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Subject[PATCH V2 3/9] OPP: Populate required opp tables from "required-opps" property
Date
The current implementation works only for the case where a single
phandle is present in the "required-opps" property, while DT allows
multiple phandles to be present there.

This patch adds new infrastructure to parse all the phandles present in
"required-opps" property and save pointers of the required OPP's OPP
tables. These will be used by later commits.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/opp/core.c | 2 +
drivers/opp/of.c | 147 +++++++++++++++++++++++++++++++++++++++++++++
drivers/opp/opp.h | 8 +++
3 files changed, 157 insertions(+)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index ebb3b648e0fd..85174a5c4850 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -901,6 +901,8 @@ static void _opp_table_kref_release(struct kref *kref)
struct opp_table *opp_table = container_of(kref, struct opp_table, kref);
struct opp_device *opp_dev, *temp;

+ _of_clear_opp_table(opp_table);
+
/* Release clk */
if (!IS_ERR(opp_table->clk))
clk_put(opp_table->clk);
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 5f114cd3d88c..b5605196122a 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -73,6 +73,147 @@ struct opp_table *_managed_opp(struct device *dev, int index)
return managed_table;
}

+/* The caller must call dev_pm_opp_put() after the OPP is used */
+static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
+ struct device_node *opp_np)
+{
+ struct dev_pm_opp *opp;
+
+ lockdep_assert_held(&opp_table_lock);
+
+ mutex_lock(&opp_table->lock);
+
+ list_for_each_entry(opp, &opp_table->opp_list, node) {
+ if (opp->np == opp_np) {
+ dev_pm_opp_get(opp);
+ mutex_unlock(&opp_table->lock);
+ return opp;
+ }
+ }
+
+ mutex_unlock(&opp_table->lock);
+
+ return NULL;
+}
+
+static struct device_node *of_parse_required_opp(struct device_node *np,
+ int index)
+{
+ struct device_node *required_np;
+
+ required_np = of_parse_phandle(np, "required-opps", index);
+ if (unlikely(!required_np)) {
+ pr_err("%s: Unable to parse required-opps: %pOF, index: %d\n",
+ __func__, np, index);
+ }
+
+ return required_np;
+}
+
+/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
+static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
+{
+ struct opp_table *opp_table;
+ struct dev_pm_opp *opp;
+
+ lockdep_assert_held(&opp_table_lock);
+
+ list_for_each_entry(opp_table, &opp_tables, node) {
+ opp = _find_opp_of_np(opp_table, opp_np);
+ if (opp) {
+ dev_pm_opp_put(opp);
+ _get_opp_table_kref(opp_table);
+ return opp_table;
+ }
+ }
+
+ return ERR_PTR(-ENODEV);
+}
+
+/* Free resources previously acquired by _opp_table_alloc_required_tables() */
+static void _opp_table_free_required_tables(struct opp_table *opp_table)
+{
+ struct opp_table **required_opp_tables = opp_table->required_opp_tables;
+ int i;
+
+ if (!required_opp_tables)
+ return;
+
+ for (i = 0; i < opp_table->required_opp_count; i++) {
+ if (IS_ERR_OR_NULL(required_opp_tables[i]))
+ break;
+
+ dev_pm_opp_put_opp_table(required_opp_tables[i]);
+ }
+
+ kfree(required_opp_tables);
+
+ opp_table->required_opp_count = 0;
+ opp_table->required_opp_tables = NULL;
+}
+
+/*
+ * Populate all devices and opp tables which are part of "required-opps" list.
+ * Checking only the first OPP node should be enough.
+ */
+static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
+ struct device *dev,
+ struct device_node *opp_np)
+{
+ struct opp_table **required_opp_tables;
+ struct device_node *required_np, *np;
+ int count, i;
+
+ /* Traversing the first OPP node is all we need */
+ np = of_get_next_available_child(opp_np, NULL);
+ if (!np) {
+ dev_err(dev, "Empty OPP table\n");
+ return;
+ }
+
+ count = of_count_phandle_with_args(np, "required-opps", NULL);
+ if (!count)
+ goto put_np;
+
+ required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
+ GFP_KERNEL);
+ if (!required_opp_tables)
+ goto put_np;
+
+ opp_table->required_opp_tables = required_opp_tables;
+ opp_table->required_opp_count = count;
+
+ for (i = 0; i < count; i++) {
+ required_np = of_parse_required_opp(np, i);
+ if (!required_np)
+ goto free_required_tables;
+
+ required_opp_tables[i] = _find_table_of_opp_np(required_np);
+ of_node_put(required_np);
+
+ if (IS_ERR(required_opp_tables[i]))
+ goto free_required_tables;
+
+ /*
+ * We only support genpd's OPPs in the "required-opps" for now,
+ * as we don't know how much about other cases. Error out if the
+ * required OPP doesn't belong to a genpd.
+ */
+ if (!required_opp_tables[i]->is_genpd) {
+ dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
+ required_np);
+ goto free_required_tables;
+ }
+ }
+
+ goto put_np;
+
+free_required_tables:
+ _opp_table_free_required_tables(opp_table);
+put_np:
+ of_node_put(np);
+}
+
void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
int index)
{
@@ -109,9 +250,15 @@ void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,

opp_table->np = opp_np;

+ _opp_table_alloc_required_tables(opp_table, dev, opp_np);
of_node_put(opp_np);
}

+void _of_clear_opp_table(struct opp_table *opp_table)
+{
+ _opp_table_free_required_tables(opp_table);
+}
+
static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
struct device_node *np)
{
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index cdb0c2b095e2..024e1be23d37 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -133,6 +133,9 @@ enum opp_table_access {
* @parsed_static_opps: True if OPPs are initialized from DT.
* @shared_opp: OPP is shared between multiple devices.
* @suspend_opp: Pointer to OPP to be used during device suspend.
+ * @required_opp_tables: List of device OPP tables that are required by OPPs in
+ * this table.
+ * @required_opp_count: Number of required devices.
* @supported_hw: Array of version number to support.
* @supported_hw_count: Number of elements in supported_hw array.
* @prop_name: A name to postfix to many DT properties, while parsing them.
@@ -172,6 +175,9 @@ struct opp_table {
enum opp_table_access shared_opp;
struct dev_pm_opp *suspend_opp;

+ struct opp_table **required_opp_tables;
+ unsigned int required_opp_count;
+
unsigned int *supported_hw;
unsigned int supported_hw_count;
const char *prop_name;
@@ -208,9 +214,11 @@ void _put_opp_list_kref(struct opp_table *opp_table);

#ifdef CONFIG_OF
void _of_init_opp_table(struct opp_table *opp_table, struct device *dev, int index);
+void _of_clear_opp_table(struct opp_table *opp_table);
struct opp_table *_managed_opp(struct device *dev, int index);
#else
static inline void _of_init_opp_table(struct opp_table *opp_table, struct device *dev, int index) {}
+static inline void _of_clear_opp_table(struct opp_table *opp_table) {}
static inline struct opp_table *_managed_opp(struct device *dev, int index) { return NULL; }
#endif

--
2.18.0.rc1.242.g61856ae69a2c
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