--- /dev/null
- static struct smp_operations bcm_smp_ops __initdata = {
+/*
+ * Copyright (C) 2014-2015 Broadcom Corporation
+ * Copyright 2014 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/of.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+/* Size of mapped Cortex A9 SCU address space */
+#define CORTEX_A9_SCU_SIZE 0x58
+
+#define SECONDARY_TIMEOUT_NS NSEC_PER_MSEC /* 1 msec (in nanoseconds) */
+#define BOOT_ADDR_CPUID_MASK 0x3
+
+/* Name of device node property defining secondary boot register location */
+#define OF_SECONDARY_BOOT "secondary-boot-reg"
+#define MPIDR_CPUID_BITMASK 0x3
+
+/* I/O address of register used to coordinate secondary core startup */
+static u32 secondary_boot_addr;
+
+/*
+ * Enable the Cortex A9 Snoop Control Unit
+ *
+ * By the time this is called we already know there are multiple
+ * cores present. We assume we're running on a Cortex A9 processor,
+ * so any trouble getting the base address register or getting the
+ * SCU base is a problem.
+ *
+ * Return 0 if successful or an error code otherwise.
+ */
+static int __init scu_a9_enable(void)
+{
+ unsigned long config_base;
+ void __iomem *scu_base;
+
+ if (!scu_a9_has_base()) {
+ pr_err("no configuration base address register!\n");
+ return -ENXIO;
+ }
+
+ /* Config base address register value is zero for uniprocessor */
+ config_base = scu_a9_get_base();
+ if (!config_base) {
+ pr_err("hardware reports only one core\n");
+ return -ENOENT;
+ }
+
+ scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE);
+ if (!scu_base) {
+ pr_err("failed to remap config base (%lu/%u) for SCU\n",
+ config_base, CORTEX_A9_SCU_SIZE);
+ return -ENOMEM;
+ }
+
+ scu_enable(scu_base);
+
+ iounmap(scu_base); /* That's the last we'll need of this */
+
+ return 0;
+}
+
+static int nsp_write_lut(void)
+{
+ void __iomem *sku_rom_lut;
+ phys_addr_t secondary_startup_phy;
+
+ if (!secondary_boot_addr) {
+ pr_warn("required secondary boot register not specified\n");
+ return -EINVAL;
+ }
+
+ sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot_addr,
+ sizeof(secondary_boot_addr));
+ if (!sku_rom_lut) {
+ pr_warn("unable to ioremap SKU-ROM LUT register\n");
+ return -ENOMEM;
+ }
+
+ secondary_startup_phy = virt_to_phys(secondary_startup);
+ BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX);
+
+ writel_relaxed(secondary_startup_phy, sku_rom_lut);
+
+ /* Ensure the write is visible to the secondary core */
+ smp_wmb();
+
+ iounmap(sku_rom_lut);
+
+ return 0;
+}
+
+static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
+{
+ static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
+ struct device_node *cpus_node = NULL;
+ struct device_node *cpu_node = NULL;
+ int ret;
+
+ /*
+ * This function is only called via smp_ops->smp_prepare_cpu().
+ * That only happens if a "/cpus" device tree node exists
+ * and has an "enable-method" property that selects the SMP
+ * operations defined herein.
+ */
+ cpus_node = of_find_node_by_path("/cpus");
+ if (!cpus_node)
+ return;
+
+ for_each_child_of_node(cpus_node, cpu_node) {
+ u32 cpuid;
+
+ if (of_node_cmp(cpu_node->type, "cpu"))
+ continue;
+
+ if (of_property_read_u32(cpu_node, "reg", &cpuid)) {
+ pr_debug("%s: missing reg property\n",
+ cpu_node->full_name);
+ ret = -ENOENT;
+ goto out;
+ }
+
+ /*
+ * "secondary-boot-reg" property should be defined only
+ * for secondary cpu
+ */
+ if ((cpuid & MPIDR_CPUID_BITMASK) == 1) {
+ /*
+ * Our secondary enable method requires a
+ * "secondary-boot-reg" property to specify a register
+ * address used to request the ROM code boot a secondary
+ * core. If we have any trouble getting this we fall
+ * back to uniprocessor mode.
+ */
+ if (of_property_read_u32(cpu_node,
+ OF_SECONDARY_BOOT,
+ &secondary_boot_addr)) {
+ pr_warn("%s: no" OF_SECONDARY_BOOT "property\n",
+ cpu_node->name);
+ ret = -ENOENT;
+ goto out;
+ }
+ }
+ }
+
+ /*
+ * Enable the SCU on Cortex A9 based SoCs. If -ENOENT is
+ * returned, the SoC reported a uniprocessor configuration.
+ * We bail on any other error.
+ */
+ ret = scu_a9_enable();
+out:
+ of_node_put(cpu_node);
+ of_node_put(cpus_node);
+
+ if (ret) {
+ /* Update the CPU present map to reflect uniprocessor mode */
+ pr_warn("disabling SMP\n");
+ init_cpu_present(&only_cpu_0);
+ }
+}
+
+/*
+ * The ROM code has the secondary cores looping, waiting for an event.
+ * When an event occurs each core examines the bottom two bits of the
+ * secondary boot register. When a core finds those bits contain its
+ * own core id, it performs initialization, including computing its boot
+ * address by clearing the boot register value's bottom two bits. The
+ * core signals that it is beginning its execution by writing its boot
+ * address back to the secondary boot register, and finally jumps to
+ * that address.
+ *
+ * So to start a core executing we need to:
+ * - Encode the (hardware) CPU id with the bottom bits of the secondary
+ * start address.
+ * - Write that value into the secondary boot register.
+ * - Generate an event to wake up the secondary CPU(s).
+ * - Wait for the secondary boot register to be re-written, which
+ * indicates the secondary core has started.
+ */
+static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ void __iomem *boot_reg;
+ phys_addr_t boot_func;
+ u64 start_clock;
+ u32 cpu_id;
+ u32 boot_val;
+ bool timeout = false;
+
+ cpu_id = cpu_logical_map(cpu);
+ if (cpu_id & ~BOOT_ADDR_CPUID_MASK) {
+ pr_err("bad cpu id (%u > %u)\n", cpu_id, BOOT_ADDR_CPUID_MASK);
+ return -EINVAL;
+ }
+
+ if (!secondary_boot_addr) {
+ pr_err("required secondary boot register not specified\n");
+ return -EINVAL;
+ }
+
+ boot_reg = ioremap_nocache(
+ (phys_addr_t)secondary_boot_addr, sizeof(u32));
+ if (!boot_reg) {
+ pr_err("unable to map boot register for cpu %u\n", cpu_id);
+ return -ENOMEM;
+ }
+
+ /*
+ * Secondary cores will start in secondary_startup(),
+ * defined in "arch/arm/kernel/head.S"
+ */
+ boot_func = virt_to_phys(secondary_startup);
+ BUG_ON(boot_func & BOOT_ADDR_CPUID_MASK);
+ BUG_ON(boot_func > (phys_addr_t)U32_MAX);
+
+ /* The core to start is encoded in the low bits */
+ boot_val = (u32)boot_func | cpu_id;
+ writel_relaxed(boot_val, boot_reg);
+
+ sev();
+
+ /* The low bits will be cleared once the core has started */
+ start_clock = local_clock();
+ while (!timeout && readl_relaxed(boot_reg) == boot_val)
+ timeout = local_clock() - start_clock > SECONDARY_TIMEOUT_NS;
+
+ iounmap(boot_reg);
+
+ if (!timeout)
+ return 0;
+
+ pr_err("timeout waiting for cpu %u to start\n", cpu_id);
+
+ return -ENXIO;
+}
+
+static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ int ret;
+
+ /*
+ * After wake up, secondary core branches to the startup
+ * address programmed at SKU ROM LUT location.
+ */
+ ret = nsp_write_lut();
+ if (ret) {
+ pr_err("unable to write startup addr to SKU ROM LUT\n");
+ goto out;
+ }
+
+ /* Send a CPU wakeup interrupt to the secondary core */
+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+out:
+ return ret;
+}
+
++static const struct smp_operations bcm_smp_ops __initconst = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_boot_secondary = kona_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
+ &bcm_smp_ops);
+
+struct smp_operations nsp_smp_ops __initdata = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_boot_secondary = nsp_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);
projects / cascardo / linux.git / commitdiff