Re: [PATCH 4/7] soundwire: intel: add definitions for shim_mask

From: Pierre-Louis Bossart
Date: Fri Mar 20 2020 - 14:18:00 EST



diff --git a/drivers/soundwire/intel.h b/drivers/soundwire/intel.h
index 568c84a80d79..cfc83120b8f9 100644
--- a/drivers/soundwire/intel.h
+++ b/drivers/soundwire/intel.h
@@ -16,6 +16,7 @@
* @ops: Shim callback ops
* @dev: device implementing hw_params and free callbacks
* @shim_lock: mutex to handle access to shared SHIM registers
+ * @shim_mask: global pointer to check SHIM register initialization
*/
struct sdw_intel_link_res {
struct platform_device *pdev;
@@ -27,6 +28,7 @@ struct sdw_intel_link_res {
const struct sdw_intel_ops *ops;
struct device *dev;
struct mutex *shim_lock; /* protect shared registers */
+ u32 *shim_mask;

You have a pointer, okay where is it initialized

same answer as shim_lock, it's initialized at the higher level

https://github.com/thesofproject/linux/blob/9c7487b33072040ab755d32ca173b75151c0160c/drivers/soundwire/intel_init.c#L252


};
#endif /* __SDW_INTEL_LOCAL_H */
diff --git a/include/linux/soundwire/sdw_intel.h b/include/linux/soundwire/sdw_intel.h
index 979b41b5dcb4..120ffddc03d2 100644
--- a/include/linux/soundwire/sdw_intel.h
+++ b/include/linux/soundwire/sdw_intel.h
@@ -115,6 +115,7 @@ struct sdw_intel_slave_id {
* links
* @link_list: list to handle interrupts across all links
* @shim_lock: mutex to handle concurrent rmw access to shared SHIM registers.
+ * @shim_mask: flags to track initialization of SHIM shared registers
*/
struct sdw_intel_ctx {
int count;
@@ -126,6 +127,7 @@ struct sdw_intel_ctx {
struct sdw_intel_slave_id *ids;
struct list_head link_list;
struct mutex shim_lock; /* lock for access to shared SHIM registers */
+ u32 shim_mask;

And a integer, question: why do you need pointer and integer, why not
use only one..?

You may have missed that the structures are different.

the sdw_intel_ctx is global for all links, so that the shim_mask integer value.
the sdw_intel_link_res is link-specific and use a pointer to the same shim_mask value, protected by shim_lock.