Re: [PATCH 12/27] ARM: mmu: move dma_sync_single_for_device to extra file

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 12.05.23 13:09, Sascha Hauer wrote:
> The next patch merges the mmu.c files with their corresponding
> mmu-early.c files. Before doing that move functions which can't
> be compiled for PBL out to extra files.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  arch/arm/cpu/Makefile |  1 +
>  arch/arm/cpu/dma_32.c | 20 ++++++++++++++++++++
>  arch/arm/cpu/dma_64.c | 16 ++++++++++++++++
>  arch/arm/cpu/mmu_32.c | 18 ------------------
>  arch/arm/cpu/mmu_64.c | 13 -------------
>  5 files changed, 37 insertions(+), 31 deletions(-)
>  create mode 100644 arch/arm/cpu/dma_32.c
>  create mode 100644 arch/arm/cpu/dma_64.c
> 
> diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
> index fef2026da5..cd5f36eb49 100644
> --- a/arch/arm/cpu/Makefile
> +++ b/arch/arm/cpu/Makefile
> @@ -4,6 +4,7 @@ obj-y += cpu.o
>  
>  obj-$(CONFIG_ARM_EXCEPTIONS) += exceptions_$(S64_32).o interrupts_$(S64_32).o
>  obj-$(CONFIG_MMU) += mmu_$(S64_32).o mmu-common.o
> +obj-$(CONFIG_MMU) += dma_$(S64_32).o
>  obj-pbl-y += lowlevel_$(S64_32).o
>  obj-pbl-$(CONFIG_MMU) += mmu-early_$(S64_32).o
>  obj-pbl-$(CONFIG_CPU_32v7) += hyp.o
> diff --git a/arch/arm/cpu/dma_32.c b/arch/arm/cpu/dma_32.c
> new file mode 100644
> index 0000000000..a66aa26b9b
> --- /dev/null
> +++ b/arch/arm/cpu/dma_32.c
> @@ -0,0 +1,20 @@
> +#include <dma.h>
> +#include <asm/mmu.h>
> +
> +void dma_sync_single_for_device(dma_addr_t address, size_t size,
> +				enum dma_data_direction dir)
> +{
> +	/*
> +	 * FIXME: This function needs a device argument to support non 1:1 mappings
> +	 */
> +
> +	if (dir == DMA_FROM_DEVICE) {
> +		__dma_inv_range(address, address + size);
> +		if (outer_cache.inv_range)
> +			outer_cache.inv_range(address, address + size);

I know this is unrelated to your series, but this is wrong. The outermost
cache must be be invalidated before L1. Otherwise we could have this
unlucky constellation:

  - CPU is invalidating L1
  - HW prefetcher wants to load something into L1
  - Stale data in L2 is loaded into L1
  - Only now CPU invalidates L2

Could you send a fix? :-)

> +	} else {
> +		__dma_clean_range(address, address + size);
> +		if (outer_cache.clean_range)
> +			outer_cache.clean_range(address, address + size);

This is fine though.

> +	}
> +}
> diff --git a/arch/arm/cpu/dma_64.c b/arch/arm/cpu/dma_64.c
> new file mode 100644
> index 0000000000..b4ae736c9b
> --- /dev/null
> +++ b/arch/arm/cpu/dma_64.c
> @@ -0,0 +1,16 @@
> +#include <dma.h>
> +#include <asm/mmu.h>
> +#include <asm/cache.h>
> +
> +void dma_sync_single_for_device(dma_addr_t address, size_t size,
> +                                enum dma_data_direction dir)
> +{
> +	/*
> +	 * FIXME: This function needs a device argument to support non 1:1 mappings
> +	 */
> +
> +	if (dir == DMA_FROM_DEVICE)
> +		v8_inv_dcache_range(address, address + size - 1);
> +	else
> +		v8_flush_dcache_range(address, address + size - 1);
> +}
> diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c
> index 7b31938ecd..10f447874c 100644
> --- a/arch/arm/cpu/mmu_32.c
> +++ b/arch/arm/cpu/mmu_32.c
> @@ -494,21 +494,3 @@ void *dma_alloc_writecombine(size_t size, dma_addr_t *dma_handle)
>  {
>  	return dma_alloc_map(size, dma_handle, ARCH_MAP_WRITECOMBINE);
>  }
> -
> -void dma_sync_single_for_device(dma_addr_t address, size_t size,
> -				enum dma_data_direction dir)
> -{
> -	/*
> -	 * FIXME: This function needs a device argument to support non 1:1 mappings
> -	 */
> -
> -	if (dir == DMA_FROM_DEVICE) {
> -		__dma_inv_range(address, address + size);
> -		if (outer_cache.inv_range)
> -			outer_cache.inv_range(address, address + size);
> -	} else {
> -		__dma_clean_range(address, address + size);
> -		if (outer_cache.clean_range)
> -			outer_cache.clean_range(address, address + size);
> -	}
> -}
> diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
> index c7c16b527b..9150de1676 100644
> --- a/arch/arm/cpu/mmu_64.c
> +++ b/arch/arm/cpu/mmu_64.c
> @@ -241,16 +241,3 @@ void dma_flush_range(void *ptr, size_t size)
>  
>  	v8_flush_dcache_range(start, end);
>  }
> -
> -void dma_sync_single_for_device(dma_addr_t address, size_t size,
> -                                enum dma_data_direction dir)
> -{
> -	/*
> -	 * FIXME: This function needs a device argument to support non 1:1 mappings
> -	 */
> -
> -	if (dir == DMA_FROM_DEVICE)
> -		v8_inv_dcache_range(address, address + size - 1);
> -	else
> -		v8_flush_dcache_range(address, address + size - 1);
> -}

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