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Date:   Fri, 30 Jul 2021 16:37:42 -0700
From:   abhinavk@codeaurora.org
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Kalyan Thota <kalyan_t@codeaurora.org>,
        Kuogee Hsieh <khsieh@codeaurora.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        Stephen Boyd <swboyd@chromium.org>,
        Rob Herring <robh+dt@kernel.org>,
        freedreno@lists.freedesktop.org
Subject: Re: [Freedreno] [PATCH 1/5] drm/msm/dp: Remove global g_dp_display
 variable
In-Reply-To: <20210725042436.3967173-2-bjorn.andersson@linaro.org>
References: <20210725042436.3967173-1-bjorn.andersson@linaro.org>
 <20210725042436.3967173-2-bjorn.andersson@linaro.org>
Message-ID: <51b482e276c6fedc91d70797aca35da6@codeaurora.org>
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On 2021-07-24 21:24, Bjorn Andersson wrote:
> As the Qualcomm DisplayPort driver only supports a single instance of
> the driver the commonly used struct dp_display is kept in a global
> variable. As we introduce additional instances this obviously doesn't
> work.
> 
> Replace this with a combination of existing references to adjacent
> objects and drvdata.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 78 ++++++++++++++---------------
>  1 file changed, 37 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
> b/drivers/gpu/drm/msm/dp/dp_display.c
> index 70b319a8fe83..8696b36d30e4 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -27,7 +27,6 @@
>  #include "dp_audio.h"
>  #include "dp_debug.h"
> 
> -static struct msm_dp *g_dp_display;
>  #define HPD_STRING_SIZE 30
> 
>  enum {
> @@ -122,6 +121,13 @@ static const struct of_device_id dp_dt_match[] = {
>  	{}
>  };
> 
> +static struct dp_display_private *dev_to_dp_display_private(struct 
> device *dev)
> +{
> +	struct msm_dp *dp = dev_get_drvdata(dev);
> +
> +	return container_of(dp, struct dp_display_private, dp_display);
> +}
> +
>  static int dp_add_event(struct dp_display_private *dp_priv, u32 event,
>  						u32 data, u32 delay)
>  {
> @@ -198,14 +204,16 @@ static int dp_display_bind(struct device *dev,
> struct device *master,
>  			   void *data)
>  {
>  	int rc = 0;
> -	struct dp_display_private *dp;
> +	struct dp_display_private *dp = dev_to_dp_display_private(dev);
>  	struct drm_device *drm;
>  	struct msm_drm_private *priv;
> 
>  	drm = dev_get_drvdata(master);
> 
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> +	if (!dp) {
> +		DRM_ERROR("DP driver bind failed. Invalid driver data\n");
> +		return -EINVAL;
> +	}
> 
>  	dp->dp_display.drm_dev = drm;
>  	priv = drm->dev_private;
> @@ -240,12 +248,14 @@ static int dp_display_bind(struct device *dev,
> struct device *master,
>  static void dp_display_unbind(struct device *dev, struct device 
> *master,
>  			      void *data)
>  {
> -	struct dp_display_private *dp;
> +	struct dp_display_private *dp = dev_to_dp_display_private(dev);
>  	struct drm_device *drm = dev_get_drvdata(master);
>  	struct msm_drm_private *priv = drm->dev_private;
> 
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> +	if (!dp) {
> +		DRM_ERROR("Invalid DP driver data\n");
> +		return;
> +	}
> 
>  	dp_power_client_deinit(dp->power);
>  	dp_aux_unregister(dp->aux);
> @@ -376,17 +386,14 @@ static void dp_display_host_deinit(struct
> dp_display_private *dp)
>  static int dp_display_usbpd_configure_cb(struct device *dev)
>  {
>  	int rc = 0;
> -	struct dp_display_private *dp;
> +	struct dp_display_private *dp = dev_to_dp_display_private(dev);
> 
> -	if (!dev) {
> -		DRM_ERROR("invalid dev\n");
> -		rc = -EINVAL;
> +	if (!dp) {
> +		DRM_ERROR("no driver data found\n");
> +		rc = -ENODEV;
>  		goto end;
>  	}
> 
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> -
>  	dp_display_host_init(dp, false);
> 
>  	rc = dp_display_process_hpd_high(dp);
> @@ -397,17 +404,14 @@ static int dp_display_usbpd_configure_cb(struct
> device *dev)
>  static int dp_display_usbpd_disconnect_cb(struct device *dev)
>  {
>  	int rc = 0;
> -	struct dp_display_private *dp;
> +	struct dp_display_private *dp = dev_to_dp_display_private(dev);
> 
> -	if (!dev) {
> -		DRM_ERROR("invalid dev\n");
> -		rc = -EINVAL;
> +	if (!dp) {
> +		DRM_ERROR("no driver data found\n");
> +		rc = -ENODEV;
>  		return rc;
>  	}
> 
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> -
>  	dp_add_event(dp, EV_USER_NOTIFICATION, false, 0);
> 
>  	return rc;
> @@ -466,15 +470,15 @@ static int dp_display_usbpd_attention_cb(struct
> device *dev)
>  {
>  	int rc = 0;
>  	u32 sink_request;
> -	struct dp_display_private *dp;
> +	struct dp_display_private *dp = dev_to_dp_display_private(dev);
> +	struct dp_usbpd *hpd;
> 
> -	if (!dev) {
> -		DRM_ERROR("invalid dev\n");
> -		return -EINVAL;
> +	if (!dp) {
> +		DRM_ERROR("no driver data found\n");
> +		return -ENODEV;
>  	}
> 
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> +	hpd = dp->usbpd;
hpd is unused here. It was removed with 
https://patches.linaro.org/patch/416670/

> 
>  	/* check for any test request issued by sink */
>  	rc = dp_link_process_request(dp->link);
> @@ -638,7 +642,7 @@ static int dp_hpd_unplug_handle(struct
> dp_display_private *dp, u32 data)
>  	dp_add_event(dp, EV_DISCONNECT_PENDING_TIMEOUT, 0, 
> DP_TIMEOUT_5_SECOND);
> 
>  	/* signal the disconnect event early to ensure proper teardown */
> -	dp_display_handle_plugged_change(g_dp_display, false);
> +	dp_display_handle_plugged_change(&dp->dp_display, false);
> 
>  	/* enable HDP plug interrupt to prepare for next plugin */
>  	dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_PLUG_INT_MASK, 
> true);
> @@ -832,9 +836,7 @@ static int dp_display_prepare(struct msm_dp *dp)
>  static int dp_display_enable(struct dp_display_private *dp, u32 data)
>  {
>  	int rc = 0;
> -	struct msm_dp *dp_display;
> -
> -	dp_display = g_dp_display;
> +	struct msm_dp *dp_display = &dp->dp_display;
> 
>  	if (dp_display->power_on) {
>  		DRM_DEBUG_DP("Link already setup, return\n");
> @@ -869,9 +871,7 @@ static int dp_display_post_enable(struct msm_dp 
> *dp_display)
> 
>  static int dp_display_disable(struct dp_display_private *dp, u32 data)
>  {
> -	struct msm_dp *dp_display;
> -
> -	dp_display = g_dp_display;
> +	struct msm_dp *dp_display = &dp->dp_display;
> 
>  	if (!dp_display->power_on)
>  		return 0;
> @@ -1229,14 +1229,13 @@ static int dp_display_probe(struct
> platform_device *pdev)
>  	}
> 
>  	mutex_init(&dp->event_mutex);
> -	g_dp_display = &dp->dp_display;
> 
>  	/* Store DP audio handle inside DP display */
> -	g_dp_display->dp_audio = dp->audio;
> +	dp->dp_display.dp_audio = dp->audio;
> 
>  	init_completion(&dp->audio_comp);
> 
> -	platform_set_drvdata(pdev, g_dp_display);
> +	platform_set_drvdata(pdev, &dp->dp_display);
> 
>  	rc = component_add(&pdev->dev, &dp_display_comp_ops);
>  	if (rc) {
> @@ -1249,10 +1248,7 @@ static int dp_display_probe(struct 
> platform_device *pdev)
> 
>  static int dp_display_remove(struct platform_device *pdev)
>  {
> -	struct dp_display_private *dp;
> -
> -	dp = container_of(g_dp_display,
> -			struct dp_display_private, dp_display);
> +	struct dp_display_private *dp = platform_get_drvdata(pdev);
> 
>  	dp_display_deinit_sub_modules(dp);