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. josh _______________________________________________ Linuxppc-dev mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-dev
