diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/idle.c')
-rw-r--r-- | arch/powerpc/platforms/powernv/idle.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index 5c799324b695..bd39a120bd60 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c @@ -13,6 +13,8 @@ #include <linux/mm.h> #include <linux/slab.h> #include <linux/of.h> +#include <linux/device.h> +#include <linux/cpu.h> #include <asm/firmware.h> #include <asm/opal.h> @@ -137,6 +139,96 @@ u32 pnv_get_supported_cpuidle_states(void) } 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 atleast 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); + static int __init pnv_init_idle_states(void) { struct device_node *power_mgt; @@ -181,7 +273,16 @@ static int __init pnv_init_idle_states(void) 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(); out_free: kfree(flags); |