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,
Nicolas Boichat <drinkcat@chromium.org>,
Matthias Kaehlcke <mka@chromium.org>,
anan.sun@mediatek.com, ming-fan.chen@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>,
Xia Jiang <xia.jiang@mediatek.com>,
Tiffany Lin <tiffany.lin@mediatek.com>,
Hsin-Yi Wang <hsinyi@chromium.org>,
Eizan Miyamoto <eizan@chromium.org>,
anthony.huang@mediatek.com
Subject: Re: [PATCH v6 03/11] iommu/mediatek: Add device_link between the consumer and the larb devices
Date: Wed, 14 Jul 2021 10:26:20 +0200 [thread overview]
Message-ID: <f7b2c5e5-f540-b885-f063-9611031035bc@collabora.com> (raw)
In-Reply-To: <20210714025626.5528-4-yong.wu@mediatek.com>
On 14.07.21 04:56, 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>
> ---
> 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 a02dde094788..ee742900cf4b 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -571,22 +571,44 @@ 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]);
> + 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));
shoudn't ERR_PTR be returned in case of failure?
Thanks,
Dafna
> 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 d9365a3d8dc9..d2a7c66b8239 100644
> --- a/drivers/iommu/mtk_iommu_v1.c
> +++ b/drivers/iommu/mtk_iommu_v1.c
> @@ -424,7 +424,9 @@ 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;
>
> while (!of_parse_phandle_with_args(dev->of_node, "iommus",
> "#iommu-cells",
> @@ -445,6 +447,14 @@ 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;
> }
>
> @@ -465,10 +475,18 @@ 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);
> }
>
>
next prev parent reply other threads:[~2021-07-14 8:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 2:56 [PATCH v6 00/11] Clean up "mediatek,larb" Yong Wu
2021-07-14 2:56 ` [PATCH v6 01/11] dt-binding: mediatek: Get rid of mediatek,larb for multimedia HW Yong Wu
2021-07-14 8:13 ` [PATCH v6 01/11] dt-binding: mediatek: Get rid of mediatek, larb " Dafna Hirschfeld
2021-07-14 8:49 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 02/11] iommu/mediatek: Add probe_defer for smi-larb Yong Wu
2021-07-14 2:56 ` [PATCH v6 03/11] iommu/mediatek: Add device_link between the consumer and the larb devices Yong Wu
2021-07-14 8:26 ` Dafna Hirschfeld [this message]
2021-07-14 11:16 ` Yong Wu
2021-07-14 2:56 ` [PATCH v6 04/11] media: mtk-jpeg: Get rid of mtk_smi_larb_get/put Yong Wu
2021-07-14 8:28 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 05/11] media: mtk-mdp: " Yong Wu
2021-07-14 8:29 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 06/11] drm/mediatek: Add pm runtime support for ovl and rdma Yong Wu
2021-07-14 8:44 ` Dafna Hirschfeld
2021-07-14 11:17 ` Yong Wu
2021-07-14 2:56 ` [PATCH v6 07/11] drm/mediatek: Get rid of mtk_smi_larb_get/put Yong Wu
2021-07-14 8:30 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 08/11] media: mtk-vcodec: " Yong Wu
2021-07-14 8:31 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 09/11] memory: mtk-smi: " Yong Wu
2021-07-14 8:32 ` Dafna Hirschfeld
2021-07-14 2:56 ` [PATCH v6 10/11] arm: dts: mediatek: Get rid of mediatek,larb for MM nodes Yong Wu
2021-07-14 2:56 ` [PATCH v6 11/11] arm64: " Yong Wu
2021-07-14 8:56 ` [PATCH v6 00/11] Clean up "mediatek,larb" Dafna Hirschfeld
2021-07-14 11:18 ` Yong Wu
2021-07-14 8:59 ` Aw: " Frank Wunderlich
2021-07-14 11:18 ` Yong Wu
2021-07-14 11:23 ` Aw: " Frank Wunderlich
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