* [PATCH 2/2] MIPS: mm: remove no-op dma_map_ops where possible
2017-12-05 11:50 [PATCH 1/2] MIPS: mm: remove mips_dma_mapping_error Felix Fietkau
@ 2017-12-05 11:50 ` Felix Fietkau
2018-02-01 11:56 ` [PATCH 1/2] MIPS: mm: remove mips_dma_mapping_error James Hogan
1 sibling, 0 replies; 3+ messages in thread
From: Felix Fietkau @ 2017-12-05 11:50 UTC (permalink / raw)
To: linux-mips
If no post-DMA flush is required, and the platform does not provide
plat_unmap_dma_mem(), there is no need to include unmap or sync_for_cpu
ops.
With this patch they are compiled out to improve icache footprint
on devices that handle lots of DMA traffic (especially network routers).
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
arch/mips/Kconfig | 9 +++++++++
arch/mips/mm/dma-default.c | 29 +++++++++++++++++------------
2 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 350a990fc719..95e58d45a9c1 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -220,6 +220,7 @@ config BMIPS_GENERIC
select BRCMSTB_L2_IRQ
select IRQ_MIPS_CPU
select DMA_NONCOHERENT
+ select DMA_UNMAP_POST_FLUSH
select SYS_SUPPORTS_32BIT_KERNEL
select SYS_SUPPORTS_LITTLE_ENDIAN
select SYS_SUPPORTS_BIG_ENDIAN
@@ -347,6 +348,7 @@ config MACH_JAZZ
select CSRC_R4K
select DEFAULT_SGI_PARTITION if CPU_BIG_ENDIAN
select GENERIC_ISA_DMA
+ select DMA_UNMAP_POST_FLUSH
select HAVE_PCSPKR_PLATFORM
select IRQ_MIPS_CPU
select I8253
@@ -1109,6 +1111,9 @@ config DMA_NONCOHERENT
bool
select NEED_DMA_MAP_STATE
+config DMA_UNMAP_POST_FLUSH
+ bool
+
config NEED_DMA_MAP_STATE
bool
@@ -1633,6 +1638,7 @@ config CPU_R10000
select CPU_SUPPORTS_64BIT_KERNEL
select CPU_SUPPORTS_HIGHMEM
select CPU_SUPPORTS_HUGEPAGES
+ select DMA_UNMAP_POST_FLUSH
help
MIPS Technologies R10000-series processors.
@@ -1881,9 +1887,11 @@ config SYS_HAS_CPU_MIPS32_R3_5
bool
config SYS_HAS_CPU_MIPS32_R5
+ select DMA_UNMAP_POST_FLUSH
bool
config SYS_HAS_CPU_MIPS32_R6
+ select DMA_UNMAP_POST_FLUSH
bool
config SYS_HAS_CPU_MIPS64_R1
@@ -1893,6 +1901,7 @@ config SYS_HAS_CPU_MIPS64_R2
bool
config SYS_HAS_CPU_MIPS64_R6
+ select DMA_UNMAP_POST_FLUSH
bool
config SYS_HAS_CPU_R3000
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 1af0cd90cc34..ecca8782d6fb 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -267,8 +267,9 @@ static inline void __dma_sync(struct page *page,
} while (left);
}
-static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
- size_t size, enum dma_data_direction direction, unsigned long attrs)
+static void __maybe_unused
+mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
+ enum dma_data_direction direction, unsigned long attrs)
{
if (cpu_needs_post_dma_flush(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_sync(dma_addr_to_page(dev, dma_addr),
@@ -308,9 +309,10 @@ static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
return plat_map_dma_mem_page(dev, page) + offset;
}
-static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
- int nhwentries, enum dma_data_direction direction,
- unsigned long attrs)
+static void __maybe_unused
+mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+ int nhwentries, enum dma_data_direction direction,
+ unsigned long attrs)
{
int i;
struct scatterlist *sg;
@@ -325,8 +327,9 @@ static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
}
}
-static void mips_dma_sync_single_for_cpu(struct device *dev,
- dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
+static void __maybe_unused
+mips_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction direction)
{
if (cpu_needs_post_dma_flush(dev))
__dma_sync(dma_addr_to_page(dev, dma_handle),
@@ -342,9 +345,9 @@ static void mips_dma_sync_single_for_device(struct device *dev,
dma_handle & ~PAGE_MASK, size, direction);
}
-static void mips_dma_sync_sg_for_cpu(struct device *dev,
- struct scatterlist *sglist, int nelems,
- enum dma_data_direction direction)
+static void __maybe_unused
+mips_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist,
+ int nelems, enum dma_data_direction direction)
{
int i;
struct scatterlist *sg;
@@ -392,12 +395,14 @@ static const struct dma_map_ops mips_default_dma_map_ops = {
.free = mips_dma_free_coherent,
.mmap = mips_dma_mmap,
.map_page = mips_dma_map_page,
- .unmap_page = mips_dma_unmap_page,
.map_sg = mips_dma_map_sg,
+#ifdef CONFIG_DMA_UNMAP_POST_FLUSH
+ .unmap_page = mips_dma_unmap_page,
.unmap_sg = mips_dma_unmap_sg,
.sync_single_for_cpu = mips_dma_sync_single_for_cpu,
- .sync_single_for_device = mips_dma_sync_single_for_device,
.sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
+#endif
+ .sync_single_for_device = mips_dma_sync_single_for_device,
.sync_sg_for_device = mips_dma_sync_sg_for_device,
.dma_supported = mips_dma_supported,
.cache_sync = mips_dma_cache_sync,
--
2.14.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH 1/2] MIPS: mm: remove mips_dma_mapping_error
2017-12-05 11:50 [PATCH 1/2] MIPS: mm: remove mips_dma_mapping_error Felix Fietkau
2017-12-05 11:50 ` [PATCH 2/2] MIPS: mm: remove no-op dma_map_ops where possible Felix Fietkau
@ 2018-02-01 11:56 ` James Hogan
1 sibling, 0 replies; 3+ messages in thread
From: James Hogan @ 2018-02-01 11:56 UTC (permalink / raw)
To: Felix Fietkau; +Cc: linux-mips
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On Tue, Dec 05, 2017 at 12:50:33PM +0100, Felix Fietkau wrote:
> dma_mapping_error() already checks if ops->mapping_error is a null
> pointer
>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
Thanks, I've already applied this to my 4.16 branch.
Cheers
James
> ---
> arch/mips/mm/dma-default.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index e3e94d05f0fd..1af0cd90cc34 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -373,11 +373,6 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
> }
> }
>
> -static int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
> -{
> - return 0;
> -}
> -
> static int mips_dma_supported(struct device *dev, u64 mask)
> {
> return plat_dma_supported(dev, mask);
> @@ -404,7 +399,6 @@ static const struct dma_map_ops mips_default_dma_map_ops = {
> .sync_single_for_device = mips_dma_sync_single_for_device,
> .sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
> .sync_sg_for_device = mips_dma_sync_sg_for_device,
> - .mapping_error = mips_dma_mapping_error,
> .dma_supported = mips_dma_supported,
> .cache_sync = mips_dma_cache_sync,
> };
> --
> 2.14.2
>
>
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