Hi YF,

Thanks very much for this patch. Nearly all the lastest SoC like mt8192/mt8195 support this.

On Fri, 2022-04-29 at 22:34 +0800, yf.wang@mediatek.com wrote:

From: Yunfei Wang yf.wang@mediatek.com

Add the quirk IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT support, so that level 2 page table can allocate in normal memory.

Could you help comment more detailedly here and in the title?, this patch just allows the level 2 pgtable PA up to 35bits, not only in ZONE_DMA32(GFP_DMA32).

Signed-off-by: Ning Li ning.li@mediatek.com Signed-off-by: Yunfei Wang yf.wang@mediatek.com Cc: stable@vger.kernel.org # 5.10.*

If you add this for stable, Which commit do you need for "Fixes:" tag?

It looks you add a new feature, rather than fixing a bug of the current kernel. I didn't get a issue report for this. If this is a bug, we need more information like under which condition/SoC the error will occur.

The code is ok for me.

Thanks.

---

drivers/iommu/mtk_iommu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 6fd75a60abd6..27481f562df7 100644 --- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -118,6 +118,7 @@ #define WR_THROT_EN BIT(6) #define HAS_LEGACY_IVRP_PADDR BIT(7) #define IOVA_34_EN BIT(8) +#define PGTABLE_L2_PA_35_EN BIT(9) #define MTK_IOMMU_HAS_FLAG(pdata, _x) \ ((((pdata)->flags) & (_x)) == (_x)) @@ -401,6 +402,9 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom, .iommu_dev = data->dev, };

• if (MTK_IOMMU_HAS_FLAG(data->plat_data, PGTABLE_L2_PA_35_EN))

• dom->cfg.quirks |= IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT;
  

• if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) dom->cfg.oas = data->enable_4GB ? 33 : 32; else

@@ -1038,7 +1042,8 @@ static const struct mtk_iommu_plat_data mt2712_data = { static const struct mtk_iommu_plat_data mt6779_data = { .m4u_plat = M4U_MT6779,

• .flags = HAS_SUB_COMM | OUT_ORDER_WR_EN | WR_THROT_EN,

• .flags = HAS_SUB_COMM | OUT_ORDER_WR_EN | WR_THROT_EN |

• 	 PGTABLE_L2_PA_35_EN,
  

  .inv_sel_reg = REG_MMU_INV_SEL_GEN2, .iova_region = single_domain, .iova_region_nr = ARRAY_SIZE(single_domain),