On 6/29/2023 12:46 AM, Srinivasan Shanmugam wrote:
Conform to Linux kernel coding style.
Reported by checkpatch:
WARNING: please, no space before tabs
And promote sysfs entry for set/get srm to kdoc
Suggested-by: Rodrigo Siqueira <[email protected]>
Cc: Rodrigo Siqueira <[email protected]>
Cc: Aurabindo Pillai <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
---
.../amd/display/amdgpu_dm/amdgpu_dm_hdcp.c | 50 +++++++++++--------
1 file changed, 28 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
index 5536d17306d0..308f2b0687b5 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
@@ -576,7 +576,10 @@ static void update_config(void *handle, struct
cp_psp_stream_config *config)
}
-/* NOTE: From the usermodes prospective you only need to call write *ONCE*, the kernel
+/**
+ * DOC: Add sysfs interface for set/get srm
+ *
+ * NOTE: From the usermodes prospective you only need to call write *ONCE*,
the kernel
* will automatically call once or twice depending on the size
*
* call: "cat file > /sys/class/drm/card0/device/hdcp_srm" from usermode no
matter what the size is
@@ -591,19 +594,19 @@ static void update_config(void *handle, struct
cp_psp_stream_config *config)
* cannot throw errors early as it will stop the kernel from writing to sysfs
*
* Example 1:
- * Good SRM size = 5096
- * first call to write 4096 -> PSP fails
- * Second call to write 1000 -> PSP Pass -> SRM is set
+ * Good SRM size = 5096
+ * first call to write 4096 -> PSP fails
+ * Second call to write 1000 -> PSP Pass -> SRM is set
*
* Example 2:
- * Bad SRM size = 4096
- * first call to write 4096 -> PSP fails (This is the same as above, but
we don't know if this
- * is the last call)
+ * Bad SRM size = 4096
+ * first call to write 4096 -> PSP fails (This is the same as above, but
we don't know if this
+ * is the last call)
*
* Solution?:
- * 1: Parse the SRM? -> It is signed so we don't know the EOF
- * 2: We can have another sysfs that passes the size before calling set.
-> simpler solution
- * below
+ * 1: Parse the SRM? -> It is signed so we don't know the EOF
+ * 2: We can have another sysfs that passes the size before calling set.
-> simpler solution
+ * below
*
* Easy Solution:
* Always call get after Set to verify if set was successful.
@@ -612,14 +615,14 @@ static void update_config(void *handle, struct
cp_psp_stream_config *config)
* +----------------------+
* PSP will only update its srm if its older than the one we are trying to
load.
* Always do set first than get.
- * -if we try to "1. SET" a older version PSP will reject it and we can "2.
GET" the newer
- * version and save it
+ * -if we try to "1. SET" a older version PSP will reject it and we can "2.
GET" the newer
+ * version and save it
*
- * -if we try to "1. SET" a newer version PSP will accept it and we can "2.
GET" the
- * same(newer) version back and save it
+ * -if we try to "1. SET" a newer version PSP will accept it and we can "2.
GET" the
+ * same(newer) version back and save it
*
- * -if we try to "1. SET" a newer version and PSP rejects it. That means
the format is
- * incorrect/corrupted and we should correct our SRM by getting it from PSP
+ * -if we try to "1. SET" a newer version and PSP rejects it. That means
the format is
+ * incorrect/corrupted and we should correct our SRM by getting it from PSP
*/
static ssize_t srm_data_write(struct file *filp, struct kobject *kobj, struct
bin_attribute *bin_attr, char *buffer,
loff_t pos, size_t count)
@@ -681,12 +684,15 @@ static ssize_t srm_data_read(struct file *filp, struct
kobject *kobj, struct bin
return ret;
}
-/* From the hdcp spec (5.Renewability) SRM needs to be stored in a non-volatile memory.
+/**
+ * DOC: SRM should be persistent across boot/reboots/suspend/resume/shutdown
+ *
+ * From the hdcp spec (5.Renewability) SRM needs to be stored in a
non-volatile memory.
*
* For example,
- * if Application "A" sets the SRM (ver 2) and we reboot/suspend and later when
Application "B"
- * needs to use HDCP, the version in PSP should be SRM(ver 2). So SRM
should be persistent
- * across boot/reboots/suspend/resume/shutdown
+ * if Application "A" sets the SRM (ver 2) and we reboot/suspend and later when
Application "B"
+ * needs to use HDCP, the version in PSP should be SRM(ver 2). So SRM
should be persistent
+ * across boot/reboots/suspend/resume/shutdown
*
* Currently when the system goes down (suspend/shutdown) the SRM is cleared
from PSP. For HDCP we need
* to make the SRM persistent.
@@ -699,8 +705,8 @@ static ssize_t srm_data_read(struct file *filp, struct
kobject *kobj, struct bin
*
* Usermode can read/write to/from PSP using the sysfs interface
* For example:
- * to save SRM from PSP to storage : cat /sys/class/drm/card0/device/hdcp_srm
> srmfile
- * to load from storage to PSP: cat srmfile >
/sys/class/drm/card0/device/hdcp_srm
+ * to save SRM from PSP to storage : cat /sys/class/drm/card0/device/hdcp_srm
> srmfile
+ * to load from storage to PSP: cat srmfile >
/sys/class/drm/card0/device/hdcp_srm
*/
static const struct bin_attribute data_attr = {
.attr = {.name = "hdcp_srm", .mode = 0664},
Reviewed-by: Aurabindo Pillai <[email protected]>
