[PATCH v5 4/5] lib/igt_sysfs: add helpers to access engine sysfs directory

[Kamil Konieczny]

Hi Andrzej,
On 2024-05-28 at 16:04:50 +0200, Andrzej Hajda wrote:
> Helpers follow convention of xe_sysfs_gt_(path|open).
> 
> Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>
> ---
>  lib/igt_sysfs.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/igt_sysfs.h |  3 +++
>  2 files changed, 74 insertions(+)
> 
> diff --git a/lib/igt_sysfs.c b/lib/igt_sysfs.c
> index 0c5817eb1580..e11eecc25aa1 100644
> --- a/lib/igt_sysfs.c
> +++ b/lib/igt_sysfs.c
> @@ -40,7 +40,9 @@
>  #include <dirent.h>
>  #include <unistd.h>
>  #include <fcntl.h>
> +#include <xe_drm.h>
>  
> +#include "drmtest.h"
>  #include "igt_core.h"
>  #include "igt_sysfs.h"
>  #include "igt_device.h"
> @@ -263,6 +265,75 @@ int xe_sysfs_gt_open(int xe_device, int gt)
>  	return open(path, O_RDONLY);
>  }
>  
> +static const char *engine_class_to_str(__u16 class)
> +{
> +	const char *str[] = {
> +		[DRM_XE_ENGINE_CLASS_RENDER] = "rcs",
> +		[DRM_XE_ENGINE_CLASS_COPY] = "bcs",
> +		[DRM_XE_ENGINE_CLASS_VIDEO_DECODE] = "vcs",
> +		[DRM_XE_ENGINE_CLASS_VIDEO_ENHANCE] = "vecs",
> +		[DRM_XE_ENGINE_CLASS_COMPUTE] = "ccs",
> +	};

These looks like intel-specific global helper.

> +
> +	if (class < ARRAY_SIZE(str))
> +		return str[class];
> +
> +	return "unk";
> +}
> +
> +/**
> + * xe_sysfs_engine_path:
> + * @xe_device: fd of the device
> + * @gt: gt number
> + * @class: engine class
> + * @path: buffer to fill with the sysfs gt path to the device
> + * @pathlen: length of @path buffer
> + *
> + * Returns:
> + * The directory path, or NULL on failure.
> + */
> +char *
> +xe_sysfs_engine_path(int xe_device, int gt, int class, char *path, int pathlen)
> +{
> +	struct stat st;
> +	int tile = IS_PONTEVECCHIO(intel_get_drm_devid(xe_device)) ? gt : 0;
> +
> +	if (xe_device < 0)
> +		return NULL;
> +
> +	if (igt_debug_on(fstat(xe_device, &st)) || igt_debug_on(!S_ISCHR(st.st_mode)))
> +		return NULL;
> +
> +	snprintf(path, pathlen, "/sys/dev/char/%d:%d/device/tile%d/gt%d/engines/%s",
> +		 major(st.st_rdev), minor(st.st_rdev), tile, gt, engine_class_to_str(class));
> +
> +	if (!access(path, F_OK))
> +		return path;
> +
> +	return NULL;
> +}
> +
> +/**
> + * xe_sysfs_engine_open:
> + * @xe_device: fd of the device
> + * @gt: gt number
> + * @class: engine class
> + *
> + * This opens the sysfs gt directory corresponding to device and tile for use
> + *
> + * Returns:
> + * The directory fd, or -1 on failure.
> + */
> +int xe_sysfs_engine_open(int xe_device, int gt, int class)
> +{
> +	char path[96];
------------- ^^
Is it enough?

Regards,
Kamil

> +
> +	if (!xe_sysfs_engine_path(xe_device, gt, class, path, sizeof(path)))
> +		return -1;
> +
> +	return open(path, O_RDONLY);
> +}
> +
>  /**
>   * igt_sysfs_gt_path:
>   * @device: fd of the device
> diff --git a/lib/igt_sysfs.h b/lib/igt_sysfs.h
> index f37d80ec130e..6c604d939013 100644
> --- a/lib/igt_sysfs.h
> +++ b/lib/igt_sysfs.h
> @@ -166,4 +166,7 @@ int xe_sysfs_gt_open(int xe_device, int gt);
>  char *xe_sysfs_tile_path(int xe_device, int tile, char *path, int pathlen);
>  int xe_sysfs_tile_open(int xe_device, int tile);
>  int xe_sysfs_get_num_tiles(int xe_device);
> +char *xe_sysfs_engine_path(int xe_device, int gt, int class, char *path, int pathlen);
> +int xe_sysfs_engine_open(int xe_device, int gt, int class);
> +
>  #endif /* __IGT_SYSFS_H__ */
> 
> -- 
> 2.34.1
>