On Oct 13, 2008, at 10:41 AM, Josh Boyer wrote:
On Mon, Oct 13, 2008 at 10:49:04AM -0400, Josh Boyer wrote:
On Fri, Sep 12, 2008 at 03:34:46PM -0500, Becky Bruce wrote:
We essentially adopt the 64-bit dma code, with some changes to
support
32-bit systems, including HIGHMEM. dma functions on 32-bit are now
invoked via accessor functions which call the correct op for a
device based
on archdata dma_ops. If there is no archdata dma_ops, this defaults
to dma_direct_ops.
In addition, the dma_map/unmap_page functions are added to dma_ops
because we can't just fall back on map/unmap_single when HIGHMEM is
enabled. In the case of dma_direct_*, we stop using map/unmap_single
and just use the page version - this saves a lot of ugly
ifdeffing. We leave map/unmap_single in the dma_ops definition,
though, because they are needed by the iommu code, which does not
implement map/unmap_page. Ideally, going forward, we will
completely
eliminate map/unmap_single and just have map/unmap_page, if it's
workable for 64-bit.
Signed-off-by: Becky Bruce <[EMAIL PROTECTED]>
While doing a buildall this morning, I notice chrp32_defconfig fails
to build with:
drivers/built-in.o: In function `hard_dma_setup':
floppy.c:(.text+0x6e40e): undefined reference to `isa_bridge_pcidev'
floppy.c:(.text+0x6e412): undefined reference to `isa_bridge_pcidev'
floppy.c:(.text+0x6e53e): undefined reference to `isa_bridge_pcidev'
floppy.c:(.text+0x6e546): undefined reference to `isa_bridge_pcidev'
floppy.c:(.text+0x6e54a): undefined reference to `isa_bridge_pcidev'
make[1]: *** [.tmp_vmlinux1] Error 1
(the hard_dma_setup thing is in arch/powerpc/include/asm/floppy.h).
I did a git bisect and it pointed at this commit as causing the build
to fail. Why, I have no idea.
Ok, I was annoyed enough to look at why.
Basically, before this patch pci_map_single on 32-bit PPC seemed to
be compiled down to __dma_sync(ptr, size, direction); and the "dev"
parameter to the function was never actually used. The compiler
seems to have optimized this out entirely, so we don't get the odd
link reference to isa_bridge_pcidev at all. (Neither pci_map_single
or isa_bridge_pcidev are present in the vmlinux at all).
With the patch, the compiler doesn't do this code elimination
because pci_map_single boils down to dma_map_page, which calls
get_dma_direct_offset with the "dev" parameter. So since it is
still used, the compiler can't eliminate it and hence FAIL.
I have no patch for this at the moment. Someone should look at
it more closely, because this is causing the 5 chrp32_defconfig
users to weep.
Isn't this the type of regression we should fix post -rc1 :)
- k
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