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-rw-r--r--arch/powerpc/platforms/powernv/idle.c293
1 files changed, 293 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
new file mode 100644
index 000000000000..59d735d2e5c0
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -0,0 +1,293 @@
+/*
+ * 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 <linux/types.h>
+#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/machdep.h>
+#include <asm/opal.h>
+#include <asm/cputhreads.h>
+#include <asm/cpuidle.h>
+#include <asm/code-patching.h>
+#include <asm/smp.h>
+
+#include "powernv.h"
+#include "subcore.h"
+
+static u32 supported_cpuidle_states;
+
+int pnv_save_sprs_for_winkle(void)
+{
+ int cpu;
+ int rc;
+
+ /*
+ * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric accross
+ * all cpus at boot. Get these reg values of current cpu and use the
+ * same accross 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];
+
+ /*
+ * 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.
+ */
+ 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_WINKLE_ENABLED)
+ pnv_save_sprs_for_winkle();
+}
+
+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 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;
+ int dt_idle_states;
+ u32 *flags;
+ int i;
+
+ supported_cpuidle_states = 0;
+
+ if (cpuidle_disable != IDLE_NO_OVERRIDE)
+ goto out;
+
+ if (!firmware_has_feature(FW_FEATURE_OPALv3))
+ goto out;
+
+ power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
+ if (!power_mgt) {
+ pr_warn("opal: PowerMgmt Node not found\n");
+ goto out;
+ }
+ dt_idle_states = of_property_count_u32_elems(power_mgt,
+ "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 = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
+ if (of_property_read_u32_array(power_mgt,
+ "ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
+ pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
+ goto out_free;
+ }
+
+ for (i = 0; i < dt_idle_states; i++)
+ supported_cpuidle_states |= flags[i];
+
+ 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();
+out_free:
+ kfree(flags);
+out:
+ return 0;
+}
+machine_subsys_initcall(powernv, pnv_init_idle_states);