Message-ID: <2534c41188d6f740da9930d1de3daf16cbc99614.camel@mediatek.com>
Date:   Thu, 16 Feb 2023 02:40:18 +0000
From:   TingHan Shen (沈廷翰) 
        <TingHan.Shen@...iatek.com>
To:     "mathieu.poirier@...aro.org" <mathieu.poirier@...aro.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>,
        "andersson@...nel.org" <andersson@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>
CC:     "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v7 07/12] remoteproc: mediatek: Probe multi-core SCP

On Wed, 2023-02-15 at 13:29 +0100, AngeloGioacchino Del Regno wrote:
> Il 15/02/23 05:12, Tinghan Shen ha scritto:
> > The difference of single-core SCP and multi-core SCP device tree is
> > the presence of child device nodes described SCP cores. The SCP
> > driver populates the platform device and checks the child nodes
> > to identify whether it's a single-core SCP or a multi-core SCP.
> > 
> > The resource structure of the multi-core SCP is a list of remoteproc
> > instances which is different to the single-core SCP. The corresponding
> > resource releasing action is based on the type of SCP.
> > 
> > Signed-off-by: Tinghan Shen <tinghan.shen@...iatek.com>
> > ---
> >   drivers/remoteproc/mtk_common.h |   4 +
> >   drivers/remoteproc/mtk_scp.c    | 179 +++++++++++++++++++++++++++++---
> >   2 files changed, 168 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
> > index 3778894c96f3..7821cb15d6fd 100644
> > --- a/drivers/remoteproc/mtk_common.h
> > +++ b/drivers/remoteproc/mtk_common.h
> > @@ -140,6 +140,10 @@ struct mtk_scp {
> >   	size_t dram_size;
> >   
> >   	struct rproc_subdev *rpmsg_subdev;
> > +
> > +	struct list_head elem;
> > +	struct list_head cluster_cores;
> > +	struct list_head *cluster;
> 
> I don't understand why you need both `cluster_cores` and `cluster`... check below.
> 
> >   };
> >   
> >   /**
> > diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> > index 6270c388727a..6588e5acb159 100644
> > --- a/drivers/remoteproc/mtk_scp.c
> > +++ b/drivers/remoteproc/mtk_scp.c
> > @@ -862,7 +862,9 @@ static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
> >   }
> >   
> >   static int scp_rproc_init(struct platform_device *pdev,
> > -			  struct mtk_scp_of_regs *of_regs)
> > +			  struct mtk_scp_of_regs *of_regs,
> > +			  const struct mtk_scp_of_data *of_data,
> > +			  bool is_multi_core)
> >   {
> >   	struct device *dev = &pdev->dev;
> >   	struct device_node *np = dev->of_node;
> > @@ -883,7 +885,7 @@ static int scp_rproc_init(struct platform_device *pdev,
> >   	scp = (struct mtk_scp *)rproc->priv;
> >   	scp->rproc = rproc;
> >   	scp->dev = dev;
> > -	scp->data = of_device_get_match_data(dev);
> > +	scp->data = of_data;
> >   	platform_set_drvdata(pdev, scp);
> >   
> >   	scp->reg_base = of_regs->reg_base;
> > @@ -932,9 +934,11 @@ static int scp_rproc_init(struct platform_device *pdev,
> >   		goto remove_subdev;
> >   	}
> >   
> > -	ret = rproc_add(rproc);
> > -	if (ret)
> > -		goto remove_subdev;
> > +	if (!is_multi_core) {
> > +		ret = rproc_add(rproc);
> > +		if (ret)
> > +			goto remove_subdev;
> > +	}
> >   
> >   	return 0;
> >   
> > @@ -950,9 +954,125 @@ static int scp_rproc_init(struct platform_device *pdev,
> >   	return ret;
> >   }
> >   
> > +static void scp_rproc_free(struct mtk_scp *scp)
> > +{
> > +	int i;
> > +
> > +	scp_remove_rpmsg_subdev(scp);
> > +	scp_ipi_unregister(scp, SCP_IPI_INIT);
> > +	scp_unmap_memory_region(scp);
> > +	for (i = 0; i < SCP_IPI_MAX; i++)
> > +		mutex_destroy(&scp->ipi_desc[i].lock);
> > +	mutex_destroy(&scp->send_lock);
> > +}
> > +
> > +static void scp_rproc_exit(struct platform_device *pdev)
> > +{
> > +	struct mtk_scp *scp = platform_get_drvdata(pdev);
> > +
> > +	rproc_del(scp->rproc);
> > +	scp_rproc_free(scp);
> > +}
> > +
> > +static int scp_cluster_init(struct platform_device *pdev,
> > +			    struct mtk_scp_of_regs *of_regs)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev_of_node(dev);
> > +	struct platform_device *cpdev;
> > +	struct device_node *child;
> > +	const struct mtk_scp_of_data **cluster_of_data;
> > +	struct list_head *cluster;
> 
> Here you have a local `cluster` pointer.....
> 
> > +	struct mtk_scp *scp, *temp;
> > +	int core_id, num_cores;
> > +	int ret;
> > +
> > +	cluster_of_data = (const struct mtk_scp_of_data **)of_device_get_match_data(dev);
> > +
> > +	for (num_cores = 0; cluster_of_data[num_cores]; num_cores++)
> > +		;
> > +
> > +	cluster = NULL;
> 
> (unrelated: please initialize cluster and core_id on the declaration, not here)

Ok. I'll update this in the next version.

> 
> > +	core_id = 0;
> > +	for_each_available_child_of_node(np, child) {
> > +		if (core_id >= num_cores) {
> > +			ret = -EINVAL;
> > +			dev_err(dev, "Not support core %d\n", core_id);
> > +			of_node_put(child);
> > +			goto init_fail;
> > +		}
> > +
> > +		cpdev = of_find_device_by_node(child);
> > +		if (!cpdev) {
> > +			ret = -ENODEV;
> > +			dev_err(dev, "Not found platform device for core %d\n", core_id);
> > +			of_node_put(child);
> > +			goto init_fail;
> > +		}
> > +
> > +		ret = scp_rproc_init(cpdev, of_regs, cluster_of_data[core_id], true);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to initialize core %d rproc\n", core_id);
> > +			put_device(&cpdev->dev);
> > +			of_node_put(child);
> > +			goto init_fail;
> > +		}
> > +
> > +		scp = platform_get_drvdata(cpdev);
> > +		put_device(&cpdev->dev);
> > +		if (core_id == 0) {
> > +			INIT_LIST_HEAD(&scp->cluster_cores);
> 
> ...then here you initialize cluster_cores,
> 
> > +			cluster = &scp->cluster_cores;
> 
> and assign to your local `cluster` pointer and even set it
> 
> > +			platform_set_drvdata(pdev, cluster);
> 
> as platform drvdata.
> 
> > +		}
> > +
> > +		list_add_tail(&scp->elem, cluster);
> 
> Still using the local `cluster` pointer, which is `scp->cluster_cores`
> 
> > +		scp->cluster = cluster;
> 
> ...and here, `scp->cluster` effectively points to local `cluster`, which is
> anyway `scp->cluster_cores`.
> 
> As far as I understand, `scp->cluster` is EITHER `scp->cluster_cores` or NULL,
> hence the question: why do you need both scp->cluster and scp->cluster_cores,
> if they're always pointing to the same list?
> 
> P.S.: I won't cut the rest of the patch so that the readers of this reply won't
>        have to click around to see the whole code; comments end here!
> 
> Regards,
> Angelo

It's because each core is represented by a mtk_scp structure and they are linked in the list of core 0.

After initialized, the data structure is depicted as below,

mtk_scp for core 0          mtk_scp for core 1
  elem <----------------------elem (list)
    |
    V
  cluster_cores <----┐        cluster_cores (not used)
    Λ                |
    |                |
  *cluster           └--------*cluster (pointer)

For the 2nd core scp, its cluster_cores is useless.
So, I add the *cluster to point back to the cores list in the 1st core's data structure.

Best regards,
TingHan

> 
> > +
> > +		of_node_put(child);
> > +		core_id++;
> > +	}
> > +
> > +	list_for_each_entry_safe_reverse(scp, temp, cluster, elem) {
> > +		ret = rproc_add(scp->rproc);
> > +		if (ret)
> > +			goto add_fail;
> > +	}
> > +
> > +	return 0;
> > +
> > +add_fail:
> > +	list_for_each_entry_continue(scp, cluster, elem) {
> > +		rproc_del(scp->rproc);
> > +	}
> > +init_fail:
> > +	if (cluster) {
> > +		list_for_each_entry_safe_reverse(scp, temp, cluster, elem) {
> > +			list_del(&scp->elem);
> > +			scp_rproc_free(scp);
> > +		}
> > +	}
> > +	return ret;
> > +}
> > +
> > +static void scp_cluster_exit(struct platform_device *pdev)
> > +{
> > +	struct list_head *cluster = platform_get_drvdata(pdev);
> > +	struct platform_device *cpdev;
> > +	struct mtk_scp *scp, *temp;
> > +
> > +	list_for_each_entry_safe_reverse(scp, temp, cluster, elem) {
> > +		list_del(&scp->elem);
> > +		cpdev = to_platform_device(scp->dev);
> > +		scp_rproc_exit(cpdev);
> > +	}
> > +}
> > +
> >   static int scp_probe(struct platform_device *pdev)
> >   {
> >   	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node;
> > +	struct device_node *core_node;
> >   	struct resource *res;
> >   	struct mtk_scp_of_regs scp_regs;
> >   	int ret;
> > @@ -975,21 +1095,43 @@ static int scp_probe(struct platform_device *pdev)
> >   		scp_regs.l1tcm_phys = res->start;
> >   	}
> >   
> > -	return scp_rproc_init(pdev, &scp_regs);
> > +	ret = devm_of_platform_populate(dev);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret, "Failed to populate platform devices\n");
> > +
> > +	core_node = of_get_child_by_name(np, "scp");
> > +	of_node_put(core_node);
> > +
> > +	if (!core_node) {
> > +		dev_info(dev, "single-core scp\n");
> > +
> > +		ret = scp_rproc_init(pdev, &scp_regs, of_device_get_match_data(dev), false);
> > +		if (ret)
> > +			return dev_err_probe(dev, ret, "Failed to initialize single-core scp\n");
> > +	} else {
> > +		dev_info(dev, "multi-core scp\n");
> > +
> > +		ret = scp_cluster_init(pdev, &scp_regs);
> > +		if (ret)
> > +			return dev_err_probe(dev, ret, "Failed to initialize scp cluster\n");
> > +	}
> > +
> > +	return 0;
> >   }
> >   
> >   static int scp_remove(struct platform_device *pdev)
> >   {
> > -	struct mtk_scp *scp = platform_get_drvdata(pdev);
> > -	int i;
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node;
> > +	struct device_node *core_node;
> >   
> > -	rproc_del(scp->rproc);
> > -	scp_remove_rpmsg_subdev(scp);
> > -	scp_ipi_unregister(scp, SCP_IPI_INIT);
> > -	scp_unmap_memory_region(scp);
> > -	for (i = 0; i < SCP_IPI_MAX; i++)
> > -		mutex_destroy(&scp->ipi_desc[i].lock);
> > -	mutex_destroy(&scp->send_lock);
> > +	core_node = of_get_child_by_name(np, "scp");
> > +	of_node_put(core_node);
> > +
> > +	if (!core_node)
> > +		scp_rproc_exit(pdev);
> > +	else
> > +		scp_cluster_exit(pdev);
> >   
> >   	return 0;
> >   }
> > @@ -1068,12 +1210,19 @@ static const struct mtk_scp_of_data mt8195_of_data_c1 = {
> >   	.host_to_scp_int_bit = MT8195_CORE1_HOST_IPC_INT_BIT,
> >   };
> >   
> > +static const struct mtk_scp_of_data *mt8195_of_data_cores[] = {
> > +	&mt8195_of_data,
> > +	&mt8195_of_data_c1,
> > +	NULL
> > +};
> > +
> >   static const struct of_device_id mtk_scp_of_match[] = {
> >   	{ .compatible = "mediatek,mt8183-scp", .data = &mt8183_of_data },
> >   	{ .compatible = "mediatek,mt8186-scp", .data = &mt8186_of_data },
> >   	{ .compatible = "mediatek,mt8188-scp", .data = &mt8188_of_data },
> >   	{ .compatible = "mediatek,mt8192-scp", .data = &mt8192_of_data },
> >   	{ .compatible = "mediatek,mt8195-scp", .data = &mt8195_of_data },
> > +	{ .compatible = "mediatek,mt8195-scp-dual", .data = &mt8195_of_data_cores },
> >   	{},
> >   };
> >   MODULE_DEVICE_TABLE(of, mtk_scp_of_match);
> 
> 

-- 
Best regards,
TingHan

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