resend On May 14, 2011, at 10:01 AM, Philip Rakity wrote:
> > On May 13, 2011, at 10:11 PM, zhangfei gao wrote: > >> On Fri, May 13, 2011 at 9:47 PM, Chris Ball <c...@laptop.org> wrote: >>> Hi, >>> >>> On Thu, May 12 2011, Philip Rakity wrote: >>>> All other platform specific code is in the host/ directory. >>>> >>>> This moves it to arch/arm >>>> >>>> If that is the direction the group wants to go in --> then the patch >>>> is fine provided the mmc group can review the patches. Otherwise they >>>> are handled by the arm maintainer. >>> >>> Thanks. Wolfram, do you have any ideas on what the best design is for >>> these SoC-specific changes to sdhci-pxa? >>> >>> - Chris. >> >> The code in arch/arm is >> 1. Accessing private register, take pxa910 and mmp2 we want to support >> as example, there are several private registers differece, though they >> are same ip, with same issues and quirk. >> 2. Handle platform difference, for example, mmp2 used in two different >> platform, one use wp pin, the other does not. > > The situation is a little more complicated. > > pxa168 and pxa910 share (almost) the same IP The are both based on SD 2.0 > controller spec with extensions. The pxa910 controller has fixes to the > pxa168 controller. They share the same private registers that allow support > for clock gating and timing adjustments. > > mmp2 is based on SD 3.0 spec. The private register space is different. > > mmc/host/Kconfig takes no account of these differences. mmp2 and pxa168/910 > cannot co-exist. What is currently submitted does not work. One cannot > compile mmp2 and pxa910 nor would they work if one could. > > Mark Brown and I submitted patches to fix this. We added code to the host/ > directory > that took into account these differences. It provided a common interface > layer > that then used platform specific code in the host/ directory to handle the > different > behavior. > > Arng Bergmann provided advice and reviewed the patches to allow explicit > selection of the > pxa familty controller and board. Based on this comments we submitted a patch > to allow selection if the appropriate SoC. > > These are two approaches. > >> >> Thanks >>> -- >>> Chris Ball <c...@laptop.org> <http://printf.net/> >>> One Laptop Per Child >>> > -- 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
