[PATCH v3 01/15] PM / Domains: Allow domain power states to be read from DT

Lina Iyer
2016-08-04T23:04:48Z

From: Axel Haslam <ahaslam+renesas@baylibre.com>

This patch allows domains to define idle states in the DT. SoC's can
define domain idle states in DT using the "domain-idle-states" property
of the domain provider. Calling of_pm_genpd_init() will read the idle
states and initialize the genpd for the domain.

In addition to the entry and exit latency for idle state, also add
residency_ns, param and of_node property to each state. A domain idling
in a state is only power effecient if it stays idle for a certain period
in that state. The residency provides this minimum time for the idle
state to provide power benefits. The param is a state specific u32 value
that the platform may use for that idle state.

Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Lina: Added state properties, removed state names, wakeup-latency,
added of_pm_genpd_init() API, pruned commit text]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[Ulf: Moved around code to make it compile properly, rebased on top of multiple
state support,changed to use pm_genpd_init()]
---
drivers/base/power/domain.c | 92 ++++++++++++++++++++++++++++++++++++++++++++-
include/linux/pm_domain.h | 11 +++++-
2 files changed, 101 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a1f2aff..3aecac3 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1253,6 +1253,90 @@ out:
}
EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);

+static const struct of_device_id arm_idle_state_match[] = {
+ { .compatible = "arm,idle-state", },
+ { }
+};
+
+static int genpd_of_get_power_state(struct genpd_power_state *genpd_state,
+ struct device_node *state_node)
+{
+ int err = 0;
+ u32 latency;
+ u32 residency;
+ u32 entry_latency, exit_latency;
+ const struct of_device_id *match_id;
+
+ match_id = of_match_node(arm_idle_state_match, state_node);
+ if (!match_id)
+ return -EINVAL;
+
+ err = of_property_read_u32(state_node, "entry-latency-us",
+ &entry_latency);
+ if (err) {
+ pr_debug(" * %s missing entry-latency-us property\n",
+ state_node->full_name);
+ return -EINVAL;
+ }
+
+ err = of_property_read_u32(state_node, "exit-latency-us",
+ &exit_latency);
+ if (err) {
+ pr_debug(" * %s missing exit-latency-us property\n",
+ state_node->full_name);
+ return -EINVAL;
+ }
+
+ err = of_property_read_u32(state_node, "min-residency-us", &residency);
+ if (!err)
+ genpd_state->residency_ns = 1000 * residency;
+
+ latency = entry_latency + exit_latency;
+ genpd_state->power_on_latency_ns = 1000 * latency;
+ genpd_state->power_off_latency_ns = 1000 * entry_latency;
+ genpd_state->of_node = state_node;
+
+ return 0;
+}
+
+int pm_genpd_of_parse_power_states(struct generic_pm_domain *genpd)
+{
+ struct device_node *np;
+ int i, err = 0;
+
+ for (i = 0; i < GENPD_MAX_NUM_STATES; i++) {
+ np = of_parse_phandle(genpd->of_node, "domain-idle-states", i);
+ if (!np)
+ break;
+
+ err = genpd_of_get_power_state(&genpd->states[i], np);
+ if (err) {
+ pr_err
+ ("Parsing idle state node %s failed with err %d\n",
+ np->full_name, err);
+ err = -EINVAL;
+ of_node_put(np);
+ break;
+ }
+ of_node_put(np);
+ }
+
+ if (err)
+ return err;
+
+ genpd->state_count = i;
+ return 0;
+}
+EXPORT_SYMBOL(pm_genpd_of_parse_power_states);
+
+static int genpd_of_parse(struct generic_pm_domain *genpd)
+{
+ if (!genpd->of_node || (genpd->state_count > 0))
+ return 0;
+
+ return pm_genpd_of_parse_power_states(genpd);
+}
+
/**
* pm_genpd_init - Initialize a generic I/O PM domain object.
* @genpd: PM domain object to initialize.
@@ -1262,8 +1346,10 @@ EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
* Returns 0 on successful initialization, else a negative error code.
*/
int pm_genpd_init(struct generic_pm_domain *genpd,
- struct dev_power_governor *gov, bool is_off)
+ struct dev_power_governor *gov, bool is_off)
{
+ int ret;
+
if (IS_ERR_OR_NULL(genpd))
return -EINVAL;

@@ -1306,6 +1392,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
genpd->dev_ops.start = pm_clk_resume;
}

+ ret = genpd_of_parse(genpd);
+ if (ret)
+ return ret;
+
if (genpd->state_idx >= GENPD_MAX_NUM_STATES) {
pr_warn("Initial state index out of bounds.\n");
genpd->state_idx = GENPD_MAX_NUM_STATES - 1;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 31fec85..c5d14b9 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -40,6 +40,9 @@ struct gpd_dev_ops {
struct genpd_power_state {
s64 power_off_latency_ns;
s64 power_on_latency_ns;
+ s64 residency_ns;
+ u32 param;
+ struct device_node *of_node;
};

struct generic_pm_domain {
@@ -51,6 +54,7 @@ struct generic_pm_domain {
struct mutex lock;
struct dev_power_governor *gov;
struct work_struct power_off_work;
+ struct device_node *of_node; /* Device node of the PM domain */
const char *name;
atomic_t sd_count; /* Number of subdomains with power "on" */
enum gpd_status status; /* Current state of the domain */
@@ -129,7 +133,7 @@ extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
struct generic_pm_domain *target);
extern int pm_genpd_init(struct generic_pm_domain *genpd,
struct dev_power_governor *gov, bool is_off);
-
+extern int pm_genpd_of_parse_power_states(struct generic_pm_domain *genpd);
extern struct dev_power_governor simple_qos_governor;
extern struct dev_power_governor pm_domain_always_on_gov;
#else
@@ -168,6 +172,11 @@ static inline int pm_genpd_init(struct generic_pm_domain *genpd,
{
return -ENOSYS;
}
+static inline int pm_genpd_of_parse_power_states(
+ struct generic_pm_domain *genpd)
+{
+ return -ENODEV;
+}
#endif

static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
--
2.7.4