[U-Boot] mx6cuboxi fails to load u-boot.img

Baruch Siach baruch at tkos.co.il
Sun Oct 6 15:55:47 UTC 2019


Hi Adam,

On Sun, Oct 06 2019, Adam Ford wrote:
> On Sun, Oct 6, 2019 at 7:48 AM Baruch Siach <baruch at tkos.co.il> wrote:
>> On Sun, Oct 06 2019, Adam Ford wrote:
>> > On Sun, Oct 6, 2019 at 7:30 AM Adam Ford <aford173 at gmail.com> wrote:
>> >>
>> >> On Sun, Oct 6, 2019 at 7:22 AM Baruch Siach <baruch at tkos.co.il> wrote:
>> >> >
>> >> > Hi Adam,
>> >> >
>> >> > On Sun, Oct 06 2019, Adam Ford wrote:
>> >> > > On Sun, Oct 6, 2019 at 5:23 AM Baruch Siach <baruch at tkos.co.il> wrote:
>> >> > >> (Adding MMC and i.MX maintainers to Cc)
>> >> > >>
>> >> > >> On Fri, Sep 27 2019, Adam Ford wrote:
>> >> > >> > On Fri, Sep 27, 2019 at 4:38 AM Jonathan Gray <jsg at jsg.id.au> wrote:
>> >> > >> >>
>> >> > >> >> On Thu, Sep 26, 2019 at 05:07:21PM -0300, Fabio Estevam wrote:
>> >> > >> >> > Hi Vagrant,
>> >> > >> >> >
>> >> > >> >> > On Thu, Sep 26, 2019 at 4:16 PM Vagrant Cascadian <vagrant at debian.org> wrote:
>> >> > >> >> > >
>> >> > >> >> > > I just tested mx6cuboxi with 2019.10-rc4, and it fails to load
>> >> > >> >> > > u-boot.img from MMC:
>> >> > >> >> > >
>> >> > >> >> > > 1 2019-09-26_17:31:27.63089 U-Boot SPL 2019.10-rc4+dfsg-1 (Sep 24 2019 -
>> >> > >> >> > > 08:03:23 +0000)
>> >> > >> >> > > 2 2019-09-26_17:31:27.63092 Trying to boot from MMC2
>> >> > >> >> > > 3 2019-09-26_17:31:27.63095 MMC Device 1 not found
>> >> > >> >> > > 4 2019-09-26_17:31:27.63097 spl: could not find mmc device 1. error: -19
>> >> > >> >> > > 5 2019-09-26_17:31:27.63099 SPL: failed to boot from all boot devices
>> >> > >> >> > > 6 2019-09-26_17:31:27.63101 ### ERROR ### Please RESET the board ###
>> >> > >> >> >
>> >> > >> >> > Thanks for reporting this issue.
>> >> > >> >> >
>> >> > >> >> > Unfortunately, I don't have access to my Cuboxi, so I am adding Jon
>> >> > >> >> > and Baruch on Cc.
>> >> > >> >>
>> >> > >> >> Works after reverting the following commit.
>> >> > >> >>
>> >> > >> > I am going to argue that making the board comply with DM_MMC is why I
>> >> > >> > needed to make the patch, because when booting from MMC2, the function
>> >> > >> > was returning MMC1 which was clearly not the boot source.
>> >> > >> >
>> >> > >> > If the boards that fail accept MMC2 as a response when booting from
>> >> > >> > MMC2, that seems like a bug on the indvidual boards.  Instead they
>> >> > >> > should setup their boot sequence to configure MMC2 when MMC2 is the
>> >> > >> > boot source.  Instead, it seems like some boards are configuring MMC1
>> >> > >> > with MMC2 info which only prolongs the conversion to DM_MMC.
>> >> > >> >
>> >> > >> > If we revert the patch, then boards like imx6_logic who rely solely on
>> >> > >> > device tree and DM_MMC for booting will have to manually override the
>> >> > >> > MMC driver in order to boot from MMC2, and that seems like a step
>> >> > >> > backwards.  I would argue that this board should migrate to DM_MMC and
>> >> > >> > use the device tree to boot, and the problem should go away.
>> >> > >>
>> >> > >> I started working on migration to DM_MMC as you suggested. Unfortunately
>> >> > >> I can't see how this solves the problem for Cubox-i/Hummingboard, nor in
>> >> > >> the general case.
>> >> > >>
>> >> > >> The imx6_logic board happens to use only usdhc1 and usdhc2 for boot, and
>> >> > >> both are always enabled. This matches perfectly to BOOT_DEVICE_MMC{1,2},
>> >> > >> and their corresponding DT representation.
>> >> > >>
>> >> > >> However, the 'index' parameter in uclass_get_device() that is set
>> >> > >> according to BOOT_DEVICE_MMC{1,2} selection has nothing to do with the
>> >> > >> usdhcX sequence number. It simply returns the Nth probed SD/eMMC device
>> >> > >> (see uclass_find_device()). In the case of Cubox-i/Hummingboard, usdhc1
>> >> > >> is never used for boot, usdhc2 is always an SD card, and usdhc3 is an
>> >> > >> optional eMMC. When booting from SD card, uclass_get_device(), returns
>> >> > >> -ENODEV when eMMC is not available, or the eMMC device when it is
>> >> > >> available. In both cases, boot fails.
>> >> >
>> >> > I think you missed this part. See more below.
>> >> >
>> >> > >> In addition, your patch returns BOOT_DEVICE_MMC2 only for usdhc2
>> >> > >> boot. All others return BOOT_DEVICE_MMC1. What about usdhc{3,4}?
>> >> > >>
>> >> > >
>> >> > > My patch only extended it to support MMC1 or MMC2.  I don't have
>> >> > > hardware to test MMC3 or MMC4, nor where they defined in the boot
>> >> > > table.
>> >> > > The intention what to eliminate all functions from board files which
>> >> > > did a something like:
>> >> > >
>> >> > > static int mmc_init_spl(bd_t *bis)
>> >> > > {
>> >> > >      struct src *psrc = (struct src *)SRC_BASE_ADDR;
>> >> > >       unsigned reg = readl(&psrc->sbmr1) >> 11;
>> >> > >
>> >> > >      /*
>> >> > >      * Upon reading BOOT_CFG register the following map is done:
>> >> > >      * Bit 11 and 12 of BOOT_CFG register can determine the current
>> >> > >      * mmc port
>> >> > >      * 0x1                  SD2
>> >> > >      * 0x2                  SD3
>> >> > >      */
>> >> > >      switch (reg & 0x3) {
>> >> > >      ...
>> >> > >      }
>> >> > > }
>> >> > >
>> >> > >> How is all that intended to work?
>> >> > >
>> >> > > Basically the above function determines which BOOT_CFG regiser is used
>> >> > > and returns sets MMC1 values to the returned value.  In my case MMC1
>> >> > > was going to be configured with the clock and pin mux of mmc1 or 2.
>> >> > > In your case, mmc1 gets configured with the information for mmc2 or 3.
>> >> >
>> >> > But there is another side effect to this change. The code in spl_mmc.c
>> >> > uses BOOT_DEVICE_MMC* macros to determine the boot device as I mentioned
>> >> > above. These macros have nothing to do with usdhcX sequence
>> >> > numbering. When usdhc1 is missing, BOOT_DEVICE_MMC1 refers to usdhc2
>> >> > which happens to be the first probed device, and BOOT_DEVICE_MMC2
>> >> > becomes usdhc3. This code is broken since commit 14d319b185.
>> >> >
>> >> > spl_boot_device() can not blindly return BOOT_DEVICE_MMC{1,2} without
>> >> > knowing which devices are actually available.
>> >>
>> >> It returns MMC1 or MMC2 based on what loaded SPL.  If SPL was loaded
>> >> from MMC1, it should return MMC1.  If if SPL is loaded from MMC2, it
>> >> should return MMC2, not return MMC1.  The previous code always assumed
>> >> that spl_boot_device() would always return MMC1. Each individual board
>> >> would then do a manual check to see what their boot source was, then
>> >> pin-mux and configure MMC1 with the clocking and pin mux for whatever
>> >> their MMC source is.
>> >>
>> >> >
>> >> > There must be some other way to achieve what you want without breaking
>> >> > boot when usdhc1 is missing.
>> >>
>> >> If your board is not using SPL_OF_CONTROL, maybe we can put an ifdef
>> >> before my patch so people who don't use device tree will default the
>> >> older style where all MMC/SDHC controllers return MMC1.
>> >
>> > For boards without SPL_OF_CONTROL, this might help, I don't know if
>> > you use OF_CONTROL or not.
>>
>> I do use SPL_OF_CONTROL. usdhc1 is not enabled in DT because there is no
>> SD/eMMC there.
>
> I guess i am confused as to how it works for you with the patch
> reverted.  If this function returns MMC1 as the boot source with the
> patch reverted, you and everyone else will need to check the register
> to see what the boot source is.  This is the same register I am
> reading in the patch.  From there, the MMC data gets loaded based on
> the boot source.  This is the very thing my patch was trying to
> address, but admittedly without automatic support for MMC3 or MMC4,
> but my thought process was that those board would be no worse off than
> they are now because mmc3 and mmc4 would still return mmc1 as it does
> now.

I think I explained the problem clearly enough already. I'll only add
this advice:

Carefully read spl_mmc_find_device() and spl_mmc_get_device_index() in
common/spl/spl_mmc.c. Keep in mind that when 'mmc_dev' is
BOOT_DEVICE_MMC1 it refers to the first _PROBED_ SD/eMMC device. That
is, the first device that is both enabled in DT and probed successfully,
regardless of the value of X in usdhcX.

For the rest, see above.

Thanks,
baruch

> I'd like to hear from either the NXP people or the MMC maintainer to
> better determine how to utilize the return values of MMC1 or MMC2.
>
> adam
>
>>
>> > Does this help:
>> >
>> > diff --git a/arch/arm/mach-imx/spl.c b/arch/arm/mach-imx/spl.c
>> > index 1f230aca33..27eb8cc0df 100644
>> > --- a/arch/arm/mach-imx/spl.c
>> > +++ b/arch/arm/mach-imx/spl.c
>> > @@ -24,7 +24,9 @@ u32 spl_boot_device(void)
>> >  {
>> >         unsigned int bmode = readl(&src_base->sbmr2);
>> >         u32 reg = imx6_src_get_boot_mode();
>> > +#ifdef CONFIG_SPL_OF_CONTROL
>> >         u32 mmc_index = ((reg >> 11) & 0x03);
>> > +#endif
>> >
>> >         /*
>> >          * Check for BMODE if serial downloader is enabled
>> > @@ -87,10 +89,13 @@ u32 spl_boot_device(void)
>> >         case IMX6_BMODE_ESD:
>> >         case IMX6_BMODE_MMC:
>> >         case IMX6_BMODE_EMMC:
>> > +#ifdef CONFIG_SPL_OF_CONTROL
>> >                 if (mmc_index == 1)
>> >                         return BOOT_DEVICE_MMC2;
>> >                 else
>> > +#else
>> >                         return BOOT_DEVICE_MMC1;
>> > +#endif
>> >         /* NAND Flash: 8.5.2, Table 8-10 */
>> >         case IMX6_BMODE_NAND_MIN ... IMX6_BMODE_NAND_MAX:
>> >                 return BOOT_DEVICE_NAND;
>>
>> So this patch can't help either.
>>
>> baruch
>>
>> >> > >   Since it appears that arch/arm/mach-imx/spl.c is supposed to be able
>> >> > > to return the correct boot source, my goal was to make that function
>> >> > > actually return that which could eliminate the above function on all
>> >> > > boards.  Unfortunately, I don't have hardware with MMC3 or MMC4, so I
>> >> > > couldn't test it and therefore didn't write it into the code.  It was
>> >> > > my hope that someone with MMC3 or MMC4 would be able to easily expand
>> >> > > it in the hope to better facilitate support for DM_MMC and device tree
>> >> > > in SPL.
>> >> > >
>> >> > >> Aren't other i.MX boards impacted by this commit?
>> >> > >
>> >> > > Yes and no.  If they only support MMC1 or MMC2 and have DM_MMC with
>> >> > > device tree support, the theory is that mmc_init_spl(bd_t *bis)
>> >> > > function can be completely eliminated.  People with MMC3 and MMC4 as
>> >> > > boot sources are quite possibly impacted, but like I said before, I
>> >> > > was trying to lay the foundation for people to migrate into a
>> >> > > direction to eliminate individual functions and share common files
>> >> > > more easily.
>> >> > >
>> >> > > You can try this:
>> >> > >
>> >> > > diff --git a/arch/arm/include/asm/spl.h b/arch/arm/include/asm/spl.h
>> >> > > index e568af2561..e94a295eda 100644
>> >> > > --- a/arch/arm/include/asm/spl.h
>> >> > > +++ b/arch/arm/include/asm/spl.h
>> >> > > @@ -18,6 +18,8 @@ enum {
>> >> > >         BOOT_DEVICE_MMC1,
>> >> > >         BOOT_DEVICE_MMC2,
>> >> > >         BOOT_DEVICE_MMC2_2,
>> >> > > +       BOOT_DEVICE_MMC3,
>> >> > > +       BOOT_DEVICE_MMC4,
>> >> > >         BOOT_DEVICE_NAND,
>> >> > >         BOOT_DEVICE_ONENAND,
>> >> > >         BOOT_DEVICE_NOR,
>> >> > > diff --git a/arch/arm/mach-imx/spl.c b/arch/arm/mach-imx/spl.c
>> >> > > index 1f230aca33..bf72d03eee 100644
>> >> > > --- a/arch/arm/mach-imx/spl.c
>> >> > > +++ b/arch/arm/mach-imx/spl.c
>> >> > > @@ -87,7 +87,11 @@ u32 spl_boot_device(void)
>> >> > >         case IMX6_BMODE_ESD:
>> >> > >         case IMX6_BMODE_MMC:
>> >> > >         case IMX6_BMODE_EMMC:
>> >> > > -               if (mmc_index == 1)
>> >> > > +               if (mmc_index == 3)
>> >> > > +                       return BOOT_DEVICE_MMC4;
>> >> > > +               else if (mmc_index == 2)
>> >> > > +                       return BOOT_DEVICE_MMC3;
>> >> > > +               else if (mmc_index == 1)
>> >> > >                         return BOOT_DEVICE_MMC2;
>> >> > >                 else
>> >> > >                         return BOOT_DEVICE_MMC1;
>> >> > >
>> >> > > It's only compile-only tested.
>> >> >
>> >> > This patch deals with another issue that commit 14d319b185 causes. But
>> >> > I'm afraid this patch can not fix boot for me, as explained above.
>> >> >
>> >> > baruch
>> >> >
>> >> > > I am hoping someone from NXP or the MMC maintainer might having some
>> >> > > thoughts on what might be missing (if anything)
>> >> > >
>> >> > > adam
>> >> > >>
>> >> > >> Thanks,
>> >> > >> baruch
>> >> > >>
>> >> > >> >> 14d319b1856b86e593e01abd0a1e3c2d63b52a8a is the first bad commit
>> >> > >> >> commit 14d319b1856b86e593e01abd0a1e3c2d63b52a8a
>> >> > >> >> Author: Adam Ford <aford173 at gmail.com>
>> >> > >> >> Date:   Thu May 23 14:11:30 2019 -0500
>> >> > >> >>
>> >> > >> >>     spl: imx6: Let spl_boot_device return USDHC1 or USDHC2
>> >> > >> >>
>> >> > >> >>     Currently, when the spl_boot_device checks the boot device, it
>> >> > >> >>     will only return MMC1 when it's either sd or eMMC regardless
>> >> > >> >>     of whether or not it's MMC1 or MMC2.  This is a problem when
>> >> > >> >>     booting from MMC2 if MMC isn't being manually configured like in
>> >> > >> >>     the DM_SPL case with SPL_OF_CONTROL.
>> >> > >> >>
>> >> > >> >>     This patch will check the register and return either MMC1 or MMC2.
>> >> > >> >>
>> >> > >> >>     Signed-off-by: Adam Ford <aford173 at gmail.com>
>> >> > >> >>
>> >> > >> >>  arch/arm/mach-imx/spl.c | 8 +++++---
>> >> > >> >>  1 file changed, 5 insertions(+), 3 deletions(-)

--
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -


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