[PM-WIP-OPP][PATCH 3/4] omap: pm: opp: add ability to store data per opp

[Nishanth Menon <nm@ti.com>]

Many modules seem to need some sort of flexible storage mechanism
which is corresponds to a specific opp. To cater to this need, we
provide store, restore and removal apis.

Cc: Ambresh K <ambresh@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Eduardo Valentin <eduardo.valentin@nokia.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Sanjeev Premi <premi@ti.com>
Cc: Tero Kristo <tero.kristo@nokia.com>
Cc: Thara Gopinath <thara@ti.com>

Signed-off-by: Nishanth Menon <nm@ti.com>
---
 arch/arm/plat-omap/include/plat/opp.h |   56 ++++++++++++++++++++++++++++
 arch/arm/plat-omap/opp.c              |   66 +++++++++++++++++++++++++++++++++
 2 files changed, 122 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/opp.h b/arch/arm/plat-omap/include/plat/opp.h
index dc9a0d9..666c514 100644
--- a/arch/arm/plat-omap/include/plat/opp.h
+++ b/arch/arm/plat-omap/include/plat/opp.h
@@ -231,6 +231,47 @@ struct omap_opp * __deprecated opp_find_by_opp_id(enum opp_t opp_type,
 						  u8 opp_id);
 u8 __deprecated opp_get_opp_id(struct omap_opp *opp);
 
+/**
+ * opp_store_data() - Store a data corresponding to an opp
+ * @opp: opp where to store
+ * @name: unique string to identify the type of data stored
+ * @data: The pointer which is used to the actual data
+ *
+ * Many scenarios require a custom data to be stored corresponding to a
+ * specific OPP which may need to be retrieved for operations. The actual
+ * type of data might be very specific to a CPU, allowing opp layer to store
+ * any type or mixture of types of data to be adequately retrieved
+ * by corresponding modules which consume that data.
+ * typical examples are Smart reflex nTarget values, L3 threshold dependencies
+ *
+ * Returns 0 if successful or a corresponding error value if failed.
+ */
+int opp_store_data(struct omap_opp *opp, char *name, void *data);
+
+/**
+ * opp_get_data() - get a stored data corresponding to an opp
+ * @opp: pointer to opp
+ * @name: unique string to identify the type of data stored
+ *
+ * Retrieve a stored data identified by the name allowing usage
+ * accross modules on a need basis
+ *
+ * Returns ERR_PTRs and should be checked with IS_ERR() macros
+ */
+void *opp_get_data(struct omap_opp *opp, char *name);
+
+/**
+ * opp_remove_data() - remove the stored data corresponding to an opp
+ * @opp: pointer to opp
+ * @name: unique string to identify the type of data stored
+ *
+ * Remove a stored data identified by the name allowing replacing
+ * old values with new or removing the information altogether if needed
+ *
+ * Returns 0 if successfully removed, else returns corresponding error value
+ */
+int opp_remove_data(struct omap_opp *opp, char *name);
+
 void opp_init_cpufreq_table(enum opp_t opp_type,
 			    struct cpufreq_frequency_table **table);
 #else
@@ -300,6 +341,21 @@ static inline u8 __deprecated opp_get_opp_id(struct omap_opp *opp)
 	return 0;
 }
 
+int opp_store_data(struct omap_opp *opp, char *name, void *data)
+{
+	return -EINVAL;
+}
+
+void *opp_get_data(struct omap_opp *opp, char *name)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+int opp_remove_data(struct omap_opp *opp, char *name)
+{
+	return -EINVAL;
+}
+
 static inline void opp_init_cpufreq_table(struct omap_opp *opps,
 			    struct cpufreq_frequency_table **table)
 {
diff --git a/arch/arm/plat-omap/opp.c b/arch/arm/plat-omap/opp.c
index bb8120e..15f6f7c 100644
--- a/arch/arm/plat-omap/opp.c
+++ b/arch/arm/plat-omap/opp.c
@@ -14,12 +14,19 @@
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
+#include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/cpufreq.h>
 
 #include <plat/opp_twl_tps.h>
 #include <plat/opp.h>
 
+struct omap_opp_data {
+	char *name;
+	void *data;
+	struct list_head list;
+};
+
 /**
  * struct omap_opp - OMAP OPP description structure
  * @enabled:	true/false - marking this OPP as enabled/disabled
@@ -37,6 +44,7 @@ struct omap_opp {
 	unsigned long rate;
 	unsigned long u_volt;
 	u8 opp_id;
+	struct list_head data_list;
 };
 
 /*
@@ -218,6 +226,7 @@ static void omap_opp_populate(struct omap_opp *opp,
 	opp->rate = opp_def->freq;
 	opp->enabled = opp_def->enabled;
 	opp->u_volt = opp_def->u_volt;
+	INIT_LIST_HEAD(&opp->data_list);
 }
 
 int opp_add(enum opp_t opp_type, const struct omap_opp_def *opp_def)
@@ -352,6 +361,63 @@ int opp_disable(struct omap_opp *opp)
 	return 0;
 }
 
+void *opp_get_data(struct omap_opp *opp, char *name)
+{
+	void *data = ERR_PTR(-EINVAL);
+	struct omap_opp_data *tmp;
+
+	if (unlikely(!opp || !name))
+		return ERR_PTR(-EINVAL);
+
+	list_for_each_entry(tmp, &opp->data_list, list)
+		if (!strcmp(name, tmp->name)) {
+			data = tmp->data;
+			break;
+		}
+	return data;
+}
+
+int opp_store_data(struct omap_opp *opp, char *name, void *data)
+{
+	struct omap_opp_data *new;
+	if (unlikely(!opp || !name))
+		return -EINVAL;
+	/* NAK to double registration */
+	if (unlikely(!IS_ERR(opp_get_data(opp, name))))
+		return -EINVAL;
+
+	new = kmalloc(sizeof(struct omap_opp), GFP_KERNEL);
+	if (!new)
+		return -ENOMEM;
+	new->name = kmalloc(strlen(name) + 1, GFP_KERNEL);
+	if (!new->name) {
+		kfree(new);
+		return -ENOMEM;
+	}
+	new->data = data;
+	strcpy(new->name, name);
+	INIT_LIST_HEAD(&new->list);
+	list_add(&new->list, &opp->data_list);
+	return 0;
+}
+
+int opp_remove_data(struct omap_opp *opp, char *name)
+{
+	struct omap_opp_data *tmp;
+
+	if (unlikely(!opp || !name))
+		return -EINVAL;
+
+	list_for_each_entry(tmp, &opp->data_list, list)
+		if (!strcmp(name, tmp->name)) {
+			list_del(&tmp->list);
+			kfree(tmp->name);
+			kfree(tmp);
+			return 0;
+		}
+	return -EINVAL;
+}
+
 /* XXX document */
 void opp_init_cpufreq_table(enum opp_t opp_type,
 			    struct cpufreq_frequency_table **table)
-- 
1.6.3.3