stm class: Introduce framing protocol drivers

At the moment, the stm class applies a certain STP framing pattern to
the data as it is written to the underlying STM device. In order to
allow different framing patterns (aka protocols), this patch introduces
the concept of STP protocol drivers, defines data structures and APIs
for the protocol drivers to use.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 43 insertions, 8 deletions

diff --git a/drivers/hwtracing/stm/stm.h b/drivers/hwtracing/stm/stm.h
index e5df08ae59cf..ed7f3d07fa47 100644
--- a/drivers/hwtracing/stm/stm.h
+++ b/drivers/hwtracing/stm/stm.h
@@ -10,20 +10,17 @@
 #ifndef _STM_STM_H_
 #define _STM_STM_H_
 
+#include <linux/configfs.h>
+
 struct stp_policy;
 struct stp_policy_node;
+struct stm_protocol_driver;
 
-struct stp_policy_node *
-stp_policy_node_lookup(struct stm_device *stm, char *s);
-void stp_policy_node_put(struct stp_policy_node *policy_node);
-void stp_policy_unbind(struct stp_policy *policy);
-
-void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
-				unsigned int *mstart, unsigned int *mend,
-				unsigned int *cstart, unsigned int *cend);
 int stp_configfs_init(void);
 void stp_configfs_exit(void);
 
+void *stp_policy_node_priv(struct stp_policy_node *pn);
+
 struct stp_master {
 	unsigned int	nr_free;
 	unsigned long	chan_map[0];
@@ -40,6 +37,9 @@ struct stm_device {
 	struct mutex		link_mutex;
 	spinlock_t		link_lock;
 	struct list_head	link_list;
+	/* framing protocol in use */
+	const struct stm_protocol_driver	*pdrv;
+	const struct config_item_type		*pdrv_node_type;
 	/* master allocation */
 	spinlock_t		mc_lock;
 	struct stp_master	*masters[0];
@@ -48,11 +48,24 @@ struct stm_device {
 #define to_stm_device(_d)				\
 	container_of((_d), struct stm_device, dev)
 
+struct stp_policy_node *
+stp_policy_node_lookup(struct stm_device *stm, char *s);
+void stp_policy_node_put(struct stp_policy_node *policy_node);
+void stp_policy_unbind(struct stp_policy *policy);
+
+void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
+				unsigned int *mstart, unsigned int *mend,
+				unsigned int *cstart, unsigned int *cend);
+
+const struct config_item_type *
+get_policy_node_type(struct configfs_attribute **attrs);
+
 struct stm_output {
 	spinlock_t		lock;
 	unsigned int		master;
 	unsigned int		channel;
 	unsigned int		nr_chans;
+	void			*pdrv_private;
 };
 
 struct stm_file {
@@ -76,4 +89,26 @@ struct stm_source_device {
 #define to_stm_source_device(_d)				\
 	container_of((_d), struct stm_source_device, dev)
 
+void *to_pdrv_policy_node(struct config_item *item);
+
+struct stm_protocol_driver {
+	struct module	*owner;
+	const char	*name;
+	ssize_t		(*write)(struct stm_data *data,
+				 struct stm_output *output, unsigned int chan,
+				 const char *buf, size_t count);
+	void		(*policy_node_init)(void *arg);
+	int		(*output_open)(void *priv, struct stm_output *output);
+	void		(*output_close)(struct stm_output *output);
+	ssize_t		priv_sz;
+	struct configfs_attribute	**policy_attr;
+};
+
+int stm_register_protocol(const struct stm_protocol_driver *pdrv);
+void stm_unregister_protocol(const struct stm_protocol_driver *pdrv);
+int stm_lookup_protocol(const char *name,
+			const struct stm_protocol_driver **pdrv,
+			const struct config_item_type **type);
+void stm_put_protocol(const struct stm_protocol_driver *pdrv);
+
 #endif /* _STM_STM_H_ */