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In-Reply-To: <7eb1d912-9115-ecd6-f1ca-28ac5063bcf0@collabora.com>
From:   Eizan Miyamoto <eizan@google.com>
Date:   Fri, 15 May 2020 15:21:21 +1000
Message-ID: <CAOak1e_OFzfmecRnQP9m3PPQ1cXQ7B_sK32WMyA_MVEZH=LfHg@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] [media] mtk-mdp: add driver to probe mdp components
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     Enric Balletbo Serra <eballetbo@gmail.com>,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Minghsiu Tsai <minghsiu.tsai@mediatek.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Houlong Wei <houlong.wei@mediatek.com>,
        Eizan Miyamoto <eizan@chromium.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-media@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, May 7, 2020 at 11:44 PM Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
>
> Hi Eizan,
>
> On 7/5/20 13:11, Eizan Miyamoto wrote:
> > On Thu, May 7, 2020 at 2:54 AM Enric Balletbo Serra <eballetbo@gmail.com> wrote:
> >>
> >> Hi Eizan,
> >>
> >> Thank you for the patch.
> >>
> >> Missatge de Eizan Miyamoto <eizan@chromium.org> del dia dc., 6 de maig
> >> 2020 a les 10:41:
> >>>
> >>> Broadly, this patch (1) adds a driver for various MTK MDP components to
> >>> go alongside the main MTK MDP driver, and (2) hooks them all together
> >>> using the component framework.
> >>>
> >>> (1) Up until now, the MTK MDP driver controls 8 devices in the device
> >>> tree on its own. When running tests for the hardware video decoder, we
> >>> found that the iommus and LARBs were not being properly configured. To
> >>> configure them, a driver for each be added to mtk_mdp_comp so that
> >>> mtk_iommu_add_device() can (eventually) be called from dma_configure()
> >>> inside really_probe().
> >>>
> >>> (2) The integration into the component framework allows us to defer the
> >>> registration with the v4l2 subsystem until all the MDP-related devices
> >>> have been probed, so that the relevant device node does not become
> >>> available until initialization of all the components is complete.
> >>>
> >>> Some notes about how the component framework has been integrated:
> >>>
> >>> - The driver for the rdma0 component serves double duty as the "master"
> >>>   (aggregate) driver as well as a component driver. This is a non-ideal
> >>>   compromise until a better solution is developed. This device is
> >>>   differentiated from the rest by checking for a "mediatek,vpu" property
> >>>   in the device node.
> >>>
> >>> - The list of mdp components remains hard-coded as mtk_mdp_comp_dt_ids[]
> >>>   in mtk_mdp_core.c, and as mtk_mdp_comp_driver_dt_match[] in
> >>>   mtk_mdp_comp.c. This unfortunate duplication of information is
> >>>   addressed in a following patch in this series.
> >>>
> >>> - The component driver calls component_add() for each device that is
> >>>   probed.
> >>>
> >>> - In mtk_mdp_probe (the "master" device), we scan the device tree for
> >>>   any matching nodes against mtk_mdp_comp_dt_ids, and add component
> >>>   matches for them. The match criteria is a matching device node
> >>>   pointer.
> >>>
> >>> - When the set of components devices that have been probed corresponds
> >>>   with the list that is generated by the "master", the callback to
> >>>   mtk_mdp_master_bind() is made, which then calls the component bind
> >>>   functions.
> >>>
> >>> - Inside mtk_mdp_master_bind(), once all the component bind functions
> >>>   have been called, we can then register our device to the v4l2
> >>>   subsystem.
> >>>
> >>> - The call to pm_runtime_enable() in the master device is called after
> >>>   all the components have been registered by their bind() functions
> >>>   called by mtk_mtp_master_bind(). As a result, the list of components
> >>>   will not change while power management callbacks mtk_mdp_suspend()/
> >>>   resume() are accessing the list of components.
> >>>
> >>> Signed-off-by: Eizan Miyamoto <eizan@chromium.org>
> >>> ---
> >>>
> >>> Changes in v2: None
> >>>
> >>
> >> Not really true :-)
> >>
> >>>  drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 150 +++++++++++++--
> >>>  drivers/media/platform/mtk-mdp/mtk_mdp_comp.h |  26 +--
> >>>  drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 176 +++++++++++++-----
> >>>  drivers/media/platform/mtk-mdp/mtk_mdp_core.h |   1 +
> >>>  4 files changed, 263 insertions(+), 90 deletions(-)
> >>>
> >>> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> >>> index 362fff924aef..5b4d482df778 100644
> >>> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> >>> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> >>> @@ -5,14 +5,53 @@
> >>>   */
> >>>
> >>>  #include <linux/clk.h>
> >>> +#include <linux/component.h>
> >>>  #include <linux/device.h>
> >>> -#include <linux/of.h>
> >>> +#include <linux/module.h>
> >>>  #include <linux/of_address.h>
> >>> +#include <linux/of_device.h>
> >>> +#include <linux/of.h>
> >>> +#include <linux/of_irq.h>
> >>>  #include <linux/of_platform.h>
> >>>  #include <soc/mediatek/smi.h>
> >>> +#include <linux/platform_device.h>
> >>>
> >>>  #include "mtk_mdp_comp.h"
> >>> -
> >>> +#include "mtk_mdp_core.h"
> >>> +
> >>> +/**
> >>> + * enum mtk_mdp_comp_type - the MDP component
> >>> + * @MTK_MDP_RDMA:              Read DMA
> >>> + * @MTK_MDP_RSZ:               Reszer
> >>> + * @MTK_MDP_WDMA:              Write DMA
> >>> + * @MTK_MDP_WROT:              Write DMA with rotation
> >>> + * @MTK_MDP_COMP_TYPE_MAX:     Placeholder for num elems in this enum
> >>> + */
> >>> +enum mtk_mdp_comp_type {
> >>> +       MTK_MDP_RDMA,
> >>> +       MTK_MDP_RSZ,
> >>> +       MTK_MDP_WDMA,
> >>> +       MTK_MDP_WROT,
> >>> +       MTK_MDP_COMP_TYPE_MAX,
> >>> +};
> >>> +
> >>> +static const struct of_device_id mtk_mdp_comp_driver_dt_match[] = {
> >>> +       {
> >>> +               .compatible = "mediatek,mt8173-mdp-rdma",
> >>> +               .data = (void *)MTK_MDP_RDMA
> >>> +       }, {
> >>> +               .compatible = "mediatek,mt8173-mdp-rsz",
> >>> +               .data = (void *)MTK_MDP_RSZ
> >>> +       }, {
> >>> +               .compatible = "mediatek,mt8173-mdp-wdma",
> >>> +               .data = (void *)MTK_MDP_WDMA
> >>> +       }, {
> >>> +               .compatible = "mediatek,mt8173-mdp-wrot",
> >>> +               .data = (void *)MTK_MDP_WROT
> >>> +       },
> >>> +       { }
> >>> +};
> >>> +MODULE_DEVICE_TABLE(of, mtk_mdp_comp_driver_dt_match);
> >>>
> >>>  void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> >>>  {
> >>> @@ -20,10 +59,14 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> >>>
> >>>         if (comp->larb_dev) {
> >>>                 err = mtk_smi_larb_get(comp->larb_dev);
> >>> -               if (err)
> >>> +               if (err) {
> >>> +                       enum mtk_mdp_comp_type comp_type =
> >>> +                               (enum mtk_mdp_comp_type)
> >>> +                               of_device_get_match_data(dev);
> >>>                         dev_err(dev,
> >>>                                 "failed to get larb, err %d. type:%d\n",
> >>> -                               err, comp->type);
> >>> +                               err, comp_type);
> >>> +               }
> >>>         }
> >>>
> >>>         for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
> >>> @@ -32,8 +75,8 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> >>>                 err = clk_prepare_enable(comp->clk[i]);
> >>>                 if (err)
> >>>                         dev_err(dev,
> >>> -                       "failed to enable clock, err %d. type:%d i:%d\n",
> >>> -                               err, comp->type, i);
> >>> +                               "failed to enable clock, err %d. i:%d\n",
> >>> +                               err, i);
> >>>         }
> >>>  }
> >>>
> >>> @@ -51,16 +94,41 @@ void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
> >>>                 mtk_smi_larb_put(comp->larb_dev);
> >>>  }
> >>>
> >>> -int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
> >>> -                     struct mtk_mdp_comp *comp,
> >>> -                     enum mtk_mdp_comp_type comp_type)
> >>> +static int mtk_mdp_comp_bind(struct device *dev, struct device *master,
> >>> +                       void *data)
> >>> +{
> >>> +       struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
> >>> +       struct mtk_mdp_dev *mdp = data;
> >>> +
> >>> +       mtk_mdp_register_component(mdp, comp);
> >>> +
> >>> +       return 0;
> >>> +}
> >>> +
> >>> +static void mtk_mdp_comp_unbind(struct device *dev, struct device *master,
> >>> +                          void *data)
> >>> +{
> >>> +       struct mtk_mdp_dev *mdp = data;
> >>> +       struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
> >>> +
> >>> +       mtk_mdp_unregister_component(mdp, comp);
> >>> +}
> >>> +
> >>> +static const struct component_ops mtk_mdp_component_ops = {
> >>> +       .bind   = mtk_mdp_comp_bind,
> >>> +       .unbind = mtk_mdp_comp_unbind,
> >>> +};
> >>> +
> >>> +int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev)
> >>>  {
> >>>         struct device_node *larb_node;
> >>>         struct platform_device *larb_pdev;
> >>>         int i;
> >>> +       struct device_node *node = dev->of_node;
> >>> +       enum mtk_mdp_comp_type comp_type =
> >>> +                (enum mtk_mdp_comp_type)of_device_get_match_data(dev);
> >>>
> >>> -       comp->dev_node = of_node_get(node);
> >>> -       comp->type = comp_type;
> >>> +       INIT_LIST_HEAD(&comp->node);
> >>>
> >>>         for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
> >>>                 comp->clk[i] = of_clk_get(node, i);
> >>> @@ -72,15 +140,15 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
> >>>                 }
> >>>
> >>>                 /* Only RDMA needs two clocks */
> >>> -               if (comp->type != MTK_MDP_RDMA)
> >>> +               if (comp_type != MTK_MDP_RDMA)
> >>>                         break;
> >>>         }
> >>>
> >>>         /* Only DMA capable components need the LARB property */
> >>>         comp->larb_dev = NULL;
> >>> -       if (comp->type != MTK_MDP_RDMA &&
> >>> -           comp->type != MTK_MDP_WDMA &&
> >>> -           comp->type != MTK_MDP_WROT)
> >>> +       if (comp_type != MTK_MDP_RDMA &&
> >>> +           comp_type != MTK_MDP_WDMA &&
> >>> +           comp_type != MTK_MDP_WROT)
> >>>                 return 0;
> >>>
> >>>         larb_node = of_parse_phandle(node, "mediatek,larb", 0);
> >>> @@ -103,7 +171,55 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
> >>>         return 0;
> >>>  }
> >>>
> >>> -void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp)
> >>> +static int mtk_mdp_comp_probe(struct platform_device *pdev)
> >>> +{
> >>> +       struct device *dev = &pdev->dev;
> >>> +       struct device_node *vpu_node;
> >>> +       int status;
> >>> +       struct mtk_mdp_comp *comp;
> >>> +
> >>> +       vpu_node = of_parse_phandle(dev->of_node, "mediatek,vpu", 0);
> >>> +       if (vpu_node) {
> >>> +               of_node_put(vpu_node);
> >>> +               /*
> >>> +                * The device tree node with a mediatek,vpu property is deemed
> >>> +                * the MDP "master" device, we don't want to add a component
> >>> +                * for it in this function because the initialization for the
> >>> +                * master is done elsewhere.
> >>> +                */
> >>> +               dev_info(dev, "vpu node found, not probing\n");
> >>
> >> Could you explain a bit more this? When this can happen? I am
> >> wondering if you are trying to solve a non-existing problem upstream.
> >
> > That line of code will be executed when probing for the rdma@14001000
> > device, for which the probe function in mtk_mdp_core.c will also be run
> > because there is a second '.compatible' string ("mediatek,mt8173-mdp") in
> > that device node.
> >
>
> Shouldn't we remove that second compatible then? (I don't think we break
> compatibility, so should be safe)

Hmm, it is possible to remove it, but then I think we will need to add
similar logic to the probe() function in mtk_mdp_core to return early as well
but when the vpu node is *not* found. My rationale is that there are two
device nodes with a .compatible = "mediatek,mt8173-mdp-rdma" property:
rdma@14001000 and rdma@14002000 and so the probe functions for the different
drivers need to be careful about what device they run for.

On the other hand, I wonder if our effort is better spent splitting the
rdma@14001000 into two: one for a component device that retains just
a .compatible = "mediatek,mt8173-mdp-rdma", and another for an aggregate
that contains a .compatible = "mediatek,mt8173-mdp". If we go this way, I
propose we do it in a subsequent change.

>
> FWIW I didn't see this message on my tests on Elm, do you know why?

I think the reason is that the probe function in mtk_mdp_core.c is (by
happenstance) called first, and because it succeeds, the probe function in
mtk_mdp_comp.c won't get called for that device node.

Specifically, __driver_attach only calls driver_probe_device (through
__driver_attach_async_helper) if dev->driver is NULL. dev->driver is set
before the probe function is called from really_probe, and if the probe
function fails, dev->driver is set to NULL.

>
> > In the probe function in mtk_mdp_core.c, a component is initialized, which
> > is component_add()ed separately by the master_bind function and so we don't
> > need to go through the component creation/initialization/addition done
> > here.
> >
> > I think, ideally, the master component wouldn't also be responsible for
> > rdma@14001000 and we would split apart the device node. I'd like to propose
> > that we work on that in a follow-up change while we make incremental
> > progress. (There are also other changes we'd like to propose in the
> > meantime, like not hard-coding the components that the master binds
> > together into the driver but instead make it possible to specify that in
> > the device tree itself).
> >
> >>
> >>> +               return -ENODEV;
> >>> +       }
> >>> +
> >>> +       comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
> >>> +       if (!comp)
> >>> +               return -ENOMEM;
> >>> +
> >>> +       status = mtk_mdp_comp_init(comp, dev);
> >>> +       if (status) {
> >>> +               dev_err(dev, "Failed to initialize component: %d\n", status);
> >>> +               return status;
> >>> +       }
> >>> +
> >>> +       dev_set_drvdata(dev, comp);
> >>> +
> >>> +       return component_add(dev, &mtk_mdp_component_ops);
> >>> +}
> >>> +
> >>> +static int mtk_mdp_comp_remove(struct platform_device *pdev)
> >>>  {
> >>> -       of_node_put(comp->dev_node);
> >>> +       struct device *dev = &pdev->dev;
> >>> +
> >>> +       component_del(dev, &mtk_mdp_component_ops);
> >>> +       return 0;
> >>>  }
> >>> +
> >>> +struct platform_driver mtk_mdp_component_driver = {
> >>> +       .probe          = mtk_mdp_comp_probe,
> >>> +       .remove         = mtk_mdp_comp_remove,
> >>> +       .driver         = {
> >>> +               .name   = "mediatek-mdp-comp",
> >>> +               .owner  = THIS_MODULE,
> >>> +               .of_match_table = mtk_mdp_comp_driver_dt_match,
> >>> +       },
> >>> +};
> >>> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> >>> index 1bf0242cce46..b5a18fe567aa 100644
> >>> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> >>> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> >>> @@ -7,43 +7,23 @@
> >>>  #ifndef __MTK_MDP_COMP_H__
> >>>  #define __MTK_MDP_COMP_H__
> >>>
> >>> -/**
> >>> - * enum mtk_mdp_comp_type - the MDP component
> >>> - * @MTK_MDP_RDMA:      Read DMA
> >>> - * @MTK_MDP_RSZ:       Riszer
> >>> - * @MTK_MDP_WDMA:      Write DMA
> >>> - * @MTK_MDP_WROT:      Write DMA with rotation
> >>> - */
> >>> -enum mtk_mdp_comp_type {
> >>> -       MTK_MDP_RDMA,
> >>> -       MTK_MDP_RSZ,
> >>> -       MTK_MDP_WDMA,
> >>> -       MTK_MDP_WROT,
> >>> -       MTK_MDP_COMP_TYPE_MAX,
> >>> -};
> >>> -
> >>>  /**
> >>>   * struct mtk_mdp_comp - the MDP's function component data
> >>>   * @node:      list node to track sibing MDP components
> >>> - * @dev_node:  component device node
> >>>   * @clk:       clocks required for component
> >>>   * @larb_dev:  SMI device required for component
> >>> - * @type:      component type
> >>>   */
> >>>  struct mtk_mdp_comp {
> >>>         struct list_head        node;
> >>> -       struct device_node      *dev_node;
> >>>         struct clk              *clk[2];
> >>>         struct device           *larb_dev;
> >>> -       enum mtk_mdp_comp_type  type;
> >>>  };
> >>>
> >>> -int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
> >>> -                     struct mtk_mdp_comp *comp,
> >>> -                     enum mtk_mdp_comp_type comp_type);
> >>> -void mtk_mdp_comp_deinit(struct device *dev, struct mtk_mdp_comp *comp);
> >>> +int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev);
> >>> +
> >>>  void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp);
> >>>  void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp);
> >>>
> >>> +extern struct platform_driver mtk_mdp_component_driver;
> >>>
> >>>  #endif /* __MTK_MDP_COMP_H__ */
> >>> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> >>> index acbc5a01ae4c..539a7942e3cb 100644
> >>> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> >>> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> >>> @@ -6,6 +6,7 @@
> >>>   */
> >>>
> >>>  #include <linux/clk.h>
> >>> +#include <linux/component.h>
> >>>  #include <linux/device.h>
> >>>  #include <linux/errno.h>
> >>>  #include <linux/interrupt.h>
> >>> @@ -19,6 +20,7 @@
> >>>  #include <linux/workqueue.h>
> >>>  #include <soc/mediatek/smi.h>
> >>>
> >>> +#include "mtk_mdp_comp.h"
> >>>  #include "mtk_mdp_core.h"
> >>>  #include "mtk_mdp_m2m.h"
> >>>  #include "mtk_vpu.h"
> >>> @@ -32,16 +34,12 @@ module_param(mtk_mdp_dbg_level, int, 0644);
> >>>  static const struct of_device_id mtk_mdp_comp_dt_ids[] = {
> >>>         {
> >>>                 .compatible = "mediatek,mt8173-mdp-rdma",
> >>> -               .data = (void *)MTK_MDP_RDMA
> >>>         }, {
> >>>                 .compatible = "mediatek,mt8173-mdp-rsz",
> >>> -               .data = (void *)MTK_MDP_RSZ
> >>>         }, {
> >>>                 .compatible = "mediatek,mt8173-mdp-wdma",
> >>> -               .data = (void *)MTK_MDP_WDMA
> >>>         }, {
> >>>                 .compatible = "mediatek,mt8173-mdp-wrot",
> >>> -               .data = (void *)MTK_MDP_WROT
> >>>         },
> >>>         { },
> >>>  };
> >>> @@ -91,6 +89,64 @@ static void mtk_mdp_reset_handler(void *priv)
> >>>         queue_work(mdp->wdt_wq, &mdp->wdt_work);
> >>>  }
> >>>
> >>> +static int compare_of(struct device *dev, void *data)
> >>> +{
> >>> +       return dev->of_node == data;
> >>> +}
> >>> +
> >>> +static void release_of(struct device *dev, void *data)
> >>> +{
> >>> +       of_node_put(data);
> >>> +}
> >>> +
> >>> +static int mtk_mdp_master_bind(struct device *dev)
> >>> +{
> >>> +       int status;
> >>> +       struct mtk_mdp_dev *mdp = dev_get_drvdata(dev);
> >>> +
> >>> +       mtk_mdp_register_component(mdp, &mdp->comp_self);
> >>> +
> >>> +       status = component_bind_all(dev, mdp);
> >>> +       if (status) {
> >>> +               dev_err(dev, "Failed to bind all components: %d\n", status);
> >>> +               goto err_component_bind_all;
> >>> +       }
> >>> +
> >>> +       status = mtk_mdp_register_m2m_device(mdp);
> >>> +       if (status) {
> >>> +               dev_err(dev, "Failed to register m2m device: %d\n", status);
> >>> +               v4l2_err(&mdp->v4l2_dev, "Failed to init mem2mem device\n");
> >>> +               goto err_mtk_mdp_register_m2m_device;
> >>> +       }
> >>> +
> >>> +       pm_runtime_enable(dev);
> >>> +
> >>> +       return 0;
> >>> +
> >>> +err_mtk_mdp_register_m2m_device:
> >>> +       component_unbind_all(dev, mdp);
> >>> +
> >>> +err_component_bind_all:
> >>> +       mtk_mdp_unregister_component(mdp, &mdp->comp_self);
> >>> +
> >>> +       return status;
> >>> +}
> >>> +
> >>> +static void mtk_mdp_master_unbind(struct device *dev)
> >>> +{
> >>> +       struct mtk_mdp_dev *mdp = dev_get_drvdata(dev);
> >>> +
> >>> +       pm_runtime_disable(dev);
> >>> +       mtk_mdp_unregister_m2m_device(mdp);
> >>> +       component_unbind_all(dev, mdp);
> >>> +       mtk_mdp_unregister_component(mdp, &mdp->comp_self);
> >>> +}
> >>> +
> >>> +static const struct component_master_ops mtk_mdp_com_ops = {
> >>> +       .bind           = mtk_mdp_master_bind,
> >>> +       .unbind         = mtk_mdp_master_unbind,
> >>> +};
> >>> +
> >>>  void mtk_mdp_register_component(struct mtk_mdp_dev *mdp,
> >>>                                 struct mtk_mdp_comp *comp)
> >>>  {
> >>> @@ -108,8 +164,8 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>         struct mtk_mdp_dev *mdp;
> >>>         struct device *dev = &pdev->dev;
> >>>         struct device_node *node, *parent;
> >>> -       struct mtk_mdp_comp *comp, *comp_temp;
> >>> -       int ret = 0;
> >>> +       int i, ret = 0;
> >>> +       struct component_match *match = NULL;
> >>>
> >>>         mdp = devm_kzalloc(dev, sizeof(*mdp), GFP_KERNEL);
> >>>         if (!mdp)
> >>> @@ -134,37 +190,43 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>         }
> >>>
> >>>         /* Iterate over sibling MDP function blocks */
> >>> +       i = 0;
> >>>         for_each_child_of_node(parent, node) {
> >>> -               const struct of_device_id *of_id;
> >>> -               enum mtk_mdp_comp_type comp_type;
> >>> +               struct platform_device *pdev;
> >>>
> >>> -               of_id = of_match_node(mtk_mdp_comp_dt_ids, node);
> >>> -               if (!of_id)
> >>> +               if (!of_match_node(mtk_mdp_comp_dt_ids, node))
> >>>                         continue;
> >>>
> >>> -               if (!of_device_is_available(node)) {
> >>> -                       dev_err(dev, "Skipping disabled component %pOF\n",
> >>> -                               node);
> >>> +               if (!of_device_is_available(node))
> >>>                         continue;
> >>> -               }
> >>> -
> >>> -               comp_type = (enum mtk_mdp_comp_type)of_id->data;
> >>>
> >>> -
> >>> -               comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
> >>> -               if (!comp) {
> >>> -                       ret = -ENOMEM;
> >>> -                       of_node_put(node);
> >>> -                       goto err_comp;
> >>> +               pdev = of_find_device_by_node(node);
> >>> +               if (!pdev) {
> >>> +                       dev_warn(dev, "Unable to find comp device %s\n",
> >>> +                                node->full_name);
> >>> +                       continue;
> >>>                 }
> >>>
> >>> -               ret = mtk_mdp_comp_init(dev, node, comp, comp_type);
> >>> -               if (ret) {
> >>> -                       of_node_put(node);
> >>> -                       goto err_comp;
> >>> +               /*
> >>> +                * Do not add add a match for my own (rdma0) device node.
> >>> +                * I will be managing it directly instead using comp_self.
> >>> +                */
> >>> +               if (&pdev->dev != dev) {
> >>> +                       dev_dbg(dev, "adding match %d for: %pOF\n", i++, node);
> >>> +                       component_match_add_release(dev, &match, release_of,
> >>> +                                                   compare_of,
> >>> +                                                   of_node_get(node));
> >>>                 }
> >>> +       }
> >>>
> >>> -               mtk_mdp_register_component(mdp, comp);
> >>> +       /*
> >>> +        * Create a component for myself so that clocks can be toggled in
> >>> +        * clock_on().
> >>> +        */
> >>> +       ret = mtk_mdp_comp_init(&mdp->comp_self, dev);
> >>> +       if (ret) {
> >>> +               dev_err(dev, "Failed to initialize component\n");
> >>> +               goto err_comp;
> >>>         }
> >>>
> >>>         mdp->job_wq = create_singlethread_workqueue(MTK_MDP_MODULE_NAME);
> >>> @@ -189,18 +251,12 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>                 goto err_dev_register;
> >>>         }
> >>>
> >>> -       ret = mtk_mdp_register_m2m_device(mdp);
> >>> -       if (ret) {
> >>> -               v4l2_err(&mdp->v4l2_dev, "Failed to init mem2mem device\n");
> >>> -               goto err_m2m_register;
> >>> -       }
> >>> -
> >>>         mdp->vpu_dev = vpu_get_plat_device(pdev);
> >>>         ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp,
> >>>                                   VPU_RST_MDP);
> >>>         if (ret) {
> >>>                 dev_err(&pdev->dev, "Failed to register reset handler\n");
> >>> -               goto err_m2m_register;
> >>> +               goto err_wdt_reg;
> >>>         }
> >>>
> >>>         platform_set_drvdata(pdev, mdp);
> >>> @@ -208,15 +264,25 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>         ret = vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
> >>>         if (ret) {
> >>>                 dev_err(&pdev->dev, "Failed to set vb2 dma mag seg size\n");
> >>> -               goto err_m2m_register;
> >>> +               goto err_set_max_seg_size;
> >>> +       }
> >>> +
> >>> +       ret = component_master_add_with_match(dev, &mtk_mdp_com_ops, match);
> >>> +       if (ret) {
> >>> +               dev_err(dev, "Component master add failed\n");
> >>> +               goto err_component_master_add;
> >>>         }
> >>>
> >>> -       pm_runtime_enable(dev);
> >>>         dev_dbg(dev, "mdp-%d registered successfully\n", mdp->id);
> >>>
> >>>         return 0;
> >>>
> >>> -err_m2m_register:
> >>> +err_component_master_add:
> >>> +       vb2_dma_contig_clear_max_seg_size(&pdev->dev);
> >>> +
> >>> +err_set_max_seg_size:
> >>> +
> >>> +err_wdt_reg:
> >>
> >> No need for two labels here, rework the above goto logic.
> >>
> >>>         v4l2_device_unregister(&mdp->v4l2_dev);
> >>>
> >>>  err_dev_register:
> >>> @@ -228,11 +294,6 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>  err_alloc_job_wq:
> >>>
> >>>  err_comp:
> >>> -       list_for_each_entry_safe(comp, comp_temp, &mdp->comp_list, node) {
> >>> -               mtk_mdp_unregister_component(mdp, comp);
> >>> -               mtk_mdp_comp_deinit(dev, comp);
> >>> -       }
> >>> -
> >>>         dev_dbg(dev, "err %d\n", ret);
> >>>         return ret;
> >>>  }
> >>> @@ -240,11 +301,10 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> >>>  static int mtk_mdp_remove(struct platform_device *pdev)
> >>>  {
> >>>         struct mtk_mdp_dev *mdp = platform_get_drvdata(pdev);
> >>> -       struct mtk_mdp_comp *comp, *comp_temp;
> >>>
> >>> -       pm_runtime_disable(&pdev->dev);
> >>> +       component_master_del(&pdev->dev, &mtk_mdp_com_ops);
> >>> +
> >>>         vb2_dma_contig_clear_max_seg_size(&pdev->dev);
> >>> -       mtk_mdp_unregister_m2m_device(mdp);
> >>>         v4l2_device_unregister(&mdp->v4l2_dev);
> >>>
> >>>         flush_workqueue(mdp->wdt_wq);
> >>> @@ -253,10 +313,8 @@ static int mtk_mdp_remove(struct platform_device *pdev)
> >>>         flush_workqueue(mdp->job_wq);
> >>>         destroy_workqueue(mdp->job_wq);
> >>>
> >>> -       list_for_each_entry_safe(comp, comp_temp, &mdp->comp_list, node) {
> >>> -               mtk_mdp_unregister_component(mdp, comp);
> >>> -               mtk_mdp_comp_deinit(&pdev->dev, comp);
> >>> -       }
> >>> +       if (!list_empty(&mdp->comp_list))
> >>> +               dev_err(&pdev->dev, "not all components removed\n");
> >>>
> >>>         dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name);
> >>>         return 0;
> >>> @@ -311,7 +369,25 @@ static struct platform_driver mtk_mdp_driver = {
> >>>         }
> >>>  };
> >>>
> >>> -module_platform_driver(mtk_mdp_driver);
> >>> +static struct platform_driver * const mtk_mdp_drivers[] = {
> >>> +       &mtk_mdp_driver,
> >>> +       &mtk_mdp_component_driver,
> >>> +};
> >>> +
> >>> +static int __init mtk_mdp_init(void)
> >>> +{
> >>> +       return platform_register_drivers(mtk_mdp_drivers,
> >>> +                                        ARRAY_SIZE(mtk_mdp_drivers));
> >>> +}
> >>> +
> >>> +static void __exit mtk_mdp_exit(void)
> >>> +{
> >>> +       platform_unregister_drivers(mtk_mdp_drivers,
> >>> +                                   ARRAY_SIZE(mtk_mdp_drivers));
> >>> +}
> >>> +
> >>> +module_init(mtk_mdp_init);
> >>> +module_exit(mtk_mdp_exit);
> >>>
> >>>  MODULE_AUTHOR("Houlong Wei <houlong.wei@mediatek.com>");
> >>>  MODULE_DESCRIPTION("Mediatek image processor driver");
> >>> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> >>> index a7da14b97077..230f531400ca 100644
> >>> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> >>> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> >>> @@ -155,6 +155,7 @@ struct mtk_mdp_dev {
> >>>         struct mtk_mdp_variant          *variant;
> >>>         u16                             id;
> >>>         struct list_head                comp_list;
> >>> +       struct mtk_mdp_comp             comp_self;
> >>>         struct v4l2_m2m_dev             *m2m_dev;
> >>>         struct list_head                ctx_list;
> >>>         struct video_device             *vdev;
> >>> --
> >>> 2.26.2.526.g744177e7f7-goog
> >>>
> >>>
> >>> _______________________________________________
> >>> Linux-mediatek mailing list
> >>> Linux-mediatek@lists.infradead.org
> >>> http://lists.infradead.org/mailman/listinfo/linux-mediatek
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >