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Merge tag 'dma-mapping-5.2' of git://git.infradead.org/users/hch/dma-mapping

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Pull DMA mapping updates from Christoph Hellwig:

 - remove the already broken support for NULL dev arguments to the DMA
   API calls

 - Kconfig tidyups

* tag 'dma-mapping-5.2' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: add a Kconfig symbol to indicate arch_dma_prep_coherent presence
  dma-mapping: remove an unnecessary NULL check
  x86/dma: Remove the x86_dma_fallback_dev hack
  dma-mapping: remove leftover NULL device support
  arm: use a dummy struct device for ISA DMA use of the DMA API
  pxa3xx-gcu: pass struct device to dma_mmap_coherent
  gbefb: switch to managed version of the DMA allocator
  da8xx-fb: pass struct device to DMA API functions
  parport_ip32: pass struct device to DMA API functions
  dma: select GENERIC_ALLOCATOR for DMA_REMAP
This commit is contained in:
Linus Torvalds
2019-05-09 08:40:55 -07:00
parent e57ccca1ba 13bf5ced93
commit ddab5337b2
17 changed files with 65 additions and 88 deletions
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13
Documentation/DMA-API-HOWTO.txt
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@@ -365,13 +365,12 @@ __get_free_pages() (but takes size instead of a page order). If your
driver needs regions sized smaller than a page, you may prefer using
the dma_pool interface, described below.
The consistent DMA mapping interfaces, for non-NULL dev, will by
default return a DMA address which is 32-bit addressable. Even if the
device indicates (via DMA mask) that it may address the upper 32-bits,
consistent allocation will only return > 32-bit addresses for DMA if
the consistent DMA mask has been explicitly changed via
dma_set_coherent_mask(). This is true of the dma_pool interface as
well.
The consistent DMA mapping interfaces, will by default return a DMA address
which is 32-bit addressable. Even if the device indicates (via the DMA mask)
that it may address the upper 32-bits, consistent allocation will only
return > 32-bit addresses for DMA if the consistent DMA mask has been
explicitly changed via dma_set_coherent_mask(). This is true of the
dma_pool interface as well.
dma_alloc_coherent() returns two values: the virtual address which you
can use to access it from the CPU and dma_handle which you pass to the