[igt-dev] [PATCH i-g-t v6 1/4] lib/igt_sysfs: Add support to query number of tiles

[Dixit, Ashutosh]

On Wed, 05 Jul 2023 06:18:50 -0700, Himal Prasad Ghimiray wrote:
>

Hi Himal,

> With tile and GT seperation in KMD, we need to know
> number of tiles supported by platform.
> We will need to access tile associated properties from IGT.
> Hence adding iterator for all supported tiles.
>
> v2:
> - Calculate number of tiles once within iterator. (Rahul)
> - Use snprintf instead of sprintf.
>
> v3:
> - Remove unrequired for_each_sysfs_tile_dirfd (Ashutosh)
>
> Reviewed-by: Upadhyay <tejas.upadhyay at intel.com>
> Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
> Cc: Aravind Iddamsetty <aravind.iddamsetty at intel.com>
> Cc: Upadhyay <tejas.upadhyay at intel.com>
> Cc: Janga Rahul Kumar <janga.rahul.kumar at intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
> ---
>  lib/igt_sysfs.c | 30 ++++++++++++++++++++++++++++++
>  lib/igt_sysfs.h |  7 +++++++
>  2 files changed, 37 insertions(+)
>
> diff --git a/lib/igt_sysfs.c b/lib/igt_sysfs.c
> index 0876f4c6b..2ea9eb1b9 100644
> --- a/lib/igt_sysfs.c
> +++ b/lib/igt_sysfs.c
> @@ -287,6 +287,36 @@ int igt_sysfs_get_num_gt(int device)
>	return num_gts;
>  }
>
> +/**
> + * igt_sysfs_get_num_tiles:
> + * @device: fd of the device
> + *
> + * Reads number of tiles sysfs entries.
> + * Asserts for at least one tile entry.
> + *
> + * Returns: Number of tiles.
> + */
> +int igt_sysfs_get_num_tiles(int device)
> +{
> +	int num_tiles;
> +	char sysfs[48];
> +	char tiledir[96];
> +
> +	num_tiles = 0;
> +	if (!igt_sysfs_path(device, sysfs, sizeof(sysfs)))
> +		return -1;
> +
> +	do {
> +		igt_assert(snprintf(tiledir, sizeof(tiledir), "%s/device/tile%d",
> +				    sysfs, num_tiles) < sizeof(tiledir));
> +		num_tiles++;
> +	} while (!access(tiledir, F_OK));
> +
> +	num_tiles--;

This decrement is ugly. Can we get rid of it?

I seriously think we should model these functions similar to
igt_sysfs_gt_open, igt_sysfs_get_num_gt, igt_sysfs_gt_path,
for_each_sysfs_gt_dirfd. So we could have xe_sysfs_tile_open,
xe_sysfs_get_num_tile, xe_sysfs_tile_path, xe_for_each_sysfs_tile_dirfd
etc. This will cleanup patch 4 too.

Thanks.
--
Ashutosh

> +	igt_assert_f(num_tiles > 0, "No tiles sysfs entry is found.");
> +	return num_tiles;
> +}
> +
>  /**
>   * igt_sysfs_write:
>   * @dir: directory for the device from igt_sysfs_open()
> diff --git a/lib/igt_sysfs.h b/lib/igt_sysfs.h
> index 5635fc690..c31765542 100644
> --- a/lib/igt_sysfs.h
> +++ b/lib/igt_sysfs.h
> @@ -73,6 +73,12 @@
>  #define igt_sysfs_rps_set_boolean(dir, id, value) \
>	igt_sysfs_set_boolean(dir, igt_sysfs_dir_id_to_name(dir, id), value)
>
> +#define xe_for_each_tile(xe__, tile__, tile_cnt__) \
> +	for (tile__ = 0, tile_cnt__ = igt_sysfs_get_num_tiles(xe__); \
> +	     tile__ < tile_cnt__; \
> +	     ++tile__)
> +
> +
>  enum i915_attr_id {
>	RPS_ACT_FREQ_MHZ,
>	RPS_CUR_FREQ_MHZ,
> @@ -97,6 +103,7 @@ int igt_sysfs_open(int device);
>  char *igt_sysfs_gt_path(int device, int gt, char *path, int pathlen);
>  int igt_sysfs_gt_open(int device, int gt);
>  int igt_sysfs_get_num_gt(int device);
> +int igt_sysfs_get_num_tiles(int device);
>  bool igt_sysfs_has_attr(int dir, const char *attr);
>  const char *igt_sysfs_dir_id_to_name(int dir, enum i915_attr_id id);
>  const char *igt_sysfs_path_id_to_name(const char *path, enum i915_attr_id id);
> --
> 2.25.1
>