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Message-ID: <80a4602f-8105-fe2e-0f52-ee23f2c0b2e4@arm.com>
Date: Tue, 9 Aug 2016 12:51:09 +0100
From: Robin Murphy <robin.murphy@....com>
To: Kwangwoo Lee <kwangwoo.lee@...com>,
Russell King - ARM Linux <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Mark Rutland <mark.rutland@....com>,
linux-arm-kernel@...ts.infradead.org
Cc: Woosuk Chung <woosuk.chung@...com>,
Hyunchul Kim <hyunchul3.kim@...com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] arm64: mm: convert __dma_* routines to use start, size
On 02/08/16 01:50, Kwangwoo Lee wrote:
> __dma_* routines have been converted to use start and size instread of
> start and end addresses. The patch was origianlly for adding
> __clean_dcache_area_poc() which will be used in pmem driver to clean
> dcache to the PoC(Point of Coherency) in arch_wb_cache_pmem().
>
> The functionality of __clean_dcache_area_poc() was equivalent to
> __dma_clean_range(). The difference was __dma_clean_range() uses the end
> address, but __clean_dcache_area_poc() uses the size to clean.
>
> Thus, __clean_dcache_area_poc() has been revised with a fallthrough
> function of __dma_clean_range() after the change that __dma_* routines
> use start and size instead of using start and end.
>
> As a consequence of using start and size, the name of __dma_* routines
> has also been altered following the terminology below:
> area: takes a start and size
> range: takes a start and end
This looks pretty nice and tidy now; I don't see anything obviously
wrong, and comparing before-and-after disassemblies shows essentially
nothing more than the movement of some add instructions as expected, so:
Reviewed-by: Robin Murphy <robin.murphy@....com>
> Signed-off-by: Kwangwoo Lee <kwangwoo.lee@...com>
> ---
> v3)
> clean up in __dma_clean_area() based on 823066d9edcd dcache_by_line_op fix
>
> v2)
> change the names of __dma_* rountines to use area instead of range
> fix to use __dma_flush_area() in dma-mapping.c
>
> v1)
> change __dma_* routines to use start, size
> add __clean_dcache_area_poc() as a fallthrough of __dma_clean_range()
>
> arch/arm64/include/asm/cacheflush.h | 3 +-
> arch/arm64/mm/cache.S | 82 ++++++++++++++++++-------------------
> arch/arm64/mm/dma-mapping.c | 6 +--
> 3 files changed, 44 insertions(+), 47 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
> index c64268d..2e5fb97 100644
> --- a/arch/arm64/include/asm/cacheflush.h
> +++ b/arch/arm64/include/asm/cacheflush.h
> @@ -68,6 +68,7 @@
> extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
> extern void flush_icache_range(unsigned long start, unsigned long end);
> extern void __flush_dcache_area(void *addr, size_t len);
> +extern void __clean_dcache_area_poc(void *addr, size_t len);
> extern void __clean_dcache_area_pou(void *addr, size_t len);
> extern long __flush_cache_user_range(unsigned long start, unsigned long end);
>
> @@ -85,7 +86,7 @@ static inline void flush_cache_page(struct vm_area_struct *vma,
> */
> extern void __dma_map_area(const void *, size_t, int);
> extern void __dma_unmap_area(const void *, size_t, int);
> -extern void __dma_flush_range(const void *, const void *);
> +extern void __dma_flush_area(const void *, size_t);
>
> /*
> * Copy user data from/to a page which is mapped into a different
> diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
> index 07d7352..58b5a90 100644
> --- a/arch/arm64/mm/cache.S
> +++ b/arch/arm64/mm/cache.S
> @@ -105,19 +105,20 @@ ENTRY(__clean_dcache_area_pou)
> ENDPROC(__clean_dcache_area_pou)
>
> /*
> - * __inval_cache_range(start, end)
> - * - start - start address of region
> - * - end - end address of region
> + * __dma_inv_area(start, size)
> + * - start - virtual start address of region
> + * - size - size in question
> */
> -ENTRY(__inval_cache_range)
> +__dma_inv_area:
> + add x1, x1, x0
> /* FALLTHROUGH */
>
> /*
> - * __dma_inv_range(start, end)
> - * - start - virtual start address of region
> - * - end - virtual end address of region
> + * __inval_cache_range(start, end)
> + * - start - start address of region
> + * - end - end address of region
> */
> -__dma_inv_range:
> +ENTRY(__inval_cache_range)
> dcache_line_size x2, x3
> sub x3, x2, #1
> tst x1, x3 // end cache line aligned?
> @@ -136,46 +137,43 @@ __dma_inv_range:
> dsb sy
> ret
> ENDPIPROC(__inval_cache_range)
> -ENDPROC(__dma_inv_range)
> +ENDPROC(__dma_inv_area)
> +
> +/*
> + * __clean_dcache_area_poc(kaddr, size)
> + *
> + * Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
> + * are cleaned to the PoC.
> + *
> + * - kaddr - kernel address
> + * - size - size in question
> + */
> +ENTRY(__clean_dcache_area_poc)
> + /* FALLTHROUGH */
>
> /*
> - * __dma_clean_range(start, end)
> + * __dma_clean_area(start, size)
> * - start - virtual start address of region
> - * - end - virtual end address of region
> + * - size - size in question
> */
> -__dma_clean_range:
> - dcache_line_size x2, x3
> - sub x3, x2, #1
> - bic x0, x0, x3
> -1:
> -alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
> - dc cvac, x0
> -alternative_else
> - dc civac, x0
> -alternative_endif
> - add x0, x0, x2
> - cmp x0, x1
> - b.lo 1b
> - dsb sy
> +__dma_clean_area:
> + dcache_by_line_op cvac, sy, x0, x1, x2, x3
> ret
> -ENDPROC(__dma_clean_range)
> +ENDPIPROC(__clean_dcache_area_poc)
> +ENDPROC(__dma_clean_area)
>
> /*
> - * __dma_flush_range(start, end)
> + * __dma_flush_area(start, size)
> + *
> + * clean & invalidate D / U line
> + *
> * - start - virtual start address of region
> - * - end - virtual end address of region
> + * - size - size in question
> */
> -ENTRY(__dma_flush_range)
> - dcache_line_size x2, x3
> - sub x3, x2, #1
> - bic x0, x0, x3
> -1: dc civac, x0 // clean & invalidate D / U line
> - add x0, x0, x2
> - cmp x0, x1
> - b.lo 1b
> - dsb sy
> +ENTRY(__dma_flush_area)
> + dcache_by_line_op civac, sy, x0, x1, x2, x3
> ret
> -ENDPIPROC(__dma_flush_range)
> +ENDPIPROC(__dma_flush_area)
>
> /*
> * __dma_map_area(start, size, dir)
> @@ -184,10 +182,9 @@ ENDPIPROC(__dma_flush_range)
> * - dir - DMA direction
> */
> ENTRY(__dma_map_area)
> - add x1, x1, x0
> cmp w2, #DMA_FROM_DEVICE
> - b.eq __dma_inv_range
> - b __dma_clean_range
> + b.eq __dma_inv_area
> + b __dma_clean_area
> ENDPIPROC(__dma_map_area)
>
> /*
> @@ -197,8 +194,7 @@ ENDPIPROC(__dma_map_area)
> * - dir - DMA direction
> */
> ENTRY(__dma_unmap_area)
> - add x1, x1, x0
> cmp w2, #DMA_TO_DEVICE
> - b.ne __dma_inv_range
> + b.ne __dma_inv_area
> ret
> ENDPIPROC(__dma_unmap_area)
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index f6c55af..88922e8 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -168,7 +168,7 @@ static void *__dma_alloc(struct device *dev, size_t size,
> return ptr;
>
> /* remove any dirty cache lines on the kernel alias */
> - __dma_flush_range(ptr, ptr + size);
> + __dma_flush_area(ptr, size);
>
> /* create a coherent mapping */
> page = virt_to_page(ptr);
> @@ -387,7 +387,7 @@ static int __init atomic_pool_init(void)
> void *page_addr = page_address(page);
>
> memset(page_addr, 0, atomic_pool_size);
> - __dma_flush_range(page_addr, page_addr + atomic_pool_size);
> + __dma_flush_area(page_addr, atomic_pool_size);
>
> atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
> if (!atomic_pool)
> @@ -548,7 +548,7 @@ fs_initcall(dma_debug_do_init);
> /* Thankfully, all cache ops are by VA so we can ignore phys here */
> static void flush_page(struct device *dev, const void *virt, phys_addr_t phys)
> {
> - __dma_flush_range(virt, virt + PAGE_SIZE);
> + __dma_flush_area(virt, PAGE_SIZE);
> }
>
> static void *__iommu_alloc_attrs(struct device *dev, size_t size,
>
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