RE: [PATCH V8 03/10] USB/ppc4xx: Add Synopsys DWC OTG CoreInterface Layer
-Original Message- From: linuxppc-dev-bounces+tmarri=amcc@lists.ozlabs.org [mailto:linuxppc-dev-bounces+tmarri=amcc@lists.ozlabs.org] On Behalf Of David Laight Sent: Wednesday, January 26, 2011 8:35 AM Cc: linux-...@vger.kernel.org; linuxppc-dev@lists.ozlabs.org Subject: RE: [PATCH V8 03/10] USB/ppc4xx: Add Synopsys DWC OTG CoreInterface Layer > Also in_le32/out_le32/in_be32/out_be32 are > architecture-specific AFAIK. Isn't the whole patch architecture-specific ? > I'd suggest using readl/writel for LE ops and > __be32_to_cpu(__raw_readl(addr))/__raw_writel(__cpu_to_be32(b),addr) > for BE ops. Since the ppc doesn't have a byteswap instruction (and the LE memory transfers might even be slow!) you really don't want to be doing software byteswap. Not to mention the horrific synchronistion instructions that in_le32() and out_le32() actually contain. I didn't find __raw_readl() when I was looking for asm patterns that byteswapped memory transfers. I did find st_le32() and ld_le32() in arch/powerpc/include/asm/swab.h but that file is actually quite difficult to #include because there is another swab.h that gets included instead. [marri] Initial version of DWC-IP did not have feature to swap endianness. Whereas next versions have it. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH V8 03/10] USB/ppc4xx: Add Synopsys DWC OTG CoreInterface Layer
В Wed, 26 Jan 2011 16:35:05 - "David Laight" пишет: > > > Also in_le32/out_le32/in_be32/out_be32 are > > architecture-specific AFAIK. > > Isn't the whole patch architecture-specific ? I use this driver on MIPS board right now. :) This core from Synopsys is used in many SOCs with various architectures. > > I'd suggest using readl/writel for LE ops and > > __be32_to_cpu(__raw_readl(addr))/__raw_writel(__cpu_to_be32(b),addr) > > for BE ops. > > Since the ppc doesn't have a byteswap instruction (and the LE > memory transfers might even be slow!) you really don't want to > be doing software byteswap. > > Not to mention the horrific synchronistion instructions > that in_le32() and out_le32() actually contain. > > I didn't find __raw_readl() when I was looking for asm > patterns that byteswapped memory transfers. > > I did find st_le32() and ld_le32() in arch/powerpc/include/asm/swab.h > but that file is actually quite difficult to #include because > there is another swab.h that gets included instead. I see. readl/writel are defined in asm-generic/io.h. So IMHO there should be also le and be versions that can be redefined in arch-specific code. -- Alexander signature.asc Description: PGP signature ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
RE: [PATCH V8 03/10] USB/ppc4xx: Add Synopsys DWC OTG CoreInterface Layer
> Also in_le32/out_le32/in_be32/out_be32 are > architecture-specific AFAIK. Isn't the whole patch architecture-specific ? > I'd suggest using readl/writel for LE ops and > __be32_to_cpu(__raw_readl(addr))/__raw_writel(__cpu_to_be32(b),addr) > for BE ops. Since the ppc doesn't have a byteswap instruction (and the LE memory transfers might even be slow!) you really don't want to be doing software byteswap. Not to mention the horrific synchronistion instructions that in_le32() and out_le32() actually contain. I didn't find __raw_readl() when I was looking for asm patterns that byteswapped memory transfers. I did find st_le32() and ld_le32() in arch/powerpc/include/asm/swab.h but that file is actually quite difficult to #include because there is another swab.h that gets included instead. David ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
