Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

[ARM] Don't call consistent_sync() for DMA coherent memory

Browse source 
Memory allocated by the coherent memory allocators will be marked
uncacheable, which means it's pointless calling consistent_sync()
to perform cache maintainence on this memory; it's just a waste of
CPU cycles.

Moreover, with the (subsequent) merge of outer cache support, it
actually breaks things to call consistent_sync() on anything but
direct-mapped memory.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2007-02-06 17:29:53 +00:00 committed by Russell King
parent 56660faf9e
commit 7f8e33546d
1 changed files with 10 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
arch/arm/common/dmabounce.c
View file

@ -281,10 +281,14 @@ map_single(struct device *dev, void *ptr, size_t size,
ptr = buf->safe;
dma_addr = buf->safe_dma_addr;
} else {
/*
* We don't need to sync the DMA buffer since
* it was allocated via the coherent allocators.
*/
consistent_sync(ptr, size, dir);
}
consistent_sync(ptr, size, dir);
return dma_addr;
}
@ -397,7 +401,10 @@ sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
default:
BUG();
}
consistent_sync(buf->safe, size, dir);
/*
* No need to sync the safe buffer - it was allocated
* via the coherent allocators.
*/
} else {
consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
}