drm/i915: Add /proc debugging entry for reading out the HWS.

Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_gem_proc.c

@@ -250,6 +250,39 @@ static int i915_interrupt_info(char *buf, char **start, off_t offset,
 	return len - offset;
 }
 
+static int i915_hws_info(char *buf, char **start, off_t offset,
+			 int request, int *eof, void *data)
+{
+	struct drm_minor *minor = (struct drm_minor *) data;
+	struct drm_device *dev = minor->dev;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	int len = 0, i;
+	volatile u32 *hws;
+
+	if (offset > DRM_PROC_LIMIT) {
+		*eof = 1;
+		return 0;
+	}
+
+	hws = (volatile u32 *)dev_priv->hw_status_page;
+	if (hws == NULL) {
+		*eof = 1;
+		return 0;
+	}
+
+	*start = &buf[offset];
+	*eof = 0;
+	for (i = 0; i < 4096 / sizeof(u32) / 4; i += 4) {
+		DRM_PROC_PRINT("0x%08x: 0x%08x 0x%08x 0x%08x 0x%08x\n",
+			       i * 4,
+			       hws[i], hws[i + 1], hws[i + 2], hws[i + 3]);
+	}
+	if (len > request + offset)
+		return request;
+	*eof = 1;
+	return len - offset;
+}
+
 static struct drm_proc_list {
 	/** file name */
 	const char *name;
@@ -262,6 +295,7 @@ static struct drm_proc_list {
 	{"i915_gem_request", i915_gem_request_info},
 	{"i915_gem_seqno", i915_gem_seqno_info},
 	{"i915_gem_interrupt", i915_interrupt_info},
+	{"i915_gem_hws", i915_hws_info},
 };
 
 #define I915_GEM_PROC_ENTRIES ARRAY_SIZE(i915_gem_proc_list)