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From: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
To: Yong Wu <yong.wu@mediatek.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	David Airlie <airlied@linux.ie>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Evan Green <evgreen@chromium.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Tomasz Figa <tfiga@chromium.org>,
	Will Deacon <will.deacon@arm.com>,
	linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	iommu@lists.linux-foundation.org, youlin.pei@mediatek.com,
	Matthias Kaehlcke <mka@chromium.org>,
	anan.sun@mediatek.com, yi.kuo@mediatek.com,
	acourbot@chromium.org, linux-media@vger.kernel.org,
	dri-devel@lists.freedesktop.org, Daniel Vetter <daniel@ffwll.ch>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Tiffany Lin <tiffany.lin@mediatek.com>,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Eizan Miyamoto <eizan@chromium.org>,
	anthony.huang@mediatek.com,
	Frank Wunderlich <frank-w@public-files.de>
Subject: Re: [PATCH v8 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices
Date: Mon, 11 Oct 2021 14:36:13 +0200	[thread overview]
Message-ID: <e00b92db-0562-27ca-2f96-1f03ff824988@collabora.com> (raw)
In-Reply-To: <20210929013719.25120-5-yong.wu@mediatek.com>



On 29.09.21 03:37, Yong Wu wrote:
> MediaTek IOMMU-SMI diagram is like below. all the consumer connect with
> smi-larb, then connect with smi-common.
> 
>          M4U
>           |
>      smi-common
>           |
>    -------------
>    |         |    ...
>    |         |
> larb1     larb2
>    |         |
> vdec       venc
> 
> When the consumer works, it should enable the smi-larb's power which
> also need enable the smi-common's power firstly.
> 
> Thus, First of all, use the device link connect the consumer and the
> smi-larbs. then add device link between the smi-larb and smi-common.
> 
> This patch adds device_link between the consumer and the larbs.
> 
> When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling
> pm_runtime_xx to keep the original status of clocks. It can avoid two
> issues:
> 1) Display HW show fastlogo abnormally reported in [1]. At the beggining,
> all the clocks are enabled before entering kernel, but the clocks for
> display HW(always in larb0) will be gated after clk_enable and clk_disable
> called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock
> operation happened before display driver probe. At that time, the display
> HW will be abnormal.
> 
> 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip
> pm_runtime_xx to avoid the deadlock.
> 
> Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then
> device_link_removed should be added explicitly.
> 
> [1] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/
> [2] https://lore.kernel.org/patchwork/patch/1086569/
> 
> Suggested-by: Tomasz Figa <tfiga@chromium.org>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> Tested-by: Frank Wunderlich <frank-w@public-files.de> # BPI-R2/MT7623
> ---
>   drivers/iommu/mtk_iommu.c    | 22 ++++++++++++++++++++++
>   drivers/iommu/mtk_iommu_v1.c | 20 +++++++++++++++++++-
>   2 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index d5848f78a677..a2fa55899434 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -560,22 +560,44 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
>   {
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>   	struct mtk_iommu_data *data;
> +	struct device_link *link;
> +	struct device *larbdev;
> +	unsigned int larbid;
>   
>   	if (!fwspec || fwspec->ops != &mtk_iommu_ops)
>   		return ERR_PTR(-ENODEV); /* Not a iommu client device */
>   
>   	data = dev_iommu_priv_get(dev);
>   
> +	/*
> +	 * Link the consumer device with the smi-larb device(supplier)
> +	 * The device in each a larb is a independent HW. thus only link
> +	 * one larb here.
> +	 */
> +	larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);

so larbid is always the same for all the ids of a device? If so
maybe it worth testing it and return error if this is not the case.

Thanks,
Dafna

> +	larbdev = data->larb_imu[larbid].dev;
> +	link = device_link_add(dev, larbdev,
> +			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
> +	if (!link)
> +		dev_err(dev, "Unable to link %s\n", dev_name(larbdev));
>   	return &data->iommu;
>   }
>   
>   static void mtk_iommu_release_device(struct device *dev)
>   {
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +	struct mtk_iommu_data *data;
> +	struct device *larbdev;
> +	unsigned int larbid;
>   
>   	if (!fwspec || fwspec->ops != &mtk_iommu_ops)
>   		return;
>   
> +	data = dev_iommu_priv_get(dev);
> +	larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);
> +	larbdev = data->larb_imu[larbid].dev;
> +	device_link_remove(dev, larbdev);
> +
>   	iommu_fwspec_free(dev);
>   }
>   
> diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> index 4d7809432239..e6f13459470e 100644
> --- a/drivers/iommu/mtk_iommu_v1.c
> +++ b/drivers/iommu/mtk_iommu_v1.c
> @@ -423,7 +423,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>   	struct of_phandle_args iommu_spec;
>   	struct mtk_iommu_data *data;
> -	int err, idx = 0;
> +	int err, idx = 0, larbid;
> +	struct device_link *link;
> +	struct device *larbdev;
>   
>   	/*
>   	 * In the deferred case, free the existed fwspec.
> @@ -453,6 +455,14 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
>   
>   	data = dev_iommu_priv_get(dev);
>   
> +	/* Link the consumer device with the smi-larb device(supplier) */
> +	larbid = mt2701_m4u_to_larb(fwspec->ids[0]);
> +	larbdev = data->larb_imu[larbid].dev;
> +	link = device_link_add(dev, larbdev,
> +			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
> +	if (!link)
> +		dev_err(dev, "Unable to link %s\n", dev_name(larbdev));
> +
>   	return &data->iommu;
>   }
>   
> @@ -473,10 +483,18 @@ static void mtk_iommu_probe_finalize(struct device *dev)
>   static void mtk_iommu_release_device(struct device *dev)
>   {
>   	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +	struct mtk_iommu_data *data;
> +	struct device *larbdev;
> +	unsigned int larbid;
>   
>   	if (!fwspec || fwspec->ops != &mtk_iommu_ops)
>   		return;
>   
> +	data = dev_iommu_priv_get(dev);
> +	larbid = mt2701_m4u_to_larb(fwspec->ids[0]);
> +	larbdev = data->larb_imu[larbid].dev;
> +	device_link_remove(dev, larbdev);
> +
>   	iommu_fwspec_free(dev);
>   }
>   
> 

  reply	other threads:[~2021-10-11 12:36 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29  1:37 [PATCH v8 00/12] Clean up "mediatek,larb" Yong Wu
2021-09-29  1:37 ` [PATCH v8 01/12] dt-binding: mediatek: Get rid of mediatek, larb for multimedia HW Yong Wu
2021-09-29  1:37 ` [PATCH v8 02/12] iommu/mediatek-v1: Free the existed fwspec if the master dev already has Yong Wu
2021-09-29  1:37 ` [PATCH v8 03/12] iommu/mediatek: Add probe_defer for smi-larb Yong Wu
2021-09-29 16:33   ` Dafna Hirschfeld
2021-09-30  7:14     ` Yong Wu
2021-09-29  1:37 ` [PATCH v8 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices Yong Wu
2021-10-11 12:36   ` Dafna Hirschfeld [this message]
2021-10-16  2:23     ` Yong Wu
2021-10-18  7:13       ` Dafna Hirschfeld
2021-10-25  3:57         ` Yong Wu
2021-09-29  1:37 ` [PATCH v8 05/12] media: mtk-jpeg: Get rid of mtk_smi_larb_get/put Yong Wu
2021-09-29  1:37 ` [PATCH v8 06/12] media: mtk-mdp: " Yong Wu
2021-09-29  1:37 ` [PATCH v8 07/12] drm/mediatek: Add pm runtime support for ovl and rdma Yong Wu
2021-09-29  1:37 ` [PATCH v8 08/12] drm/mediatek: Get rid of mtk_smi_larb_get/put Yong Wu
2021-09-29  1:37 ` [PATCH v8 09/12] media: mtk-vcodec: " Yong Wu
2021-09-29 12:13   ` Dafna Hirschfeld
2021-09-30  3:28     ` Yong Wu
2021-09-30 10:57       ` Dafna Hirschfeld
2021-10-07  2:57         ` Yong Wu
2021-09-29  1:37 ` [PATCH v8 10/12] memory: mtk-smi: " Yong Wu
2021-09-29  1:37 ` [PATCH v8 11/12] arm: dts: mediatek: Get rid of mediatek,larb for MM nodes Yong Wu
2021-09-29  1:37 ` [PATCH v8 12/12] arm64: " Yong Wu

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