[PATCH v3 4/6] drm: lcdif: Check consistent bus format and flags across first bridges

From: Liu Ying
Date: Mon Feb 13 2023 - 03:55:58 EST


The single LCDIF embedded in i.MX93 SoC may drive multiple displays
simultaneously. Check bus format and flags across first bridges in
->atomic_check() to ensure they are consistent. This is a preparation
for adding i.MX93 LCDIF support.

Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
---
v2->v3:
* No change.

v1->v2:
* Split from patch 2/2 in v1. (Marek, Alexander)
* Drop a comment about bridge input bus format from lcdif_crtc_atomic_check().

drivers/gpu/drm/mxsfb/lcdif_drv.c | 2 -
drivers/gpu/drm/mxsfb/lcdif_drv.h | 1 -
drivers/gpu/drm/mxsfb/lcdif_kms.c | 76 ++++++++++++++++++++++---------
3 files changed, 55 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/lcdif_drv.c b/drivers/gpu/drm/mxsfb/lcdif_drv.c
index cc2ceb301b96..b5b9a8e273c6 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_drv.c
+++ b/drivers/gpu/drm/mxsfb/lcdif_drv.c
@@ -52,8 +52,6 @@ static int lcdif_attach_bridge(struct lcdif_drm_private *lcdif)
if (ret)
return dev_err_probe(drm->dev, ret, "Failed to attach bridge\n");

- lcdif->bridge = bridge;
-
return 0;
}

diff --git a/drivers/gpu/drm/mxsfb/lcdif_drv.h b/drivers/gpu/drm/mxsfb/lcdif_drv.h
index 6cdba6e20c02..aa6d099a1897 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_drv.h
+++ b/drivers/gpu/drm/mxsfb/lcdif_drv.h
@@ -31,7 +31,6 @@ struct lcdif_drm_private {
} planes;
struct drm_crtc crtc;
struct drm_encoder encoder;
- struct drm_bridge *bridge;
};

static inline struct lcdif_drm_private *
diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c
index 294cecdf5439..4ea3d2b2cf61 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
+++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
@@ -17,6 +17,7 @@
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_color_mgmt.h>
+#include <drm/drm_connector.h>
#include <drm/drm_crtc.h>
#include <drm/drm_encoder.h>
#include <drm/drm_fb_dma_helper.h>
@@ -424,15 +425,19 @@ static int lcdif_crtc_atomic_check(struct drm_crtc *crtc,
struct drm_atomic_state *state)
{
struct drm_device *drm = crtc->dev;
- struct lcdif_drm_private *lcdif = to_lcdif_drm_private(drm);
struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
crtc);
struct lcdif_crtc_state *lcdif_crtc_state = to_lcdif_crtc_state(crtc_state);
bool has_primary = crtc_state->plane_mask &
drm_plane_mask(crtc->primary);
+ struct drm_connector_state *connector_state;
+ struct drm_connector *connector;
+ struct drm_encoder *encoder;
struct drm_bridge_state *bridge_state;
- struct drm_bridge *bridge = lcdif->bridge;
- int ret;
+ struct drm_bridge *bridge;
+ u32 bus_format, bus_flags;
+ bool format_set = false, flags_set = false;
+ int ret, i;

/* The primary plane has to be enabled when the CRTC is active. */
if (crtc_state->active && !has_primary)
@@ -442,26 +447,55 @@ static int lcdif_crtc_atomic_check(struct drm_crtc *crtc,
if (ret)
return ret;

- bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
- if (!bridge_state)
- lcdif_crtc_state->bus_format = MEDIA_BUS_FMT_FIXED;
- else
- lcdif_crtc_state->bus_format = bridge_state->input_bus_cfg.format;
-
- if (lcdif_crtc_state->bus_format == MEDIA_BUS_FMT_FIXED) {
- dev_warn_once(drm->dev,
- "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
- "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
- lcdif_crtc_state->bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+ /* Try to find consistent bus format and flags across first bridges. */
+ for_each_new_connector_in_state(state, connector, connector_state, i) {
+ if (!connector_state->crtc)
+ continue;
+
+ encoder = connector_state->best_encoder;
+
+ bridge = drm_bridge_chain_get_first_bridge(encoder);
+ if (!bridge)
+ continue;
+
+ bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+ if (!bridge_state)
+ bus_format = MEDIA_BUS_FMT_FIXED;
+ else
+ bus_format = bridge_state->input_bus_cfg.format;
+
+ if (bus_format == MEDIA_BUS_FMT_FIXED) {
+ dev_warn(drm->dev,
+ "[ENCODER:%d:%s]'s bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
+ "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n",
+ encoder->base.id, encoder->name);
+ bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+ }
+
+ if (!format_set) {
+ lcdif_crtc_state->bus_format = bus_format;
+ format_set = true;
+ } else if (lcdif_crtc_state->bus_format != bus_format) {
+ DRM_DEV_DEBUG_DRIVER(drm->dev, "inconsistent bus format\n");
+ return -EINVAL;
+ }
+
+ if (bridge->timings)
+ bus_flags = bridge->timings->input_bus_flags;
+ else if (bridge_state)
+ bus_flags = bridge_state->input_bus_cfg.flags;
+ else
+ bus_flags = 0;
+
+ if (!flags_set) {
+ lcdif_crtc_state->bus_flags = bus_flags;
+ flags_set = true;
+ } else if (lcdif_crtc_state->bus_flags != bus_flags) {
+ DRM_DEV_DEBUG_DRIVER(drm->dev, "inconsistent bus flags\n");
+ return -EINVAL;
+ }
}

- if (bridge->timings)
- lcdif_crtc_state->bus_flags = bridge->timings->input_bus_flags;
- else if (bridge_state)
- lcdif_crtc_state->bus_flags = bridge_state->input_bus_cfg.flags;
- else
- lcdif_crtc_state->bus_flags = 0;
-
return 0;
}

--
2.37.1