firmware: ti_sci: Add helper apis to manage resources

Each resource with in the device can be uniquely identified as defined
by TISCI. Since this is generic across the devices, resource allocation
also can be made generic instead of each client driver handling the
resource. So add helper apis to manage the resource.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/firmware/ti_sci.c

@@ -2262,6 +2262,136 @@ const struct ti_sci_handle *devm_ti_sci_get_by_phandle(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_ti_sci_get_by_phandle);
 
+/**
+ * ti_sci_get_free_resource() - Get a free resource from TISCI resource.
+ * @res:	Pointer to the TISCI resource
+ *
+ * Return: resource num if all went ok else TI_SCI_RESOURCE_NULL.
+ */
+u16 ti_sci_get_free_resource(struct ti_sci_resource *res)
+{
+	unsigned long flags;
+	u16 set, free_bit;
+
+	raw_spin_lock_irqsave(&res->lock, flags);
+	for (set = 0; set < res->sets; set++) {
+		free_bit = find_first_zero_bit(res->desc[set].res_map,
+					       res->desc[set].num);
+		if (free_bit != res->desc[set].num) {
+			set_bit(free_bit, res->desc[set].res_map);
+			raw_spin_unlock_irqrestore(&res->lock, flags);
+			return res->desc[set].start + free_bit;
+		}
+	}
+	raw_spin_unlock_irqrestore(&res->lock, flags);
+
+	return TI_SCI_RESOURCE_NULL;
+}
+EXPORT_SYMBOL_GPL(ti_sci_get_free_resource);
+
+/**
+ * ti_sci_release_resource() - Release a resource from TISCI resource.
+ * @res:	Pointer to the TISCI resource
+ * @id:		Resource id to be released.
+ */
+void ti_sci_release_resource(struct ti_sci_resource *res, u16 id)
+{
+	unsigned long flags;
+	u16 set;
+
+	raw_spin_lock_irqsave(&res->lock, flags);
+	for (set = 0; set < res->sets; set++) {
+		if (res->desc[set].start <= id &&
+		    (res->desc[set].num + res->desc[set].start) > id)
+			clear_bit(id - res->desc[set].start,
+				  res->desc[set].res_map);
+	}
+	raw_spin_unlock_irqrestore(&res->lock, flags);
+}
+EXPORT_SYMBOL_GPL(ti_sci_release_resource);
+
+/**
+ * ti_sci_get_num_resources() - Get the number of resources in TISCI resource
+ * @res:	Pointer to the TISCI resource
+ *
+ * Return: Total number of available resources.
+ */
+u32 ti_sci_get_num_resources(struct ti_sci_resource *res)
+{
+	u32 set, count = 0;
+
+	for (set = 0; set < res->sets; set++)
+		count += res->desc[set].num;
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(ti_sci_get_num_resources);
+
+/**
+ * devm_ti_sci_get_of_resource() - Get a TISCI resource assigned to a device
+ * @handle:	TISCI handle
+ * @dev:	Device pointer to which the resource is assigned
+ * @dev_id:	TISCI device id to which the resource is assigned
+ * @of_prop:	property name by which the resource are represented
+ *
+ * Return: Pointer to ti_sci_resource if all went well else appropriate
+ *	   error pointer.
+ */
+struct ti_sci_resource *
+devm_ti_sci_get_of_resource(const struct ti_sci_handle *handle,
+			    struct device *dev, u32 dev_id, char *of_prop)
+{
+	struct ti_sci_resource *res;
+	u32 resource_subtype;
+	int i, ret;
+
+	res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return ERR_PTR(-ENOMEM);
+
+	res->sets = of_property_count_elems_of_size(dev_of_node(dev), of_prop,
+						    sizeof(u32));
+	if (res->sets < 0) {
+		dev_err(dev, "%s resource type ids not available\n", of_prop);
+		return ERR_PTR(res->sets);
+	}
+
+	res->desc = devm_kcalloc(dev, res->sets, sizeof(*res->desc),
+				 GFP_KERNEL);
+	if (!res->desc)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < res->sets; i++) {
+		ret = of_property_read_u32_index(dev_of_node(dev), of_prop, i,
+						 &resource_subtype);
+		if (ret)
+			return ERR_PTR(-EINVAL);
+
+		ret = handle->ops.rm_core_ops.get_range(handle, dev_id,
+							resource_subtype,
+							&res->desc[i].start,
+							&res->desc[i].num);
+		if (ret) {
+			dev_err(dev, "dev = %d subtype %d not allocated for this host\n",
+				dev_id, resource_subtype);
+			return ERR_PTR(ret);
+		}
+
+		dev_dbg(dev, "dev = %d, subtype = %d, start = %d, num = %d\n",
+			dev_id, resource_subtype, res->desc[i].start,
+			res->desc[i].num);
+
+		res->desc[i].res_map =
+			devm_kzalloc(dev, BITS_TO_LONGS(res->desc[i].num) *
+				     sizeof(*res->desc[i].res_map), GFP_KERNEL);
+		if (!res->desc[i].res_map)
+			return ERR_PTR(-ENOMEM);
+	}
+	raw_spin_lock_init(&res->lock);
+
+	return res;
+}
+
 static int tisci_reboot_handler(struct notifier_block *nb, unsigned long mode,
 				void *cmd)
 {

include/linux/soc/ti/ti_sci_protocol.h

@@ -266,6 +266,33 @@ struct ti_sci_handle {
 	struct ti_sci_ops ops;
 };
 
+#define TI_SCI_RESOURCE_NULL	0xffff
+
+/**
+ * struct ti_sci_resource_desc - Description of TI SCI resource instance range.
+ * @start:	Start index of the resource.
+ * @num:	Number of resources.
+ * @res_map:	Bitmap to manage the allocation of these resources.
+ */
+struct ti_sci_resource_desc {
+	u16 start;
+	u16 num;
+	unsigned long *res_map;
+};
+
+/**
+ * struct ti_sci_resource - Structure representing a resource assigned
+ *			    to a device.
+ * @sets:	Number of sets available from this resource type
+ * @lock:	Lock to guard the res map in each set.
+ * @desc:	Array of resource descriptors.
+ */
+struct ti_sci_resource {
+	u16 sets;
+	raw_spinlock_t lock;
+	struct ti_sci_resource_desc *desc;
+};
+
 #if IS_ENABLED(CONFIG_TI_SCI_PROTOCOL)
 const struct ti_sci_handle *ti_sci_get_handle(struct device *dev);
 int ti_sci_put_handle(const struct ti_sci_handle *handle);
@@ -274,6 +301,12 @@ const struct ti_sci_handle *ti_sci_get_by_phandle(struct device_node *np,
 						  const char *property);
 const struct ti_sci_handle *devm_ti_sci_get_by_phandle(struct device *dev,
 						       const char *property);
+u16 ti_sci_get_free_resource(struct ti_sci_resource *res);
+void ti_sci_release_resource(struct ti_sci_resource *res, u16 id);
+u32 ti_sci_get_num_resources(struct ti_sci_resource *res);
+struct ti_sci_resource *
+devm_ti_sci_get_of_resource(const struct ti_sci_handle *handle,
+			    struct device *dev, u32 dev_id, char *of_prop);
 
 #else	/* CONFIG_TI_SCI_PROTOCOL */
 
@@ -306,6 +339,27 @@ const struct ti_sci_handle *devm_ti_sci_get_by_phandle(struct device *dev,
 {
 	return ERR_PTR(-EINVAL);
 }
+
+static inline u16 ti_sci_get_free_resource(struct ti_sci_resource *res)
+{
+	return TI_SCI_RESOURCE_NULL;
+}
+
+static inline void ti_sci_release_resource(struct ti_sci_resource *res, u16 id)
+{
+}
+
+static inline u32 ti_sci_get_num_resources(struct ti_sci_resource *res)
+{
+	return 0;
+}
+
+static inline struct ti_sci_resource *
+devm_ti_sci_get_of_resource(const struct ti_sci_handle *handle,
+			    struct device *dev, u32 dev_id, char *of_prop)
+{
+	return ERR_PTR(-EINVAL);
+}
 #endif	/* CONFIG_TI_SCI_PROTOCOL */
 
 #endif	/* __TISCI_PROTOCOL_H */