PM / Domains: Support for multiple states
Some hardware (eg. OMAP), has the ability to enter different low power
modes for a given power domain. This allows for more fine grained control
over the power state of the platform. As a typical example, some registers
of the hardware may be implemented with retention flip-flops and be able
to retain their state at lower voltages allowing for faster on/off
latencies and an increased window of opportunity to enter an intermediate
low power state other than "off"
When trying to set a power domain to off, the genpd governor will choose
the deepest state that will respect the qos constraints of all the devices
and sub-domains on the power domain. The state chosen by the governor is
saved in the "state_idx" field of the generic_pm_domain structure and
shall be used by the power_off and power_on callbacks to perform the
necessary actions to set the power domain into (and out of) the state
indicated by state_idx.
States must be declared in ascending order from shallowest to deepest,
deepest meaning the state which takes longer to enter and exit.
For platforms that don't declare any states, a single a single "off"
state is used. Once all platforms are converted to use the state array,
the legacy on/off latencies will be removed.
[ Lina: Modified genpd state initialization and remove use of
save_state_latency_ns in genpd timing data ]
Suggested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Axel Haslam <ahaslam+renesas@baylibre.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index db21d39..1726c4a 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -19,6 +19,8 @@
/* Defines used for the flags field in the struct generic_pm_domain */
#define GENPD_FLAG_PM_CLK (1U << 0) /* PM domain uses PM clk */
+#define GENPD_MAX_NUM_STATES 8 /* Number of possible low power states */
+
enum gpd_status {
GPD_STATE_ACTIVE = 0, /* PM domain is active */
GPD_STATE_POWER_OFF, /* PM domain is off */
@@ -37,6 +39,11 @@
bool (*active_wakeup)(struct device *dev);
};
+struct genpd_power_state {
+ s64 power_off_latency_ns;
+ s64 power_on_latency_ns;
+};
+
struct generic_pm_domain {
struct dev_pm_domain domain; /* PM domain operations */
struct list_head gpd_list_node; /* Node in the global PM domains list */
@@ -66,6 +73,10 @@
void (*detach_dev)(struct generic_pm_domain *domain,
struct device *dev);
unsigned int flags; /* Bit field of configs for genpd */
+ struct genpd_power_state states[GENPD_MAX_NUM_STATES];
+ unsigned int state_count; /* number of states */
+ unsigned int state_idx; /* state that genpd will go to when off */
+
};
static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)