Message-ID: <fhgqv3cvjktmgpwuaxi2bfz5iebpwuodhg4eiezvrznxi7zm4i@vsc3ukxo6uox>
Date: Sun, 9 Feb 2025 09:06:29 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Maxime Ripard <mripard@...nel.org>
Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Andrzej Hajda <andrzej.hajda@...el.com>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Douglas Anderson <dianders@...omium.org>, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 32/35] drm/bridge: cdns-csi: Switch to atomic helpers

On Tue, Feb 04, 2025 at 03:58:00PM +0100, Maxime Ripard wrote:
> The Cadence DSI driver follows the drm_encoder->crtc pointer that is
> deprecated and shouldn't be used by atomic drivers.
> 
> This was due to the fact that we did't have any other alternative to
> retrieve the CRTC pointer.

See below.

> Fortunately, the crtc pointer is now provided

Nit: CRTC

> in the bridge state, so we can move to atomic callbacks and drop that
> deprecated pointer usage.
> 
> Signed-off-by: Maxime Ripard <mripard@...nel.org>
> ---
>  drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 27 +++++++++++++++++---------
>  1 file changed, 18 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> index 8f54c034ac4f3e82c38607a0e52d4745654b571f..c856e7843f83b363340443dec1deb26c9ae1b912 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> @@ -654,11 +654,12 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>  		return MODE_BAD;
>  
>  	return MODE_OK;
>  }
>  
> -static void cdns_dsi_bridge_disable(struct drm_bridge *bridge)
> +static void cdns_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
> +					   struct drm_atomic_state *state)
>  {
>  	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
>  	struct cdns_dsi *dsi = input_to_dsi(input);
>  	u32 val;
>  
> @@ -674,11 +675,12 @@ static void cdns_dsi_bridge_disable(struct drm_bridge *bridge)
>  		dsi->platform_ops->disable(dsi);
>  
>  	pm_runtime_put(dsi->base.dev);
>  }
>  
> -static void cdns_dsi_bridge_post_disable(struct drm_bridge *bridge)
> +static void cdns_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
> +						struct drm_atomic_state *state)
>  {
>  	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
>  	struct cdns_dsi *dsi = input_to_dsi(input);
>  
>  	pm_runtime_put(dsi->base.dev);
> @@ -751,15 +753,17 @@ static void cdns_dsi_init_link(struct cdns_dsi *dsi)
>  	writel(val, dsi->regs + MCTL_MAIN_EN);
>  
>  	dsi->link_initialized = true;
>  }
>  
> -static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
> +static void cdns_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
> +					  struct drm_atomic_state *state)
>  {
>  	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_bridge_state *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;
>  	struct cdns_dsi_cfg dsi_cfg;
>  	u32 tmp, reg_wakeup, div;
> @@ -769,11 +773,12 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
>  		return;
>  
>  	if (dsi->platform_ops && dsi->platform_ops->enable)
>  		dsi->platform_ops->enable(dsi);
>  
> -	mode = &bridge->encoder->crtc->state->adjusted_mode;
> +	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
> +	mode = &bridge_state->crtc->state->adjusted_mode;

And then it also follows crtc->state, which might fail for non-blocking
commits.

I think a proper way would be to

connector = drm_atomic_get_new_connector_for_encoder(state, encoder);
conn_state = drm_atomic_get_new_connector_state(state, connector);
crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);

>  	nlanes = output->dev->lanes;
>  
>  	WARN_ON_ONCE(cdns_dsi_check_conf(dsi, mode, &dsi_cfg, false));
>  
>  	cdns_dsi_hs_init(dsi);
> @@ -891,11 +896,12 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
>  
>  	tmp = readl(dsi->regs + MCTL_MAIN_EN) | IF_EN(input->id);
>  	writel(tmp, dsi->regs + MCTL_MAIN_EN);
>  }
>  
> -static void cdns_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> +static void cdns_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
> +					      struct drm_atomic_state *state)
>  {
>  	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
>  	struct cdns_dsi *dsi = input_to_dsi(input);
>  
>  	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
> @@ -906,14 +912,17 @@ static void cdns_dsi_bridge_pre_enable(struct drm_bridge *bridge)
>  }
>  
>  static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
>  	.attach = cdns_dsi_bridge_attach,
>  	.mode_valid = cdns_dsi_bridge_mode_valid,
> -	.disable = cdns_dsi_bridge_disable,
> -	.pre_enable = cdns_dsi_bridge_pre_enable,
> -	.enable = cdns_dsi_bridge_enable,
> -	.post_disable = cdns_dsi_bridge_post_disable,
> +	.atomic_disable = cdns_dsi_bridge_atomic_disable,
> +	.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_reset = drm_atomic_helper_bridge_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>  };
>  
>  static int cdns_dsi_attach(struct mipi_dsi_host *host,
>  			   struct mipi_dsi_device *dev)
>  {
> 
> -- 
> 2.48.0
> 

-- 
With best wishes
Dmitry

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