[igt-dev] [PATCH i-g-t v7 1/4] lib/igt_sysfs: Add support to query number of tiles

[Ghimiray, Himal Prasad]

> -----Original Message-----
> From: Dixit, Ashutosh <ashutosh.dixit at intel.com>
> Sent: 07 July 2023 05:16
> To: Ghimiray, Himal Prasad <himal.prasad.ghimiray at intel.com>
> Cc: igt-dev at lists.freedesktop.org; Iddamsetty, Aravind
> <aravind.iddamsetty at intel.com>; Upadhyay, Tejas
> <tejas.upadhyay at intel.com>; Kumar, Janga Rahul
> <janga.rahul.kumar at intel.com>
> Subject: Re: [PATCH i-g-t v7 1/4] lib/igt_sysfs: Add support to query number
> of tiles
> 
> On Thu, 06 Jul 2023 03:44:57 -0700, Himal Prasad Ghimiray wrote:
> >
> > 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)
> >
> > v4:
> > - Implement tiles related functions in lib.
> >
> > 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 | 77
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> >  lib/igt_sysfs.h | 10 +++++++
> >  2 files changed, 87 insertions(+)
> >
> > diff --git a/lib/igt_sysfs.c b/lib/igt_sysfs.c index
> > 0876f4c6b..dcb38cfc9 100644
> > --- a/lib/igt_sysfs.c
> > +++ b/lib/igt_sysfs.c
> > @@ -903,3 +903,80 @@ void igt_sysfs_engines(int xe, int engines, const
> char **property,
> >		close(engine_fd);
> >	}
> >  }
> > +
> > +/**
> > + * xe_sysfs_tile_path:
> > + * @device: fd of the device
> 
> xe_device

Sure.

> 
> > + * @tile: tile number
> > + * @path: buffer to fill with the sysfs tile path to the device
> > + * @pathlen: length of @path buffer
> > + *
> > + * This finds the sysfs directory corresponding to @device and @tile.
> > +If the tile
> > + * specific directory is not available and tile is 0, path is filled
> > +with sysfs
> > + * base directory.
> > + *
> > + * Returns:
> > + * The directory path, or NULL on failure.
> > + */
> > +char *xe_sysfs_tile_path(int xe_device, int tile, char *path, int
> > +pathlen) {
> > +	struct stat st;
> > +
> > +	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",
> > +		 major(st.st_rdev), minor(st.st_rdev), tile);
> > +
> > +	if (!access(path, F_OK))
> > +		return path;
> > +	if (!tile)
> > +		return igt_sysfs_path(xe_device, path, pathlen);
> 
> This if () is in igt_sysfs_gt_path to take care of the legacy case. There is no
> such thing for xe, so let's remove this if ().

Ok.

> 
> Fix the comment above the function too.
> 
> > +	return NULL;
> > +}
> > +
> > +/**
> > + * xe_sysfs_tile_open:
> > + * @xe_device: fd of the device
> > + * @tile: tile number
> > + *
> > + * This opens the sysfs tile directory corresponding to device and
> > +tile for use
> > + *
> > + * Returns:
> > + * The directory fd, or -1 on failure.
> > + */
> > +int xe_sysfs_tile_open(int xe_device, int tile) {
> > +	char path[96];
> > +
> > +	if (!xe_sysfs_tile_path(xe_device, tile, path, sizeof(path)))
> > +		return -1;
> > +
> > +	return open(path, O_RDONLY);
> > +}
> > +
> > +/**
> > + * xe_sysfs_get_num_tiles:
> > + * @xe_device: fd of the device
> > + *
> > + * Reads number of tile sysfs entries.
> > + * Asserts for at least one tile entry.
> > + * (see xe_sysfs_tile_path).
> > + *
> > + * Returns: Number of tiles.
> > + */
> > +int xe_sysfs_get_num_tiles(int xe_device) {
> > +	int num_tiles = 0;
> > +	char path[96];
> > +
> > +	while (xe_sysfs_tile_path(xe_device, num_tiles, path, sizeof(path)))
> > +		++num_tiles;
> > +
> > +	igt_assert_f(num_tiles > 0, "No GT sysfs entry is found.");
> > +
> > +	return num_tiles;
> > +}
> > diff --git a/lib/igt_sysfs.h b/lib/igt_sysfs.h index
> > 5635fc690..5d584b1c7 100644
> > --- a/lib/igt_sysfs.h
> > +++ b/lib/igt_sysfs.h
> > @@ -38,6 +38,11 @@
> >	     (dirfd__ = igt_sysfs_gt_open(i915__, gt__)) != -1; \
> >	     close(dirfd__), gt__++)
> >
> > +#define for_each_sysfs_tile_dirfd(xe__, dirfd__, tile__) \
> > +	for (tile__ = 0; \
> > +	     (dirfd__ = xe_sysfs_tile_open(xe__, tile__)) != -1; \
> > +	     close(dirfd__), tile__++)
> > +
> >  #define i915_for_each_gt for_each_sysfs_gt_dirfd
> >
> >  #define igt_sysfs_rps_write(dir, id, data, len) \  @@ -73,6 +78,8 @@
> >  #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 for_each_sysfs_tile_dirfd
> > +
> >  enum i915_attr_id {
> >	RPS_ACT_FREQ_MHZ,
> >	RPS_CUR_FREQ_MHZ,
> > @@ -150,4 +157,7 @@ void igt_sysfs_rw_attr_verify(igt_sysfs_rw_attr_t
> >*rw);
> >  void igt_sysfs_engines(int xe, int engines, const char **property,
> >		       void (*test)(int, int, const char **));
> >
> > +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);
> >  #endif /* __IGT_SYSFS_H__ */
> > --
> > 2.25.1
> >