/* * PowerNV cpuidle code * * Copyright 2015 IBM Corp. * * 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 "powernv.h" #include "subcore.h" /* Power ISA 3.0 allows for stop states 0x0 - 0xF */ #define MAX_STOP_STATE 0xF static u32 supported_cpuidle_states; static int pnv_save_sprs_for_deep_states(void) { int cpu; int rc; /* * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across * all cpus at boot. Get these reg values of current cpu and use the * same across all cpus. */ uint64_t lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1; uint64_t hid0_val = mfspr(SPRN_HID0); uint64_t hid1_val = mfspr(SPRN_HID1); uint64_t hid4_val = mfspr(SPRN_HID4); uint64_t hid5_val = mfspr(SPRN_HID5); uint64_t hmeer_val = mfspr(SPRN_HMEER); for_each_possible_cpu(cpu) { uint64_t pir = get_hard_smp_processor_id(cpu); uint64_t hsprg0_val = (uint64_t)&paca[cpu]; if (!cpu_has_feature(CPU_FTR_ARCH_300)) { /* * HSPRG0 is used to store the cpu's pointer to paca. * Hence last 3 bits are guaranteed to be 0. Program * slw to restore HSPRG0 with 63rd bit set, so that * when a thread wakes up at 0x100 we can use this bit * to distinguish between fastsleep and deep winkle. * This is not necessary with stop/psscr since PLS * field of psscr indicates which state we are waking * up from. */ hsprg0_val |= 1; } rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val); if (rc != 0) return rc; rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val); if (rc != 0) return rc; /* HIDs are per core registers */ if (cpu_thread_in_core(cpu) == 0) { rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val); if (rc != 0) return rc; rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val); if (rc != 0) return rc; rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val); if (rc != 0) return rc; rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val); if (rc != 0) return rc; rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val); if (rc != 0) return rc; } } return 0; } static void pnv_alloc_idle_core_states(void) { int i, j; int nr_cores = cpu_nr_cores(); u32 *core_idle_state; /* * core_idle_state - First 8 bits track the idle state of each thread * of the core. The 8th bit is the lock bit. Initially all thread bits * are set. They are cleared when the thread enters deep idle state * like sleep and winkle. Initially the lock bit is cleared. * The lock bit has 2 purposes * a. While the first thread is restoring core state, it prevents * other threads in the core from switching to process context. * b. While the last thread in the core is saving the core state, it * prevents a different thread from waking up. */ for (i = 0; i < nr_cores; i++) { int first_cpu = i * threads_per_core; int node = cpu_to_node(first_cpu); core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, node); *core_idle_state = PNV_CORE_IDLE_THREAD_BITS; for (j = 0; j < threads_per_core; j++) { int cpu = first_cpu + j; paca[cpu].core_idle_state_ptr = core_idle_state; paca[cpu].thread_idle_state = PNV_THREAD_RUNNING; paca[cpu].thread_mask = 1 << j; } } update_subcore_sibling_mask(); if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) pnv_save_sprs_for_deep_states(); } u32 pnv_get_supported_cpuidle_states(void) { return supported_cpuidle_states; } EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states); static void pnv_fastsleep_workaround_apply(void *info) { int rc; int *err = info; rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP, OPAL_CONFIG_IDLE_APPLY); if (rc) *err = 1; } /* * Used to store fastsleep workaround state * 0 - Workaround applied/undone at fastsleep entry/exit path (Default) * 1 - Workaround applied once, never undone. */ static u8 fastsleep_workaround_applyonce; static ssize_t show_fastsleep_workaround_applyonce(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%u\n", fastsleep_workaround_applyonce); } static ssize_t store_fastsleep_workaround_applyonce(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { cpumask_t primary_thread_mask; int err; u8 val; if (kstrtou8(buf, 0, &val) || val != 1) return -EINVAL; if (fastsleep_workaround_applyonce == 1) return count; /* * fastsleep_workaround_applyonce = 1 implies * fastsleep workaround needs to be left in 'applied' state on all * the cores. Do this by- * 1. Patching out the call to 'undo' workaround in fastsleep exit path * 2. Sending ipi to all the cores which have at least one online thread * 3. Patching out the call to 'apply' workaround in fastsleep entry * path * There is no need to send ipi to cores which have all threads * offlined, as last thread of the core entering fastsleep or deeper * state would have applied workaround. */ err = patch_instruction( (unsigned int *)pnv_fastsleep_workaround_at_exit, PPC_INST_NOP); if (err) { pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_exit"); goto fail; } get_online_cpus(); primary_thread_mask = cpu_online_cores_map(); on_each_cpu_mask(&primary_thread_mask, pnv_fastsleep_workaround_apply, &err, 1); put_online_cpus(); if (err) { pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply"); goto fail; } err = patch_instruction( (unsigned int *)pnv_fastsleep_workaround_at_entry, PPC_INST_NOP); if (err) { pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_entry"); goto fail; } fastsleep_workaround_applyonce = 1; return count; fail: return -EIO; } static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600, show_fastsleep_workaround_applyonce, store_fastsleep_workaround_applyonce); /* * Used for ppc_md.power_save which needs a function with no parameters */ static void power9_idle(void) { /* Requesting stop state 0 */ power9_idle_stop(0); } /* * First deep stop state. Used to figure out when to save/restore * hypervisor context. */ u64 pnv_first_deep_stop_state = MAX_STOP_STATE; /* * Deepest stop idle state. Used when a cpu is offlined */ u64 pnv_deepest_stop_state; /* * Power ISA 3.0 idle initialization. * * POWER ISA 3.0 defines a new SPR Processor stop Status and Control * Register (PSSCR) to control idle behavior. * * PSSCR layout: * ---------------------------------------------------------- * | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL | * ---------------------------------------------------------- * 0 4 41 42 43 44 48 54 56 60 * * PSSCR key fields: * Bits 0:3 - Power-Saving Level Status (PLS). This field indicates the * lowest power-saving state the thread entered since stop instruction was * last executed. * * Bit 41 - Status Disable(SD) * 0 - Shows PLS entries * 1 - PLS entries are all 0 * * Bit 42 - Enable State Loss * 0 - No state is lost irrespective of other fields * 1 - Allows state loss * * Bit 43 - Exit Criterion * 0 - Exit from power-save mode on any interrupt * 1 - Exit from power-save mode controlled by LPCR's PECE bits * * Bits 44:47 - Power-Saving Level Limit * This limits the power-saving level that can be entered into. * * Bits 60:63 - Requested Level * Used to specify which power-saving level must be entered on executing * stop instruction * * @np: /ibm,opal/power-mgt device node * @flags: cpu-idle-state-flags array * @dt_idle_states: Number of idle state entries * Returns 0 on success */ static int __init pnv_arch300_idle_init(struct device_node *np, u32 *flags, int dt_idle_states) { u64 *psscr_val = NULL; int rc = 0, i; psscr_val = kcalloc(dt_idle_states, sizeof(*psscr_val), GFP_KERNEL); if (!psscr_val) { rc = -1; goto out; } if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) { pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n"); rc = -1; goto out; } /* * Set pnv_first_deep_stop_state and pnv_deepest_stop_state. * pnv_first_deep_stop_state should be set to the first stop * level to cause hypervisor state loss. * pnv_deepest_stop_state should be set to the deepest stop * stop state. */ pnv_first_deep_stop_state = MAX_STOP_STATE; for (i = 0; i < dt_idle_states; i++) { u64 psscr_rl = psscr_val[i] & PSSCR_RL_MASK; if ((flags[i] & OPAL_PM_LOSE_FULL_CONTEXT) && (pnv_first_deep_stop_state > psscr_rl)) pnv_first_deep_stop_state = psscr_rl; if (pnv_deepest_stop_state < psscr_rl) pnv_deepest_stop_state = psscr_rl; } out: kfree(psscr_val); return rc; } /* * Probe device tree for supported idle states */ static void __init pnv_probe_idle_states(void) { struct device_node *np; int dt_idle_states; u32 *flags = NULL; int i; np = of_find_node_by_path("/ibm,opal/power-mgt"); if (!np) { pr_warn("opal: PowerMgmt Node not found\n"); goto out; } dt_idle_states = of_property_count_u32_elems(np, "ibm,cpu-idle-state-flags"); if (dt_idle_states < 0) { pr_warn("cpuidle-powernv: no idle states found in the DT\n"); goto out; } flags = kcalloc(dt_idle_states, sizeof(*flags), GFP_KERNEL); if (of_property_read_u32_array(np, "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n"); goto out; } if (cpu_has_feature(CPU_FTR_ARCH_300)) { if (pnv_arch300_idle_init(np, flags, dt_idle_states)) goto out; } for (i = 0; i < dt_idle_states; i++) supported_cpuidle_states |= flags[i]; out: kfree(flags); } static int __init pnv_init_idle_states(void) { supported_cpuidle_states = 0; if (cpuidle_disable != IDLE_NO_OVERRIDE) goto out; pnv_probe_idle_states(); if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) { patch_instruction( (unsigned int *)pnv_fastsleep_workaround_at_entry, PPC_INST_NOP); patch_instruction( (unsigned int *)pnv_fastsleep_workaround_at_exit, PPC_INST_NOP); } else { /* * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that * workaround is needed to use fastsleep. Provide sysfs * control to choose how this workaround has to be applied. */ device_create_file(cpu_subsys.dev_root, &dev_attr_fastsleep_workaround_applyonce); } pnv_alloc_idle_core_states(); if (supported_cpuidle_states & OPAL_PM_NAP_ENABLED) ppc_md.power_save = power7_idle; else if (supported_cpuidle_states & OPAL_PM_STOP_INST_FAST) ppc_md.power_save = power9_idle; out: return 0; } machine_subsys_initcall(powernv, pnv_init_idle_states);