2023-06-02 09:11:23

by Yong Wu (吴勇)

Subject: [PATCH v12 2/7] iommu/mediatek: Fix two IOMMU share pagetable issue

From: "Chengci.Xu" <[email protected]>

Prepare for mt8188 to fix a two IOMMU HWs share pagetable issue.

We have two MM IOMMU HWs in mt8188, one is VPP-IOMMU, the other is
VDO-IOMMU. The 2 MM IOMMU HWs share pagetable don't work in this case:
a) VPP-IOMMU probe firstly.
b) VDO-IOMMU probe.
c) The master for VDO-IOMMU probe (means frstdata is vpp-iommu).
d) The master in another domain probe. No matter it is vdo or vpp.
Then it still create a new pagetable in step d). The problem is
"frstdata->bank[0]->m4u_dom" was not initialized. Then when d) enter, it
still create a new one.

In this patch, we create a new variable "share_dom" for this share
pgtable case, it should be helpful for readable. and put all the share
pgtable logic in the mtk_iommu_domain_finalise.

In mt8195, the master of VPP-IOMMU probes before than VDO-IOMMU
from its dtsi node sequence, we don't see this issue in it. Prepare for
mt8188.

Fixes: 645b87c190c9 ("iommu/mediatek: Fix 2 HW sharing pgtable issue")
Signed-off-by: Chengci.Xu <[email protected]>
Signed-off-by: Yong Wu <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
---
drivers/iommu/mtk_iommu.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index aecc7d154f28..7287be67bd1f 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -258,6 +258,8 @@ struct mtk_iommu_data {
struct device *smicomm_dev;

struct mtk_iommu_bank_data *bank;
+ struct mtk_iommu_domain *share_dom; /* For 2 HWs share pgtable */
+
struct regmap *pericfg;
struct mutex mutex; /* Protect m4u_group/m4u_dom above */

@@ -620,15 +622,14 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
struct mtk_iommu_data *data,
unsigned int region_id)
{
+ struct mtk_iommu_domain *share_dom = data->share_dom;
const struct mtk_iommu_iova_region *region;
- struct mtk_iommu_domain *m4u_dom;
-
- /* Always use bank0 in sharing pgtable case */
- m4u_dom = data->bank[0].m4u_dom;
- if (m4u_dom) {
- dom->iop = m4u_dom->iop;
- dom->cfg = m4u_dom->cfg;
- dom->domain.pgsize_bitmap = m4u_dom->cfg.pgsize_bitmap;
+
+ /* Always use share domain in sharing pgtable case */
+ if (MTK_IOMMU_HAS_FLAG(data->plat_data, SHARE_PGTABLE) && share_dom) {
+ dom->iop = share_dom->iop;
+ dom->cfg = share_dom->cfg;
+ dom->domain.pgsize_bitmap = share_dom->cfg.pgsize_bitmap;
goto update_iova_region;
}

@@ -658,6 +659,9 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
/* Update our support page sizes bitmap */
dom->domain.pgsize_bitmap = dom->cfg.pgsize_bitmap;

+ if (MTK_IOMMU_HAS_FLAG(data->plat_data, SHARE_PGTABLE))
+ data->share_dom = dom;
+
update_iova_region:
/* Update the iova region for this domain */
region = data->plat_data->iova_region + region_id;
@@ -708,7 +712,9 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
/* Data is in the frstdata in sharing pgtable case. */
frstdata = mtk_iommu_get_frst_data(hw_list);

+ mutex_lock(&frstdata->mutex);
ret = mtk_iommu_domain_finalise(dom, frstdata, region_id);
+ mutex_unlock(&frstdata->mutex);
if (ret) {
mutex_unlock(&dom->mutex);
return ret;
--
2.25.1

2023-06-06 14:17:01

by Alexandre Mergnat

Subject: Re: [PATCH v12 2/7] iommu/mediatek: Fix two IOMMU share pagetable issue

On 02/06/2023 11:02, Yong Wu wrote:
> Prepare for mt8188 to fix a two IOMMU HWs share pagetable issue.
>
> We have two MM IOMMU HWs in mt8188, one is VPP-IOMMU, the other is
> VDO-IOMMU. The 2 MM IOMMU HWs share pagetable don't work in this case:
> a) VPP-IOMMU probe firstly.
> b) VDO-IOMMU probe.
> c) The master for VDO-IOMMU probe (means frstdata is vpp-iommu).
> d) The master in another domain probe. No matter it is vdo or vpp.
> Then it still create a new pagetable in step d). The problem is
> "frstdata->bank[0]->m4u_dom" was not initialized. Then when d) enter, it
> still create a new one.
>
> In this patch, we create a new variable "share_dom" for this share
> pgtable case, it should be helpful for readable. and put all the share
> pgtable logic in the mtk_iommu_domain_finalise.
>
> In mt8195, the master of VPP-IOMMU probes before than VDO-IOMMU
> from its dtsi node sequence, we don't see this issue in it. Prepare for
> mt8188.

Reviewed-by: Alexandre Mergnat <[email protected]>

--
Regards,
Alexandre