drm/mgag200: Split up connector's mode_valid helper

Split up the connector's mode_valid helper into a simple-pipe and a
mode-config helper. The simple-pipe helper tests for display-size
limits while the mode-config helper tests for memory-bandwidth limits.

Also add the mgag200_ prefix to mga_vga_calculate_mode_bandwidth() and
comment on the function's purpose.

The memory-bandwidth tests assume that the display uses 4 bytes per
pixel. The first models of G200SE-A only had 1.75 MiB of VRAM, which
limits these devices to 640x480-32.

v2:
	* note the memory constraints on early G200SE-A

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220516134343.6085-8-tzimmermann@suse.de

1 files changed, 69 insertions, 77 deletions

diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index a718a20b3a20..028c6ba7124c 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -705,38 +705,27 @@ static int mgag200_vga_connector_helper_get_modes(struct drm_connector *connecto
 	return ret;
 }
 
-static uint32_t mga_vga_calculate_mode_bandwidth(struct drm_display_mode *mode,
-							int bits_per_pixel)
-{
-	uint32_t total_area, divisor;
-	uint64_t active_area, pixels_per_second, bandwidth;
-	uint64_t bytes_per_pixel = (bits_per_pixel + 7) / 8;
-
-	divisor = 1024;
-
-	if (!mode->htotal || !mode->vtotal || !mode->clock)
-		return 0;
-
-	active_area = mode->hdisplay * mode->vdisplay;
-	total_area = mode->htotal * mode->vtotal;
-
-	pixels_per_second = active_area * mode->clock * 1000;
-	do_div(pixels_per_second, total_area);
-
-	bandwidth = pixels_per_second * bytes_per_pixel * 100;
-	do_div(bandwidth, divisor);
+static const struct drm_connector_helper_funcs mga_vga_connector_helper_funcs = {
+	.get_modes  = mgag200_vga_connector_helper_get_modes,
+};
 
-	return (uint32_t)(bandwidth);
-}
+static const struct drm_connector_funcs mga_vga_connector_funcs = {
+	.reset                  = drm_atomic_helper_connector_reset,
+	.fill_modes             = drm_helper_probe_single_connector_modes,
+	.destroy                = drm_connector_cleanup,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
+};
 
-#define MODE_BANDWIDTH	MODE_BAD
+/*
+ * Simple Display Pipe
+ */
 
-static enum drm_mode_status mga_vga_mode_valid(struct drm_connector *connector,
-				 struct drm_display_mode *mode)
+static enum drm_mode_status
+mgag200_simple_display_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
+				       const struct drm_display_mode *mode)
 {
-	struct drm_device *dev = connector->dev;
-	struct mga_device *mdev = to_mga_device(dev);
-	int bpp = 32;
+	struct mga_device *mdev = to_mga_device(pipe->crtc.dev);
 
 	if (IS_G200_SE(mdev)) {
 		u32 unique_rev_id = mdev->model.g200se.unique_rev_id;
@@ -746,42 +735,17 @@ static enum drm_mode_status mga_vga_mode_valid(struct drm_connector *connector,
 				return MODE_VIRTUAL_X;
 			if (mode->vdisplay > 1200)
 				return MODE_VIRTUAL_Y;
-			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
-				> (24400 * 1024))
-				return MODE_BANDWIDTH;
 		} else if (unique_rev_id == 0x02) {
 			if (mode->hdisplay > 1920)
 				return MODE_VIRTUAL_X;
 			if (mode->vdisplay > 1200)
 				return MODE_VIRTUAL_Y;
-			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
-				> (30100 * 1024))
-				return MODE_BANDWIDTH;
-		} else {
-			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
-				> (55000 * 1024))
-				return MODE_BANDWIDTH;
 		}
 	} else if (mdev->type == G200_WB) {
 		if (mode->hdisplay > 1280)
 			return MODE_VIRTUAL_X;
 		if (mode->vdisplay > 1024)
 			return MODE_VIRTUAL_Y;
-		if (mga_vga_calculate_mode_bandwidth(mode, bpp) >
-		    (31877 * 1024))
-			return MODE_BANDWIDTH;
-	} else if (mdev->type == G200_EV &&
-		(mga_vga_calculate_mode_bandwidth(mode, bpp)
-			> (32700 * 1024))) {
-		return MODE_BANDWIDTH;
-	} else if (mdev->type == G200_EH &&
-		(mga_vga_calculate_mode_bandwidth(mode, bpp)
-			> (37500 * 1024))) {
-		return MODE_BANDWIDTH;
-	} else if (mdev->type == G200_ER &&
-		(mga_vga_calculate_mode_bandwidth(mode,
-			bpp) > (55000 * 1024))) {
-		return MODE_BANDWIDTH;
 	}
 
 	if ((mode->hdisplay % 8) != 0 || (mode->hsync_start % 8) != 0 ||
@@ -799,30 +763,6 @@ static enum drm_mode_status mga_vga_mode_valid(struct drm_connector *connector,
 	return MODE_OK;
 }
 
-static const struct drm_connector_helper_funcs mga_vga_connector_helper_funcs = {
-	.get_modes  = mgag200_vga_connector_helper_get_modes,
-	.mode_valid = mga_vga_mode_valid,
-};
-
-static const struct drm_connector_funcs mga_vga_connector_funcs = {
-	.reset                  = drm_atomic_helper_connector_reset,
-	.fill_modes             = drm_helper_probe_single_connector_modes,
-	.destroy                = drm_connector_cleanup,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
-};
-
-/*
- * Simple Display Pipe
- */
-
-static enum drm_mode_status
-mgag200_simple_display_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
-				       const struct drm_display_mode *mode)
-{
-	return MODE_OK;
-}
-
 static void
 mgag200_handle_damage(struct mga_device *mdev, struct drm_framebuffer *fb,
 		      struct drm_rect *clip, const struct iosys_map *map)
@@ -1055,6 +995,31 @@ static const uint64_t mgag200_simple_display_pipe_fmtmods[] = {
  * Mode config
  */
 
+/* Calculates a mode's required memory bandwidth (in KiB/sec). */
+static uint32_t mgag200_calculate_mode_bandwidth(const struct drm_display_mode *mode,
+						 unsigned int bits_per_pixel)
+{
+	uint32_t total_area, divisor;
+	uint64_t active_area, pixels_per_second, bandwidth;
+	uint64_t bytes_per_pixel = (bits_per_pixel + 7) / 8;
+
+	divisor = 1024;
+
+	if (!mode->htotal || !mode->vtotal || !mode->clock)
+		return 0;
+
+	active_area = mode->hdisplay * mode->vdisplay;
+	total_area = mode->htotal * mode->vtotal;
+
+	pixels_per_second = active_area * mode->clock * 1000;
+	do_div(pixels_per_second, total_area);
+
+	bandwidth = pixels_per_second * bytes_per_pixel * 100;
+	do_div(bandwidth, divisor);
+
+	return (uint32_t)bandwidth;
+}
+
 static enum drm_mode_status mgag200_mode_config_mode_valid(struct drm_device *dev,
 							   const struct drm_display_mode *mode)
 {
@@ -1070,6 +1035,33 @@ static enum drm_mode_status mgag200_mode_config_mode_valid(struct drm_device *de
 	if (fbpages > max_fbpages)
 		return MODE_MEM;
 
+	if (IS_G200_SE(mdev)) {
+		u32 unique_rev_id = mdev->model.g200se.unique_rev_id;
+
+		if (unique_rev_id == 0x01) {
+			if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (24400 * 1024))
+				return MODE_BAD;
+		} else if (unique_rev_id == 0x02) {
+			if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (30100 * 1024))
+				return MODE_BAD;
+		} else {
+			if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (55000 * 1024))
+				return MODE_BAD;
+		}
+	} else if (mdev->type == G200_WB) {
+		if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (31877 * 1024))
+			return MODE_BAD;
+	} else if (mdev->type == G200_EV) {
+		if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (32700 * 1024))
+			return MODE_BAD;
+	} else if (mdev->type == G200_EH) {
+		if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (37500 * 1024))
+			return MODE_BAD;
+	} else if (mdev->type == G200_ER) {
+		if (mgag200_calculate_mode_bandwidth(mode, max_bpp * 8) > (55000 * 1024))
+			return MODE_BAD;
+	}
+
 	return MODE_OK;
 }