[PATCH] parisc: improve cach flushing in arch_sync_dma_for_cpu()

[Helge Deller <deller@gmx.de>]

Handle the direction flag in arch_sync_dma_for_device() and
arch_sync_dma_for_cpu().

When receiving data from the device (DMA_FROM_DEVICE and DMA_BIDIRECTIONAL)
purge the data cache in arch_sync_dma_for_cpu().

Run-tested on C8000 workstation.

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/kernel/pci-dma.c b/arch/parisc/kernel/pci-dma.c
index ba87f791323b..f8337c1820fc 100644
--- a/arch/parisc/kernel/pci-dma.c
+++ b/arch/parisc/kernel/pci-dma.c
@@ -446,11 +446,36 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
 		enum dma_data_direction dir)
 {
-	flush_kernel_dcache_range((unsigned long)phys_to_virt(paddr), size);
+	unsigned long addr = (unsigned long) phys_to_virt(paddr);
+
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		flush_kernel_dcache_range(addr, size);
+		break;
+	case DMA_FROM_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		flush_kernel_dcache_range(addr, size);
+		purge_kernel_dcache_range_asm(addr, addr + size);
+		break;
+	default:
+		BUG();
+	}
 }

 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 		enum dma_data_direction dir)
 {
-	flush_kernel_dcache_range((unsigned long)phys_to_virt(paddr), size);
+	unsigned long addr = (unsigned long) phys_to_virt(paddr);
+
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		flush_kernel_dcache_range(addr, size);
+		return;
+	case DMA_FROM_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		purge_kernel_dcache_range_asm(addr, addr + size);
+		break;
+	default:
+		BUG();
+	}
 }