The patch titled
DMA-API.txt: add dma_sync_single/sg API description
has been added to the -mm tree. Its filename is
dma-apitxt-add-dma_sync_single-sg-api-description.patch
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Subject: DMA-API.txt: add dma_sync_single/sg API description
From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
This adds the description of the following eight function:
dma_sync_single_for_cpu
pci_dma_sync_single_for_cpu
dma_sync_single_for_device
pci_dma_sync_single_for_device
dma_sync_sg_for_cpu
pci_dma_sync_sg_for_cpu
dma_sync_sg_for_device
pci_dma_sync_sg_for_device
It was unclear that the API permits a partial sync (some network drivers
already do though). I made it clear that the sync_single API can do a
partial sync but the sync_sg API can't.
We could do a partial sync with the sync_sg API too, however, it's
difficult for driver writers to correctly use the sync_sg API for a
partial sync since the scatterlists passed in to the mapping API can't be
modified. It's unlikely that driver writers want to do a partial sync
with the sync_sg API (because the sync_sg API are usually used for block
drivers). So I think that it's better to forbid a partial sync with the
sync_sg API.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Acked-by: David Miller <davem@xxxxxxxxxxxxx>
Acked-by: James Bottomley <James.Bottomley@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/DMA-API.txt | 42 ++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff -puN Documentation/DMA-API.txt~dma-apitxt-add-dma_sync_single-sg-api-description Documentation/DMA-API.txt
--- a/Documentation/DMA-API.txt~dma-apitxt-add-dma_sync_single-sg-api-description
+++ a/Documentation/DMA-API.txt
@@ -364,6 +364,48 @@ API.
Note: <nents> must be the number you passed in, *not* the number of
physical entries returned.
+void
+dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction)
+void
+pci_dma_sync_single_for_cpu(struct pci_dev *hwdev, dma_addr_t dma_handle,
+ size_t size, int direction)
+void
+dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction)
+void
+pci_dma_sync_single_for_device(struct pci_dev *hwdev, dma_addr_t dma_handle,
+ size_t size, int direction)
+void
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction)
+void
+pci_dma_sync_sg_for_cpu(struct pci_dev *hwdev, struct scatterlist *sg,
+ int nelems, int direction)
+void
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction)
+void
+pci_dma_sync_sg_for_device(struct pci_dev *hwdev, struct scatterlist *sg,
+ int nelems, int direction)
+
+Synchronise a single contiguous or scatter/gather mapping for the cpu
+and device. With the sync_sg API, all the parameters must be the same
+as those passed into the single mapping API. With the sync_single API,
+you can use dma_handle and size parameters that aren't identical to
+those passed into the single mapping API to do a partial sync.
+
+Notes: You must do this:
+
+- Before reading values that have been written by DMA from the device
+ (use the DMA_FROM_DEVICE direction)
+- After writing values that will be written to the device using DMA
+ (use the DMA_TO_DEVICE) direction
+- before *and* after handing memory to the device if the memory is
+ DMA_BIDIRECTIONAL
+
+See also dma_map_single().
+
dma_addr_t
dma_map_single_attrs(struct device *dev, void *cpu_addr, size_t size,
enum dma_data_direction dir,
_
Patches currently in -mm which might be from fujita.tomonori@xxxxxxxxxxxxx are
origin.patch
linux-next.patch
x86-agp-fix-agp_amd64_init-module-initialization-regression.patch
scsi-add-__init-__exit-macros-to-ibmvstgtc.patch
frv-remove-pci_dma_sync_single-and-pci_dma_sync_sg.patch
documentation-dma-apitxt-remove-deprecated-function-descriptions.patch
dma-apitxt-add-dma_sync_single-sg-api-description.patch
dma-apitxt-remove-dma_sync_single_range-description.patch
alpha-remove-dma_sync_single_range.patch
um-remove-dma_sync_single_range.patch
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