From: Jean Pihet <j-pihet@xxxxxx>
When a PM QoS device latency constraint is requested or removed the
PM QoS layer notifies the underlying layer with the updated aggregated
constraint value. The constraint is stored in the powerdomain constraints
list and then applied to the corresponding power domain.
The power domains get the next power state programmed directly in the
registers via pwrdm_wakeuplat_update_pwrst.
Tested on OMAP3 Beagleboard and OMAP4 Pandaboard in RET/OFF using
wake-up latency constraints on MPU, CORE and PER.
Signed-off-by: Jean Pihet <j-pihet@xxxxxx>
---
arch/arm/mach-omap2/powerdomain.c | 245 +++++++++++++++++++++++++++++++++++++
arch/arm/mach-omap2/powerdomain.h | 36 +++++-
2 files changed, 279 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 8a18d1b..677a182 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -17,8 +17,10 @@
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
+#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/string.h>
+#include <linux/pm_qos.h>
#include <trace/events/power.h>
#include "cm2xxx_3xxx.h"
@@ -112,6 +114,12 @@ static int _pwrdm_register(struct powerdomain *pwrdm)
for (i = 0; i < pwrdm->banks; i++)
pwrdm->ret_mem_off_counter[i] = 0;
+ /* Initialize the per-device wake-up constraints framework data */
+ spin_lock_init(&pwrdm->wkup_lat_plist_lock);
+ plist_head_init(&pwrdm->wkup_lat_plist_head);
+ pwrdm->wkup_lat_next_state = PWRDM_POWER_OFF;
+
+ /* Initialize the pwrdm state */
pwrdm_wait_transition(pwrdm);
pwrdm->state = pwrdm_read_pwrst(pwrdm);
pwrdm->state_counter[pwrdm->state] = 1;
@@ -199,6 +207,158 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
return 0;
}
+/**
+ * _pwrdm_wakeuplat_update_list - Set/update/remove a powerdomain wakeup
+ * latency constraint from the pwrdm's constraint list
+ * @pwrdm: struct powerdomain * which the constraint applies to
+ * @cookie: constraint identifier, used for tracking.
+ * @min_latency: minimum wakeup latency constraint (in microseconds) for
+ * the given pwrdm. The value of PM_QOS_DEV_LAT_DEFAULT_VALUE removes
+ * the constraint.
+ * @user: pointer to the current list entry
+ * @new_user: allocated list entry, used for insertion of new constraints
+ * in the list
+ * @free_new_user: set to non-zero if the newly allocated list entry
+ * is unused and needs to be freed
+ * @free_node: set to non-zero if the current list entry is not in use
+ * anymore and needs to be freed
+ *
+ * Tracks the constraints by @cookie.
+ * Constraint set/update: Adds a new entry to powerdomain's wake-up latency
+ * constraint list.
+ * If the constraint identifier already exists in the list, the old value is
+ * overwritten.
+ * Constraint removal: Removes the identifier's entry from powerdomain's
+ * wakeup latency constraint list.
+ *
+ * Called with the pwrdm wakeup latency spinlock held.
+ *
+ * Returns 0 upon success, -EINVAL if the constraint is not existing.
+ */
+static inline int _pwrdm_update_wakeuplat_list(
+ struct powerdomain *pwrdm,
+ void *cookie,
+ long min_latency,
+ struct pwrdm_wkup_constraints_entry *user,
+ struct pwrdm_wkup_constraints_entry *new_user,
+ int *free_new_user,
+ int *free_node)
+{
+ struct pwrdm_wkup_constraints_entry *tmp_user;
+
+ /* Check if there already is a constraint for cookie */
+ plist_for_each_entry(tmp_user, &pwrdm->wkup_lat_plist_head, node) {
+ if (tmp_user->cookie == cookie) {
+ user = tmp_user;
+ break;
+ }
+ }
+
+ if (min_latency != PM_QOS_DEV_LAT_DEFAULT_VALUE) {
+ /* If nothing to update, job done */
+ if (user && (user->node.prio == min_latency))
+ return 0;
+
+ if (!user) {
+ /* Add new entry to the list */
+ user = new_user;
+ user->cookie = cookie;
+ *free_new_user = 0;
+ } else {
+ /* Update existing entry */
+ plist_del(&user->node, &pwrdm->wkup_lat_plist_head);
+ }
+
+ plist_node_init(&user->node, min_latency);
+ plist_add(&user->node, &pwrdm->wkup_lat_plist_head);
+ } else {
+ if (user) {
+ /* Remove the constraint from the list */
+ plist_del(&user->node, &pwrdm->wkup_lat_plist_head);
+ *free_node = 1;
+ } else {
+ /* Constraint not existing or list empty, do nothing */
+ return -EINVAL;
+ }
+
+ }
+
+ return 0;
+}
+
+/**
+ * _pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
+ * @pwrdm: struct powerdomain * to which requesting device belongs to.
+ * @min_latency: the allowed wake-up latency for the given power domain. A
+ * value of PM_QOS_DEV_LAT_DEFAULT_VALUE means 'no constraint' on the pwrdm.
+ *
+ * Finds the power domain next power state that fulfills the constraint.
+ * Programs a new target state if it is different from current power state.
+ * The power domains get the next power state programmed directly in the
+ * registers.
+ *
+ * Returns 0 in case of success, -EINVAL in case of invalid parameters,
+ * or the return value from omap_set_pwrdm_state.
+ */
+static int _pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm,
+ long min_latency)
+{
+ int ret = 0, new_state;
+
+ if (!pwrdm) {
+ WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
+ return -EINVAL;
+ }
+
+ /*
+ * Find the next supported power state with
+ * wakeup latency < minimum constraint
+ */
+ for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
+ if (min_latency == PM_QOS_DEV_LAT_DEFAULT_VALUE)
+ break;
+ if ((pwrdm->wakeup_lat[new_state] != UNSUP_STATE) &&
+ (pwrdm->wakeup_lat[new_state] <= min_latency))
+ break;
+ }
+
+ switch (new_state) {
+ case PWRDM_FUNC_PWRST_OFF:
+ new_state = PWRDM_POWER_OFF;
+ break;
+ case PWRDM_FUNC_PWRST_OSWR:
+ pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
+ new_state = PWRDM_POWER_RET;
+ break;
+ case PWRDM_FUNC_PWRST_CSWR:
+ pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
+ new_state = PWRDM_POWER_RET;
+ break;
+ case PWRDM_FUNC_PWRST_INACTIVE:
+ new_state = PWRDM_POWER_INACTIVE;
+ break;
+ case PWRDM_FUNC_PWRST_ON:
+ new_state = PWRDM_POWER_ON;
+ break;
+ default:
+ pr_warn("powerdomain: requested latency constraint not "
+ "supported %s set to ON state\n", pwrdm->name);
+ new_state = PWRDM_POWER_ON;
+ break;
+ }
+
+ pwrdm->wkup_lat_next_state = new_state;
+ if (pwrdm_read_next_pwrst(pwrdm) != new_state)
+ ret = omap_set_pwrdm_state(pwrdm, new_state);
+
+ pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
+ "min_latency=%ld, set_state=%d\n", pwrdm->name,
+ pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
+ pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
+
+ return ret;
+}
+
/* Public functions */
/**
@@ -998,6 +1158,91 @@ int pwrdm_post_transition(void)
}
/**
+ * pwrdm_set_wkup_lat_constraint - Set/update/remove a powerdomain wakeup
+ * latency constraint and apply it
+ * @pwrdm: struct powerdomain * which the constraint applies to
+ * @cookie: constraint identifier, used for tracking.
+ * @min_latency: minimum wakeup latency constraint (in microseconds) for
+ * the given pwrdm. The value of PM_QOS_DEV_LAT_DEFAULT_VALUE removes
+ * the constraint.
+ *
+ * Tracks the constraints by @cookie.
+ * Constraint set/update: Adds a new entry to powerdomain's wake-up latency
+ * constraint list.
+ * If the constraint identifier already exists in the list, the old value is
+ * overwritten.
+ * Constraint removal: Removes the identifier's entry from powerdomain's
+ * wakeup latency constraint list.
+ *
+ * Applies the aggregated constraint value for the given pwrdm by calling
+ * _pwrdm_wakeuplat_update_pwrst.
+ *
+ * Returns 0 upon success, -ENOMEM in case of memory shortage, -EINVAL in
+ * case of invalid parameters, or the return value from
+ * _pwrdm_wakeuplat_update_pwrst.
+ *
+ * The caller must check the validity of the parameters.
+ *
+ * Note about the resources allocation and release:
+ * The free_new_user and free_node variables are used to indicate
+ * if the allocated resources can be freed, respectively for the
+ * newly allocated list entry and the current list entry.
+ * Cf. kerneldoc for the _pwrdm_update_wakeuplat_list function for
+ * detailed information about those variables and the
+ * allocation and release of the constraints list entries.
+ */
+int pwrdm_set_wkup_lat_constraint(struct powerdomain *pwrdm, void *cookie,
+ long min_latency)
+{
+ struct pwrdm_wkup_constraints_entry *user = NULL, *new_user = NULL;
+ int ret = 0, free_new_user = 0, free_node = 0;
+ long value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ unsigned long flags;
+
+ pr_debug("powerdomain: %s: pwrdm %s, cookie=0x%p, min_latency=%ld\n",
+ __func__, pwrdm->name, cookie, min_latency);
+
+ if (min_latency != PM_QOS_DEV_LAT_DEFAULT_VALUE) {
+ new_user = kzalloc(sizeof(struct pwrdm_wkup_constraints_entry),
+ GFP_KERNEL);
+ if (!new_user) {
+ pr_err("%s: FATAL ERROR: kzalloc failed\n", __func__);
+ return -ENOMEM;
+ }
+ free_new_user = 1;
+ }
+
+ spin_lock_irqsave(&pwrdm->wkup_lat_plist_lock, flags);
+
+ /* Manage the constraints list */
+ ret = _pwrdm_update_wakeuplat_list(pwrdm, cookie, min_latency,
+ user, new_user,
+ &free_new_user, &free_node);
+
+ /* Find the aggregated constraint value from the list */
+ if (!ret)
+ if (!plist_head_empty(&pwrdm->wkup_lat_plist_head))
+ value = plist_first(&pwrdm->wkup_lat_plist_head)->prio;
+
+ spin_unlock_irqrestore(&pwrdm->wkup_lat_plist_lock, flags);
+
+ if (free_node)
+ kfree(user);
+
+ if (free_new_user)
+ kfree(new_user);
+
+ /* Apply the constraint to the pwrdm */
+ if (!ret) {
+ pr_debug("powerdomain: %s: pwrdm %s, value=%ld\n",
+ __func__, pwrdm->name, value);
+ ret = _pwrdm_wakeuplat_update_pwrst(pwrdm, value);
+ }
+
+ return ret;
+}
+
+/**
* pwrdm_get_context_loss_count - get powerdomain's context loss count
* @pwrdm: struct powerdomain * to wait for
*
diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
index 0d72a8a..b4a60cf 100644
--- a/arch/arm/mach-omap2/powerdomain.h
+++ b/arch/arm/mach-omap2/powerdomain.h
@@ -19,7 +19,9 @@
#include <linux/types.h>
#include <linux/list.h>
-
+#include <linux/plist.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <plat/cpu.h>
@@ -45,6 +47,16 @@
#define PWRSTS_RET_ON (PWRSTS_RET | PWRSTS_ON)
#define PWRSTS_OFF_RET_ON (PWRSTS_OFF_RET | PWRSTS_ON)
+/* Powerdomain functional power states */
+#define PWRDM_FUNC_PWRST_OFF 0x0
+#define PWRDM_FUNC_PWRST_OSWR 0x1
+#define PWRDM_FUNC_PWRST_CSWR 0x2
+#define PWRDM_FUNC_PWRST_INACTIVE 0x3
+#define PWRDM_FUNC_PWRST_ON 0x4
+
+#define PWRDM_MAX_FUNC_PWRSTS 5
+
+#define UNSUP_STATE -1
/* Powerdomain flags */
#define PWRDM_HAS_HDWR_SAR (1 << 0) /* hardware save-and-restore support */
@@ -96,7 +108,13 @@ struct powerdomain;
* @state_counter:
* @timer:
* @state_timer:
- *
+ * @wakeup_lat: wakeup latencies (in us) for possible powerdomain power states
+ * Note about the wakeup latencies ordering: the values must be sorted
+ * in decremental order
+ * @wkup_lat_plist_head: pwrdm wake-up latency constraints list
+ * @wkup_lat_plist_lock: spinlock that protects the constraints lists
+ * domains states
+ * @wkup_lat_next_state: next pwrdm state, calculated from the constraints list
* @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
*/
struct powerdomain {
@@ -125,6 +143,16 @@ struct powerdomain {
s64 timer;
s64 state_timer[PWRDM_MAX_PWRSTS];
#endif
+ const s32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
+ struct plist_head wkup_lat_plist_head;
+ spinlock_t wkup_lat_plist_lock;
+ int wkup_lat_next_state;
+};
+
+/* Linked list for the wake-up latency constraints */
+struct pwrdm_wkup_constraints_entry {
+ void *cookie;
+ struct plist_node node;
};
/**
@@ -217,6 +245,10 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
int pwrdm_pre_transition(void);
int pwrdm_post_transition(void);
int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
+
+int pwrdm_set_wkup_lat_constraint(struct powerdomain *pwrdm, void *cookie,
+ long min_latency);
+
int pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
bool pwrdm_can_ever_lose_context(struct powerdomain *pwrdm);
--
1.7.5.4
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