MIPS: smp-cps: Support MIPSr6 Virtual Processors

Introduce support for bringing up Virtual Processors in MIPSr6 systems
as CPUs, much like their VPE parallel from the now-deprecated MT ASE.
The existing mips_cps_boot_vpes function fits the MIPSr6 architecture
pretty well - it can now simply write the mask of running VPs to the
VC_RUN register, rather than looping through each & starting or stopping
as appropriate as is done for VPEs from the MT ASE. Thus the VP support
is in general an extension & simplification of the existing MT ASE VPE
(aka SMVP) support.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Niklas Cassel <niklas.cassel@axis.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12339/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 882e73c..e77a439 100644 (file)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2282,7 +2282,7 @@ config MIPS_CMP
 
 config MIPS_CPS
        bool "MIPS Coherent Processing System support"
-       depends on SYS_SUPPORTS_MIPS_CPS && !CPU_MIPSR6
+       depends on SYS_SUPPORTS_MIPS_CPS
        select MIPS_CM
        select MIPS_CPC
        select MIPS_CPS_PM if HOTPLUG_CPU

diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
index af12c1f..9ec8168 100644 (file)
--- a/arch/mips/include/asm/cpu-info.h
+++ b/arch/mips/include/asm/cpu-info.h
@@ -68,7 +68,7 @@ struct cpuinfo_mips {
 #ifdef CONFIG_64BIT
        int                     vmbits; /* Virtual memory size in bits */
 #endif
-#ifdef CONFIG_MIPS_MT_SMP
+#if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6)
        /*
         * There is not necessarily a 1:1 mapping of VPE num to CPU number
         * in particular on multi-core systems.
@@ -125,7 +125,7 @@ struct proc_cpuinfo_notifier_args {
        unsigned long n;
 };
 
-#ifdef CONFIG_MIPS_MT_SMP
+#if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6)
 # define cpu_vpe_id(cpuinfo)   ((cpuinfo)->vpe_id)
 #else
 # define cpu_vpe_id(cpuinfo)   ({ (void)cpuinfo; 0; })

diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S
index 4849cbd..c28138d 100644 (file)
--- a/arch/mips/kernel/cps-vec.S
+++ b/arch/mips/kernel/cps-vec.S
@@ -18,9 +18,12 @@
 #include <asm/mipsmtregs.h>
 #include <asm/pm.h>
 
+#define GCR_CPC_BASE_OFS       0x0088
 #define GCR_CL_COHERENCE_OFS   0x2008
 #define GCR_CL_ID_OFS          0x2028
 
+#define CPC_CL_VC_RUN_OFS      0x2028
+
 .extern mips_cm_base
 
 .set noreorder
@@ -60,6 +63,26 @@
         nop
        .endm
 
+       /*
+        * Set dest to non-zero if the core supports MIPSr6 multithreading
+        * (ie. VPs), else zero. If MIPSr6 multithreading is not supported then
+        * branch to nomt.
+        */
+       .macro  has_vp  dest, nomt
+       mfc0    \dest, CP0_CONFIG, 1
+       bgez    \dest, \nomt
+        mfc0   \dest, CP0_CONFIG, 2
+       bgez    \dest, \nomt
+        mfc0   \dest, CP0_CONFIG, 3
+       bgez    \dest, \nomt
+        mfc0   \dest, CP0_CONFIG, 4
+       bgez    \dest, \nomt
+        mfc0   \dest, CP0_CONFIG, 5
+       andi    \dest, \dest, MIPS_CONF5_VP
+       beqz    \dest, \nomt
+        nop
+       .endm
+
        /* Calculate an uncached address for the CM GCRs */
        .macro  cmgcrb  dest
        .set    push
@@ -296,7 +319,17 @@ LEAF(mips_cps_get_bootcfg)
 
        /* Calculate this VPEs ID. If the core doesn't support MT use 0 */
        li      t9, 0
-#ifdef CONFIG_MIPS_MT_SMP
+#if defined(CONFIG_CPU_MIPSR6)
+       has_vp  ta2, 1f
+
+       /*
+        * Assume non-contiguous numbering. Perhaps some day we'll need
+        * to handle contiguous VP numbering, but no such systems yet
+        * exist.
+        */
+       mfc0    t9, $3, 1
+       andi    t9, t9, 0xff
+#elif defined(CONFIG_MIPS_MT_SMP)
        has_mt  ta2, 1f
 
        /* Find the number of VPEs present in the core */
@@ -332,7 +365,23 @@ LEAF(mips_cps_boot_vpes)
        PTR_L   ta2, COREBOOTCFG_VPEMASK(a0)
        PTR_L   ta3, COREBOOTCFG_VPECONFIG(a0)
 
-#ifdef CONFIG_MIPS_MT
+#if defined(CONFIG_CPU_MIPSR6)
+
+       has_vp  t0, 5f
+
+       /* Find base address of CPC */
+       cmgcrb  t3
+       PTR_L   t1, GCR_CPC_BASE_OFS(t3)
+       PTR_LI  t2, ~0x7fff
+       and     t1, t1, t2
+       PTR_LI  t2, UNCAC_BASE
+       PTR_ADD t1, t1, t2
+
+       /* Set VC_RUN to the VPE mask */
+       PTR_S   ta2, CPC_CL_VC_RUN_OFS(t1)
+       ehb
+
+#elif defined(CONFIG_MIPS_MT)
 
        .set    push
        .set    mt

diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index 1a289db..0651217 100644 (file)
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -35,7 +35,8 @@ static unsigned core_vpe_count(unsigned core)
 {
        unsigned cfg;
 
-       if (!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
+       if ((!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
+               && (!config_enabled(CONFIG_CPU_MIPSR6) || !cpu_has_vp))
                return 1;
 
        mips_cm_lock_other(core, 0);
@@ -47,11 +48,12 @@ static unsigned core_vpe_count(unsigned core)
 static void __init cps_smp_setup(void)
 {
        unsigned int ncores, nvpes, core_vpes;
+       unsigned long core_entry;
        int c, v;
 
        /* Detect & record VPE topology */
        ncores = mips_cm_numcores();
-       pr_info("VPE topology ");
+       pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
        for (c = nvpes = 0; c < ncores; c++) {
                core_vpes = core_vpe_count(c);
                pr_cont("%c%u", c ? ',' : '{', core_vpes);
@@ -62,7 +64,7 @@ static void __init cps_smp_setup(void)
 
                for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
                        cpu_data[nvpes + v].core = c;
-#ifdef CONFIG_MIPS_MT_SMP
+#if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6)
                        cpu_data[nvpes + v].vpe_id = v;
 #endif
                }
@@ -91,6 +93,11 @@ static void __init cps_smp_setup(void)
        /* Make core 0 coherent with everything */
        write_gcr_cl_coherence(0xff);
 
+       if (mips_cm_revision() >= CM_REV_CM3) {
+               core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
+               write_gcr_bev_base(core_entry);
+       }
+
 #ifdef CONFIG_MIPS_MT_FPAFF
        /* If we have an FPU, enroll ourselves in the FPU-full mask */
        if (cpu_has_fpu)
@@ -213,6 +220,18 @@ static void boot_core(unsigned core)
        if (mips_cpc_present()) {
                /* Reset the core */
                mips_cpc_lock_other(core);
+
+               if (mips_cm_revision() >= CM_REV_CM3) {
+                       /* Run VP0 following the reset */
+                       write_cpc_co_vp_run(0x1);
+
+                       /*
+                        * Ensure that the VP_RUN register is written before the
+                        * core leaves reset.
+                        */
+                       wmb();
+               }
+
                write_cpc_co_cmd(CPC_Cx_CMD_RESET);
 
                timeout = 100;
@@ -262,6 +281,7 @@ static void cps_boot_secondary(int cpu, struct task_struct *idle)
        unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
        struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
        struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
+       unsigned long core_entry;
        unsigned int remote;
        int err;
 
@@ -279,6 +299,13 @@ static void cps_boot_secondary(int cpu, struct task_struct *idle)
                goto out;
        }
 
+       if (cpu_has_vp) {
+               mips_cm_lock_other(core, vpe_id);
+               core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
+               write_gcr_co_reset_base(core_entry);
+               mips_cm_unlock_other();
+       }
+
        if (core != current_cpu_data.core) {
                /* Boot a VPE on another powered up core */
                for (remote = 0; remote < NR_CPUS; remote++) {
@@ -296,7 +323,7 @@ static void cps_boot_secondary(int cpu, struct task_struct *idle)
                goto out;
        }
 
-       BUG_ON(!cpu_has_mipsmt);
+       BUG_ON(!cpu_has_mipsmt && !cpu_has_vp);
 
        /* Boot a VPE on this core */
        mips_cps_boot_vpes(core_cfg, vpe_id);