broadcom/common: Add maximum number of perf counters to v3d_device_info

Now, the kernel has the ability to inform about the maximum number of
performance counters of a V3D device. Let's add this information to the
`struct v3d_device_info` to use it when performing performance queries.

From now on, V3D_PERFCNT_NUM must not be used to retrieve the maximum
number of performance counters. We must use `devinfo->max_perfcnt`,
except on the case that the kernel doesn't support DRM_V3D_PARAM_MAX_PERF_COUNTERS.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29154>

src/broadcom/common/v3d_device_info.c

@@ -39,6 +39,9 @@ v3d_get_device_info(int fd, struct v3d_device_info* devinfo, v3d_ioctl_fun drm_i
     struct drm_v3d_get_param hub_ident3 = {
             .param = DRM_V3D_PARAM_V3D_HUB_IDENT3,
     };
+    struct drm_v3d_get_param max_perfcnt = {
+            .param = DRM_V3D_PARAM_MAX_PERF_COUNTERS,
+    };
     int ret;
 
     ret = drm_ioctl(fd, DRM_IOCTL_V3D_GET_PARAM, &ident0);
@@ -88,5 +91,15 @@ v3d_get_device_info(int fd, struct v3d_device_info* devinfo, v3d_ioctl_fun drm_i
 
    devinfo->rev = (hub_ident3.value >> 8) & 0xff;
 
+    ret = drm_ioctl(fd, DRM_IOCTL_V3D_GET_PARAM, &max_perfcnt);
+    if (ret != 0) {
+            /* Kernel doesn't have support to return the maximum number of
+             * performance counters.
+             */
+            devinfo->max_perfcnt = 0;
+    } else {
+            devinfo->max_perfcnt = max_perfcnt.value;
+    }
+
    return true;
 }

src/broadcom/common/v3d_device_info.h

@@ -37,6 +37,9 @@ struct v3d_device_info {
         /** V3D revision number */
         uint8_t rev;
 
+        /** Maximum number of performance counters for a given V3D version **/
+        uint8_t max_perfcnt;
+
         /** Size of the VPM, in bytes. */
         int vpm_size;