[source] kernel: MIPS compile out no-op DMA mapping ops where possible
LEDE Commits
lede-commits at lists.infradead.org
Fri Dec 8 10:55:36 PST 2017
nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/668eb70157be59b17bb6da4a6de5d5e71a7c832b
commit 668eb70157be59b17bb6da4a6de5d5e71a7c832b
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Tue Dec 5 13:01:40 2017 +0100
kernel: MIPS compile out no-op DMA mapping ops where possible
Slightly improves networking throughput on some devices
Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
.../ar71xx/patches-4.9/500-MIPS-fw-myloader.patch | 2 +-
...340-MIPS-mm-remove-mips_dma_mapping_error.patch | 32 +++++
...m-remove-no-op-dma_map_ops-where-possible.patch | 140 +++++++++++++++++++++
3 files changed, 173 insertions(+), 1 deletion(-)
diff --git a/target/linux/ar71xx/patches-4.9/500-MIPS-fw-myloader.patch b/target/linux/ar71xx/patches-4.9/500-MIPS-fw-myloader.patch
index bcb1937..d6a9276 100644
--- a/target/linux/ar71xx/patches-4.9/500-MIPS-fw-myloader.patch
+++ b/target/linux/ar71xx/patches-4.9/500-MIPS-fw-myloader.patch
@@ -10,7 +10,7 @@
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -1144,6 +1144,9 @@ config MIPS_MSC
+@@ -1149,6 +1149,9 @@ config MIPS_MSC
config MIPS_NILE4
bool
diff --git a/target/linux/generic/pending-4.9/340-MIPS-mm-remove-mips_dma_mapping_error.patch b/target/linux/generic/pending-4.9/340-MIPS-mm-remove-mips_dma_mapping_error.patch
new file mode 100644
index 0000000..4091542
--- /dev/null
+++ b/target/linux/generic/pending-4.9/340-MIPS-mm-remove-mips_dma_mapping_error.patch
@@ -0,0 +1,32 @@
+From: Felix Fietkau <nbd at nbd.name>
+Date: Tue, 5 Dec 2017 12:34:31 +0100
+Subject: [PATCH] MIPS: mm: remove mips_dma_mapping_error
+
+dma_mapping_error() already checks if ops->mapping_error is a null
+pointer
+
+Signed-off-by: Felix Fietkau <nbd at nbd.name>
+---
+
+--- a/arch/mips/mm/dma-default.c
++++ b/arch/mips/mm/dma-default.c
+@@ -394,11 +394,6 @@ static void mips_dma_sync_sg_for_device(
+ }
+ }
+
+-int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+-{
+- return 0;
+-}
+-
+ int mips_dma_supported(struct device *dev, u64 mask)
+ {
+ return plat_dma_supported(dev, mask);
+@@ -427,7 +422,6 @@ static struct dma_map_ops mips_default_d
+ .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
+ };
+
diff --git a/target/linux/generic/pending-4.9/341-MIPS-mm-remove-no-op-dma_map_ops-where-possible.patch b/target/linux/generic/pending-4.9/341-MIPS-mm-remove-no-op-dma_map_ops-where-possible.patch
new file mode 100644
index 0000000..5b237a6
--- /dev/null
+++ b/target/linux/generic/pending-4.9/341-MIPS-mm-remove-no-op-dma_map_ops-where-possible.patch
@@ -0,0 +1,140 @@
+From: Felix Fietkau <nbd at nbd.name>
+Date: Tue, 5 Dec 2017 12:46:01 +0100
+Subject: [PATCH] MIPS: mm: remove no-op dma_map_ops where possible
+
+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 at nbd.name>
+---
+
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -213,6 +213,7 @@ 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
+@@ -338,6 +339,7 @@ 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
+@@ -1125,6 +1127,9 @@ config DMA_NONCOHERENT
+ bool
+ select NEED_DMA_MAP_STATE
+
++config DMA_UNMAP_POST_FLUSH
++ bool
++
+ config NEED_DMA_MAP_STATE
+ bool
+
+@@ -1649,6 +1654,7 @@ 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.
+
+@@ -1894,9 +1900,11 @@ 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
+@@ -1906,6 +1914,7 @@ config SYS_HAS_CPU_MIPS64_R2
+ bool
+
+ config SYS_HAS_CPU_MIPS64_R6
++ select DMA_UNMAP_POST_FLUSH
+ bool
+
+ config SYS_HAS_CPU_R3000
+--- a/arch/mips/mm/dma-default.c
++++ b/arch/mips/mm/dma-default.c
+@@ -290,8 +290,9 @@ static inline void __dma_sync(struct pag
+ } 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))
+ __dma_sync(dma_addr_to_page(dev, dma_addr),
+@@ -330,9 +331,10 @@ static dma_addr_t mips_dma_map_page(stru
+ 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;
+@@ -346,8 +348,9 @@ static void mips_dma_unmap_sg(struct dev
+ }
+ }
+
+-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),
+@@ -363,9 +366,9 @@ static void mips_dma_sync_single_for_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;
+@@ -415,12 +418,14 @@ static struct dma_map_ops mips_default_d
+ .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
+ };
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