Hi,

On 14/01/2025 07:56, Aradhya Bhatia wrote:
From: Aradhya Bhatia <a-bhat...@ti.com>

At present, the DSI mode configuration check happens during the
_atomic_enable() phase, which is not really the best place for this.
Moreover, if the mode is not valid, the driver gives a warning and
continues the hardware configuration.

Move the DSI mode configuration check to _atomic_check() instead, which
can properly report back any invalid mode, before the _enable phase even
begins.

Signed-off-by: Aradhya Bhatia <a-bhat...@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bha...@linux.dev>
---
  .../gpu/drm/bridge/cadence/cdns-dsi-core.c    | 87 +++++++++++++++++--
  1 file changed, 82 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c 
b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
index b8db984ea9fa..d60254e1270c 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
@@ -425,6 +425,17 @@
  #define DSI_NULL_FRAME_OVERHEAD               6
  #define DSI_EOT_PKT_SIZE              4
+struct cdns_dsi_bridge_state {
+       struct drm_bridge_state base;
+       struct cdns_dsi_cfg dsi_cfg;
+};
+
+static inline struct cdns_dsi_bridge_state *
+to_cdns_dsi_bridge_state(struct drm_bridge_state *bridge_state)
+{
+       return container_of(bridge_state, struct cdns_dsi_bridge_state, base);
+}
+
  static inline struct cdns_dsi *input_to_dsi(struct cdns_dsi_input *input)
  {
        return container_of(input, struct cdns_dsi, input);
@@ -768,6 +779,9 @@ static void cdns_dsi_bridge_atomic_enable(struct drm_bridge 
*bridge,
        struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
        struct cdns_dsi *dsi = input_to_dsi(input);
        struct cdns_dsi_output *output = &dsi->output;
+       struct drm_atomic_state *state = old_bridge_state->base.state;
+       struct cdns_dsi_bridge_state *dsi_state;
+       struct drm_bridge_state *new_bridge_state;
        struct drm_display_mode *mode;
        struct phy_configure_opts_mipi_dphy *phy_cfg = 
&output->phy_opts.mipi_dphy;
        unsigned long tx_byte_period;
@@ -778,14 +792,19 @@ static void cdns_dsi_bridge_atomic_enable(struct 
drm_bridge *bridge,
        if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
                return;
+ new_bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+       if (WARN_ON(!new_bridge_state))
+               return;
+
+       dsi_state = to_cdns_dsi_bridge_state(new_bridge_state);
+       dsi_cfg = dsi_state->dsi_cfg;
+
        if (dsi->platform_ops && dsi->platform_ops->enable)
                dsi->platform_ops->enable(dsi);
mode = &bridge->encoder->crtc->state->adjusted_mode;
        nlanes = output->dev->lanes;
- WARN_ON_ONCE(cdns_dsi_check_conf(dsi, mode, &dsi_cfg, false));
-
        cdns_dsi_init_link(dsi);
        cdns_dsi_hs_init(dsi);
@@ -956,6 +975,63 @@ static u32 *cdns_dsi_bridge_get_input_bus_fmts(struct drm_bridge *bridge,
        return input_fmts;
  }
+static int cdns_dsi_bridge_atomic_check(struct drm_bridge *bridge,
+                                       struct drm_bridge_state *bridge_state,
+                                       struct drm_crtc_state *crtc_state,
+                                       struct drm_connector_state *conn_state)
+{
+       struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
+       struct cdns_dsi *dsi = input_to_dsi(input);
+       struct cdns_dsi_bridge_state *dsi_state = 
to_cdns_dsi_bridge_state(bridge_state);
+       struct drm_display_mode *mode = &crtc_state->mode;

const

+       struct cdns_dsi_cfg *dsi_cfg = &dsi_state->dsi_cfg;
+
+       return cdns_dsi_check_conf(dsi, mode, dsi_cfg, false);
+}
+
+static struct drm_bridge_state *
+cdns_dsi_bridge_atomic_duplicate_state(struct drm_bridge *bridge)
+{
+       struct cdns_dsi_bridge_state *dsi_state;
+
+       if (WARN_ON(!bridge->base.state))
+               return NULL;
+
+       dsi_state = kzalloc(sizeof(*dsi_state), GFP_KERNEL);
+       if (!dsi_state)
+               return NULL;
+
+       __drm_atomic_helper_bridge_duplicate_state(bridge, &dsi_state->base);

Hmm, if I'm not mistaken, you should copy the private state here (cdns_dsi_cfg).

+       return &dsi_state->base;
+}
+
+static void
+cdns_dsi_bridge_atomic_destroy_state(struct drm_bridge *bridge,
+                                    struct drm_bridge_state *state)
+{
+       struct cdns_dsi_bridge_state *dsi_state;
+
+       dsi_state = to_cdns_dsi_bridge_state(state);
+
+       kfree(dsi_state);
+}
+
+static struct drm_bridge_state *
+cdns_dsi_bridge_atomic_reset(struct drm_bridge *bridge)
+{
+       struct cdns_dsi_bridge_state *dsi_state;
+
+       dsi_state = kzalloc(sizeof(*dsi_state), GFP_KERNEL);
+       if (!dsi_state)
+               return NULL;
+
+       memset(dsi_state, 0, sizeof(*dsi_state));
+       dsi_state->base.bridge = bridge;
+
+       return &dsi_state->base;
+}
+
  static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
        .attach = cdns_dsi_bridge_attach,
        .mode_valid = cdns_dsi_bridge_mode_valid,
@@ -963,9 +1039,10 @@ static const struct drm_bridge_funcs 
cdns_dsi_bridge_funcs = {
        .atomic_pre_enable = cdns_dsi_bridge_atomic_pre_enable,
        .atomic_enable = cdns_dsi_bridge_atomic_enable,
        .atomic_post_disable = cdns_dsi_bridge_atomic_post_disable,
-       .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
-       .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
-       .atomic_reset = drm_atomic_helper_bridge_reset,
+       .atomic_check = cdns_dsi_bridge_atomic_check,
+       .atomic_duplicate_state = cdns_dsi_bridge_atomic_duplicate_state,
+       .atomic_destroy_state = cdns_dsi_bridge_atomic_destroy_state,
+       .atomic_reset = cdns_dsi_bridge_atomic_reset,
        .atomic_get_input_bus_fmts = cdns_dsi_bridge_get_input_bus_fmts,
  };

Other than the two small comments:

Reviewed-by: Tomi Valkeinen <tomi.valkei...@ideasonboard.com>

 Tomi

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