dma-noncoherent: add a arch_sync_dma_for_cpu_all hook

The MIPS bmips platform needs a global flush when transferring ownership
back to the CPU.  Add a hook for that to the dma-noncoherent
implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/19549/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Tom Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org

include/linux/dma-noncoherent.h

@@ -44,4 +44,12 @@ static inline void arch_sync_dma_for_cpu(struct device *dev,
 }
 #endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
 
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
+void arch_sync_dma_for_cpu_all(struct device *dev);
+#else
+static inline void arch_sync_dma_for_cpu_all(struct device *dev)
+{
+}
+#endif /* CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL */
+
 #endif /* _LINUX_DMA_NONCOHERENT_H */

kernel/dma/noncoherent.c

@@ -49,11 +49,13 @@ static int dma_noncoherent_map_sg(struct device *dev, struct scatterlist *sgl,
 	return nents;
 }
 
-#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
+    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 static void dma_noncoherent_sync_single_for_cpu(struct device *dev,
 		dma_addr_t addr, size_t size, enum dma_data_direction dir)
 {
 	arch_sync_dma_for_cpu(dev, dma_to_phys(dev, addr), size, dir);
+	arch_sync_dma_for_cpu_all(dev);
 }
 
 static void dma_noncoherent_sync_sg_for_cpu(struct device *dev,
@@ -64,6 +66,7 @@ static void dma_noncoherent_sync_sg_for_cpu(struct device *dev,
 
 	for_each_sg(sgl, sg, nents, i)
 		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
+	arch_sync_dma_for_cpu_all(dev);
 }
 
 static void dma_noncoherent_unmap_page(struct device *dev, dma_addr_t addr,
@@ -89,7 +92,8 @@ const struct dma_map_ops dma_noncoherent_ops = {
 	.sync_sg_for_device	= dma_noncoherent_sync_sg_for_device,
 	.map_page		= dma_noncoherent_map_page,
 	.map_sg			= dma_noncoherent_map_sg,
-#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
+    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 	.sync_single_for_cpu	= dma_noncoherent_sync_single_for_cpu,
 	.sync_sg_for_cpu	= dma_noncoherent_sync_sg_for_cpu,
 	.unmap_page		= dma_noncoherent_unmap_page,