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Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for iommu

From Robin Murphy <robin.murphy@arm.com>
Newsgroups linux.kernel
Subject Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for iommu
Date 2016-05-23 12:50 +0200
Message-ID <rBVAR-4HP-11@gated-at.bofh.it> (permalink)
References <rBN0C-7Wt-5@gated-at.bofh.it> <rBN0C-7Wt-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 23/05/16 02:37, Shunqian Zheng wrote:
> From: Simon <xxm@rock-chips.com>
>
> Signed-off-by: Simon <xxm@rock-chips.com>
> ---
>   drivers/iommu/rockchip-iommu.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
> index 043d18c..1741b65 100644
> --- a/drivers/iommu/rockchip-iommu.c
> +++ b/drivers/iommu/rockchip-iommu.c
> @@ -95,12 +95,16 @@ struct rk_iommu {
>
>   static inline void rk_table_flush(u32 *va, unsigned int count)
>   {
> +#if defined(CONFIG_ARM)
>   	phys_addr_t pa_start = virt_to_phys(va);
>   	phys_addr_t pa_end = virt_to_phys(va + count);
>   	size_t size = pa_end - pa_start;
>
>   	__cpuc_flush_dcache_area(va, size);
>   	outer_flush_range(pa_start, pa_end);
> +#elif defined(CONFIG_ARM64)
> +	__dma_flush_range(va, va + count);
> +#endif

Ugh, please don't use arch-private cache maintenance functions directly 
from a driver. Allocating/mapping page tables to be read by the IOMMU is 
still DMA, so using the DMA APIs is the correct way to manage them, 
*especially* if it needs to work across multiple architectures.

Robin.

>   }
>
>   static struct rk_iommu_domain *to_rk_domain(struct iommu_domain *dom)
>

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Thread

[PATCH 0/5] iommu/rockchip: fix bugs; enable iommu for ARM64 Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-23 03:40 +0200
  [PATCH 5/5] iommu/rockchip: enable rockchip iommu on ARM64 platform Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-23 03:40 +0200
  [PATCH 2/5] iommu/rockchip: add map_sg callback for rk_iommu_ops Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-23 03:40 +0200
  [PATCH 3/5] iommu/rockchip: add sanity check for virtual device Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-23 03:40 +0200
  [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for iommu Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-23 03:40 +0200
    Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for  iommu Robin Murphy <robin.murphy@arm.com> - 2016-05-23 12:50 +0200
      Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for  iommu Catalin Marinas <catalin.marinas@arm.com> - 2016-05-23 15:40 +0200
        Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for  iommu Shunqian Zheng <zhengsq@rock-chips.com> - 2016-05-24 04:40 +0200
          Re: [PATCH 4/5] iommu/rockchip: add ARM64 cache flush operation for  iommu Catalin Marinas <catalin.marinas@arm.com> - 2016-05-24 12:00 +0200

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