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Diffstat (limited to 'arch/mips/kernel/smp-cps.c')
-rw-r--r--arch/mips/kernel/smp-cps.c476
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(&current_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(&current_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;
+}