OPP: Populate required opp tables from "required-opps" property

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.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index ebb3b648e0fd882fd9b8c3414a7bda58416d457b..85174a5c48507220c637798bb4f31bce9108a166 100644 (file)
--- 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 5f114cd3d88c4aa49cf86b1e82dff9e782fa0b60..b5605196122af0e41f3aa052e9f5a8cb0b3fe0c6 100644 (file)
--- 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 cdb0c2b095e2fecebc450725fbc5fa4ab93d3b1b..024e1be23d3749a434ecb1ff75f3d31ef76da9d7 100644 (file)
--- 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