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.
This patch is based on the original patch by Marc Titinger.
Signed-off-by: Marc Titinger <mtitinger+renesas@xxxxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
---
drivers/base/power/domain.c | 103 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/pm_domain.h | 8 ++++
2 files changed, 111 insertions(+)
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 740afa9..368a5b8 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1895,6 +1895,109 @@ out:
return ret ? -EPROBE_DEFER : 0;
}
EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
+
+static const struct of_device_id idle_state_match[] = {
+ { .compatible = "arm,idle-state", },
+ { }
+};
+
+static int read_genpd_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(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;
+
+ return 0;
+}
+
+/**
+ * of_genpd_parse_idle_states: Return array of idle states for the genpd.
+ *
+ * @dn: The genpd device node
+ * @states: The pointer to which the state array will be saved.
+ * @n: The count of elements in the array returned from this function.
+ *
+ * Returns the device states parsed from the OF node. The memory for the states
+ * is allocated by this function and is the responsibility of the caller to
+ * free the memory after use.
+ */
+int of_genpd_parse_idle_states(struct device_node *dn,
+ struct genpd_power_state **states, int *n)
+{
+ struct genpd_power_state *st;
+ struct device_node *np;
+ int i, ret = 0;
+ int count;
+
+ for (count = 0; ; count++)
+ if (!of_parse_phandle(dn, "domain-idle-states", count))
+ break;
+
+ st = kcalloc(count, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ for (i = 0; i < count; i++) {
+ np = of_parse_phandle(dn, "domain-idle-states", i);
+ if (!np) {
+ ret = -EFAULT;
+ break;
+ }
+
+ ret = read_genpd_state(&st[i], np);
+ if (ret) {
+ pr_err
+ ("Parsing idle state node %s failed with err %d\n",
+ np->full_name, ret);
+ of_node_put(np);
+ break;
+ }
+ of_node_put(np);
+ }
+
+ if (ret) {
+ kfree(st);
+ return ret;
+ }
+
+ *n = count;
+ *states = st;
+
+ return 0;
+}
+EXPORT_SYMBOL(of_genpd_parse_idle_states);
+
#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index c113713..4c9152d 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -204,6 +204,8 @@ extern int of_genpd_add_device(struct of_phandle_args *args,
extern int of_genpd_add_subdomain(struct of_phandle_args *parent,
struct of_phandle_args *new_subdomain);
extern struct generic_pm_domain *of_genpd_remove_last(struct device_node *np);
+extern int of_genpd_parse_idle_states(struct device_node *dn,
+ struct genpd_power_state **states, int *n);
int genpd_dev_pm_attach(struct device *dev);
#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
@@ -233,6 +235,12 @@ static inline int of_genpd_add_subdomain(struct of_phandle_args *parent,
return -ENODEV;
}
+static inline int of_genpd_parse_idle_states(struct device_node *dn,
+ struct genpd_power_state **states, int *n)
+{
+ return -ENODEV;
+}
+
static inline int genpd_dev_pm_attach(struct device *dev)
{
return -ENODEV;
--
2.7.4
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