drm/i915/guc: add doorbell map to debugfs/i915_guc_info

To properly verify the driver->doorbell->GuC functionality, validation
needs to know how the driver has assigned the doorbell cache lines and
registers, so make them visible through debugfs.

v2: use kernel bitmap-printing format (%pb) rather than %x.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2574,6 +2574,10 @@ static int i915_guc_info(struct seq_file *m, void *data)
 
 	mutex_unlock(&dev->struct_mutex);
 
+	seq_printf(m, "Doorbell map:\n");
+	seq_printf(m, "\t%*pb\n", GUC_MAX_DOORBELLS, guc.doorbell_bitmap);
+	seq_printf(m, "Doorbell next cacheline: 0x%x\n\n", guc.db_cacheline);
+
 	seq_printf(m, "GuC total action count: %llu\n", guc.action_count);
 	seq_printf(m, "GuC action failure count: %u\n", guc.action_fail);
 	seq_printf(m, "GuC last action command: 0x%x\n", guc.action_cmd);