Re: [PATCH v1 1/4] mtk-mdp: add driver to probe mdp components

Enric Balletbo i Serra
2021-05-14T08:20:03Z

Hi Eizan,

Thank kyou for your patch.

On 23/4/21 7:58, Eizan Miyamoto wrote:
> 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>
> ---
>
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 139 ++++++++++++--
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.h | 26 +--
> drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 175 +++++++++++++-----
> drivers/media/platform/mtk-mdp/mtk_mdp_core.h | 1 +
> 4 files changed, 255 insertions(+), 86 deletions(-)
>
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index 1e3833f1c9ae..3fbbcf05440a 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -5,13 +5,51 @@
> */
>
> #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 "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)
> {
> @@ -23,8 +61,8 @@ 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);

I think youcan take advantage of the new line lenght limit and put all in one
line here.

> }
> }
>
> @@ -39,15 +77,40 @@ void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
> }
> }
>
> -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)
> {
> int ret;
> 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);
> @@ -55,23 +118,71 @@ int mtk_mdp_comp_init(struct device *dev, struct device_node *node,
> if (PTR_ERR(comp->clk[i]) != -EPROBE_DEFER)
> dev_err(dev, "Failed to get clock\n");
> ret = PTR_ERR(comp->clk[i]);
> - goto put_dev;
> + goto err;
> }
>
> /* Only RDMA needs two clocks */
> - if (comp->type != MTK_MDP_RDMA)
> + if (comp_type != MTK_MDP_RDMA)
> break;
> }
>
> return 0;
>
> -put_dev:
> - of_node_put(comp->dev_node);
> +err:
> + dev_err(dev, "err %d\n", ret);

This error is too generic. You can remove. Anyway you're printing the same error
code if mtk_mdp_comp_init fails in probe function, there makes more sense.

>
> return ret;
> }
>
> -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");

This is the thing that I'm not completely sure is doing the right thing. Having
a DT propriety to indicate to skip the probing is really weird to me. Also the
name is quite confusing. When I read this name I'd expect mediatek,vpu being a
phandle to the VPU device node. If there is a master and childs below from
hardware POV, the DT graph should reflect that, if this is only a way to
instantiate properly the devices then I think we can find other solutions. If
you know that RDMA is always the master maybe we can just find this node.

Other thoughts?

> + 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 36bc1b8f6222..956d20c01e34 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> @@ -7,41 +7,21 @@
> #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
> - * @type: component type
> */
> struct mtk_mdp_comp {
> struct list_head node;
> - struct device_node *dev_node;
> struct clk *clk[2];
> - 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 70a8eab16863..d79bf7f0031a 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>
> @@ -18,6 +19,7 @@
> #include <linux/pm_runtime.h>
> #include <linux/workqueue.h>
>
> +#include "mtk_mdp_comp.h"
> #include "mtk_mdp_core.h"
> #include "mtk_mdp_m2m.h"
> #include "mtk_vpu.h"
> @@ -31,16 +33,12 @@ 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
> },
> { },
> };
> @@ -90,6 +88,64 @@ 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)
> {
> @@ -107,8 +163,8 @@ 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)
> @@ -133,36 +189,43 @@ 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 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);
> @@ -187,18 +250,12 @@ 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);
> @@ -206,15 +263,25 @@ 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:
> v4l2_device_unregister(&mdp->v4l2_dev);
>
> err_dev_register:
> @@ -226,11 +293,6 @@ 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;
> }
> @@ -238,11 +300,10 @@ 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);
> @@ -251,10 +312,8 @@ 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;
> @@ -309,7 +368,25 @@ 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;