From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH v11 4/5] powerpc/fsl: move mpc85xx.h to include/linux/fsl Date: Tue, 26 Jul 2016 19:38:02 -0500 Message-ID: <1469579882.25630.168.camel@buserror.net> References: <1468723822-30457-1-git-send-email-oss@buserror.net> <1468723822-30457-5-git-send-email-oss@buserror.net> <4016699.uYaV8nWfqC@wuerfel> <1469039508.25630.17.camel@buserror.net> <146909676646.16700.8383344640490662952@concordia> <1469119526.25630.42.camel@buserror.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Yangbo Lu , Michael Ellerman , Arnd Bergmann , Ulf Hansson Cc: "linux-mmc@vger.kernel.org" , "devicetree@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Mon, 2016-07-25 at 06:12 +0000, Yangbo Lu wrote: > Hi Scott, >=20 >=20 > >=20 > > -----Original Message----- > > From: Scott Wood [mailto:oss@buserror.net] > > Sent: Friday, July 22, 2016 12:45 AM > > To: Michael Ellerman; Arnd Bergmann > > Cc: linux-mmc@vger.kernel.org; devicetree@vger.kernel.org; linuxppc= - > > dev@lists.ozlabs.org; linux-kernel@vger.kernel.org; Yangbo Lu > > Subject: Re: [PATCH v11 4/5] powerpc/fsl: move mpc85xx.h to > > include/linux/fsl > >=20 > > On Thu, 2016-07-21 at 20:26 +1000, Michael Ellerman wrote: > > >=20 > > > Quoting Scott Wood (2016-07-21 04:31:48) > > > >=20 > > > >=20 > > > > On Wed, 2016-07-20 at 13:24 +0200, Arnd Bergmann wrote: > > > > >=20 > > > > >=20 > > > > > On Saturday, July 16, 2016 9:50:21 PM CEST Scott Wood wrote: > > > > > >=20 > > > > > >=20 > > > > > >=20 > > > > > > From: yangbo lu > > > > > >=20 > > > > > > Move mpc85xx.h to include/linux/fsl and rename it to svr.h = as a > > > > > > common header file.=C2=A0=C2=A0This 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. > > > > > >=20 > > > > > > Signed-off-by: Yangbo Lu > > > > > > Acked-by: Wolfram Sang > > > > > > Acked-by: Stephen Boyd > > > > > > Acked-by: Joerg Roedel > > > > > > [scottwood: update description] > > > > > > Signed-off-by: Scott Wood > > > > > >=20 > > > > > As discussed before, please don't introduce yet another vendo= r > > > > > specific way to match a SoC ID from a device driver. > > > > >=20 > > > > > 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 ar= e you > > > > NACKing this? > > > I'll nack the powerpc part until you guys can agree. > > OK, I've pulled these patches out. > >=20 > > For the MMC issue I suggest using ifdef CONFIG_PPC and mfspr(SPRN_S= VR) > > 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 ') > in mmc driver initially. So I think it will not be accepted to use if= def > CONFIG_PPC and mfspr(SPRN_SVR)... > And this method still couldn=E2=80=99t get SVR of ARM chip now. Right, as I said we'll have to revisit the issue if/when we have the sa= me problem on an ARM chip. =C2=A0That also applies if the PPC ifdef is sti= ll getting NACKed from the MMC side. > Any other suggestion here? The other option is to try to come up with something that fits into Arn= d's framework while addressing the concerns I raised. =C2=A0The soc_id stri= ng should be well-structured to avoid mismatches and compatibility problems (especia= lly since it would get exposed to userspace). =C2=A0Maybe something like: svr:,svre:,name:,d= ie:,rev:X.Y,,,<...>, with the final comma used so that globs can put a colon on either end t= o be sure they're matching a full field. =C2=A0The SoC die name would be the= primary chip for a given die (e.g. p4040 would have a die name of p4080). =C2=A0= 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. =C2=A0Once 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. =C2=A0 -Scott