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| author |   Bjorn Helgaas <bhelgaas@google.com> | 2014-05-20 16:54:22 -0600 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2014-05-20 16:55:23 -0600 |
| commit | 88a984ba0795f14a3847edbd7fabe652289ea89b (patch) | |
| tree | cf82c612f595bf8296892ca5bfb0672d6d6f6f0f /Documentation/DMA-API.txt | |
| parent | DMA-API: Clarify physical/bus address distinction (diff) | |
| download | linux-dev-88a984ba0795f14a3847edbd7fabe652289ea89b.tar.xz linux-dev-88a984ba0795f14a3847edbd7fabe652289ea89b.zip | |
DMA-API: Change dma_declare_coherent_memory() CPU address to phys_addr_t
dma_declare_coherent_memory() takes two addresses for a region of memory: a
"bus_addr" and a "device_addr". I think the intent is that "bus_addr" is
the physical address a *CPU* would use to access the region, and
"device_addr" is the bus address the *device* would use to address the
region.
Rename "bus_addr" to "phys_addr" and change its type to phys_addr_t.
Most callers already supply a phys_addr_t for this argument. The others
supply a 32-bit integer (a constant, unsigned int, or __u32) and need no
change.
Use "unsigned long", not phys_addr_t, to hold PFNs.
No functional change (this could theoretically fix a truncation in a config
with 32-bit dma_addr_t and 64-bit phys_addr_t, but I don't think there are
any such cases involving this code).
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: James Bottomley <jbottomley@Parallels.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Diffstat (limited to 'Documentation/DMA-API.txt')
| -rw-r--r-- | Documentation/DMA-API.txt | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 1147eba43128..4f1cdc5febd1 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -497,19 +497,18 @@ continuing on for size. Again, you *must* observe the cache line boundaries when doing this. int -dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, +dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags) Declare region of memory to be handed out by dma_alloc_coherent() when it's asked for coherent memory for this device. -bus_addr is the physical address to which the memory is currently -assigned in the bus responding region (this will be used by the -platform to perform the mapping). +phys_addr is the cpu physical address to which the memory is currently +assigned (this will be ioremapped so the cpu can access the region). device_addr is the bus address the device needs to be programmed -with actually to address this memory (this will be handed out as the +with to actually address this memory (this will be handed out as the dma_addr_t in dma_alloc_coherent()). size is the size of the area (must be multiples of PAGE_SIZE). |