drm: Mark constant arrays of drm_display_mode const

... and fixup some methods to accept the constant argument.

Now that constant module arrays are loaded into read-only memory, using
const appropriately has some benefits beyond warning the programmer
about likely mistakes.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

9 files changed, 27 insertions, 23 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index a245d17165a..af60d9be963 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -449,12 +449,11 @@ static void edid_fixup_preferred(struct drm_connector *connector,
 struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
 					   int hsize, int vsize, int fresh)
 {
+	struct drm_display_mode *mode = NULL;
 	int i;
-	struct drm_display_mode *ptr, *mode;
 
-	mode = NULL;
 	for (i = 0; i < drm_num_dmt_modes; i++) {
-		ptr = &drm_dmt_modes[i];
+		const struct drm_display_mode *ptr = &drm_dmt_modes[i];
 		if (hsize == ptr->hdisplay &&
 			vsize == ptr->vdisplay &&
 			fresh == drm_mode_vrefresh(ptr)) {
@@ -885,7 +884,7 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
 }
 
 static bool
-mode_is_rb(struct drm_display_mode *mode)
+mode_is_rb(const struct drm_display_mode *mode)
 {
 	return (mode->htotal - mode->hdisplay == 160) &&
 	       (mode->hsync_end - mode->hdisplay == 80) &&
@@ -894,7 +893,8 @@ mode_is_rb(struct drm_display_mode *mode)
 }
 
 static bool
-mode_in_hsync_range(struct drm_display_mode *mode, struct edid *edid, u8 *t)
+mode_in_hsync_range(const struct drm_display_mode *mode,
+		    struct edid *edid, u8 *t)
 {
 	int hsync, hmin, hmax;
 
@@ -910,7 +910,8 @@ mode_in_hsync_range(struct drm_display_mode *mode, struct edid *edid, u8 *t)
 }
 
 static bool
-mode_in_vsync_range(struct drm_display_mode *mode, struct edid *edid, u8 *t)
+mode_in_vsync_range(const struct drm_display_mode *mode,
+		    struct edid *edid, u8 *t)
 {
 	int vsync, vmin, vmax;
 
@@ -941,7 +942,7 @@ range_pixel_clock(struct edid *edid, u8 *t)
 }
 
 static bool
-mode_in_range(struct drm_display_mode *mode, struct edid *edid,
+mode_in_range(const struct drm_display_mode *mode, struct edid *edid,
 	      struct detailed_timing *timing)
 {
 	u32 max_clock;
@@ -1472,7 +1473,7 @@ int drm_add_modes_noedid(struct drm_connector *connector,
 			int hdisplay, int vdisplay)
 {
 	int i, count, num_modes = 0;
-	struct drm_display_mode *mode, *ptr;
+	struct drm_display_mode *mode;
 	struct drm_device *dev = connector->dev;
 
 	count = sizeof(drm_dmt_modes) / sizeof(struct drm_display_mode);
@@ -1482,7 +1483,7 @@ int drm_add_modes_noedid(struct drm_connector *connector,
 		vdisplay = 0;
 
 	for (i = 0; i < count; i++) {
-		ptr = &drm_dmt_modes[i];
+		const struct drm_display_mode *ptr = &drm_dmt_modes[i];
 		if (hdisplay && vdisplay) {
 			/*
 			 * Only when two are valid, they will be used to check
diff --git a/drivers/gpu/drm/drm_edid_modes.h b/drivers/gpu/drm/drm_edid_modes.h
index 6eb7592e152..5f2064489fd 100644
--- a/drivers/gpu/drm/drm_edid_modes.h
+++ b/drivers/gpu/drm/drm_edid_modes.h
@@ -32,7 +32,7 @@
  * This table is copied from xfree86/modes/xf86EdidModes.c.
  * But the mode with Reduced blank feature is deleted.
  */
-static struct drm_display_mode drm_dmt_modes[] = {
+static const struct drm_display_mode drm_dmt_modes[] = {
 	/* 640x350@85Hz */
 	{ DRM_MODE("640x350", DRM_MODE_TYPE_DRIVER, 31500, 640, 672,
 		   736, 832, 0, 350, 382, 385, 445, 0,
@@ -266,7 +266,7 @@ static struct drm_display_mode drm_dmt_modes[] = {
 static const int drm_num_dmt_modes =
 	sizeof(drm_dmt_modes) / sizeof(struct drm_display_mode);
 
-static struct drm_display_mode edid_est_modes[] = {
+static const struct drm_display_mode edid_est_modes[] = {
 	{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 40000, 800, 840,
 		   968, 1056, 0, 600, 601, 605, 628, 0,
 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@60Hz */
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 58e65f92c23..25bf87390f5 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -593,7 +593,7 @@ EXPORT_SYMBOL(drm_mode_height);
  *
  * Return @modes's hsync rate in kHz, rounded to the nearest int.
  */
-int drm_mode_hsync(struct drm_display_mode *mode)
+int drm_mode_hsync(const struct drm_display_mode *mode)
 {
 	unsigned int calc_val;
 
@@ -627,7 +627,7 @@ EXPORT_SYMBOL(drm_mode_hsync);
  * If it is 70.288, it will return 70Hz.
  * If it is 59.6, it will return 60Hz.
  */
-int drm_mode_vrefresh(struct drm_display_mode *mode)
+int drm_mode_vrefresh(const struct drm_display_mode *mode)
 {
 	int refresh = 0;
 	unsigned int calc_val;
@@ -725,7 +725,7 @@ EXPORT_SYMBOL(drm_mode_set_crtcinfo);
  * a pointer to it.  Used to create new instances of established modes.
  */
 struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
-					    struct drm_display_mode *mode)
+					    const struct drm_display_mode *mode)
 {
 	struct drm_display_mode *nmode;
 	int new_id;
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 6a09c1413d6..318f398e6b2 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1460,7 +1460,7 @@ static void intel_sdvo_get_ddc_modes(struct drm_connector *connector)
  * Note!  This is in reply order (see loop in get_tv_modes).
  * XXX: all 60Hz refresh?
  */
-struct drm_display_mode sdvo_tv_modes[] = {
+static const struct drm_display_mode sdvo_tv_modes[] = {
 	{ DRM_MODE("320x200", DRM_MODE_TYPE_DRIVER, 5815, 320, 321, 384,
 		   416, 0, 200, 201, 232, 233, 0,
 		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) },
diff --git a/drivers/gpu/drm/nouveau/nv17_tv.c b/drivers/gpu/drm/nouveau/nv17_tv.c
index 28119fd19d0..3900cebba56 100644
--- a/drivers/gpu/drm/nouveau/nv17_tv.c
+++ b/drivers/gpu/drm/nouveau/nv17_tv.c
@@ -197,10 +197,12 @@ static int nv17_tv_get_ld_modes(struct drm_encoder *encoder,
 				struct drm_connector *connector)
 {
 	struct nv17_tv_norm_params *tv_norm = get_tv_norm(encoder);
-	struct drm_display_mode *mode, *tv_mode;
+	const struct drm_display_mode *tv_mode;
 	int n = 0;
 
 	for (tv_mode = nv17_tv_modes; tv_mode->hdisplay; tv_mode++) {
+		struct drm_display_mode *mode;
+
 		mode = drm_mode_duplicate(encoder->dev, tv_mode);
 
 		mode->clock = tv_norm->tv_enc_mode.vrefresh *
diff --git a/drivers/gpu/drm/nouveau/nv17_tv.h b/drivers/gpu/drm/nouveau/nv17_tv.h
index 6bf03840f9e..622e7222168 100644
--- a/drivers/gpu/drm/nouveau/nv17_tv.h
+++ b/drivers/gpu/drm/nouveau/nv17_tv.h
@@ -112,7 +112,7 @@ extern struct nv17_tv_norm_params {
 } nv17_tv_norms[NUM_TV_NORMS];
 #define get_tv_norm(enc) (&nv17_tv_norms[to_tv_enc(enc)->tv_norm])
 
-extern struct drm_display_mode nv17_tv_modes[];
+extern const struct drm_display_mode nv17_tv_modes[];
 
 static inline int interpolate(int y0, int y1, int y2, int x)
 {
diff --git a/drivers/gpu/drm/nouveau/nv17_tv_modes.c b/drivers/gpu/drm/nouveau/nv17_tv_modes.c
index 9d3893c50a4..4d1d29f6030 100644
--- a/drivers/gpu/drm/nouveau/nv17_tv_modes.c
+++ b/drivers/gpu/drm/nouveau/nv17_tv_modes.c
@@ -438,7 +438,7 @@ void nv17_tv_state_load(struct drm_device *dev, struct nv17_tv_state *state)
 
 /* Timings similar to the ones the blob sets */
 
-struct drm_display_mode nv17_tv_modes[] = {
+const struct drm_display_mode nv17_tv_modes[] = {
 	{ DRM_MODE("320x200", DRM_MODE_TYPE_DRIVER, 0,
 		   320, 344, 392, 560, 0, 200, 200, 202, 220, 0,
 		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
index 29113c9b26a..b3a2cd5118d 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
@@ -345,7 +345,7 @@ static enum drm_connector_status
 	return connector_status_disconnected;
 }
 
-static struct drm_display_mode vmw_ldu_connector_builtin[] = {
+static const struct drm_display_mode vmw_ldu_connector_builtin[] = {
 	/* 640x480@60Hz */
 	{ DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 25175, 640, 656,
 		   752, 800, 0, 480, 489, 492, 525, 0,
@@ -429,7 +429,6 @@ static int vmw_ldu_connector_fill_modes(struct drm_connector *connector,
 	struct drm_device *dev = connector->dev;
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	struct drm_display_mode *mode = NULL;
-	struct drm_display_mode *bmode;
 	struct drm_display_mode prefmode = { DRM_MODE("preferred",
 		DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -459,6 +458,8 @@ static int vmw_ldu_connector_fill_modes(struct drm_connector *connector,
 	}
 
 	for (i = 0; vmw_ldu_connector_builtin[i].type != 0; i++) {
+		const struct drm_display_mode *bmode;
+
 		bmode = &vmw_ldu_connector_builtin[i];
 		if (bmode->hdisplay > max_width ||
 		    bmode->vdisplay > max_height)
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 080a6e33470..60edf9be31e 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -659,7 +659,7 @@ extern int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid
 extern void drm_mode_probed_add(struct drm_connector *connector, struct drm_display_mode *mode);
 extern void drm_mode_remove(struct drm_connector *connector, struct drm_display_mode *mode);
 extern struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev,
-						   struct drm_display_mode *mode);
+						   const struct drm_display_mode *mode);
 extern void drm_mode_debug_printmodeline(struct drm_display_mode *mode);
 extern void drm_mode_config_init(struct drm_device *dev);
 extern void drm_mode_config_reset(struct drm_device *dev);
@@ -685,8 +685,8 @@ extern void drm_mode_validate_size(struct drm_device *dev,
 extern void drm_mode_prune_invalid(struct drm_device *dev,
 				   struct list_head *mode_list, bool verbose);
 extern void drm_mode_sort(struct list_head *mode_list);
-extern int drm_mode_hsync(struct drm_display_mode *mode);
-extern int drm_mode_vrefresh(struct drm_display_mode *mode);
+extern int drm_mode_hsync(const struct drm_display_mode *mode);
+extern int drm_mode_vrefresh(const struct drm_display_mode *mode);
 extern void drm_mode_set_crtcinfo(struct drm_display_mode *p,
 				  int adjust_flags);
 extern void drm_mode_connector_list_update(struct drm_connector *connector);