[mm PATCH v3 17/23] arch/sparc: Add option to skip DMA sync as a part of map and unmap

From: Alexander Duyck
Date: Thu Nov 10 2016 - 12:37:04 EST


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.

Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: sparclinux@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
---
arch/sparc/kernel/iommu.c | 4 ++--
arch/sparc/kernel/ioport.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index 5c615ab..8fda4e4 100644
--- 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
--- 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));
}