Hi Michael, > -----Original Message----- > From: Michael Walle <michael@xxxxxxxx> > Sent: Tuesday, November 24, 2020 4:55 PM > To: Y.b. Lu <yangbo.lu@xxxxxxx> > Cc: Vladimir Oltean <vladimir.oltean@xxxxxxx>; Shawn Guo > <shawnguo@xxxxxxxxxx>; Leo Li <leoyang.li@xxxxxxx>; Rob Herring > <robh+dt@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx; Adrian Hunter <adrian.hunter@xxxxxxxxx>; Ulf > Hansson <ulf.hansson@xxxxxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Ashish Kumar <ashish.kumar@xxxxxxx> > Subject: Re: [PATCH] arm64: dts: ls1028a: make the eMMC and SD card > controllers use fixed indices > > Am 2020-11-24 09:47, schrieb Y.b. Lu: > > Hi Michael, > > > >> -----Original Message----- > >> From: Michael Walle <michael@xxxxxxxx> > >> Sent: Tuesday, November 24, 2020 4:03 PM > >> To: Y.b. Lu <yangbo.lu@xxxxxxx> > >> Cc: Vladimir Oltean <vladimir.oltean@xxxxxxx>; Shawn Guo > >> <shawnguo@xxxxxxxxxx>; Leo Li <leoyang.li@xxxxxxx>; Rob Herring > >> <robh+dt@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > >> devicetree@xxxxxxxxxxxxxxx; Adrian Hunter <adrian.hunter@xxxxxxxxx>; > >> Ulf > >> Hansson <ulf.hansson@xxxxxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx; > >> linux-kernel@xxxxxxxxxxxxxxx; Ashish Kumar <ashish.kumar@xxxxxxx> > >> Subject: Re: [PATCH] arm64: dts: ls1028a: make the eMMC and SD card > >> controllers use fixed indices > >> > >> Am 2020-11-24 08:41, schrieb Y.b. Lu: > >> > Hi Vladimir, > >> > > >> >> -----Original Message----- > >> >> From: Vladimir Oltean <vladimir.oltean@xxxxxxx> > >> >> Sent: Friday, November 20, 2020 5:30 PM > >> >> To: Y.b. Lu <yangbo.lu@xxxxxxx> > >> >> Cc: Shawn Guo <shawnguo@xxxxxxxxxx>; Leo Li <leoyang.li@xxxxxxx>; > Rob > >> >> Herring <robh+dt@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > >> >> devicetree@xxxxxxxxxxxxxxx; Adrian Hunter <adrian.hunter@xxxxxxxxx>; > >> >> Ulf > >> >> Hansson <ulf.hansson@xxxxxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx; > >> >> linux-kernel@xxxxxxxxxxxxxxx; Ashish Kumar <ashish.kumar@xxxxxxx>; > >> >> Michael Walle <michael@xxxxxxxx> > >> >> Subject: Re: [PATCH] arm64: dts: ls1028a: make the eMMC and SD card > >> >> controllers use fixed indices > >> >> > >> >> On Fri, Nov 20, 2020 at 02:04:02AM +0000, Y.b. Lu wrote: > >> >> > Hi Vladimir, > >> >> > > >> >> > I have already upstreamed a patch for all affected layerscape boards. > >> >> > > >> >> > >> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern > >> > el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fshawnguo%2Flinux.git%2 > >> > Fcommit%2F&data=04%7C01%7Cyangbo.lu%40nxp.com%7C498622ade > >> > e704fc0042008d8904f6184%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0 > >> %7C0%7C637418017917635725%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi > M > >> > C4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000 > >> > &sdata=OciS3q%2BmP%2Bz4x1ewPHDigmUkgIZmBgUlRRTm4yaxB7s%3D > >> &reserved=0? > >> >> h=imx/dt64&id=342ab37ecaf8c1b10dd3ca9a1271db29a6af0705 > >> >> > > >> >> > Please check whether it works for you. > >> >> > >> >> Thanks, one can tell that I haven't done my due diligence of checking > >> >> Shawn's tree first. I'll cherry-pick that patch and carry on with my > >> >> work. > >> >> > >> >> However, the fact still remains that Michael has expressed his opinion > >> >> regarding mmcblk0 vs mmcblk1. Do you think that we could make the > >> >> aliases a per-board option instead of per-SoC? Consider that there > >> >> might > >> >> even be boards that only use SD card. It would be strange for the > >> >> block > >> >> device in that case to be called /dev/mmcblk1. > >> > > >> > I don't think it's a problem in board dts to define board specific > >> > thing, like re-defining alias, and disabling any IP it not using. > >> > >> First, why would you put it in the architecture include anyway? That > >> is really board-specific. That is like you would say, we enable all > >> devices and a board could potentially disable it. TBH it seems that > >> this will fit your reference boards and you don't care about the > >> other ones which uses that include. > > > > In soc dtsi, this is giving default alias for two esdhc controllers. > > This is not board specific. > > That's natural esdhc0 is mmc0 and esdhc1 is mmc1. > > How could this be not board specific if there are at least three > different use cases the board can choose from - and needs three > different configurations: > > (1) eMMC at /dev/mmcblk0, SD card at /dev/mmcblk1 > (2) SD card at /dev/mmcblk0, eMMC at /dev/mmcblk1 > (3) no eMMC at all, SD card at /dev/mmcblk0 Not matter it's SD card or eMMC card, if it's on esdhc0, use /dev/mmcblk0. Not matter it's SD card or eMMC card, if it's on esdhc1, use /dev/mmcblk1. It's not related to board and card type, it's only related to esdhc interface in use. Thanks. > > your include only support (1). If a board needs (2) or (3) it has to > override the configuration in the _common_ include. > > >> And as Vladimir pointed out, what do you do if you just have the eMMC > >> on the LS1028A. It will be mmcblk1 unless you do something like the > >> following in the board dts: > >> > >> mmc0 = &esdhc; > >> /delete-property/ mmc1; > >> > >> That is really cumbersome, isnt it? > > > > The soc dtsi gives default alias to make esdhc0 as mmc0, and esdhc1 as > > mmc1, the use case just needs to consider which esdhc controller is > > used. That's fixed index for it. > > No matter how the board is designed, there are two esdhc controllers > > in soc. It's probed as mmc0 and mmc1. > > It's use case that should choose the right mmc device. It is not the > > dts that should be changed to suit use case. > > If the board owner insists to change alias to make esdhc1 as mmc0, I > > think no problem. Just do it in board dts to override the default one. > > Still, why would this be enforced in the common include? What is the > advnatage here? I only see disadvantages. > > -michael
