![Preeti U Murthy](/assets/img/avatar_default.png)
We currently read the information about idle states from the DT so as to populate the cpuidle table. Use those APIs to read from the DT that can avoid endianness conversions of the property values in the cpuidle driver. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
282 lines
6.6 KiB
C
282 lines
6.6 KiB
C
/*
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* cpuidle-powernv - idle state cpuidle driver.
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* Adapted from drivers/cpuidle/cpuidle-pseries
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <linux/cpuidle.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <linux/clockchips.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <asm/machdep.h>
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#include <asm/firmware.h>
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#include <asm/opal.h>
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#include <asm/runlatch.h>
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#define MAX_POWERNV_IDLE_STATES 8
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struct cpuidle_driver powernv_idle_driver = {
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.name = "powernv_idle",
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.owner = THIS_MODULE,
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};
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static int max_idle_state;
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static struct cpuidle_state *cpuidle_state_table;
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static int snooze_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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local_irq_enable();
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set_thread_flag(TIF_POLLING_NRFLAG);
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ppc64_runlatch_off();
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while (!need_resched()) {
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HMT_low();
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HMT_very_low();
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}
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HMT_medium();
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ppc64_runlatch_on();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb();
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return index;
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}
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static int nap_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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ppc64_runlatch_off();
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power7_idle();
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ppc64_runlatch_on();
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return index;
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}
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static int fastsleep_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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unsigned long old_lpcr = mfspr(SPRN_LPCR);
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unsigned long new_lpcr;
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if (unlikely(system_state < SYSTEM_RUNNING))
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return index;
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new_lpcr = old_lpcr;
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/* Do not exit powersave upon decrementer as we've setup the timer
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* offload.
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*/
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new_lpcr &= ~LPCR_PECE1;
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mtspr(SPRN_LPCR, new_lpcr);
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power7_sleep();
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mtspr(SPRN_LPCR, old_lpcr);
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return index;
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}
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/*
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* States for dedicated partition case.
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*/
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static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
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{ /* Snooze */
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.name = "snooze",
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.desc = "snooze",
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.exit_latency = 0,
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.target_residency = 0,
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.enter = &snooze_loop },
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};
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static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
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unsigned long action, void *hcpu)
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{
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int hotcpu = (unsigned long)hcpu;
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struct cpuidle_device *dev =
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per_cpu(cpuidle_devices, hotcpu);
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if (dev && cpuidle_get_driver()) {
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switch (action) {
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case CPU_ONLINE:
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case CPU_ONLINE_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_enable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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case CPU_DEAD:
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case CPU_DEAD_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_disable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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default:
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return NOTIFY_DONE;
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}
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}
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return NOTIFY_OK;
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}
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static struct notifier_block setup_hotplug_notifier = {
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.notifier_call = powernv_cpuidle_add_cpu_notifier,
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};
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/*
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* powernv_cpuidle_driver_init()
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*/
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static int powernv_cpuidle_driver_init(void)
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{
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int idle_state;
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struct cpuidle_driver *drv = &powernv_idle_driver;
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drv->state_count = 0;
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for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
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/* Is the state not enabled? */
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if (cpuidle_state_table[idle_state].enter == NULL)
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continue;
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drv->states[drv->state_count] = /* structure copy */
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cpuidle_state_table[idle_state];
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drv->state_count += 1;
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}
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return 0;
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}
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static int powernv_add_idle_states(void)
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{
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struct device_node *power_mgt;
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int nr_idle_states = 1; /* Snooze */
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int dt_idle_states;
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u32 *latency_ns, *residency_ns, *flags;
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int i, rc;
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/* Currently we have snooze statically defined */
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power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
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if (!power_mgt) {
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pr_warn("opal: PowerMgmt Node not found\n");
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goto out;
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}
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/* Read values of any property to determine the num of idle states */
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dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");
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if (dt_idle_states < 0) {
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pr_warn("cpuidle-powernv: no idle states found in the DT\n");
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goto out;
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}
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flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL);
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if (of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-flags", flags, dt_idle_states)) {
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pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
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goto out_free_flags;
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}
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latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
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rc = of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
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if (rc) {
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pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
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goto out_free_latency;
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}
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residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
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rc = of_property_read_u32_array(power_mgt,
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"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
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for (i = 0; i < dt_idle_states; i++) {
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/*
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* Cpuidle accepts exit_latency and target_residency in us.
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* Use default target_residency values if f/w does not expose it.
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*/
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if (flags[i] & OPAL_PM_NAP_ENABLED) {
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/* Add NAP state */
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strcpy(powernv_states[nr_idle_states].name, "Nap");
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strcpy(powernv_states[nr_idle_states].desc, "Nap");
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powernv_states[nr_idle_states].flags = 0;
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powernv_states[nr_idle_states].target_residency = 100;
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powernv_states[nr_idle_states].enter = &nap_loop;
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} else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
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flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
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/* Add FASTSLEEP state */
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strcpy(powernv_states[nr_idle_states].name, "FastSleep");
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strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
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powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
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powernv_states[nr_idle_states].target_residency = 300000;
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powernv_states[nr_idle_states].enter = &fastsleep_loop;
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}
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powernv_states[nr_idle_states].exit_latency =
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((unsigned int)latency_ns[i]) / 1000;
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if (!rc) {
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powernv_states[nr_idle_states].target_residency =
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((unsigned int)residency_ns[i]) / 1000;
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}
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nr_idle_states++;
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}
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kfree(residency_ns);
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out_free_latency:
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kfree(latency_ns);
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out_free_flags:
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kfree(flags);
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out:
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return nr_idle_states;
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}
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/*
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* powernv_idle_probe()
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* Choose state table for shared versus dedicated partition
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*/
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static int powernv_idle_probe(void)
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{
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if (cpuidle_disable != IDLE_NO_OVERRIDE)
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return -ENODEV;
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if (firmware_has_feature(FW_FEATURE_OPALv3)) {
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cpuidle_state_table = powernv_states;
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/* Device tree can indicate more idle states */
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max_idle_state = powernv_add_idle_states();
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} else
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return -ENODEV;
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return 0;
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}
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static int __init powernv_processor_idle_init(void)
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{
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int retval;
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retval = powernv_idle_probe();
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if (retval)
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return retval;
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powernv_cpuidle_driver_init();
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retval = cpuidle_register(&powernv_idle_driver, NULL);
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if (retval) {
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printk(KERN_DEBUG "Registration of powernv driver failed.\n");
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return retval;
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}
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register_cpu_notifier(&setup_hotplug_notifier);
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printk(KERN_DEBUG "powernv_idle_driver registered\n");
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return 0;
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}
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device_initcall(powernv_processor_idle_init);
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