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From: Heiko =?ISO-8859-1?Q?St=FCbner?= <heiko@sntech.de>
To: Farouk Bouabid <farouk.bouabid@theobroma-systems.com>, victor.liu@nxp.com,
 andrzej.hajda@intel.com, rfoss@kernel.org, jonas@kwiboo.se,
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 shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
 festevam@gmail.com, linux-imx@nxp.com, khilman@baylibre.com,
 jbrunet@baylibre.com, martin.blumenstingl@googlemail.com, hjc@rock-chips.com,
 yannick.fertre@foss.st.com, raphael.gallais-pou@foss.st.com,
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 linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
 linux-amlogic@lists.infradead.org, linux-rockchip@lists.infradead.org,
 linux-stm32@st-md-mailman.stormreply.com, neil.armstrong@linaro.org
Cc: quentin.schulz@theobroma-systems.com, bouabid.farouk97@gmail.com
Subject:
 Re: [PATCH] drm/bridge: synopsys: dw-mipi-dsi: fix deferred dsi host probe
 breaks dsi device probe
Date: Mon, 15 Jan 2024 11:07:14 +0100
Message-ID: <8542394.JRmrKFJ9eK@diego>
In-Reply-To: <9dd100de-6d33-4872-8619-1df6ee520c5a@linaro.org>
References:
 <20240112180737.551318-1-farouk.bouabid@theobroma-systems.com>
 <9dd100de-6d33-4872-8619-1df6ee520c5a@linaro.org>
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Am Montag, 15. Januar 2024, 09:45:10 CET schrieb neil.armstrong@linaro.org:
> Hi,
> 
> On 12/01/2024 19:07, Farouk Bouabid wrote:
> > dw-mipi-dsi based drivers such as dw-mipi-dsi-rockchip or dw_mipi_dsi-stm
> > depend on dw_mipi_dsi_probe() to initialize the dw_mipi_dsi driver
> > structure (dmd pointer). This structure is only initialized once
> > dw_mipi_dsi_probe() returns, creating the link between the locally created
> > structure and the actual dmd pointer.
> > 
> > Probing the dsi host can be deferred in case of dependency to a dsi
> > phy-supply (eg. "rockchip,px30-dsi-dphy"). Meanwhile dsi-device drivers
> > like panels (eg. "ltk050h3146w") can already be registered on the bus.
> > In that case, when attempting, to register the dsi host from
> > dw_mipi_dsi_probe() using mipi_dsi_host_register(), the panel probe is
> > called with a dsi-host pointer that is still locally allocated in
> > dw_mipi_dsi_probe().
> > 
> > While probing, the panel driver tries to attach to a dsi host
> > (mipi_dsi_attach()) which calls in return for the specific dsi host
> > attach hook. (e.g. dw_mipi_dsi_rockchip_host_attach()).
> > dw_mipi_dsi_rockchip uses the component framework.
> > In the attach hook, the host component is registered which calls in return
> > for drm_bridge_attach() while trying to bind the component
> > (dw_mipi_dsi_bind())
> 
> In meson_dw_mipi_dsi I simply fixed this by getting rid of components...

If I remember correctly, the component element is there on Rockchip to
facilitate running dual-dsi displays (1 panel driven by 2 dsi controllers),
because it allows to wait for both controllers to have probed individually
before trying to drive the display.

Not sure if there is a better way to do that now.


Heiko


> > drm_bridge_attach() requires a valid drm bridge parameter. However, the
> > drm bridge (&dmd->bridge) that will be passed, is not yet initialized since
> > the dw_mipi_dsi_probe() has not yet returned. This call will fail with a
> > fatal error (invalid bridge) causing the panel to not be probed again.
> > 
> > To simplify the issue: drm_bridge_attach() depends on the result pointer
> > of dw_mipi_dsi_probe().
> > While, if the dsi probe is deferred, drm_bridge_attach() is called before
> > dw_mipi_dsi_probe() returns.
> > 
> > drm_bridge_attach+0x14/0x1ac
> > dw_mipi_dsi_bind+0x24/0x30
> > dw_mipi_dsi_rockchip_bind+0x258/0x378
> > component_bind_all+0x118/0x248
> > rockchip_drm_bind+0xb0/0x1f8
> > try_to_bring_up_aggregate_device+0x168/0x1d4
> > __component_add+0xa4/0x170
> > component_add+0x14/0x20
> > dw_mipi_dsi_rockchip_host_attach+0x54/0x144
> > dw_mipi_dsi_host_attach+0x9c/0xcc
> > mipi_dsi_attach+0x28/0x3c
> > ltk050h3146w_probe+0x10c/0x1a4
> > mipi_dsi_drv_probe+0x20/0x2c
> > really_probe+0x148/0x2ac
> > __driver_probe_device+0x78/0x12c
> > driver_probe_device+0xdc/0x160
> > __device_attach_driver+0xb8/0x134
> > bus_for_each_drv+0x80/0xdc
> > __device_attach+0xa8/0x1b0
> > device_initial_probe+0x14/0x20
> > bus_probe_device+0xa8/0xac
> > device_add+0x5cc/0x778
> > mipi_dsi_device_register_full+0xd8/0x198
> > mipi_dsi_host_register+0x98/0x18c
> > __dw_mipi_dsi_probe+0x290/0x35c
> > dw_mipi_dsi_probe+0x10/0x6c
> > dw_mipi_dsi_rockchip_probe+0x208/0x3e4
> > platform_probe+0x68/0xdc
> > really_probe+0x148/0x2ac
> > __driver_probe_device+0x78/0x12c
> > driver_probe_device+0xdc/0x160
> > __device_attach_driver+0xb8/0x134
> > bus_for_each_drv+0x80/0xdc
> > __device_attach+0xa8/0x1b0
> > device_initial_probe+0x14/0x20
> > bus_probe_device+0xa8/0xac
> > deferred_probe_work_func+0x88/0xc0
> > process_one_work+0x138/0x260
> > worker_thread+0x32c/0x438
> > kthread+0x118/0x11c
> > ret_from_fork+0x10/0x20
> > ---[ end trace 0000000000000000 ]---
> > 
> > Fix this by initializing directly the dmd pointer in dw_mipi_dsi_probe(),
> > which requires also initializting the dmd->bridge attributes that are
> > required in drm_bridge_attach() before calling mipi_dsi_host_register().
> > 
> > Signed-off-by: Farouk Bouabid <farouk.bouabid@theobroma-systems.com>
> > ---
> >   drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c   |  4 +-
> >   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 42 ++++++++++---------
> >   drivers/gpu/drm/meson/meson_dw_mipi_dsi.c     |  8 ++--
> >   .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   |  5 +--
> >   drivers/gpu/drm/stm/dw_mipi_dsi-stm.c         |  5 +--
> >   include/drm/bridge/dw_mipi_dsi.h              |  5 ++-
> >   6 files changed, 35 insertions(+), 34 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > index 3ff30ce80c5b..469976ad3b19 100644
> > --- a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > +++ b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > @@ -881,8 +881,8 @@ static int imx93_dsi_probe(struct platform_device *pdev)
> >   	dsi->pdata.priv_data = dsi;
> >   	platform_set_drvdata(pdev, dsi);
> >   
> > -	dsi->dmd = dw_mipi_dsi_probe(pdev, &dsi->pdata);
> > -	if (IS_ERR(dsi->dmd))
> > +	ret = dw_mipi_dsi_probe(pdev, &dsi->pdata, &dsi->dmd);
> > +	if (ret < 0)
> >   		return dev_err_probe(dev, PTR_ERR(dsi->dmd),
> >   				     "failed to probe dw_mipi_dsi\n");
> >   
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > index 824fb3c65742..306cba366ba8 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > @@ -1184,18 +1184,19 @@ static void dw_mipi_dsi_debugfs_remove(struct dw_mipi_dsi *dsi) { }
> >   
> >   #endif /* CONFIG_DEBUG_FS */
> >   
> > -static struct dw_mipi_dsi *
> > -__dw_mipi_dsi_probe(struct platform_device *pdev,
> > -		    const struct dw_mipi_dsi_plat_data *plat_data)
> > +int __dw_mipi_dsi_probe(struct platform_device *pdev,
> > +		    const struct dw_mipi_dsi_plat_data *plat_data, struct dw_mipi_dsi **dsi_p)
> >   {
> >   	struct device *dev = &pdev->dev;
> >   	struct reset_control *apb_rst;
> >   	struct dw_mipi_dsi *dsi;
> >   	int ret;
> >   
> > -	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> > -	if (!dsi)
> > -		return ERR_PTR(-ENOMEM);
> > +	*dsi_p = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> > +	if (!*dsi_p)
> > +		return -ENOMEM;
> > +
> > +	dsi = *dsi_p;
> >   
> >   	dsi->dev = dev;
> >   	dsi->plat_data = plat_data;
> > @@ -1203,13 +1204,13 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> >   	if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps ||
> >   	    !plat_data->phy_ops->get_timing) {
> >   		DRM_ERROR("Phy not properly configured\n");
> > -		return ERR_PTR(-ENODEV);
> > +		return -ENODEV;
> >   	}
> >   
> >   	if (!plat_data->base) {
> >   		dsi->base = devm_platform_ioremap_resource(pdev, 0);
> >   		if (IS_ERR(dsi->base))
> > -			return ERR_PTR(-ENODEV);
> > +			return -ENODEV;
> >   
> >   	} else {
> >   		dsi->base = plat_data->base;
> > @@ -1219,7 +1220,7 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> >   	if (IS_ERR(dsi->pclk)) {
> >   		ret = PTR_ERR(dsi->pclk);
> >   		dev_err(dev, "Unable to get pclk: %d\n", ret);
> > -		return ERR_PTR(ret);
> > +		return ret;
> >   	}
> >   
> >   	/*
> > @@ -1233,14 +1234,14 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> >   		if (ret != -EPROBE_DEFER)
> >   			dev_err(dev, "Unable to get reset control: %d\n", ret);
> >   
> > -		return ERR_PTR(ret);
> > +		return ret;
> >   	}
> >   
> >   	if (apb_rst) {
> >   		ret = clk_prepare_enable(dsi->pclk);
> >   		if (ret) {
> >   			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
> > -			return ERR_PTR(ret);
> > +			return ret;
> >   		}
> >   
> >   		reset_control_assert(apb_rst);
> > @@ -1255,19 +1256,20 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> >   
> >   	dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
> >   	dsi->dsi_host.dev = dev;
> > +	dsi->bridge.driver_private = dsi;
> > +	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
> > +	dsi->bridge.of_node = pdev->dev.of_node;
> > +
> >   	ret = mipi_dsi_host_register(&dsi->dsi_host);
> >   	if (ret) {
> >   		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
> >   		pm_runtime_disable(dev);
> >   		dw_mipi_dsi_debugfs_remove(dsi);
> > -		return ERR_PTR(ret);
> > +		return ret;
> >   	}
> >   
> > -	dsi->bridge.driver_private = dsi;
> > -	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
> > -	dsi->bridge.of_node = pdev->dev.of_node;
> >   
> > -	return dsi;
> > +	return 0;
> >   }
> >   
> >   static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
> > @@ -1301,11 +1303,11 @@ EXPORT_SYMBOL_GPL(dw_mipi_dsi_get_bridge);
> >   /*
> >    * Probe/remove API, used from platforms based on the DRM bridge API.
> >    */
> > -struct dw_mipi_dsi *
> > -dw_mipi_dsi_probe(struct platform_device *pdev,
> > -		  const struct dw_mipi_dsi_plat_data *plat_data)
> > +int dw_mipi_dsi_probe(struct platform_device *pdev,
> > +		  const struct dw_mipi_dsi_plat_data *plat_data,
> > +		  struct dw_mipi_dsi **dsi_p)
> >   {
> > -	return __dw_mipi_dsi_probe(pdev, plat_data);
> > +	return __dw_mipi_dsi_probe(pdev, plat_data, dsi_p);
> >   }
> >   EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
> >   
> > diff --git a/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> > index e5fe4e994f43..b103f3e31f2a 100644
> > --- a/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> > +++ b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> > @@ -262,6 +262,7 @@ static int meson_dw_mipi_dsi_probe(struct platform_device *pdev)
> >   {
> >   	struct meson_dw_mipi_dsi *mipi_dsi;
> >   	struct device *dev = &pdev->dev;
> > +	int ret;
> >   
> >   	mipi_dsi = devm_kzalloc(dev, sizeof(*mipi_dsi), GFP_KERNEL);
> >   	if (!mipi_dsi)
> > @@ -315,10 +316,9 @@ static int meson_dw_mipi_dsi_probe(struct platform_device *pdev)
> >   	mipi_dsi->pdata.priv_data = mipi_dsi;
> >   	platform_set_drvdata(pdev, mipi_dsi);
> >   
> > -	mipi_dsi->dmd = dw_mipi_dsi_probe(pdev, &mipi_dsi->pdata);
> > -	if (IS_ERR(mipi_dsi->dmd))
> > -		return dev_err_probe(dev, PTR_ERR(mipi_dsi->dmd),
> > -				     "Failed to probe dw_mipi_dsi\n");
> > +	ret = dw_mipi_dsi_probe(pdev, &mipi_dsi->pdata, &mipi_dsi->dmd);
> > +	if (ret < 0)
> > +		return dev_err_probe(dev, ret, "Failed to probe dw_mipi_dsi\n");
> >   
> >   	return 0;
> >   }
> > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > index 6396f9324dab..4df32747476c 100644
> > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> > @@ -1457,9 +1457,8 @@ static int dw_mipi_dsi_rockchip_probe(struct platform_device *pdev)
> >   	if (IS_ERR(phy_provider))
> >   		return PTR_ERR(phy_provider);
> >   
> > -	dsi->dmd = dw_mipi_dsi_probe(pdev, &dsi->pdata);
> > -	if (IS_ERR(dsi->dmd)) {
> > -		ret = PTR_ERR(dsi->dmd);
> > +	ret = dw_mipi_dsi_probe(pdev, &dsi->pdata, &dsi->dmd);
> > +	if (ret < 0) {
> >   		if (ret != -EPROBE_DEFER)
> >   			DRM_DEV_ERROR(dev,
> >   				      "Failed to probe dw_mipi_dsi: %d\n", ret);
> > diff --git a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> > index d5f8c923d7bc..44dbbfc277d8 100644
> > --- a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> > +++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> > @@ -518,9 +518,8 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
> >   
> >   	platform_set_drvdata(pdev, dsi);
> >   
> > -	dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
> > -	if (IS_ERR(dsi->dsi)) {
> > -		ret = PTR_ERR(dsi->dsi);
> > +	ret = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data, &dsi->dsi);
> > +	if (ret < 0) {
> >   		dev_err_probe(dev, ret, "Failed to initialize mipi dsi host\n");
> >   		goto err_dsi_probe;
> >   	}
> > diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
> > index 65d5e68065e3..f073e819251e 100644
> > --- a/include/drm/bridge/dw_mipi_dsi.h
> > +++ b/include/drm/bridge/dw_mipi_dsi.h
> > @@ -76,9 +76,10 @@ struct dw_mipi_dsi_plat_data {
> >   	void *priv_data;
> >   };
> >   
> > -struct dw_mipi_dsi *dw_mipi_dsi_probe(struct platform_device *pdev,
> > +int dw_mipi_dsi_probe(struct platform_device *pdev,
> >   				      const struct dw_mipi_dsi_plat_data
> > -				      *plat_data);
> > +				      *plat_data,
> > +					  struct dw_mipi_dsi **dsi_p);
> >   void dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi);
> >   int dw_mipi_dsi_bind(struct dw_mipi_dsi *dsi, struct drm_encoder *encoder);
> >   void dw_mipi_dsi_unbind(struct dw_mipi_dsi *dsi);
> 
>