[U-Boot] MMC boot broken on OMAP-L138 LCDK

[Adam Ford <aford173@gmail.com>]

On Fri, May 17, 2019 at 7:36 AM Sekhar Nori <nsekhar@ti.com> wrote:
>
> Hi Adam,
>
> MMC/SD boot is broken on OMAP-L138 LCDK. This is since v2018.11.
> v2018.09 is fine.
>
> The first breakage occurred with commit 21af33ed0319 ("ARM: davinci:
> omapl138_lcdk: Enable DM_MMC"). This commit moved to DM_MMC for U-Boot
> while keeping legacy mode for SPL.

I am going to preface this by stating I don't have the LCDK.  Peter
Howard (added in CC) asked me to submit this on his behalf, so I
reviewed his patch and submitted it which is why both our names are on
the s-o-b.

>
> The "#ifndef CONFIG_DM_MMC" introduced by this commit is incorrect I
> think because CONFIG_DM_MMC is defined in SPL build too and because of
> this board_mmc_init() never gets defined. I think the intent was to
> define board_mmc_init() for SPL case, and for that the following diff
> should do:
>
> diff --git a/board/davinci/da8xxevm/omapl138_lcdk.c b/board/davinci/da8xxevm/omapl138_lcdk.c
> index 2c2f885d43e4..fe1bf4410145 100644
> --- a/board/davinci/da8xxevm/omapl138_lcdk.c
> +++ b/board/davinci/da8xxevm/omapl138_lcdk.c
> @@ -353,7 +353,7 @@ int misc_init_r(void)
>         return 0;
>  }
>
> -#ifndef CONFIG_DM_MMC
> +#if !CONFIG_IS_ENABLED(DM_MMC)
>  #ifdef CONFIG_MMC_DAVINCI
>  static struct davinci_mmc mmc_sd0 = {
>         .reg_base = (struct davinci_mmc_regs *)DAVINCI_MMC_SD0_BASE,
>

I would agree that the #ifndef should be replaced with if
!CONFIG_IS_ENABLED(DM_MMC), but I would recomend checking into
migrating the LCDK to DM. and DM_MMC.
>
> With this fixed, MMC/SD boot is still broken after commit 15b8c7505819
> ("davinci: da850evm/omapl138-lcdk: Move BSS to SDRAM because SRAM is
> full").
>
> After this commit, mmc_initialize() in drivers/mmc/mmc.c fails because
> the static variable 'initialized' does not get initialized to 0 as
> intended in code and gets set to a random value because of which no
> MMC/SD device gets registered. I did notice that 'initialized' is in
> BSS, so I believe after this commit BSS is not getting set to 0.

I sent Peter H a list of patches to consider because I spent a lot of
time trying to modernize the da850_evm using DM, and DM_SPL and
eventually SPL_OF_CONTROL which ultimately eliminated a lot of the
manual initializing of the various drivers.

See:
commit a4670f8ebb5b4df6afeb5155fb5b44c1d1d154b9 Enable DM and device
tree support for da850-evm
commit c4fa049a121457ff38b74daac32e18d7afbd4538 shrunk SPL by 6.5k
commit 391328dc30b78be6f0d1181088eda0fd7febd5f3 removed DM_I2C_COMPAT
commit cb19c29398cb84e72236ab6bae3763028fce5d44 board: da8xxevm: Add
SPL DM for serial, spi (with platdata)
commit 591353d011b5ff6dbc8511b7a839cddf5b610495 ARM: da850evm:
Increase Malloc Size
commit 15b8c7505819fa48dd99fb51e91b9536f341fde1 moved BSS to SDRAM
because SRAM is full
commit f7c1d53605d9ec528abacda9ba1763c67221fc88 ARM: davinci:
da850evm: Enable SPL_OF_CONTROL without PLATDATA
commit fd3c26f3f921ad7addf95857cdb99a883c6e497a ARM: da850evm: Fix
broken SPI Flash

Having said that, the hardware I have for the da850 EVM doesn't
support MMC booting, so I cannot verify whether or not MMC initializes
properly in SPL.  I know the MMC initializes in U-Boot once it's
booted from SPI flash.

If someone wants to send me an LCDK, I'd be happy to look at
attempting to modernize the U-Boot for it.  Otherwise, we may want to
consider splitting the linker scripts between  LCDK and da850 evm so
da850evm can use SPL_OF_CONTROL with enough memory and LCDK can keep
it's legacy code status in SPL.

adam
>
> Thanks,
> Sekhar