drm/i915/debugfs: add rcs topology entry

While the end goal is to make this information available to userspace
through a new ioctl, there is no reason we can't display it in a human
readable fashion through debugfs.

slice0: 3 subslice(s) (0x7):
subslice0: 8 EUs (0xff)
subslice1: 8 EUs (0xff)
subslice2: 8 EUs (0xff)
subslice3: 0 EUs (0x0)
slice1: 3 subslice(s) (0x7):
subslice0: 8 EUs (0xff)
subslice1: 8 EUs (0xff)
subslice2: 8 EUs (0xff)
subslice3: 0 EUs (0x0)
slice2: 3 subslice(s) (0x7):
subslice0: 8 EUs (0xff)
subslice1: 8 EUs (0xff)
subslice2: 8 EUs (0xff)
subslice3: 0 EUs (0x0)

v2: Reformat debugfs printing (Tvrtko)
Use the new EU mask helper (Tvrtko)

v3: Move printing code to intel_device_info.c to be shared with error
state (Michal)

v4: Bump u8 to u16 when using sseu_get_eus() (Lionel)

Suggested-by: Chris Wilson <[e-mail]>
Signed-off-by: Lionel Landwerlin <[e-mail]>
Reviewed-by: Tvrtko Ursulin <[e-mail]>
Acked-by: Chris Wilson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_debugfs.c

···
 	return 0;
 }
 
+static int i915_rcs_topology(struct seq_file *m, void *unused)
+{
+	struct drm_i915_private *dev_priv = node_to_i915(m->private);
+	struct drm_printer p = drm_seq_file_printer(m);
+
+	intel_device_info_dump_topology(&INTEL_INFO(dev_priv)->sseu, &p);
+
+	return 0;
+}
+
 static int i915_shrinker_info(struct seq_file *m, void *unused)
 {
 	struct drm_i915_private *i915 = node_to_i915(m->private);
···
 	{"i915_dmc_info", i915_dmc_info, 0},
 	{"i915_display_info", i915_display_info, 0},
 	{"i915_engine_info", i915_engine_info, 0},
+	{"i915_rcs_topology", i915_rcs_topology, 0},
 	{"i915_shrinker_info", i915_shrinker_info, 0},
 	{"i915_shared_dplls_info", i915_shared_dplls_info, 0},
 	{"i915_dp_mst_info", i915_dp_mst_info, 0},

drivers/gpu/drm/i915/intel_device_info.c

···
 	intel_device_info_dump_flags(info, p);
 }
 
+void intel_device_info_dump_topology(const struct sseu_dev_info *sseu,
+				     struct drm_printer *p)
+{
+	int s, ss;
+
+	if (sseu->max_slices == 0) {
+		drm_printf(p, "Unavailable\n");
+		return;
+	}
+
+	for (s = 0; s < sseu->max_slices; s++) {
+		drm_printf(p, "slice%d: %u subslice(s) (0x%hhx):\n",
+			   s, hweight8(sseu->subslice_mask[s]),
+			   sseu->subslice_mask[s]);
+
+		for (ss = 0; ss < sseu->max_subslices; ss++) {
+			u16 enabled_eus = sseu_get_eus(sseu, s, ss);
+
+			drm_printf(p, "\tsubslice%d: %u EUs (0x%hx)\n",
+				   ss, hweight16(enabled_eus), enabled_eus);
+		}
+	}
+}
+
 static u16 compute_eu_total(const struct sseu_dev_info *sseu)
 {
 	u16 i, total = 0;

drivers/gpu/drm/i915/intel_device_info.h

···
 				  struct drm_printer *p);
 void intel_device_info_dump_runtime(const struct intel_device_info *info,
 				    struct drm_printer *p);
+void intel_device_info_dump_topology(const struct sseu_dev_info *sseu,
+				     struct drm_printer *p);
 
 void intel_driver_caps_print(const struct intel_driver_caps *caps,
 			     struct drm_printer *p);