drm/xe/topology: Add a function to find the index of the last enabled DSS in a mask

Last enabled DSS in a DSS mask can help estimate the maximum DSSes enabled
in the DSS mask, as the enabled DSSes can be discontiguous.

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/79944bb27eb4f7ce5df01f964aebbf431b3a6c61.1740533885.git.harish.chegondi@intel.com

diff --git a/drivers/gpu/drm/xe/xe_gt_topology.h b/drivers/gpu/drm/xe/xe_gt_topology.h
index 746b325bbf6e4a51fe9c6a7cb8fb6ce18f93b408..a72d26ba06530aad8eeed8743dcf83bbd724435f 100644 (file)
--- a/drivers/gpu/drm/xe/xe_gt_topology.h
+++ b/drivers/gpu/drm/xe/xe_gt_topology.h
@@ -25,6 +25,19 @@ void xe_gt_topology_init(struct xe_gt *gt);
 
 void xe_gt_topology_dump(struct xe_gt *gt, struct drm_printer *p);
 
+/**
+ * xe_gt_topology_mask_last_dss() - Returns the index of the last DSS in a mask.
+ * @mask: Input DSS mask
+ *
+ * Return: Index of the last DSS in the input DSS mask,
+ *        XE_MAX_DSS_FUSE_BITS if DSS mask is empty.
+ */
+static inline unsigned int
+xe_gt_topology_mask_last_dss(const xe_dss_mask_t mask)
+{
+       return find_last_bit(mask, XE_MAX_DSS_FUSE_BITS);
+}
+
 unsigned int
 xe_dss_mask_group_ffs(const xe_dss_mask_t mask, int groupsize, int groupnum);