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Message-ID: <026a84c3-c2d2-0ea7-0bf6-a6580abad0ef@linaro.org>
Date: Tue, 27 Jul 2021 21:15:31 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bjorn Andersson <bjorn.andersson@...aro.org>,
Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Abhinav Kumar <abhinavk@...eaurora.org>,
Kalyan Thota <kalyan_t@...eaurora.org>,
Kuogee Hsieh <khsieh@...eaurora.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Stephen Boyd <swboyd@...omium.org>,
linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] drm/msm/dp: Remove global g_dp_display variable
On 25/07/2021 07:24, 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@...aro.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)
dev_get_dp_display_private() ?
> +{
> + struct msm_dp *dp = dev_get_drvdata(dev);
> +
> + return container_of(dp, struct dp_display_private, dp_display);
> +}
> +
As a matter of preference, it might be cleaner to inline dev_get_drvdata
and then define msm_dp_get_private to convert from msm_dp to
dp_display_private, see below.
> 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) {
This is not correct, if I'm not mistaken. you wanted to check if dev's
private data is NULL (correct check), but ended up checking whether the
result of container_of is NULL (incorrect).
> + 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;
`!dev` check should remain in place. And dp should be fetched
afterwards. This applies to all the checks in the patch.
> + 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;
>
> /* 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);
dev_to_dp_display_private() rather than just get_drvdata?
>
> dp_display_deinit_sub_modules(dp);
>
>
--
With best wishes
Dmitry
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