On Mon, 2019-02-25 at 15:54 -0800, Evan Green wrote:

On Mon, Dec 31, 2018 at 8:52 PM Yong Wu [off-list ref] wrote:

quoted

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.

I will remove the "return". Thanks.

quoted

+                       }
+               } 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.

quoted

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

--
1.9.1

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