On Sat, Dec 11, 2010 at 07:23:20PM +0000, Chris Ball wrote: > Hi Will, > > On Thu, Dec 09, 2010 at 05:24:26PM +0000, Will Newton wrote: > > This adds the mmc host driver for the Synopsys DesignWare mmc > > host controller, found in a number of embedded SoC designs. > > > > Signed-off-by: Will Newton <will.new...@imgtec.com> > > Reviewed-by: Matt Fleming <m...@console-pimps.org> > > Running a test build on ARM fails: > > drivers/mmc/host/dw_mmc.c: In function ‘dw_mci_push_data64’: > drivers/mmc/host/dw_mmc.c:985: error: implicit declaration of function > ‘__raw_writeq’ > drivers/mmc/host/dw_mmc.c: In function ‘dw_mci_pull_data64’: > drivers/mmc/host/dw_mmc.c:998: error: implicit declaration of function > ‘__raw_readq’ > > because arch/arm doesn't implement raw versions of these 64-bit accesses. > I'm surprised that this driver hasn't been compiled on ARM before! What > kind of arch are you testing on? Do you have any ARM hardware (lpc313x?) > to verify the driver on?
What's the semantics of a 64-bit IO access? Does the low 32-bit get written before the high 32-bit, or is it the other way around? Does it depend on the endian-ness? What if some hardware needs the low 32-bit first and other needs the high 32-bit first? I don't think it's reasonable to expect 32-bit hardware to perform 64-bit IO accesses. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
