In Xe, the plan is to support multiple types of perf counter streams (OA is
only one type of these streams). Rather than introduce NxM ioctls for
these (N perf streams with M ioctl's per perf stream), we decide to
multiplex these (N different stream types and the M ops for each of these
stream types) through a single PERF ioctl. This multiplexing is the purpose
of the PERF layer.

In addition to PERF DRM ioctl's, another set of ioctl's on the PERF fd are
defined. These are expected to be common to different PERF stream types and
therefore defined at the PERF layer itself.

v2: Add param_size to 'struct drm_xe_perf_param' (Umesh)
v3: Rename 'enum drm_xe_perf_ops' to
    'enum drm_xe_perf_ioctls' (Guy Zadicario)
    Add DRM_ prefix to ioctl names to indicate uapi names
v4: Add 'enum drm_xe_perf_op' previously missed out (Guy Zadicario)
v5: Squash the ops and PERF layer patches into a single patch (Umesh)
    Remove param_size from struct 'drm_xe_perf_param' (Umesh)
v6: Add DRM_XE_PERF_IOCTL_STATUS
v7: Add DRM_XE_PERF_IOCTL_INFO
v8: Fix Copyright years, fix DRM_XE_PERF_TYPE_MAX, move '#include
    "xe_perf.h"' to xe_perf.c, add kernel doc (Michal)
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Guy Zadicario <gzadicario@habana.ai>
Acked-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240618014609.3233427-2-ashutosh.dixit@intel.com