arch/sparc: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113544.76501.40008.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index 852a329..9df9979 100644 (file)
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -415,7 +415,7 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
                ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
 
        /* Step 1: Kick data out of streaming buffers if necessary. */
-       if (strbuf->strbuf_enabled)
+       if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
                strbuf_flush(strbuf, iommu, bus_addr, ctx,
                             npages, direction);
 
@@ -640,7 +640,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
                base = iommu->page_table + entry;
 
                dma_handle &= IO_PAGE_MASK;
-               if (strbuf->strbuf_enabled)
+               if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
                        strbuf_flush(strbuf, iommu, dma_handle, ctx,
                                     npages, direction);
 

diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index 2344103..6ffaec4 100644 (file)
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -527,7 +527,7 @@ static dma_addr_t pci32_map_page(struct device *dev, struct page *page,
 static void pci32_unmap_page(struct device *dev, dma_addr_t ba, size_t size,
                             enum dma_data_direction dir, unsigned long attrs)
 {
-       if (dir != PCI_DMA_TODEVICE)
+       if (dir != PCI_DMA_TODEVICE && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
                dma_make_coherent(ba, PAGE_ALIGN(size));
 }
 
@@ -572,7 +572,7 @@ static void pci32_unmap_sg(struct device *dev, struct scatterlist *sgl,
        struct scatterlist *sg;
        int n;
 
-       if (dir != PCI_DMA_TODEVICE) {
+       if (dir != PCI_DMA_TODEVICE && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
                for_each_sg(sgl, sg, nents, n) {
                        dma_make_coherent(sg_phys(sg), PAGE_ALIGN(sg->length));
                }