media: platform: amd: use refcount_t instead of atomic_t

2026-07-10T12:17:56Z

We are using the refcnt variable for refcounting. Use the refcount_t type instead, as it has support for saturation and underflow. This also makes cocci happier, as it will fix the following warning: ./platform/amd/isp4/isp4_subdev.c:394:6-25: WARNING: atomic_dec_and_test variation before object free at line 395. Fixes: 4c5feef6a62c ("media: platform: amd: Add isp4 fw and hw interface") Signed-off-by: Ricardo Ribalda Reviewed-by: Pratap Nirujogi Reviewed-by: Bin Du Signed-off-by: Hans Verkuil

media: platform: amd: Add isp4 fw and hw interface

2026-05-06T10:48:09Z

ISP firmware controls ISP HW pipeline using dedicated embedded processor called ccpu. The communication between ISP FW and driver is using commands and response messages sent through the ring buffer. Command buffers support either global setting that is not specific to the stream and support stream specific parameters. Response buffers contain ISP FW notification information such as frame buffer done and command done. IRQ is used for receiving response buffer from ISP firmware, which is handled in the main isp4 media device. ISP ccpu is booted up through the firmware loading helper function prior to stream start. Memory used for command buffer and response buffer needs to be allocated from amdgpu buffer manager because isp4 is a child device of amdgpu. Co-developed-by: Sultan Alsawaf Signed-off-by: Sultan Alsawaf Co-developed-by: Svetoslav Stoilov Signed-off-by: Svetoslav Stoilov Signed-off-by: Bin Du Reviewed-by: Sultan Alsawaf Tested-by: Alexey Zagorodnikov Tested-by: Kate Hsuan Signed-off-by: Sakari Ailus

wireguard-linux/drivers/media/platform/amd/isp4/isp4_interface.h, branch stable

media: platform: amd: use refcount_t instead of atomic_t

media: platform: amd: Add isp4 fw and hw interface