << STRTAB_L1_DESC_L2PTR_SHIFT;

        *dst = cpu_to_le64(val);
}

static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
{
        struct arm_smmu_cmdq_ent cmd = {
                .opcode = CMDQ_OP_CFGI_STE,
                .cfgi   = {
                        .sid    = sid,
                        .leaf   = true,
                },
        };

        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        cmd.opcode = CMDQ_OP_CMD_SYNC;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
}

static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
                                      __le64 *dst, struct arm_smmu_strtab_ent *ste)
{
        /*
         * This is hideously complicated, but we only really care about
         * three cases at the moment:
         *
         * 1. Invalid (all zero) -> bypass  (init)
         * 2. Bypass -> translation (attach)
         * 3. Translation -> bypass (detach)
         *
         * Given that we can't update the STE atomically and the SMMU
         * doesn't read the thing in a defined order, that leaves us
         * with the following maintenance requirements:
         *
         * 1. Update Config, return (init time STEs aren't live)
         * 2. Write everything apart from dword 0, sync, write dword 0, sync
         * 3. Update Config, sync
         */
        u64 val = le64_to_cpu(dst[0]);
        bool ste_live = false;
        struct arm_smmu_cmdq_ent prefetch_cmd = {
                .opcode         = CMDQ_OP_PREFETCH_CFG,
                .prefetch       = {
                        .sid    = sid,
                },
        };

        if (val & STRTAB_STE_0_V) {
                u64 cfg;

                cfg = val & STRTAB_STE_0_CFG_MASK << STRTAB_STE_0_CFG_SHIFT;
                switch (cfg) {
                case STRTAB_STE_0_CFG_BYPASS:
                        break;
                case STRTAB_STE_0_CFG_S1_TRANS:
                case STRTAB_STE_0_CFG_S2_TRANS:
                        ste_live = true;
                        break;
                default:
                        BUG(); /* STE corruption */
                }
        }

        /* Nuke the existing Config, as we're going to rewrite it */
        val &= ~(STRTAB_STE_0_CFG_MASK << STRTAB_STE_0_CFG_SHIFT);

        if (ste->valid)
                val |= STRTAB_STE_0_V;
        else
                val &= ~STRTAB_STE_0_V;

        if (ste->bypass) {
                val |= disable_bypass ? STRTAB_STE_0_CFG_ABORT
                                      : STRTAB_STE_0_CFG_BYPASS;
                dst[0] = cpu_to_le64(val);
                dst[1] = cpu_to_le64(STRTAB_STE_1_SHCFG_INCOMING
                         << STRTAB_STE_1_SHCFG_SHIFT);
                dst[2] = 0; /* Nuke the VMID */
                if (ste_live)
                        arm_smmu_sync_ste_for_sid(smmu, sid);
                return;
        }

        if (ste->s1_cfg) {
                BUG_ON(ste_live);
                dst[1] = cpu_to_le64(
                         STRTAB_STE_1_S1C_CACHE_WBRA
                         << STRTAB_STE_1_S1CIR_SHIFT |
                         STRTAB_STE_1_S1C_CACHE_WBRA
                         << STRTAB_STE_1_S1COR_SHIFT |
                         STRTAB_STE_1_S1C_SH_ISH << STRTAB_STE_1_S1CSH_SHIFT |
#ifdef CONFIG_PCI_ATS
                         STRTAB_STE_1_EATS_TRANS << STRTAB_STE_1_EATS_SHIFT |
#endif
                         STRTAB_STE_1_STRW_NSEL1 << STRTAB_STE_1_STRW_SHIFT);

                if (smmu->features & ARM_SMMU_FEAT_STALLS)
                        dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);

                val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK
                        << STRTAB_STE_0_S1CTXPTR_SHIFT) |
                        STRTAB_STE_0_CFG_S1_TRANS;

        }

        if (ste->s2_cfg) {
                BUG_ON(ste_live);
                dst[2] = cpu_to_le64(
                         ste->s2_cfg->vmid << STRTAB_STE_2_S2VMID_SHIFT |
                         (ste->s2_cfg->vtcr & STRTAB_STE_2_VTCR_MASK)
                          << STRTAB_STE_2_VTCR_SHIFT |
#ifdef __BIG_ENDIAN
                         STRTAB_STE_2_S2ENDI |
#endif
                         STRTAB_STE_2_S2PTW | STRTAB_STE_2_S2AA64 |
                         STRTAB_STE_2_S2R);

                dst[3] = cpu_to_le64(ste->s2_cfg->vttbr &
                         STRTAB_STE_3_S2TTB_MASK << STRTAB_STE_3_S2TTB_SHIFT);

                val |= STRTAB_STE_0_CFG_S2_TRANS;
        }

        arm_smmu_sync_ste_for_sid(smmu, sid);
        dst[0] = cpu_to_le64(val);
        arm_smmu_sync_ste_for_sid(smmu, sid);

        /* It's likely that we'll want to use the new STE soon */
        if (!(smmu->options & ARM_SMMU_OPT_SKIP_PREFETCH))
                arm_smmu_cmdq_issue_cmd(smmu, &prefetch_cmd);
}

static void arm_smmu_init_bypass_stes(u64 *strtab, unsigned int nent)
{
        unsigned int i;
        struct arm_smmu_strtab_ent ste = {
                .valid  = true,
                .bypass = true,
        };

        for (i = 0; i < nent; ++i) {
                arm_smmu_write_strtab_ent(NULL, -1, strtab, &ste);
                strtab += STRTAB_STE_DWORDS;
        }
}

static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
{
        size_t size;
        void *strtab;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
        struct arm_smmu_strtab_l1_desc *desc = &cfg->l1_desc[sid >> STRTAB_SPLIT];

        if (desc->l2ptr)
                return 0;

        size = 1 << (STRTAB_SPLIT + ilog2(STRTAB_STE_DWORDS) + 3);
        strtab = &cfg->strtab[(sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS];

        desc->span = STRTAB_SPLIT + 1;
        desc->l2ptr = dmam_alloc_coherent(smmu->dev, size, &desc->l2ptr_dma,
                                          GFP_KERNEL | __GFP_ZERO);
        if (!desc->l2ptr) {
                dev_err(smmu->dev,
                        "failed to allocate l2 stream table for SID %u\n",
                        sid);
                return -ENOMEM;
        }

        arm_smmu_init_bypass_stes(desc->l2ptr, 1 << STRTAB_SPLIT);
        arm_smmu_write_strtab_l1_desc(strtab, desc);
        return 0;
}

/* IRQ and event handlers */
static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
{
        int i;
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->evtq.q;
        u64 evt[EVTQ_ENT_DWORDS];

        while (!queue_remove_raw(q, evt)) {
                u8 id = evt[0] >> EVTQ_0_ID_SHIFT & EVTQ_0_ID_MASK;

                dev_info(smmu->dev, "event 0x%02x received:\n", id);
                for (i = 0; i < ARRAY_SIZE(evt); ++i)
                        dev_info(smmu->dev, "\t0x%016llx\n",
                                 (unsigned long long)evt[i]);
        }

        /* Sync our overflow flag, as we believe we're up to speed */
        q->cons = Q_OVF(q, q->prod) | Q_WRP(q, q->cons) | Q_IDX(q, q->cons);
        return IRQ_HANDLED;
}

static irqreturn_t arm_smmu_evtq_handler(int irq, void *dev)
{
        irqreturn_t ret = IRQ_WAKE_THREAD;
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->evtq.q;

        /*
         * Not much we can do on overflow, so scream and pretend we're
         * trying harder.
         */
        if (queue_sync_prod(q) == -EOVERFLOW)
                dev_err(smmu->dev, "EVTQ overflow detected -- events lost\n");
        else if (queue_empty(q))
                ret = IRQ_NONE;

        return ret;
}

static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
{
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->priq.q;
        u64 evt[PRIQ_ENT_DWORDS];

        while (!queue_remove_raw(q, evt)) {
                u32 sid, ssid;
                u16 grpid;
                bool ssv, last;

                sid = evt[0] >> PRIQ_0_SID_SHIFT & PRIQ_0_SID_MASK;
                ssv = evt[0] & PRIQ_0_SSID_V;
                ssid = ssv ? evt[0] >> PRIQ_0_SSID_SHIFT & PRIQ_0_SSID_MASK : 0;
                last = evt[0] & PRIQ_0_PRG_LAST;
                grpid = evt[1] >> PRIQ_1_PRG_IDX_SHIFT & PRIQ_1_PRG_IDX_MASK;

                dev_info(smmu->dev, "unexpected PRI request received:\n");
                dev_info(smmu->dev,
                         "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
                         sid, ssid, grpid, last ? "L" : "",
                         evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
                         evt[0] & PRIQ_0_PERM_READ ? "R" : "",
                         evt[0] & PRIQ_0_PERM_WRITE ? "W" : "",
                         evt[0] & PRIQ_0_PERM_EXEC ? "X" : "",
                         evt[1] & PRIQ_1_ADDR_MASK << PRIQ_1_ADDR_SHIFT);

                if (last) {
                        struct arm_smmu_cmdq_ent cmd = {
                                .opcode                 = CMDQ_OP_PRI_RESP,
                                .substream_valid        = ssv,
                                .pri                    = {
                                        .sid    = sid,
                                        .ssid   = ssid,
                                        .grpid  = grpid,
                                        .resp   = PRI_RESP_DENY,
                                },
                        };

                        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
                }
        }

        /* Sync our overflow flag, as we believe we're up to speed */
        q->cons = Q_OVF(q, q->prod) | Q_WRP(q, q->cons) | Q_IDX(q, q->cons);
        return IRQ_HANDLED;
}

static irqreturn_t arm_smmu_priq_handler(int irq, void *dev)
{
        irqreturn_t ret = IRQ_WAKE_THREAD;
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->priq.q;

        /* PRIQ overflow indicates a programming error */
        if (queue_sync_prod(q) == -EOVERFLOW)
                dev_err(smmu->dev, "PRIQ overflow detected -- requests lost\n");
        else if (queue_empty(q))
                ret = IRQ_NONE;

        return ret;
}

static irqreturn_t arm_smmu_cmdq_sync_handler(int irq, void *dev)
{
        /* We don't actually use CMD_SYNC interrupts for anything */
        return IRQ_HANDLED;
}

static int arm_smmu_device_disable(struct arm_smmu_device *smmu);

static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
{
        u32 gerror, gerrorn, active;
        struct arm_smmu_device *smmu = dev;

        gerror = readl_relaxed(smmu->base + ARM_SMMU_GERROR);
        gerrorn = readl_relaxed(smmu->base + ARM_SMMU_GERRORN);

        active = gerror ^ gerrorn;
        if (!(active & GERROR_ERR_MASK))
                return IRQ_NONE; /* No errors pending */

        dev_warn(smmu->dev,
                 "unexpected global error reported (0x%08x), this could be serious\n",
                 active);

        if (active & GERROR_SFM_ERR) {
                dev_err(smmu->dev, "device has entered Service Failure Mode!\n");
                arm_smmu_device_disable(smmu);
        }

        if (active & GERROR_MSI_GERROR_ABT_ERR)
                dev_warn(smmu->dev, "GERROR MSI write aborted\n");

        if (active & GERROR_MSI_PRIQ_ABT_ERR) {
                dev_warn(smmu->dev, "PRIQ MSI write aborted\n");
                arm_smmu_priq_handler(irq, smmu->dev);
        }

        if (active & GERROR_MSI_EVTQ_ABT_ERR) {
                dev_warn(smmu->dev, "EVTQ MSI write aborted\n");
                arm_smmu_evtq_handler(irq, smmu->dev);
        }

        if (active & GERROR_MSI_CMDQ_ABT_ERR) {
                dev_warn(smmu->dev, "CMDQ MSI write aborted\n");
                arm_smmu_cmdq_sync_handler(irq, smmu->dev);
        }

        if (active & GERROR_PRIQ_ABT_ERR)
                dev_err(smmu->dev, "PRIQ write aborted -- events may have been lost\n");

        if (active & GERROR_EVTQ_ABT_ERR)
                dev_err(smmu->dev, "EVTQ write aborted -- events may have been lost\n");

        if (active & GERROR_CMDQ_ERR)
                arm_smmu_cmdq_skip_err(smmu);

        writel(gerror, smmu->base + ARM_SMMU_GERRORN);
        return IRQ_HANDLED;
}

/* IO_PGTABLE API */
static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
{
        struct arm_smmu_cmdq_ent cmd;

        cmd.opcode = CMDQ_OP_CMD_SYNC;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
}

static void arm_smmu_tlb_sync(void *cookie)
{
        struct arm_smmu_domain *smmu_domain = cookie;
        __arm_smmu_tlb_sync(smmu_domain->smmu);
}

static void arm_smmu_tlb_inv_context(void *cookie)
{
        struct arm_smmu_domain *smmu_domain = cookie;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_cmdq_ent cmd;

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                cmd.opcode      = CMDQ_OP_TLBI_NH_ASID;
                cmd.tlbi.asid   = smmu_domain->s1_cfg.cd.asid;
                cmd.tlbi.vmid   = 0;
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S12_VMALL;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
        }

        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        __arm_smmu_tlb_sync(smmu);
}

static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
                                          size_t granule, bool leaf, void *cookie)
{
        struct arm_smmu_domain *smmu_domain = cookie;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_cmdq_ent cmd = {
                .tlbi = {
                        .leaf   = leaf,
                        .addr   = iova,
                },
        };

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                cmd.opcode      = CMDQ_OP_TLBI_NH_VA;
                cmd.tlbi.asid   = smmu_domain->s1_cfg.cd.asid;
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S2_IPA;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
        }

        do {
                arm_smmu_cmdq_issue_cmd(smmu, &cmd);
                cmd.tlbi.addr += granule;
        } while (size -= granule);
}

static struct iommu_gather_ops arm_smmu_gather_ops = {
        .tlb_flush_all  = arm_smmu_tlb_inv_context,
        .tlb_add_flush  = arm_smmu_tlb_inv_range_nosync,
        .tlb_sync       = arm_smmu_tlb_sync,
};

/* IOMMU API */
static bool arm_smmu_capable(enum iommu_cap cap)
{
        switch (cap) {
        case IOMMU_CAP_CACHE_COHERENCY:
                return true;
        case IOMMU_CAP_INTR_REMAP:
                return true; /* MSIs are just memory writes */
        case IOMMU_CAP_NOEXEC:
                return true;
        default:
                return false;
        }
}

static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
{
        struct arm_smmu_domain *smmu_domain;

        if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
                return NULL;

        /*
         * Allocate the domain and initialise some of its data structures.
         * We can't really do anything meaningful until we've added a
         * master.
         */
        smmu_domain = kzalloc(sizeof(*smmu_domain), GFP_KERNEL);
        if (!smmu_domain)
                return NULL;

        if (type == IOMMU_DOMAIN_DMA &&
            iommu_get_dma_cookie(&smmu_domain->domain)) {
                kfree(smmu_domain);
                return NULL;
        }

        mutex_init(&smmu_domain->init_mutex);
        spin_lock_init(&smmu_domain->pgtbl_lock);
        return &smmu_domain->domain;
}

static int arm_smmu_bitmap_alloc(unsigned long *map, int span)
{
        int idx, size = 1 << span;

        do {
                idx = find_first_zero_bit(map, size);
                if (idx == size)
                        return -ENOSPC;
        } while (test_and_set_bit(idx, map));

        return idx;
}

static void arm_smmu_bitmap_free(unsigned long *map, int idx)
{
        clear_bit(idx, map);
}

static void arm_smmu_domain_free(struct iommu_domain *domain)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_device *smmu = smmu_domain->smmu;

        iommu_put_dma_cookie(domain);
        free_io_pgtable_ops(smmu_domain->pgtbl_ops);

        /* Free the CD and ASID, if we allocated them */
        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;

                if (cfg->cdptr) {
                        dmam_free_coherent(smmu_domain->smmu->dev,
                                           CTXDESC_CD_DWORDS << 3,
                                           cfg->cdptr,
                                           cfg->cdptr_dma);

                        arm_smmu_bitmap_free(smmu->asid_map, cfg->cd.asid);
                }
        } else {
                struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
                if (cfg->vmid)
                        arm_smmu_bitmap_free(smmu->vmid_map, cfg->vmid);
        }

        kfree(smmu_domain);
}

static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
                                       struct io_pgtable_cfg *pgtbl_cfg)
{
        int ret;
        int asid;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;

        asid = arm_smmu_bitmap_alloc(smmu->asid_map, smmu->asid_bits);
        if (IS_ERR_VALUE(asid))
                return asid;

        cfg->cdptr = dmam_alloc_coherent(smmu->dev, CTXDESC_CD_DWORDS << 3,
                                         &cfg->cdptr_dma,
                                         GFP_KERNEL | __GFP_ZERO);
        if (!cfg->cdptr) {
                dev_warn(smmu->dev, "failed to allocate context descriptor\n");
                ret = -ENOMEM;
                goto out_free_asid;
        }

        cfg->cd.asid    = (u16)asid;
        cfg->cd.ttbr    = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
        cfg->cd.tcr     = pgtbl_cfg->arm_lpae_s1_cfg.tcr;
        cfg->cd.mair    = pgtbl_cfg->arm_lpae_s1_cfg.mair[0];
        return 0;

out_free_asid:
        arm_smmu_bitmap_free(smmu->asid_map, asid);
        return ret;
}

static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
                                       struct io_pgtable_cfg *pgtbl_cfg)
{
        int vmid;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;

        vmid = arm_smmu_bitmap_alloc(smmu->vmid_map, smmu->vmid_bits);
        if (IS_ERR_VALUE(vmid))
                return vmid;

        cfg->vmid       = (u16)vmid;
        cfg->vttbr      = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
        cfg->vtcr       = pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
        return 0;
}

static struct iommu_ops arm_smmu_ops;

static int arm_smmu_domain_finalise(struct iommu_domain *domain)
{
        int ret;
        unsigned long ias, oas;
        enum io_pgtable_fmt fmt;
        struct io_pgtable_cfg pgtbl_cfg;
        struct io_pgtable_ops *pgtbl_ops;
        int (*finalise_stage_fn)(struct arm_smmu_domain *,
                                 struct io_pgtable_cfg *);
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_device *smmu = smmu_domain->smmu;

        /* Restrict the stage to what we can actually support */
        if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1))
                smmu_domain->stage = ARM_SMMU_DOMAIN_S2;
        if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
                smmu_domain->stage = ARM_SMMU_DOMAIN_S1;

        switch (smmu_domain->stage) {
        case ARM_SMMU_DOMAIN_S1:
                ias = VA_BITS;
                oas = smmu->ias;
                fmt = ARM_64_LPAE_S1;
                finalise_stage_fn = arm_smmu_domain_finalise_s1;
                break;
        case ARM_SMMU_DOMAIN_NESTED:
        case ARM_SMMU_DOMAIN_S2:
                ias = smmu->ias;
                oas = smmu->oas;
                fmt = ARM_64_LPAE_S2;
                finalise_stage_fn = arm_smmu_domain_finalise_s2;
                break;
        default:
                return -EINVAL;
        }

        pgtbl_cfg = (struct io_pgtable_cfg) {
                .pgsize_bitmap  = arm_smmu_ops.pgsize_bitmap,
                .ias            = ias,
                .oas            = oas,
                .tlb            = &arm_smmu_gather_ops,
                .iommu_dev      = smmu->dev,
        };

        pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
        if (!pgtbl_ops)
                return -ENOMEM;

        arm_smmu_ops.pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
        smmu_domain->pgtbl_ops = pgtbl_ops;

        ret = finalise_stage_fn(smmu_domain, &pgtbl_cfg);
        if (IS_ERR_VALUE(ret))
                free_io_pgtable_ops(pgtbl_ops);

        return ret;
}

static struct arm_smmu_group *arm_smmu_group_get(struct device *dev)
{
        struct iommu_group *group;
        struct arm_smmu_group *smmu_group;

        group = iommu_group_get(dev);
        if (!group)
                return NULL;

        smmu_group = iommu_group_get_iommudata(group);
        iommu_group_put(group);
        return smmu_group;
}

static __le64 *arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)
{
        __le64 *step;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;

        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
                struct arm_smmu_strtab_l1_desc *l1_desc;
                int idx;

                /* Two-level walk */
                idx = (sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS;
                l1_desc = &cfg->l1_desc[idx];
                idx = (sid & ((1 << STRTAB_SPLIT) - 1)) * STRTAB_STE_DWORDS;
                step = &l1_desc->l2ptr[idx];
        } else {
                /* Simple linear lookup */
                step = &cfg->strtab[sid * STRTAB_STE_DWORDS];
        }

        return step;
}

static int arm_smmu_install_ste_for_group(struct arm_smmu_group *smmu_group)
{
        int i;
        struct arm_smmu_domain *smmu_domain = smmu_group->domain;
        struct arm_smmu_strtab_ent *ste = &smmu_group->ste;
        struct arm_smmu_device *smmu = smmu_group->smmu;

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                ste->s1_cfg = &smmu_domain->s1_cfg;
                ste->s2_cfg = NULL;
                arm_smmu_write_ctx_desc(smmu, ste->s1_cfg);
        } else {
                ste->s1_cfg = NULL;
                ste->s2_cfg = &smmu_domain->s2_cfg;
        }

        for (i = 0; i < smmu_group->num_sids; ++i) {
                u32 sid = smmu_group->sids[i];
                __le64 *step = arm_smmu_get_step_for_sid(smmu, sid);

                arm_smmu_write_strtab_ent(smmu, sid, step, ste);
        }

        return 0;
}

static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
        int ret = 0;
        struct arm_smmu_device *smmu;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_group *smmu_group = arm_smmu_group_get(dev);

        if (!smmu_group)
                return -ENOENT;

        /* Already attached to a different domain? */
        if (smmu_group->domain && smmu_group->domain != smmu_domain)
                return -EEXIST;

        smmu = smmu_group->smmu;
        mutex_lock(&smmu_domain->init_mutex);

        if (!smmu_domain->smmu) {
                smmu_domain->smmu = smmu;
                ret = arm_smmu_domain_finalise(domain);
                if (ret) {
                        smmu_domain->smmu = NULL;
                        goto out_unlock;
                }
        } else if (smmu_domain->smmu != smmu) {
                dev_err(dev,
                        "cannot attach to SMMU %s (upstream of %s)\n",
                        dev_name(smmu_domain->smmu->dev),
                        dev_name(smmu->dev));
                ret = -ENXIO;
                goto out_unlock;
        }

        /* Group already attached to this domain? */
        if (smmu_group->domain)
                goto out_unlock;

        smmu_group->domain      = smmu_domain;
        smmu_group->ste.bypass  = false;

        ret = arm_smmu_install_ste_for_group(smmu_group);
        if (IS_ERR_VALUE(ret))
                smmu_group->domain = NULL;

out_unlock:
        mutex_unlock(&smmu_domain->init_mutex);
        return ret;
}

static void arm_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_group *smmu_group = arm_smmu_group_get(dev);

        BUG_ON(!smmu_domain);
        BUG_ON(!smmu_group);

        mutex_lock(&smmu_domain->init_mutex);
        BUG_ON(smmu_group->domain != smmu_domain);

        smmu_group->ste.bypass = true;
        if (IS_ERR_VALUE(arm_smmu_install_ste_for_group(smmu_group)))
                dev_warn(dev, "failed to install bypass STE\n");

        smmu_group->domain = NULL;
        mutex_unlock(&smmu_domain->init_mutex);
}

static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
                        phys_addr_t paddr, size_t size, int prot)
{
        int ret;
        unsigned long flags;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;

        if (!ops)
                return -ENODEV;

        spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags);
        ret = ops->map(ops, iova, paddr, size, prot);
        spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags);
        return ret;
}

static size_t
arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
{
        size_t ret;
        unsigned long flags;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;

        if (!ops)
                return 0;

        spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags);
        ret = ops->unmap(ops, iova, size);
        spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags);
        return ret;
}

static phys_addr_t
arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
{
        phys_addr_t ret;
        unsigned long flags;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;

        if (!ops)
                return 0;

        spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags);
        ret = ops->iova_to_phys(ops, iova);
        spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags);

        return ret;
}

static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *sidp)
{
        *(u32 *)sidp = alias;
        return 0; /* Continue walking */
}

static void __arm_smmu_release_pci_iommudata(void *data)
{
        kfree(data);
}

static struct arm_smmu_device *arm_smmu_get_for_pci_dev(struct pci_dev *pdev)
{
        struct device_node *of_node;
        struct platform_device *smmu_pdev;
        struct arm_smmu_device *smmu = NULL;
        struct pci_bus *bus = pdev->bus;

        /* Walk up to the root bus */
        while (!pci_is_root_bus(bus))
                bus = bus->parent;

        /* Follow the "iommus" phandle from the host controller */
        of_node = of_parse_phandle(bus->bridge->parent->of_node, "iommus", 0);
        if (!of_node)
                return NULL;

        /* See if we can find an SMMU corresponding to the phandle */
        smmu_pdev = of_find_device_by_node(of_node);
        if (smmu_pdev)
                smmu = platform_get_drvdata(smmu_pdev);

        of_node_put(of_node);
        return smmu;
}

static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
{
        unsigned long limit = smmu->strtab_cfg.num_l1_ents;

        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)
                limit *= 1UL << STRTAB_SPLIT;

        return sid < limit;
}

static int arm_smmu_add_device(struct device *dev)
{
        int i, ret;
        u32 sid, *sids;
        struct pci_dev *pdev;
        struct iommu_group *group;
        struct arm_smmu_group *smmu_group;
        struct arm_smmu_device *smmu;

        /* We only support PCI, for now */
        if (!dev_is_pci(dev))
                return -ENODEV;

        pdev = to_pci_dev(dev);
        group = iommu_group_get_for_dev(dev);
        if (IS_ERR(group))
                return PTR_ERR(group);

        smmu_group = iommu_group_get_iommudata(group);
        if (!smmu_group) {
                smmu = arm_smmu_get_for_pci_dev(pdev);
                if (!smmu) {
                        ret = -ENOENT;
                        goto out_remove_dev;
                }

                smmu_group = kzalloc(sizeof(*smmu_group), GFP_KERNEL);
                if (!smmu_group) {
                        ret = -ENOMEM;
                        goto out_remove_dev;
                }

                smmu_group->ste.valid   = true;
                smmu_group->smmu        = smmu;
                iommu_group_set_iommudata(group, smmu_group,
                                          __arm_smmu_release_pci_iommudata);
        } else {
                smmu = smmu_group->smmu;
        }

        /* Assume SID == RID until firmware tells us otherwise */
        pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid, &sid);
        for (i = 0; i < smmu_group->num_sids; ++i) {
                /* If we already know about this SID, then we're done */
                if (smmu_group->sids[i] == sid)
                        goto out_put_group;
        }

        /* Check the SID is in range of the SMMU and our stream table */
        if (!arm_smmu_sid_in_range(smmu, sid)) {
                ret = -ERANGE;
                goto out_remove_dev;
        }

        /* Ensure l2 strtab is initialised */
        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
                ret = arm_smmu_init_l2_strtab(smmu, sid);
                if (ret)
                        goto out_remove_dev;
        }

        /* Resize the SID array for the group */
        smmu_group->num_sids++;
        sids = krealloc(smmu_group->sids, smmu_group->num_sids * sizeof(*sids),
                        GFP_KERNEL);
        if (!sids) {
                smmu_group->num_sids--;
                ret = -ENOMEM;
                goto out_remove_dev;
        }

        /* Add the new SID */
        sids[smmu_group->num_sids - 1] = sid;
        smmu_group->sids = sids;

out_put_group:
        iommu_group_put(group);
        return 0;

out_remove_dev:
        iommu_group_remove_device(dev);
        iommu_group_put(group);
        return ret;
}

static void arm_smmu_remove_device(struct device *dev)
{
        iommu_group_remove_device(dev);
}

static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
                                    enum iommu_attr attr, void *data)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

        switch (attr) {
        case DOMAIN_ATTR_NESTING:
                *(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
                return 0;
        default:
                return -ENODEV;
        }
}

static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
                                    enum iommu_attr attr, void *data)
{
        int ret = 0;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

        mutex_lock(&smmu_domain->init_mutex);

        switch (attr) {
        case DOMAIN_ATTR_NESTING:
                if (smmu_domain->smmu) {
                        ret = -EPERM;
                        goto out_unlock;
                }

                if (*(int *)data)
                        smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
                else
                        smmu_domain->stage = ARM_SMMU_DOMAIN_S1;

                break;
        default:
                ret = -ENODEV;
        }

out_unlock:
        mutex_unlock(&smmu_domain->init_mutex);
        return ret;
}

static struct iommu_ops arm_smmu_ops = {
        .capable                = arm_smmu_capable,
        .domain_alloc           = arm_smmu_domain_alloc,
        .domain_free            = arm_smmu_domain_free,
        .attach_dev             = arm_smmu_attach_dev,
        .detach_dev             = arm_smmu_detach_dev,
        .map                    = arm_smmu_map,
        .unmap                  = arm_smmu_unmap,
        .iova_to_phys           = arm_smmu_iova_to_phys,
        .add_device             = arm_smmu_add_device,
        .remove_device          = arm_smmu_remove_device,
        .device_group           = pci_device_group,
        .domain_get_attr        = arm_smmu_domain_get_attr,
        .domain_set_attr        = arm_smmu_domain_set_attr,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
};

/* Probing and initialisation functions */
static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
                                   struct arm_smmu_queue *q,
                                   unsigned long prod_off,
                                   unsigned long cons_off,
                                   size_t dwords)
{
        size_t qsz = ((1 << q->max_n_shift) * dwords) << 3;

        q->base = dmam_alloc_coherent(smmu->dev, qsz, &q->base_dma, GFP_KERNEL);
        if (!q->base) {
                dev_err(smmu->dev, "failed to allocate queue (0x%zx bytes)\n",
                        qsz);
                return -ENOMEM;
        }

        q->prod_reg     = smmu->base + prod_off;
        q->cons_reg     = smmu->base + cons_off;
        q->ent_dwords   = dwords;

        q->q_base  = Q_BASE_RWA;
        q->q_base |= q->base_dma & Q_BASE_ADDR_MASK << Q_BASE_ADDR_SHIFT;
        q->q_base |= (q->max_n_shift & Q_BASE_LOG2SIZE_MASK)
                     << Q_BASE_LOG2SIZE_SHIFT;

        q->prod = q->cons = 0;
        return 0;
}

static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
{
        int ret;

        /* cmdq */
        spin_lock_init(&smmu->cmdq.lock);
        ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, ARM_SMMU_CMDQ_PROD,
                                      ARM_SMMU_CMDQ_CONS, CMDQ_ENT_DWORDS);
        if (ret)
                return ret;

        /* evtq */
        ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q, ARM_SMMU_EVTQ_PROD,
                                      ARM_SMMU_EVTQ_CONS, EVTQ_ENT_DWORDS);
        if (ret)
                return ret;

        /* priq */
        if (!(smmu->features & ARM_SMMU_FEAT_PRI))
                return 0;

        return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD,
                                       ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS);
}

static int arm_smmu_init_l1_strtab(struct arm_smmu_device *smmu)
{
        unsigned int i;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
        size_t size = sizeof(*cfg->l1_desc) * cfg->num_l1_ents;
        void *strtab = smmu->strtab_cfg.strtab;

        cfg->l1_desc = devm_kzalloc(smmu->dev, size, GFP_KERNEL);
        if (!cfg->l1_desc) {
                dev_err(smmu->dev, "failed to allocate l1 stream table desc\n");
                return -ENOMEM;
        }

        for (i = 0; i < cfg->num_l1_ents; ++i) {
                arm_smmu_write_strtab_l1_desc(strtab, &cfg->l1_desc[i]);
                strtab += STRTAB_L1_DESC_DWORDS << 3;
        }

        return 0;
}

static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu)
{
        void *strtab;
        u64 reg;
        u32 size, l1size;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;

        /*
         * If we can resolve everything with a single L2 table, then we
         * just need a single L1 descriptor. Otherwise, calculate the L1
         * size, capped to the SIDSIZE.
         */
        if (smmu->sid_bits < STRTAB_SPLIT) {
                size = 0;
        } else {
                size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3);
                size = min(size, smmu->sid_bits - STRTAB_SPLIT);
        }
        cfg->num_l1_ents = 1 << size;

        size += STRTAB_SPLIT;
        if (size < smmu->sid_bits)
                dev_warn(smmu->dev,
                         "2-level strtab only covers %u/%u bits of SID\n",
                         size, smmu->sid_bits);

        l1size = cfg->num_l1_ents * (STRTAB_L1_DESC_DWORDS << 3);
        strtab = dmam_alloc_coherent(smmu->dev, l1size, &cfg->strtab_dma,
                                     GFP_KERNEL | __GFP_ZERO);
        if (!strtab) {
                dev_err(smmu->dev,
                        "failed to allocate l1 stream table (%u bytes)\n",
                        size);
                return -ENOMEM;
        }
        cfg->strtab = strtab;

        /* Configure strtab_base_cfg for 2 levels */
        reg  = STRTAB_BASE_CFG_FMT_2LVL;
        reg |= (size & STRTAB_BASE_CFG_LOG2SIZE_MASK)
                << STRTAB_BASE_CFG_LOG2SIZE_SHIFT;
        reg |= (STRTAB_SPLIT & STRTAB_BASE_CFG_SPLIT_MASK)
                << STRTAB_BASE_CFG_SPLIT_SHIFT;
        cfg->strtab_base_cfg = reg;

        return arm_smmu_init_l1_strtab(smmu);
}

static int arm_smmu_init_strtab_linear(struct arm_smmu_device *smmu)
{
        void *strtab;
        u64 reg;
        u32 size;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;

        size = (1 << smmu->sid_bits) * (STRTAB_STE_DWORDS << 3);
        strtab = dmam_alloc_coherent(smmu->dev, size, &cfg->strtab_dma,
                                     GFP_KERNEL | __GFP_ZERO);
        if (!strtab) {
                dev_err(smmu->dev,
                        "failed to allocate linear stream table (%u bytes)\n",
                        size);
                return -ENOMEM;
        }
        cfg->strtab = strtab;
        cfg->num_l1_ents = 1 << smmu->sid_bits;

        /* Configure strtab_base_cfg for a linear table covering all SIDs */
        reg  = STRTAB_BASE_CFG_FMT_LINEAR;
        reg |= (smmu->sid_bits & STRTAB_BASE_CFG_LOG2SIZE_MASK)
                << STRTAB_BASE_CFG_LOG2SIZE_SHIFT;
        cfg->strtab_base_cfg = reg;

        arm_smmu_init_bypass_stes(strtab, cfg->num_l1_ents);
        return 0;
}

static int arm_smmu_init_strtab(struct arm_smmu_device *smmu)
{
        u64 reg;
        int ret;

        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)
                ret = arm_smmu_init_strtab_2lvl(smmu);
        else
                ret = arm_smmu_init_strtab_linear(smmu);

        if (ret)
                return ret;

        /* Set the strtab base address */
        reg  = smmu->strtab_cfg.strtab_dma &
               STRTAB_BASE_ADDR_MASK << STRTAB_BASE_ADDR_SHIFT;
        reg |= STRTAB_BASE_RA;
        smmu->strtab_cfg.strtab_base = reg;

        /* Allocate the first VMID for stage-2 bypass STEs */
        set_bit(0, smmu->vmid_map);
        return 0;
}

static int arm_smmu_init_structures(struct arm_smmu_device *smmu)
{
        int ret;

        ret = arm_smmu_init_queues(smmu);
        if (ret)
                return ret;

        return arm_smmu_init_strtab(smmu);
}

static int arm_smmu_write_reg_sync(struct arm_smmu_device *smmu, u32 val,
                                   unsigned int reg_off, unsigned int ack_off)
{
        u32 reg;

        writel_relaxed(val, smmu->base + reg_off);
        return readl_relaxed_poll_timeout(smmu->base + ack_off, reg, reg == val,
                                          1, ARM_SMMU_POLL_TIMEOUT_US);
}

static void arm_smmu_free_msis(void *data)
{
        struct device *dev = data;
        platform_msi_domain_free_irqs(dev);
}

static void arm_smmu_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
{
        phys_addr_t doorbell;
        struct device *dev = msi_desc_to_dev(desc);
        struct arm_smmu_device *smmu = dev_get_drvdata(dev);
        phys_addr_t *cfg = arm_smmu_msi_cfg[desc->platform.msi_index];

        doorbell = (((u64)msg->address_hi) << 32) | msg->address_lo;
        doorbell &= MSI_CFG0_ADDR_MASK << MSI_CFG0_ADDR_SHIFT;

        writeq_relaxed(doorbell, smmu->base + cfg[0]);
        writel_relaxed(msg->data, smmu->base + cfg[1]);
        writel_relaxed(MSI_CFG2_MEMATTR_DEVICE_nGnRE, smmu->base + cfg[2]);
}

static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
{
        struct msi_desc *desc;
        int ret, nvec = ARM_SMMU_MAX_MSIS;
        struct device *dev = smmu->dev;

        /* Clear the MSI address regs */
        writeq_relaxed(0, smmu->base + ARM_SMMU_GERROR_IRQ_CFG0);
        writeq_relaxed(0, smmu->base + ARM_SMMU_EVTQ_IRQ_CFG0);

        if (smmu->features & ARM_SMMU_FEAT_PRI)
                writeq_relaxed(0, smmu->base + ARM_SMMU_PRIQ_IRQ_CFG0);
        else
                nvec--;

        if (!(smmu->features & ARM_SMMU_FEAT_MSI))
                return;

        /* Allocate MSIs for evtq, gerror and priq. Ignore cmdq */
        ret = platform_msi_domain_alloc_irqs(dev, nvec, arm_smmu_write_msi_msg);
        if (ret) {
                dev_warn(dev, "failed to allocate MSIs\n");
                return;
        }

        for_each_msi_entry(desc, dev) {
                switch (desc->platform.msi_index) {
                case EVTQ_MSI_INDEX:
                        smmu->evtq.q.irq = desc->irq;
                        break;
                case GERROR_MSI_INDEX:
                        smmu->gerr_irq = desc->irq;
                        break;
                case PRIQ_MSI_INDEX:
                        smmu->priq.q.irq = desc->irq;
                        break;
                default:        /* Unknown */
                        continue;
                }
        }

        /* Add callback to free MSIs on teardown */
        devm_add_action(dev, arm_smmu_free_msis, dev);
}

static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
{
        int ret, irq;
        u32 irqen_flags = IRQ_CTRL_EVTQ_IRQEN | IRQ_CTRL_GERROR_IRQEN;

        /* Disable IRQs first */
        ret = arm_smmu_write_reg_sync(smmu, 0, ARM_SMMU_IRQ_CTRL,
                                      ARM_SMMU_IRQ_CTRLACK);
        if (ret) {
                dev_err(smmu->dev, "failed to disable irqs\n");
                return ret;
        }

        arm_smmu_setup_msis(smmu);

        /* Request interrupt lines */
        irq = smmu->evtq.q.irq;
        if (irq) {
                ret = devm_request_threaded_irq(smmu->dev, irq,
                                                arm_smmu_evtq_handler,
                                                arm_smmu_evtq_thread,
                                                0, "arm-smmu-v3-evtq", smmu);
                if (IS_ERR_VALUE(ret))
                        dev_warn(smmu->dev, "failed to enable evtq irq\n");
        }

        irq = smmu->cmdq.q.irq;
        if (irq) {
                ret = devm_request_irq(smmu->dev, irq,
                                       arm_smmu_cmdq_sync_handler, 0,
                                       "arm-smmu-v3-cmdq-sync", smmu);
                if (IS_ERR_VALUE(ret))
                        dev_warn(smmu->dev, "failed to enable cmdq-sync irq\n");
        }

        irq = smmu->gerr_irq;
        if (irq) {
                ret = devm_request_irq(smmu->dev, irq, arm_smmu_gerror_handler,
                                       0, "arm-smmu-v3-gerror", smmu);
                if (IS_ERR_VALUE(ret))
                        dev_warn(smmu->dev, "failed to enable gerror irq\n");
        }

        if (smmu->features & ARM_SMMU_FEAT_PRI) {
                irq = smmu->priq.q.irq;
                if (irq) {
                        ret = devm_request_threaded_irq(smmu->dev, irq,
                                                        arm_smmu_priq_handler,
                                                        arm_smmu_priq_thread,
                                                        0, "arm-smmu-v3-priq",
                                                        smmu);
                        if (IS_ERR_VALUE(ret))
                                dev_warn(smmu->dev,
                                         "failed to enable priq irq\n");
                        else
                                irqen_flags |= IRQ_CTRL_PRIQ_IRQEN;
                }
        }

        /* Enable interrupt generation on the SMMU */
        ret = arm_smmu_write_reg_sync(smmu, irqen_flags,
                                      ARM_SMMU_IRQ_CTRL, ARM_SMMU_IRQ_CTRLACK);
        if (ret)
                dev_warn(smmu->dev, "failed to enable irqs\n");

        return 0;
}

static int arm_smmu_device_disable(struct arm_smmu_device *smmu)
{
        int ret;

        ret = arm_smmu_write_reg_sync(smmu, 0, ARM_SMMU_CR0, ARM_SMMU_CR0ACK);
        if (ret)
                dev_err(smmu->dev, "failed to clear cr0\n");

        return ret;
}

static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
{
        int ret;
        u32 reg, enables;
        struct arm_smmu_cmdq_ent cmd;

        /* Clear CR0 and sync (disables SMMU and queue processing) */
        reg = readl_relaxed(smmu->base + ARM_SMMU_CR0);
        if (reg & CR0_SMMUEN)
                dev_warn(smmu->dev, "SMMU currently enabled! Resetting...\n");

        ret = arm_smmu_device_disable(smmu);
        if (ret)
                return ret;

        /* CR1 (table and queue memory attributes) */
        reg = (CR1_SH_ISH << CR1_TABLE_SH_SHIFT) |
              (CR1_CACHE_WB << CR1_TABLE_OC_SHIFT) |
              (CR1_CACHE_WB << CR1_TABLE_IC_SHIFT) |
              (CR1_SH_ISH << CR1_QUEUE_SH_SHIFT) |
              (CR1_CACHE_WB << CR1_QUEUE_OC_SHIFT) |
              (CR1_CACHE_WB << CR1_QUEUE_IC_SHIFT);
        writel_relaxed(reg, smmu->base + ARM_SMMU_CR1);

        /* CR2 (random crap) */
        reg = CR2_PTM | CR2_RECINVSID | CR2_E2H;
        writel_relaxed(reg, smmu->base + ARM_SMMU_CR2);

        /* Stream table */
        writeq_relaxed(smmu->strtab_cfg.strtab_base,
                       smmu->base + ARM_SMMU_STRTAB_BASE);
        writel_relaxed(smmu->strtab_cfg.strtab_base_cfg,
                       smmu->base + ARM_SMMU_STRTAB_BASE_CFG);

        /* Command queue */
        writeq_relaxed(smmu->cmdq.q.q_base, smmu->base + ARM_SMMU_CMDQ_BASE);
        writel_relaxed(smmu->cmdq.q.prod, smmu->base + ARM_SMMU_CMDQ_PROD);
        writel_relaxed(smmu->cmdq.q.cons, smmu->base + ARM_SMMU_CMDQ_CONS);

        enables = CR0_CMDQEN;
        ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
                                      ARM_SMMU_CR0ACK);
        if (ret) {
                dev_err(smmu->dev, "failed to enable command queue\n");
                return ret;
        }

        /* Invalidate any cached configuration */
        cmd.opcode = CMDQ_OP_CFGI_ALL;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        cmd.opcode = CMDQ_OP_CMD_SYNC;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);

        /* Invalidate any stale TLB entries */
        if (smmu->features & ARM_SMMU_FEAT_HYP) {
                cmd.opcode = CMDQ_OP_TLBI_EL2_ALL;
                arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        }

        cmd.opcode = CMDQ_OP_TLBI_NSNH_ALL;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        cmd.opcode = CMDQ_OP_CMD_SYNC;
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);

        /* Event queue */
        writeq_relaxed(smmu->evtq.q.q_base, smmu->base + ARM_SMMU_EVTQ_BASE);
        writel_relaxed(smmu->evtq.q.prod, smmu->base + ARM_SMMU_EVTQ_PROD);
        writel_relaxed(smmu->evtq.q.cons, smmu->base + ARM_SMMU_EVTQ_CONS);

        enables |= CR0_EVTQEN;
        ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
                                      ARM_SMMU_CR0ACK);
        if (ret) {
                dev_err(smmu->dev, "failed to enable event queue\n");
                return ret;
        }

        /* PRI queue */
        if (smmu->features & ARM_SMMU_FEAT_PRI) {
                writeq_relaxed(smmu->priq.q.q_base,
                               smmu->base + ARM_SMMU_PRIQ_BASE);
                writel_relaxed(smmu->priq.q.prod,
                               smmu->base + ARM_SMMU_PRIQ_PROD);
                writel_relaxed(smmu->priq.q.cons,
                               smmu->base + ARM_SMMU_PRIQ_CONS);

                enables |= CR0_PRIQEN;
                ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
                                              ARM_SMMU_CR0ACK);
                if (ret) {
                        dev_err(smmu->dev, "failed to enable PRI queue\n");
                        return ret;
                }
        }

        ret = arm_smmu_setup_irqs(smmu);
        if (ret) {
                dev_err(smmu->dev, "failed to setup irqs\n");
                return ret;
        }

        /* Enable the SMMU interface */
        enables |= CR0_SMMUEN;
        ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
                                      ARM_SMMU_CR0ACK);
        if (ret) {
                dev_err(smmu->dev, "failed to enable SMMU interface\n");
                return ret;
        }

        return 0;
}

static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
{
        u32 reg;
        bool coherent;
        unsigned long pgsize_bitmap = 0;

        /* IDR0 */
        reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);

        /* 2-level structures */
        if ((reg & IDR0_ST_LVL_MASK << IDR0_ST_LVL_SHIFT) == IDR0_ST_LVL_2LVL)
                smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;

        if (reg & IDR0_CD2L)
                smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;

        /*
         * Translation table endianness.
         * We currently require the same endianness as the CPU, but this
         * could be changed later by adding a new IO_PGTABLE_QUIRK.
         */
        switch (reg & IDR0_TTENDIAN_MASK << IDR0_TTENDIAN_SHIFT) {
        case IDR0_TTENDIAN_MIXED:
                smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
                break;
#ifdef __BIG_ENDIAN
        case IDR0_TTENDIAN_BE:
                smmu->features |= ARM_SMMU_FEAT_TT_BE;
                break;
#else
        case IDR0_TTENDIAN_LE:
                smmu->features |= ARM_SMMU_FEAT_TT_LE;
                break;
#endif
        default:
                dev_err(smmu->dev, "unknown/unsupported TT endianness!\n");
                return -ENXIO;
        }

        /* Boolean feature flags */
        if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
                smmu->features |= ARM_SMMU_FEAT_PRI;

        if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
                smmu->features |= ARM_SMMU_FEAT_ATS;

        if (reg & IDR0_SEV)
                smmu->features |= ARM_SMMU_FEAT_SEV;

        if (reg & IDR0_MSI)
                smmu->features |= ARM_SMMU_FEAT_MSI;

        if (reg & IDR0_HYP)
                smmu->features |= ARM_SMMU_FEAT_HYP;

        /*
         * The dma-coherent property is used in preference to the ID
         * register, but warn on mismatch.
         */
        coherent = of_dma_is_coherent(smmu->dev->of_node);
        if (coherent)
                smmu->features |= ARM_SMMU_FEAT_COHERENCY;

        if (!!(reg & IDR0_COHACC) != coherent)
                dev_warn(smmu->dev, "IDR0.COHACC overridden by dma-coherent property (%s)\n",
                         coherent ? "true" : "false");

        switch (reg & IDR0_STALL_MODEL_MASK << IDR0_STALL_MODEL_SHIFT) {
        case IDR0_STALL_MODEL_STALL:
                /* Fallthrough */
        case IDR0_STALL_MODEL_FORCE:
                smmu->features |= ARM_SMMU_FEAT_STALLS;
        }

        if (reg & IDR0_S1P)
                smmu->features |= ARM_SMMU_FEAT_TRANS_S1;

        if (reg & IDR0_S2P)
                smmu->features |= ARM_SMMU_FEAT_TRANS_S2;

        if (!(reg & (IDR0_S1P | IDR0_S2P))) {
                dev_err(smmu->dev, "no translation support!\n");
                return -ENXIO;
        }

        /* We only support the AArch64 table format at present */
        switch (reg & IDR0_TTF_MASK << IDR0_TTF_SHIFT) {
        case IDR0_TTF_AARCH32_64:
                smmu->ias = 40;
                /* Fallthrough */
        case IDR0_TTF_AARCH64:
                break;
        default:
                dev_err(smmu->dev, "AArch64 table format not supported!\n");
                return -ENXIO;
        }

        /* ASID/VMID sizes */
        smmu->asid_bits = reg & IDR0_ASID16 ? 16 : 8;
        smmu->vmid_bits = reg & IDR0_VMID16 ? 16 : 8;

        /* IDR1 */
        reg = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
        if (reg & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL)) {
                dev_err(smmu->dev, "embedded implementation not supported\n");
                return -ENXIO;
        }

        /* Queue sizes, capped at 4k */
        smmu->cmdq.q.max_n_shift = min((u32)CMDQ_MAX_SZ_SHIFT,
                                       reg >> IDR1_CMDQ_SHIFT & IDR1_CMDQ_MASK);
        if (!smmu->cmdq.q.max_n_shift) {
                /* Odd alignment restrictions on the base, so ignore for now */
                dev_err(smmu->dev, "unit-length command queue not supported\n");
                return -ENXIO;
        }

        smmu->evtq.q.max_n_shift = min((u32)EVTQ_MAX_SZ_SHIFT,
                                       reg >> IDR1_EVTQ_SHIFT & IDR1_EVTQ_MASK);
        smmu->priq.q.max_n_shift = min((u32)PRIQ_MAX_SZ_SHIFT,
                                       reg >> IDR1_PRIQ_SHIFT & IDR1_PRIQ_MASK);

        /* SID/SSID sizes */
        smmu->ssid_bits = reg >> IDR1_SSID_SHIFT & IDR1_SSID_MASK;
        smmu->sid_bits = reg >> IDR1_SID_SHIFT & IDR1_SID_MASK;

        /* IDR5 */
        reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);

        /* Maximum number of outstanding stalls */
        smmu->evtq.max_stalls = reg >> IDR5_STALL_MAX_SHIFT
                                & IDR5_STALL_MAX_MASK;

        /* Page sizes */
        if (reg & IDR5_GRAN64K)
                pgsize_bitmap |= SZ_64K | SZ_512M;
        if (reg & IDR5_GRAN16K)
                pgsize_bitmap |= SZ_16K | SZ_32M;
        if (reg & IDR5_GRAN4K)
                pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;

        arm_smmu_ops.pgsize_bitmap &= pgsize_bitmap;

        /* Output address size */
        switch (reg & IDR5_OAS_MASK << IDR5_OAS_SHIFT) {
        case IDR5_OAS_32_BIT:
                smmu->oas = 32;
                break;
        case IDR5_OAS_36_BIT:
                smmu->oas = 36;
                break;
        case IDR5_OAS_40_BIT:
                smmu->oas = 40;
                break;
        case IDR5_OAS_42_BIT:
                smmu->oas = 42;
                break;
        case IDR5_OAS_44_BIT:
                smmu->oas = 44;
                break;
        default:
                dev_info(smmu->dev,
                        "unknown output address size. Truncating to 48-bit\n");
                /* Fallthrough */
        case IDR5_OAS_48_BIT:
                smmu->oas = 48;
        }

        /* Set the DMA mask for our table walker */
        if (dma_set_mask_and_coherent(smmu->dev, DMA_BIT_MASK(smmu->oas)))
                dev_warn(smmu->dev,
                         "failed to set DMA mask for table walker\n");

        smmu->ias = max(smmu->ias, smmu->oas);

        dev_info(smmu->dev, "ias %lu-bit, oas %lu-bit (features 0x%08x)\n",
                 smmu->ias, smmu->oas, smmu->features);
        return 0;
}

static int arm_smmu_device_dt_probe(struct platform_device *pdev)
{
        int irq, ret;
        struct resource *res;
        struct arm_smmu_device *smmu;
        struct device *dev = &pdev->dev;

        smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
        if (!smmu) {
                dev_err(dev, "failed to allocate arm_smmu_device\n");
                return -ENOMEM;
        }
        smmu->dev = dev;

        /* Base address */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (resource_size(res) + 1 < SZ_128K) {
                dev_err(dev, "MMIO region too small (%pr)\n", res);
                return -EINVAL;
        }

        smmu->base = devm_ioremap_resource(dev, res);
        if (IS_ERR(smmu->base))
                return PTR_ERR(smmu->base);

        /* Interrupt lines */
        irq = platform_get_irq_byname(pdev, "eventq");
        if (irq > 0)
                smmu->evtq.q.irq = irq;

        irq = platform_get_irq_byname(pdev, "priq");
        if (irq > 0)
                smmu->priq.q.irq = irq;

        irq = platform_get_irq_byname(pdev, "cmdq-sync");
        if (irq > 0)
                smmu->cmdq.q.irq = irq;

        irq = platform_get_irq_byname(pdev, "gerror");
        if (irq > 0)
                smmu->gerr_irq = irq;

        parse_driver_options(smmu);

        /* Probe the h/w */
        ret = arm_smmu_device_probe(smmu);
        if (ret)
                return ret;

        /* Initialise in-memory data structures */
        ret = arm_smmu_init_structures(smmu);
        if (ret)
                return ret;

        /* Record our private device structure */
        platform_set_drvdata(pdev, smmu);

        /* Reset the device */
        return arm_smmu_device_reset(smmu);
}

static int arm_smmu_device_remove(struct platform_device *pdev)
{
        struct arm_smmu_device *smmu = platform_get_drvdata(pdev);

        arm_smmu_device_disable(smmu);
        return 0;
}

static struct of_device_id arm_smmu_of_match[] = {
        { .compatible = "arm,smmu-v3", },
        { },
};
MODULE_DEVICE_TABLE(of, arm_smmu_of_match);

static struct platform_driver arm_smmu_driver = {
        .driver = {
                .name           = "arm-smmu-v3",
                .of_match_table = of_match_ptr(arm_smmu_of_match),
        },
        .probe  = arm_smmu_device_dt_probe,
        .remove = arm_smmu_device_remove,
};

static int __init arm_smmu_init(void)
{
        struct device_node *np;
        int ret;

        np = of_find_matching_node(NULL, arm_smmu_of_match);
        if (!np)
                return 0;

        of_node_put(np);

        ret = platform_driver_register(&arm_smmu_driver);
        if (ret)
                return ret;

        return bus_set_iommu(&pci_bus_type, &arm_smmu_ops);
}

static void __exit arm_smmu_exit(void)
{
        return platform_driver_unregister(&arm_smmu_driver);
}

subsys_initcall(arm_smmu_init);
module_exit(arm_smmu_exit);

MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
MODULE_LICENSE("GPL v2");