From 0ee958e102b62b418c2fb46c3439d4262067a5fc Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Wed, 15 Jan 2014 10:31:53 +0000 Subject: [PATCH] MIPS: Coherent Processing System SMP implementation This patch introduces a new SMP implementation for systems implementing the MIPS Coherent Processing System architecture. The kernel will make use of the Coherence Manager, Cluster Power Controller & Global Interrupt Controller in order to detect, bring up & make use of other cores in the system. SMTC is not supported, so only a single TC per VPE in the system is used. That is, this option enables an SMVP style setup but across multiple cores. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6362/ Patchwork: https://patchwork.linux-mips.org/patch/6611/ Patchwork: https://patchwork.linux-mips.org/patch/6651/ Patchwork: https://patchwork.linux-mips.org/patch/6652/ Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 21 +++ arch/mips/include/asm/smp-cps.h | 33 ++++ arch/mips/include/asm/smp-ops.h | 9 ++ arch/mips/kernel/Makefile | 1 + arch/mips/kernel/asm-offsets.c | 13 ++ arch/mips/kernel/cps-vec.S | 191 +++++++++++++++++++++++ arch/mips/kernel/cpu-probe.c | 2 + arch/mips/kernel/smp-cps.c | 335 ++++++++++++++++++++++++++++++++++++++++ arch/mips/mm/c-r4k.c | 2 +- 9 files changed, 606 insertions(+), 1 deletion(-) create mode 100644 arch/mips/include/asm/smp-cps.h create mode 100644 arch/mips/kernel/cps-vec.S create mode 100644 arch/mips/kernel/smp-cps.c diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 2a9848e..a706779 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1887,6 +1887,7 @@ config MIPS_MT_SMTC bool "Use all TCs on all VPEs for SMP (DEPRECATED)" depends on CPU_MIPS32_R2 depends on SYS_SUPPORTS_MULTITHREADING + depends on !MIPS_CPS select CPU_MIPSR2_IRQ_VI select CPU_MIPSR2_IRQ_EI select MIPS_MT @@ -2003,6 +2004,23 @@ config MIPS_CMP help Enable Coherency Manager processor (CMP) support. +config MIPS_CPS + bool "MIPS Coherent Processing System support" + depends on SYS_SUPPORTS_MIPS_CPS + select MIPS_CM + select MIPS_CPC + select MIPS_GIC_IPI + select SMP + select SYNC_R4K if (CEVT_R4K || CSRC_R4K) + select SYS_SUPPORTS_SMP + select WEAK_ORDERING + help + Select this if you wish to run an SMP kernel across multiple cores + within a MIPS Coherent Processing System. When this option is + enabled the kernel will probe for other cores and boot them with + no external assistance. It is safe to enable this when hardware + support is unavailable. + config MIPS_GIC_IPI bool @@ -2191,6 +2209,9 @@ config SMP_UP config SYS_SUPPORTS_MIPS_CMP bool +config SYS_SUPPORTS_MIPS_CPS + bool + config SYS_SUPPORTS_SMP bool diff --git a/arch/mips/include/asm/smp-cps.h b/arch/mips/include/asm/smp-cps.h new file mode 100644 index 0000000..d60d1a2 --- /dev/null +++ b/arch/mips/include/asm/smp-cps.h @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2013 Imagination Technologies + * Author: Paul Burton + * + * 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; either version 2 of the License, or (at your + * option) any later version. + */ + +#ifndef __MIPS_ASM_SMP_CPS_H__ +#define __MIPS_ASM_SMP_CPS_H__ + +#ifndef __ASSEMBLY__ + +struct boot_config { + unsigned int core; + unsigned int vpe; + unsigned long pc; + unsigned long sp; + unsigned long gp; +}; + +extern struct boot_config mips_cps_bootcfg; + +extern void mips_cps_core_entry(void); + +#else /* __ASSEMBLY__ */ + +.extern mips_cps_bootcfg; + +#endif /* __ASSEMBLY__ */ +#endif /* __MIPS_ASM_SMP_CPS_H__ */ diff --git a/arch/mips/include/asm/smp-ops.h b/arch/mips/include/asm/smp-ops.h index 51458bb..a02c9d4 100644 --- a/arch/mips/include/asm/smp-ops.h +++ b/arch/mips/include/asm/smp-ops.h @@ -100,4 +100,13 @@ static inline int register_vsmp_smp_ops(void) #endif } +#ifdef CONFIG_MIPS_CPS +extern int register_cps_smp_ops(void); +#else +static inline int register_cps_smp_ops(void) +{ + return -ENODEV; +} +#endif + #endif /* __ASM_SMP_OPS_H */ diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index a6a8717..277dab3 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_MIPS_MT_FPAFF) += mips-mt-fpaff.o obj-$(CONFIG_MIPS_MT_SMTC) += smtc.o smtc-asm.o smtc-proc.o obj-$(CONFIG_MIPS_MT_SMP) += smp-mt.o obj-$(CONFIG_MIPS_CMP) += smp-cmp.o +obj-$(CONFIG_MIPS_CPS) += smp-cps.o cps-vec.o obj-$(CONFIG_MIPS_GIC_IPI) += smp-gic.o obj-$(CONFIG_CPU_MIPSR2) += spram.o diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c index 0c2e853..8a2a45d 100644 --- a/arch/mips/kernel/asm-offsets.c +++ b/arch/mips/kernel/asm-offsets.c @@ -16,6 +16,7 @@ #include #include #include +#include #include @@ -397,3 +398,15 @@ void output_kvm_defines(void) OFFSET(COP0_STATUS, mips_coproc, reg[MIPS_CP0_STATUS][0]); BLANK(); } + +#ifdef CONFIG_MIPS_CPS +void output_cps_defines(void) +{ + COMMENT(" MIPS CPS offsets. "); + OFFSET(BOOTCFG_CORE, boot_config, core); + OFFSET(BOOTCFG_VPE, boot_config, vpe); + OFFSET(BOOTCFG_PC, boot_config, pc); + OFFSET(BOOTCFG_SP, boot_config, sp); + OFFSET(BOOTCFG_GP, boot_config, gp); +} +#endif diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S new file mode 100644 index 0000000..f7a46db --- /dev/null +++ b/arch/mips/kernel/cps-vec.S @@ -0,0 +1,191 @@ +/* + * Copyright (C) 2013 Imagination Technologies + * Author: Paul Burton + * + * 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; either version 2 of the License, or (at your + * option) any later version. + */ + +#include +#include +#include +#include +#include +#include + +#define GCR_CL_COHERENCE_OFS 0x2008 + +.section .text.cps-vec +.balign 0x1000 +.set noreorder + +LEAF(mips_cps_core_entry) + /* + * These first 8 bytes will be patched by cps_smp_setup to load the + * base address of the CM GCRs into register v1. + */ + .quad 0 + + /* Check whether we're here due to an NMI */ + mfc0 k0, CP0_STATUS + and k0, k0, ST0_NMI + beqz k0, not_nmi + nop + + /* This is an NMI */ + la k0, nmi_handler + jr k0 + nop + +not_nmi: + /* Setup Cause */ + li t0, CAUSEF_IV + mtc0 t0, CP0_CAUSE + + /* Setup Status */ + li t0, ST0_CU1 | ST0_CU0 + mtc0 t0, CP0_STATUS + + /* + * Clear the bits used to index the caches. Note that the architecture + * dictates that writing to any of TagLo or TagHi selects 0 or 2 should + * be valid for all MIPS32 CPUs, even those for which said writes are + * unnecessary. + */ + mtc0 zero, CP0_TAGLO, 0 + mtc0 zero, CP0_TAGHI, 0 + mtc0 zero, CP0_TAGLO, 2 + mtc0 zero, CP0_TAGHI, 2 + ehb + + /* Primary cache configuration is indicated by Config1 */ + mfc0 v0, CP0_CONFIG, 1 + + /* Detect I-cache line size */ + _EXT t0, v0, MIPS_CONF1_IL_SHF, MIPS_CONF1_IL_SZ + beqz t0, icache_done + li t1, 2 + sllv t0, t1, t0 + + /* Detect I-cache size */ + _EXT t1, v0, MIPS_CONF1_IS_SHF, MIPS_CONF1_IS_SZ + xori t2, t1, 0x7 + beqz t2, 1f + li t3, 32 + addi t1, t1, 1 + sllv t1, t3, t1 +1: /* At this point t1 == I-cache sets per way */ + _EXT t2, v0, MIPS_CONF1_IA_SHF, MIPS_CONF1_IA_SZ + addi t2, t2, 1 + mul t1, t1, t0 + mul t1, t1, t2 + + li a0, KSEG0 + add a1, a0, t1 +1: cache Index_Store_Tag_I, 0(a0) + add a0, a0, t0 + bne a0, a1, 1b + nop +icache_done: + + /* Detect D-cache line size */ + _EXT t0, v0, MIPS_CONF1_DL_SHF, MIPS_CONF1_DL_SZ + beqz t0, dcache_done + li t1, 2 + sllv t0, t1, t0 + + /* Detect D-cache size */ + _EXT t1, v0, MIPS_CONF1_DS_SHF, MIPS_CONF1_DS_SZ + xori t2, t1, 0x7 + beqz t2, 1f + li t3, 32 + addi t1, t1, 1 + sllv t1, t3, t1 +1: /* At this point t1 == D-cache sets per way */ + _EXT t2, v0, MIPS_CONF1_DA_SHF, MIPS_CONF1_DA_SZ + addi t2, t2, 1 + mul t1, t1, t0 + mul t1, t1, t2 + + li a0, KSEG0 + addu a1, a0, t1 + subu a1, a1, t0 +1: cache Index_Store_Tag_D, 0(a0) + bne a0, a1, 1b + add a0, a0, t0 +dcache_done: + + /* Set Kseg0 cacheable, coherent, write-back, write-allocate */ + mfc0 t0, CP0_CONFIG + ori t0, 0x7 + xori t0, 0x2 + mtc0 t0, CP0_CONFIG + ehb + + /* Enter the coherent domain */ + li t0, 0xff + sw t0, GCR_CL_COHERENCE_OFS(v1) + ehb + + /* Jump to kseg0 */ + la t0, 1f + jr t0 + nop + +1: /* We're up, cached & coherent */ + + /* + * TODO: We should check the VPE number we intended to boot here, and + * if non-zero we should start that VPE and stop this one. For + * the moment this doesn't matter since CPUs are brought up + * sequentially and in order, but once hotplug is implemented + * this will need revisiting. + */ + + /* Off we go! */ + la t0, mips_cps_bootcfg + lw t1, BOOTCFG_PC(t0) + lw gp, BOOTCFG_GP(t0) + lw sp, BOOTCFG_SP(t0) + jr t1 + nop + END(mips_cps_core_entry) + +.org 0x200 +LEAF(excep_tlbfill) + b . + nop + END(excep_tlbfill) + +.org 0x280 +LEAF(excep_xtlbfill) + b . + nop + END(excep_xtlbfill) + +.org 0x300 +LEAF(excep_cache) + b . + nop + END(excep_cache) + +.org 0x380 +LEAF(excep_genex) + b . + nop + END(excep_genex) + +.org 0x400 +LEAF(excep_intex) + b . + nop + END(excep_intex) + +.org 0x480 +LEAF(excep_ejtag) + la k0, ejtag_debug_handler + jr k0 + nop + END(excep_ejtag) diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index ac09248..c1ee8b4 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -398,8 +398,10 @@ static void decode_configs(struct cpuinfo_mips *c) mips_probe_watch_registers(c); +#ifndef CONFIG_MIPS_CPS if (cpu_has_mips_r2) c->core = read_c0_ebase() & 0x3ff; +#endif } #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \ diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c new file mode 100644 index 0000000..536eec0 --- /dev/null +++ b/arch/mips/kernel/smp-cps.c @@ -0,0 +1,335 @@ +/* + * Copyright (C) 2013 Imagination Technologies + * Author: Paul Burton + * + * 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; either version 2 of the License, or (at your + * option) any later version. + */ + +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DECLARE_BITMAP(core_power, NR_CPUS); + +struct boot_config mips_cps_bootcfg; + +static void init_core(void) +{ + unsigned int nvpes, t; + u32 mvpconf0, vpeconf0, vpecontrol, tcstatus, tcbind, status; + + if (!cpu_has_mipsmt) + return; + + /* Enter VPE configuration state */ + dvpe(); + set_c0_mvpcontrol(MVPCONTROL_VPC); + + /* Retrieve the count of VPEs in this core */ + mvpconf0 = read_c0_mvpconf0(); + nvpes = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1; + smp_num_siblings = nvpes; + + for (t = 1; t < nvpes; t++) { + /* Use a 1:1 mapping of TC index to VPE index */ + settc(t); + + /* Bind 1 TC to this VPE */ + tcbind = read_tc_c0_tcbind(); + tcbind &= ~TCBIND_CURVPE; + tcbind |= t << TCBIND_CURVPE_SHIFT; + write_tc_c0_tcbind(tcbind); + + /* Set exclusive TC, non-active, master */ + vpeconf0 = read_vpe_c0_vpeconf0(); + vpeconf0 &= ~(VPECONF0_XTC | VPECONF0_VPA); + vpeconf0 |= t << VPECONF0_XTC_SHIFT; + vpeconf0 |= VPECONF0_MVP; + write_vpe_c0_vpeconf0(vpeconf0); + + /* Declare TC non-active, non-allocatable & interrupt exempt */ + tcstatus = read_tc_c0_tcstatus(); + tcstatus &= ~(TCSTATUS_A | TCSTATUS_DA); + tcstatus |= TCSTATUS_IXMT; + write_tc_c0_tcstatus(tcstatus); + + /* Halt the TC */ + write_tc_c0_tchalt(TCHALT_H); + + /* Allow only 1 TC to execute */ + vpecontrol = read_vpe_c0_vpecontrol(); + vpecontrol &= ~VPECONTROL_TE; + write_vpe_c0_vpecontrol(vpecontrol); + + /* Copy (most of) Status from VPE 0 */ + status = read_c0_status(); + status &= ~(ST0_IM | ST0_IE | ST0_KSU); + status |= ST0_CU0; + write_vpe_c0_status(status); + + /* Copy Config from VPE 0 */ + write_vpe_c0_config(read_c0_config()); + write_vpe_c0_config7(read_c0_config7()); + + /* Ensure no software interrupts are pending */ + write_vpe_c0_cause(0); + + /* Sync Count */ + write_vpe_c0_count(read_c0_count()); + } + + /* Leave VPE configuration state */ + clear_c0_mvpcontrol(MVPCONTROL_VPC); +} + +static void __init cps_smp_setup(void) +{ + unsigned int ncores, nvpes, core_vpes; + int c, v; + u32 core_cfg, *entry_code; + + /* Detect & record VPE topology */ + ncores = mips_cm_numcores(); + pr_info("VPE topology "); + for (c = nvpes = 0; c < ncores; c++) { + if (cpu_has_mipsmt && config_enabled(CONFIG_MIPS_MT_SMP)) { + write_gcr_cl_other(c << CM_GCR_Cx_OTHER_CORENUM_SHF); + core_cfg = read_gcr_co_config(); + core_vpes = ((core_cfg & CM_GCR_Cx_CONFIG_PVPE_MSK) >> + CM_GCR_Cx_CONFIG_PVPE_SHF) + 1; + } else { + core_vpes = 1; + } + + pr_cont("%c%u", c ? ',' : '{', core_vpes); + + for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) { + cpu_data[nvpes + v].core = c; +#ifdef CONFIG_MIPS_MT_SMP + cpu_data[nvpes + v].vpe_id = v; +#endif + } + + nvpes += core_vpes; + } + pr_cont("} total %u\n", nvpes); + + /* Indicate present CPUs (CPU being synonymous with VPE) */ + for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) { + set_cpu_possible(v, true); + set_cpu_present(v, true); + __cpu_number_map[v] = v; + __cpu_logical_map[v] = v; + } + + /* Core 0 is powered up (we're running on it) */ + bitmap_set(core_power, 0, 1); + + /* Disable MT - we only want to run 1 TC per VPE */ + if (cpu_has_mipsmt) + dmt(); + + /* Initialise core 0 */ + init_core(); + + /* Patch the start of mips_cps_core_entry to provide the CM base */ + entry_code = (u32 *)&mips_cps_core_entry; + UASM_i_LA(&entry_code, 3, (long)mips_cm_base); + + /* Make core 0 coherent with everything */ + write_gcr_cl_coherence(0xff); +} + +static void __init cps_prepare_cpus(unsigned int max_cpus) +{ + mips_mt_set_cpuoptions(); +} + +static void boot_core(struct boot_config *cfg) +{ + u32 access; + + /* Select the appropriate core */ + write_gcr_cl_other(cfg->core << CM_GCR_Cx_OTHER_CORENUM_SHF); + + /* Set its reset vector */ + write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry)); + + /* Ensure its coherency is disabled */ + write_gcr_co_coherence(0); + + /* Ensure the core can access the GCRs */ + access = read_gcr_access(); + access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + cfg->core); + write_gcr_access(access); + + /* Copy cfg */ + mips_cps_bootcfg = *cfg; + + if (mips_cpc_present()) { + /* Select the appropriate core */ + write_cpc_cl_other(cfg->core << CPC_Cx_OTHER_CORENUM_SHF); + + /* Reset the core */ + write_cpc_co_cmd(CPC_Cx_CMD_RESET); + } else { + /* Take the core out of reset */ + write_gcr_co_reset_release(0); + } + + /* The core is now powered up */ + bitmap_set(core_power, cfg->core, 1); +} + +static void boot_vpe(void *info) +{ + struct boot_config *cfg = info; + u32 tcstatus, vpeconf0; + + /* Enter VPE configuration state */ + dvpe(); + set_c0_mvpcontrol(MVPCONTROL_VPC); + + settc(cfg->vpe); + + /* Set the TC restart PC */ + write_tc_c0_tcrestart((unsigned long)&smp_bootstrap); + + /* Activate the TC, allow interrupts */ + tcstatus = read_tc_c0_tcstatus(); + tcstatus &= ~TCSTATUS_IXMT; + tcstatus |= TCSTATUS_A; + write_tc_c0_tcstatus(tcstatus); + + /* Clear the TC halt bit */ + write_tc_c0_tchalt(0); + + /* Activate the VPE */ + vpeconf0 = read_vpe_c0_vpeconf0(); + vpeconf0 |= VPECONF0_VPA; + write_vpe_c0_vpeconf0(vpeconf0); + + /* Set the stack & global pointer registers */ + write_tc_gpr_sp(cfg->sp); + write_tc_gpr_gp(cfg->gp); + + /* Leave VPE configuration state */ + clear_c0_mvpcontrol(MVPCONTROL_VPC); + + /* Enable other VPEs to execute */ + evpe(EVPE_ENABLE); +} + +static void cps_boot_secondary(int cpu, struct task_struct *idle) +{ + struct boot_config cfg; + unsigned int remote; + int err; + + cfg.core = cpu_data[cpu].core; + cfg.vpe = cpu_vpe_id(&cpu_data[cpu]); + cfg.pc = (unsigned long)&smp_bootstrap; + cfg.sp = __KSTK_TOS(idle); + cfg.gp = (unsigned long)task_thread_info(idle); + + if (!test_bit(cfg.core, core_power)) { + /* Boot a VPE on a powered down core */ + boot_core(&cfg); + return; + } + + if (cfg.core != current_cpu_data.core) { + /* Boot a VPE on another powered up core */ + for (remote = 0; remote < NR_CPUS; remote++) { + if (cpu_data[remote].core != cfg.core) + continue; + if (cpu_online(remote)) + break; + } + BUG_ON(remote >= NR_CPUS); + + err = smp_call_function_single(remote, boot_vpe, &cfg, 1); + if (err) + panic("Failed to call remote CPU\n"); + return; + } + + BUG_ON(!cpu_has_mipsmt); + + /* Boot a VPE on this core */ + boot_vpe(&cfg); +} + +static void cps_init_secondary(void) +{ + /* Disable MT - we only want to run 1 TC per VPE */ + if (cpu_has_mipsmt) + dmt(); + + /* TODO: revisit this assumption once hotplug is implemented */ + if (cpu_vpe_id(¤t_cpu_data) == 0) + init_core(); + + change_c0_status(ST0_IM, STATUSF_IP3 | STATUSF_IP4 | + STATUSF_IP6 | STATUSF_IP7); +} + +static void cps_smp_finish(void) +{ + write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ)); + +#ifdef CONFIG_MIPS_MT_FPAFF + /* If we have an FPU, enroll ourselves in the FPU-full mask */ + if (cpu_has_fpu) + cpu_set(smp_processor_id(), mt_fpu_cpumask); +#endif /* CONFIG_MIPS_MT_FPAFF */ + + local_irq_enable(); +} + +static void cps_cpus_done(void) +{ +} + +static struct plat_smp_ops cps_smp_ops = { + .smp_setup = cps_smp_setup, + .prepare_cpus = cps_prepare_cpus, + .boot_secondary = cps_boot_secondary, + .init_secondary = cps_init_secondary, + .smp_finish = cps_smp_finish, + .send_ipi_single = gic_send_ipi_single, + .send_ipi_mask = gic_send_ipi_mask, + .cpus_done = cps_cpus_done, +}; + +int register_cps_smp_ops(void) +{ + if (!mips_cm_present()) { + pr_warn("MIPS CPS SMP unable to proceed without a CM\n"); + return -ENODEV; + } + + /* check we have a GIC - we need one for IPIs */ + if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) { + pr_warn("MIPS CPS SMP unable to proceed without a GIC\n"); + return -ENODEV; + } + + register_smp_ops(&cps_smp_ops); + return 0; +} diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index ae81032..d72e9a1 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -57,7 +57,7 @@ static inline void r4k_on_each_cpu(void (*func) (void *info), void *info) preempt_enable(); } -#if defined(CONFIG_MIPS_CMP) +#if defined(CONFIG_MIPS_CMP) || defined(CONFIG_MIPS_CPS) #define cpu_has_safe_index_cacheops 0 #else #define cpu_has_safe_index_cacheops 1 -- 2.7.4