linux-toradex.git/Documentation/DMA-API.txt, branch v3.10.78

dma-debug: New interfaces to debug dma mapping errors

2012-10-24T15:06:43+00:00

Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.

Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
        CONFIG_DMA_API_DEBUG enabled and disabled.

Signed-off-by: Shuah Khan 
Reviewed-by: Konrad Rzeszutek Wilk 
Signed-off-by: Joerg Roedel

include/linux/dma-mapping.h: add dma_zalloc_coherent()

2011-11-02T23:07:02+00:00

Lots of driver code does a dma_alloc_coherent() and then zeroes out the
memory with a memset.  Make it easy for them.

Cc: Alexandre Bounine 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dma-mapping: remove dma_is_consistent API

2010-08-11T15:59:21+00:00

Architectures implement dma_is_consistent() in different ways (some
misinterpret the definition of API in DMA-API.txt).  So it hasn't been so
useful for drivers.  We have only one user of the API in tree.  Unlikely
out-of-tree drivers use the API.

Even if we fix dma_is_consistent() in some architectures, it doesn't look
useful at all.  It was invented long ago for some old systems that can't
allocate coherent memory at all.  It's better to export only APIs that are
definitely necessary for drivers.

Let's remove this API.

Signed-off-by: FUJITA Tomonori 
Cc: James Bottomley 
Reviewed-by: Konrad Rzeszutek Wilk 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation: rename PCI-DMA-mapping.txt to DMA-API-HOWTO.txt

2010-03-12T23:52:43+00:00

Signed-off-by: FUJITA Tomonori 
Cc: James Bottomley 
Cc: "David S. Miller" 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation: remove the PCI DMA API description in DMA-API.txt

2010-03-12T23:52:43+00:00

- remove the PCI DMA API description in DMA-API.txt
- remove the descriptions of dma_unmap macros since
  PCI-DMA-mapping.txt has the same description.

Signed-off-by: FUJITA Tomonori 
Cc: James Bottomley 
Cc: "David S. Miller" 
Reviewed-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dma-mapping: dma-mapping.h: add dma_set_coherent_mask

2010-03-12T23:52:42+00:00

dma_set_coherent_mask corresponds to pci_set_consistent_dma_mask.  This is
necessary to move to the generic device model DMA API from the PCI bus
specific API in the long term.

dma_set_coherent_mask works in the exact same way that
pci_set_consistent_dma_mask does.  So this patch also changes
pci_set_consistent_dma_mask to call dma_set_coherent_mask.

Signed-off-by: FUJITA Tomonori 
Cc: James Bottomley 
Cc: David S. Miller 
Cc: Jesse Barnes 
Cc: Benjamin Herrenschmidt 
Cc: Russell King 
Cc: Greg KH 
Cc: Kay Sievers 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dma-mapping.h: add the dma_unmap state API

2010-03-12T23:52:42+00:00

Adds the following macros:

DECLARE_DMA_UNMAP_ADDR(ADDR_NAME)
DECLARE_DMA_UNMAP_LEN(LEN_NAME)
dma_unmap_addr(PTR, ADDR_NAME)
dma_unmap_addr_set(PTR, ADDR_NAME, VAL)
dma_unmap_len(PTR, LEN_NAME)
dma_unmap_len_set(PTR, LEN_NAME, VAL)

The API corresponds to the pci_unmap state API.  We'll move to this new
generic API from the PCI specific API in the long term.  As
include/asm-generic/pci-dma-compat.h does, the pci_unmap API simply calls
the new generic API for some time.

Signed-off-by: FUJITA Tomonori 
Cc: James Bottomley 
Cc: David S. Miller 
Cc: Jesse Barnes 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

DMA-API.txt: remove dma_sync_single_range description

2010-03-12T23:52:40+00:00

dma_sync_single_for_cpu/for_device supports a partial sync so there is no
point to have dma_sync_single_range (also dma_sync_single was obsoleted
long ago, replaced with dma_sync_single_for_cpu/for_device).

There is no user of dma_sync_single_range() in mainline and only Alpha
architecture supports dma_sync_single_range().  So it's unlikely that
someone out of the tree uses it.

Signed-off-by: FUJITA Tomonori 
Acked-by: David Miller 
Acked-by: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

DMA-API.txt: add dma_sync_single/sg API description

2010-03-12T23:52:40+00:00

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 
Acked-by: David Miller 
Acked-by: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/DMA-API.txt: remove deprecated function descriptions

2010-03-12T23:52:40+00:00

dma_sync_single(), pci_dma_sync_single(), dma_sync_sg(), and
pci_dma_sync_sg() are deprecated.  We should not advertise them.

Signed-off-by: FUJITA Tomonori 
Acked-by: David S. Miller 
Acked-by: Joerg Roedel 
Cc: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds