Re: [PATCH 04/13] iommu/mediatek: Add device_link between the consumer and the larb devices

Evan Green
2019-02-25T23:54:25Z

On Mon, Dec 31, 2018 at 8:52 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> MediaTek IOMMU don't have its power-domain. 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.
>
> Suggested-by: Tomasz Figa <tfiga@chromium.org>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/iommu/mtk_iommu.c | 15 +++++++++++++--
> drivers/iommu/mtk_iommu_v1.c | 14 ++++++++++++--
> 2 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 202e41b..735ae8d 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -247,6 +247,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> struct mtk_smi_larb_iommu *larb_mmu;
> unsigned int larbid, portid;
> struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> + struct device_link *link;
> int i;
>
> for (i = 0; i < fwspec->num_ids; ++i) {
> @@ -257,10 +258,20 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> dev_dbg(dev, "%s iommu port: %d\n",
> enable ? "enable" : "disable", portid);
>
> - if (enable)
> + if (enable) {
> larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
> - else
> + /* Link the consumer with the larb device(supplier) */
> + link = device_link_add(dev, larb_mmu->dev,
> + DL_FLAG_PM_RUNTIME |
> + DL_FLAG_AUTOREMOVE_CONSUMER);
> + if (!link) {
> + dev_err(dev, "Unable to link %s\n",
> + dev_name(larb_mmu->dev));
> + return;

The return is a little odd here, given that you don't return an error
and this function doesn't do anything else. If it's non-fatal that
this link didn't get set up, then remove the return. If it is fatal,
then return an error code.

> + }
> + } else {
> larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
> + }
> }
> }
>
> diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> index 9386aee..022bad9 100644
> --- a/drivers/iommu/mtk_iommu_v1.c
> +++ b/drivers/iommu/mtk_iommu_v1.c
> @@ -201,6 +201,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> struct mtk_smi_larb_iommu *larb_mmu;
> unsigned int larbid, portid;
> struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> + struct device_link *link;
> int i;
>
> for (i = 0; i < fwspec->num_ids; ++i) {
> @@ -211,10 +212,19 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> dev_dbg(dev, "%s iommu port: %d\n",
> enable ? "enable" : "disable", portid);
>
> - if (enable)
> + if (enable) {
> larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
> - else
> + link = device_link_add(dev, larb_mmu->dev,
> + DL_FLAG_PM_RUNTIME |
> + DL_FLAG_AUTOREMOVE_CONSUMER);
> + if (!link) {
> + dev_err(dev, "Unable to link %s\n",
> + dev_name(larb_mmu->dev));
> + return;

Same for this one.

> + }
> + } else {
> larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
> + }
> }
> }
>
> --
> 1.9.1
>