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authorLinus Torvalds <torvalds@linux-foundation.org>2017-08-21 13:30:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-21 13:30:36 -0700
commit05ab303b4f9e7121b120c08081546a25e067b4f4 (patch)
treeb7e393fce74ff7028e9f67c07a14f1bf41c71322 /arch/arc/mm/dma.c
parent0b3baec853d1de731d2e984f26b92c54842c6ff7 (diff)
parenta8ec3ee861b6e4e6b82a98777c65510ae63766c1 (diff)
Merge tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC fixes from Vineet Gupta: - PAE40 related updates - SLC errata for region ops - intc line masking by default * tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: arc: Mask individual IRQ lines during core INTC init ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses ARC: dma: implement dma_unmap_page and sg variant ARCv2: SLC: Make sure busy bit is set properly for region ops ARC: [plat-sim] Include this platform unconditionally ARC: [plat-axs10x]: prepare dts files for enabling PAE40 on axs103 ARC: defconfig: Cleanup from old Kconfig options
Diffstat (limited to 'arch/arc/mm/dma.c')
-rw-r--r--arch/arc/mm/dma.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 71d3efff99d3..e9d93604ad0f 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -153,6 +153,19 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
}
}
+/*
+ * arc_dma_map_page - map a portion of a page for streaming DMA
+ *
+ * Ensure that any data held in the cache is appropriately discarded
+ * or written back.
+ *
+ * The device owns this memory once this call has completed. The CPU
+ * can regain ownership by calling dma_unmap_page().
+ *
+ * Note: while it takes struct page as arg, caller can "abuse" it to pass
+ * a region larger than PAGE_SIZE, provided it is physically contiguous
+ * and this still works correctly
+ */
static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
@@ -165,6 +178,24 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
return plat_phys_to_dma(dev, paddr);
}
+/*
+ * arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
+ *
+ * After this call, reads by the CPU to the buffer are guaranteed to see
+ * whatever the device wrote there.
+ *
+ * Note: historically this routine was not implemented for ARC
+ */
+static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
+ size_t size, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ phys_addr_t paddr = plat_dma_to_phys(dev, handle);
+
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ _dma_cache_sync(paddr, size, dir);
+}
+
static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
@@ -178,6 +209,18 @@ static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
return nents;
}
+static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ struct scatterlist *s;
+ int i;
+
+ for_each_sg(sg, s, nents, i)
+ arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,
+ attrs);
+}
+
static void arc_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
@@ -223,7 +266,9 @@ const struct dma_map_ops arc_dma_ops = {
.free = arc_dma_free,
.mmap = arc_dma_mmap,
.map_page = arc_dma_map_page,
+ .unmap_page = arc_dma_unmap_page,
.map_sg = arc_dma_map_sg,
+ .unmap_sg = arc_dma_unmap_sg,
.sync_single_for_device = arc_dma_sync_single_for_device,
.sync_single_for_cpu = arc_dma_sync_single_for_cpu,
.sync_sg_for_cpu = arc_dma_sync_sg_for_cpu,