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SubjectRe: [PATCH] iommu: io-pgtable: Support non-coherent page tables
On Thu, May 16, 2019 at 5:03 AM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> Describe the memory related to page table walks as non-cachable for iommu
> instances that are not DMA coherent.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> drivers/iommu/io-pgtable-arm.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index 4e21efbc4459..68ff22ffd2cb 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -803,9 +803,15 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
> return NULL;
>
> /* TCR */
> - reg = (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) |
> - (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT) |
> - (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT);
> + if (cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA) {
> + reg = (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) |
> + (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT) |
> + (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT);
> + } else {
> + reg = (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) |
> + (ARM_LPAE_TCR_RGN_NC << ARM_LPAE_TCR_IRGN0_SHIFT) |
> + (ARM_LPAE_TCR_RGN_NC << ARM_LPAE_TCR_ORGN0_SHIFT);
> + }

This looks okay to me based on the discussion that we had on a similar
patch that I
posted. So,
Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>

[1] https://lore.kernel.org/patchwork/patch/1032939/

Thanks & regards
Vivek

>
> switch (ARM_LPAE_GRANULE(data)) {
> case SZ_4K:
> --
> 2.18.0
>
> _______________________________________________
> iommu mailing list
> iommu@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu



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