diff options
Diffstat (limited to 'arch/mips/kernel/smp-cps.c')
| -rw-r--r-- | arch/mips/kernel/smp-cps.c | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c new file mode 100644 index 000000000..4251d390b --- /dev/null +++ b/arch/mips/kernel/smp-cps.c @@ -0,0 +1,476 @@ +/* + * Copyright (C) 2013 Imagination Technologies + * Author: Paul Burton <paul.burton@imgtec.com> + * + * 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 <linux/io.h> +#include <linux/irqchip/mips-gic.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/smp.h> +#include <linux/types.h> + +#include <asm/bcache.h> +#include <asm/mips-cm.h> +#include <asm/mips-cpc.h> +#include <asm/mips_mt.h> +#include <asm/mipsregs.h> +#include <asm/pm-cps.h> +#include <asm/r4kcache.h> +#include <asm/smp-cps.h> +#include <asm/time.h> +#include <asm/uasm.h> + +static DECLARE_BITMAP(core_power, NR_CPUS); + +struct core_boot_config *mips_cps_core_bootcfg; + +static unsigned core_vpe_count(unsigned core) +{ + unsigned cfg; + + if (!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt) + return 1; + + write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF); + cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK; + return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1; +} + +static void __init cps_smp_setup(void) +{ + unsigned int ncores, nvpes, core_vpes; + int c, v; + + /* Detect & record VPE topology */ + ncores = mips_cm_numcores(); + pr_info("VPE topology "); + for (c = nvpes = 0; c < ncores; c++) { + core_vpes = core_vpe_count(c); + pr_cont("%c%u", c ? ',' : '{', core_vpes); + + /* Use the number of VPEs in core 0 for smp_num_siblings */ + if (!c) + smp_num_siblings = 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; + } + + /* Set a coherent default CCA (CWB) */ + change_c0_config(CONF_CM_CMASK, 0x5); + + /* Core 0 is powered up (we're running on it) */ + bitmap_set(core_power, 0, 1); + + /* Initialise core 0 */ + mips_cps_core_init(); + + /* Make core 0 coherent with everything */ + write_gcr_cl_coherence(0xff); + +#ifdef CONFIG_MIPS_MT_FPAFF + /* If we have an FPU, enroll ourselves in the FPU-full mask */ + if (cpu_has_fpu) + cpumask_set_cpu(0, &mt_fpu_cpumask); +#endif /* CONFIG_MIPS_MT_FPAFF */ +} + +static void __init cps_prepare_cpus(unsigned int max_cpus) +{ + unsigned ncores, core_vpes, c, cca; + bool cca_unsuitable; + u32 *entry_code; + + mips_mt_set_cpuoptions(); + + /* Detect whether the CCA is unsuited to multi-core SMP */ + cca = read_c0_config() & CONF_CM_CMASK; + switch (cca) { + case 0x4: /* CWBE */ + case 0x5: /* CWB */ + /* The CCA is coherent, multi-core is fine */ + cca_unsuitable = false; + break; + + default: + /* CCA is not coherent, multi-core is not usable */ + cca_unsuitable = true; + } + + /* Warn the user if the CCA prevents multi-core */ + ncores = mips_cm_numcores(); + if (cca_unsuitable && ncores > 1) { + pr_warn("Using only one core due to unsuitable CCA 0x%x\n", + cca); + + for_each_present_cpu(c) { + if (cpu_data[c].core) + set_cpu_present(c, false); + } + } + + /* + * Patch the start of mips_cps_core_entry to provide: + * + * v0 = CM base address + * s0 = kseg0 CCA + */ + entry_code = (u32 *)&mips_cps_core_entry; + UASM_i_LA(&entry_code, 3, (long)mips_cm_base); + uasm_i_addiu(&entry_code, 16, 0, cca); + blast_dcache_range((unsigned long)&mips_cps_core_entry, + (unsigned long)entry_code); + bc_wback_inv((unsigned long)&mips_cps_core_entry, + (void *)entry_code - (void *)&mips_cps_core_entry); + __sync(); + + /* Allocate core boot configuration structs */ + mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg), + GFP_KERNEL); + if (!mips_cps_core_bootcfg) { + pr_err("Failed to allocate boot config for %u cores\n", ncores); + goto err_out; + } + + /* Allocate VPE boot configuration structs */ + for (c = 0; c < ncores; c++) { + core_vpes = core_vpe_count(c); + mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes, + sizeof(*mips_cps_core_bootcfg[c].vpe_config), + GFP_KERNEL); + if (!mips_cps_core_bootcfg[c].vpe_config) { + pr_err("Failed to allocate %u VPE boot configs\n", + core_vpes); + goto err_out; + } + } + + /* Mark this CPU as booted */ + atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask, + 1 << cpu_vpe_id(¤t_cpu_data)); + + return; +err_out: + /* Clean up allocations */ + if (mips_cps_core_bootcfg) { + for (c = 0; c < ncores; c++) + kfree(mips_cps_core_bootcfg[c].vpe_config); + kfree(mips_cps_core_bootcfg); + mips_cps_core_bootcfg = NULL; + } + + /* Effectively disable SMP by declaring CPUs not present */ + for_each_possible_cpu(c) { + if (c == 0) + continue; + set_cpu_present(c, false); + } +} + +static void boot_core(unsigned core) +{ + u32 access; + + /* Select the appropriate core */ + write_gcr_cl_other(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 + core); + write_gcr_access(access); + + if (mips_cpc_present()) { + /* Reset the core */ + mips_cpc_lock_other(core); + write_cpc_co_cmd(CPC_Cx_CMD_RESET); + mips_cpc_unlock_other(); + } else { + /* Take the core out of reset */ + write_gcr_co_reset_release(0); + } + + /* The core is now powered up */ + bitmap_set(core_power, core, 1); +} + +static void remote_vpe_boot(void *dummy) +{ + mips_cps_boot_vpes(); +} + +static void cps_boot_secondary(int cpu, struct task_struct *idle) +{ + unsigned core = cpu_data[cpu].core; + 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 int remote; + int err; + + vpe_cfg->pc = (unsigned long)&smp_bootstrap; + vpe_cfg->sp = __KSTK_TOS(idle); + vpe_cfg->gp = (unsigned long)task_thread_info(idle); + + atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask); + + preempt_disable(); + + if (!test_bit(core, core_power)) { + /* Boot a VPE on a powered down core */ + boot_core(core); + goto out; + } + + if (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 != core) + continue; + if (cpu_online(remote)) + break; + } + BUG_ON(remote >= NR_CPUS); + + err = smp_call_function_single(remote, remote_vpe_boot, + NULL, 1); + if (err) + panic("Failed to call remote CPU\n"); + goto out; + } + + BUG_ON(!cpu_has_mipsmt); + + /* Boot a VPE on this core */ + mips_cps_boot_vpes(); +out: + preempt_enable(); +} + +static void cps_init_secondary(void) +{ + /* Disable MT - we only want to run 1 TC per VPE */ + if (cpu_has_mipsmt) + dmt(); + + change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 | STATUSF_IP4 | + STATUSF_IP5 | 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) + cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask); +#endif /* CONFIG_MIPS_MT_FPAFF */ + + local_irq_enable(); +} + +#ifdef CONFIG_HOTPLUG_CPU + +static int cps_cpu_disable(void) +{ + unsigned cpu = smp_processor_id(); + struct core_boot_config *core_cfg; + + if (!cpu) + return -EBUSY; + + if (!cps_pm_support_state(CPS_PM_POWER_GATED)) + return -EINVAL; + + core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core]; + atomic_sub(1 << cpu_vpe_id(¤t_cpu_data), &core_cfg->vpe_mask); + smp_mb__after_atomic(); + set_cpu_online(cpu, false); + cpumask_clear_cpu(cpu, &cpu_callin_map); + + return 0; +} + +static DECLARE_COMPLETION(cpu_death_chosen); +static unsigned cpu_death_sibling; +static enum { + CPU_DEATH_HALT, + CPU_DEATH_POWER, +} cpu_death; + +void play_dead(void) +{ + unsigned cpu, core; + + local_irq_disable(); + idle_task_exit(); + cpu = smp_processor_id(); + cpu_death = CPU_DEATH_POWER; + + if (cpu_has_mipsmt) { + core = cpu_data[cpu].core; + + /* Look for another online VPE within the core */ + for_each_online_cpu(cpu_death_sibling) { + if (cpu_data[cpu_death_sibling].core != core) + continue; + + /* + * There is an online VPE within the core. Just halt + * this TC and leave the core alone. + */ + cpu_death = CPU_DEATH_HALT; + break; + } + } + + /* This CPU has chosen its way out */ + complete(&cpu_death_chosen); + + if (cpu_death == CPU_DEATH_HALT) { + /* Halt this TC */ + write_c0_tchalt(TCHALT_H); + instruction_hazard(); + } else { + /* Power down the core */ + cps_pm_enter_state(CPS_PM_POWER_GATED); + } + + /* This should never be reached */ + panic("Failed to offline CPU %u", cpu); +} + +static void wait_for_sibling_halt(void *ptr_cpu) +{ + unsigned cpu = (unsigned)ptr_cpu; + unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]); + unsigned halted; + unsigned long flags; + + do { + local_irq_save(flags); + settc(vpe_id); + halted = read_tc_c0_tchalt(); + local_irq_restore(flags); + } while (!(halted & TCHALT_H)); +} + +static void cps_cpu_die(unsigned int cpu) +{ + unsigned core = cpu_data[cpu].core; + unsigned stat; + int err; + + /* Wait for the cpu to choose its way out */ + if (!wait_for_completion_timeout(&cpu_death_chosen, + msecs_to_jiffies(5000))) { + pr_err("CPU%u: didn't offline\n", cpu); + return; + } + + /* + * Now wait for the CPU to actually offline. Without doing this that + * offlining may race with one or more of: + * + * - Onlining the CPU again. + * - Powering down the core if another VPE within it is offlined. + * - A sibling VPE entering a non-coherent state. + * + * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing + * with which we could race, so do nothing. + */ + if (cpu_death == CPU_DEATH_POWER) { + /* + * Wait for the core to enter a powered down or clock gated + * state, the latter happening when a JTAG probe is connected + * in which case the CPC will refuse to power down the core. + */ + do { + mips_cpc_lock_other(core); + stat = read_cpc_co_stat_conf(); + stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK; + mips_cpc_unlock_other(); + } while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 && + stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 && + stat != CPC_Cx_STAT_CONF_SEQSTATE_U2); + + /* Indicate the core is powered off */ + bitmap_clear(core_power, core, 1); + } else if (cpu_has_mipsmt) { + /* + * Have a CPU with access to the offlined CPUs registers wait + * for its TC to halt. + */ + err = smp_call_function_single(cpu_death_sibling, + wait_for_sibling_halt, + (void *)cpu, 1); + if (err) + panic("Failed to call remote sibling CPU\n"); + } +} + +#endif /* CONFIG_HOTPLUG_CPU */ + +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, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_disable = cps_cpu_disable, + .cpu_die = cps_cpu_die, +#endif +}; + +bool mips_cps_smp_in_use(void) +{ + extern struct plat_smp_ops *mp_ops; + return mp_ops == &cps_smp_ops; +} + +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; +} |