[PATCH 5/6] dma-mapping: Allow batched DMA sync operations if supported by the arch

[Barry Song]

> > >
> >
> > OK. Could you take a look at [1] and see if any further
> > improvements are needed before I send v2?
>
> Everything looks ok, except these renames:
> -                       arch_sync_dma_for_cpu(paddr, sg->length, dir);
> +                       arch_sync_dma_for_cpu_batch_add(paddr, sg->length, dir);

Thanks!
I'm happy to drop the rename as outlined below-feedback welcome :-)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index dd2c8586a725..487fb7c355ed 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -87,6 +87,12 @@ int cache_line_size(void);
 
 #define dma_get_cache_alignment	cache_line_size
 
+static inline void arch_sync_dma_flush(void)
+{
+	dsb(sy);
+}
+#define arch_sync_dma_flush arch_sync_dma_flush
+
 /* Compress a u64 MPIDR value into 32 bits. */
 static inline u64 arch_compact_of_hwid(u64 id)
 {
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..ae1ae0280eef 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -17,7 +17,7 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
 {
 	unsigned long start = (unsigned long)phys_to_virt(paddr);
 
-	dcache_clean_poc(start, start + size);
+	dcache_clean_poc_nosync(start, start + size);
 }
 
 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
@@ -28,7 +28,7 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 	if (dir == DMA_TO_DEVICE)
 		return;
 
-	dcache_inval_poc(start, start + size);
+	dcache_inval_poc_nosync(start, start + size);
 }
 
 void arch_dma_prep_coherent(struct page *page, size_t size)
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 4809204c674c..e7dd8a63b40e 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -361,6 +361,12 @@ static inline void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 }
 #endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
 
+#ifndef arch_sync_dma_flush
+static inline void arch_sync_dma_flush(void)
+{
+}
+#endif
+
 #ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
 void arch_sync_dma_for_cpu_all(void);
 #else