On Mon, 2016-07-25 at 06:12 +0000, Yangbo Lu wrote: > Hi Scott, > > > > > > -----Original Message----- > > From: Scott Wood [mailto:oss@xxxxxxxxxxxx] > > Sent: Friday, July 22, 2016 12:45 AM > > To: Michael Ellerman; Arnd Bergmann > > Cc: linux-mmc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linuxppc- > > dev@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Yangbo Lu > > Subject: Re: [PATCH v11 4/5] powerpc/fsl: move mpc85xx.h to > > include/linux/fsl > > > > On Thu, 2016-07-21 at 20:26 +1000, Michael Ellerman wrote: > > > > > > Quoting Scott Wood (2016-07-21 04:31:48) > > > > > > > > > > > > On Wed, 2016-07-20 at 13:24 +0200, Arnd Bergmann wrote: > > > > > > > > > > > > > > > On Saturday, July 16, 2016 9:50:21 PM CEST Scott Wood wrote: > > > > > > > > > > > > > > > > > > > > > > > > From: yangbo lu <yangbo.lu@xxxxxxx> > > > > > > > > > > > > Move mpc85xx.h to include/linux/fsl and rename it to svr.h as a > > > > > > common header file. This SVR numberspace is used on some ARM > > > > > > chips as well as PPC, and even to check for a PPC SVR multi-arch > > > > > > drivers would otherwise need to ifdef the header inclusion and > > > > > > all references to the SVR symbols. > > > > > > > > > > > > Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx> > > > > > > Acked-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> > > > > > > Acked-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > > > > > > Acked-by: Joerg Roedel <jroedel@xxxxxxx> > > > > > > [scottwood: update description] > > > > > > Signed-off-by: Scott Wood <oss@xxxxxxxxxxxx> > > > > > > > > > > > As discussed before, please don't introduce yet another vendor > > > > > specific way to match a SoC ID from a device driver. > > > > > > > > > > I've posted a patch for an extension to the soc_device > > > > > infrastructure to allow comparing the running SoC to a table of > > > > > devices, use that instead. > > > > As I asked before, in which relevant maintainership capacity are you > > > > NACKing this? > > > I'll nack the powerpc part until you guys can agree. > > OK, I've pulled these patches out. > > > > For the MMC issue I suggest using ifdef CONFIG_PPC and mfspr(SPRN_SVR) > > like the clock driver does[1] and we can revisit the issue if/when we > > need to do something similar on an ARM chip. > [Lu Yangbo-B47093] I remembered that Uffe had opposed us to introduce non- > generic header files(like '#include <asm/mpc85xx.h>') > in mmc driver initially. So I think it will not be accepted to use ifdef > CONFIG_PPC and mfspr(SPRN_SVR)... > And this method still couldn’t get SVR of ARM chip now. Right, as I said we'll have to revisit the issue if/when we have the same problem on an ARM chip. That also applies if the PPC ifdef is still getting NACKed from the MMC side. > Any other suggestion here? The other option is to try to come up with something that fits into Arnd's framework while addressing the concerns I raised. The soc_id string should be well-structured to avoid mismatches and compatibility problems (especially since it would get exposed to userspace). Maybe something like: svr:<SVR minus E bit>,svre:<full SVR including E bit>,name:<soc name>,die:<soc die name>,rev:X.Y,<tag1>,<tag2>,<...>, with the final comma used so that globs can put a colon on either end to be sure they're matching a full field. The SoC die name would be the primary chip for a given die (e.g. p4040 would have a die name of p4080). The "name" and "die" fields would never include the trailing "e" indicated by the E bit. Extra tags could be used for common groupings, such as all chips from a particular die before a certain revision. Once a tag is added it can't be removed or reordered, to maintain userspace compatibility, but new tags could be appended. Some examples: svr:0x82000020,svre:0x82000020,name:p4080,die:p4080,rev:2.0, svr:0x82000020,svr e:0x82080020,name:p4080,die:p4080,rev:2.0, svr:0x82000030,svre:0x82000030,name: p4080,die:p4080,rev:3.0, svr:0x82000030,svre:0x82080030,name:p4080,die:p4080,re v:3.0, svr:0x82010020,svre:0x82010020,name:p4040,die:p4080,rev:2.0, svr:0x820100 20,svre:0x82090020,name:p4040,die:p4080,rev:2.0, svr:0x82010030,svre:0x82010030 ,name:p4040,die:p4080,rev:3.0, svr:0x82010030,svre:0x82090030,name:p4040,die:p4 080,rev:3.0, Then if you want to apply a workaround on: - all chips using the p4080 die, match with "*,die:p4080,*" - all chips using the rev 2.0 p4080 die, match with "*,die:p4080,rev:2.0,*" - Only p4040, but of any rev, match with "*,name:p4040,*" Matching via open-coded hex number should be considered a last resort (it's more error-prone, either for getting the number wrong or for forgetting variants -- the latter is already a common problem), but preferable to adding too many tags. Using wildcards within a tag field would be discouraged. -Scott -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
