Re: [PATCH v10 1/2] iommu/io-pgtable-arm-v7s: Add a quirk to allow pgtable PA up to 35bit

On Wed, 2022-06-22 at 09:28 +0800, Yong Wu wrote:

On Thu, 2022-06-16 at 20:07 +0800, yf.wang@mediatek.com wrote:

quoted

From: Yunfei Wang <redacted>

Single memory zone feature will remove ZONE_DMA32 and ZONE_DMA and
cause pgtable PA size larger than 32bit.

Since Mediatek IOMMU hardware support at most 35bit PA in pgtable,
so add a quirk to allow the PA of pgtables support up to bit35.

Signed-off-by: Ning Li <redacted>
Signed-off-by: Yunfei Wang <redacted>
---
 drivers/iommu/io-pgtable-arm-v7s.c | 67 +++++++++++++++++++++++---
--
--
 include/linux/io-pgtable.h         | 15 ++++---
 2 files changed, 63 insertions(+), 19 deletions(-)

[...]

quoted

 	/* TTBR */
-	cfg->arm_v7s_cfg.ttbr = virt_to_phys(data->pgd) |
ARM_V7S_TTBR_S |
+	paddr = virt_to_phys(data->pgd);
+	cfg->arm_v7s_cfg.ttbr = paddr | ARM_V7S_TTBR_S |
 				(cfg->coherent_walk ? (ARM_V7S_TTBR_NOS

quoted

 				 ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_WBW
A) |
 				 ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_WBW
A)) :
 				(ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_NC)

quoted

 				 ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_NC)
));
+
+	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT)
+		cfg->arm_v7s_cfg.ttbr = (paddr & GENMASK(31, 7)) |
+					upper_32_bits(paddr);

If we keep ttbr u32, we have to put the special logic here. This line
is ok for all the MediaTek cases, not only for this quirk. It means:

    if (arm_v7s_is_mtk_enabled(cfg))
           cfg->arm_v7s_cfg.ttbr = (virt_to_phys(data->pgd) &
GENMASK(31, 7)) | upper_32_bits(paddr);
    else
           xxx
 
     Then we don't need add "& MMU_PT_ADDR_MASK" in mtk_iommu.c since
you have done it here.

Hi Yong,
Thanks for your suggestion, PATCH v11 version will modify it.

Thanks,
Yunfei.

quoted

+
 	return &data->iop;
 

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