[U-Boot] Cannot boot mx6qsabred with 2019.07-rc2

[Peng Fan]

Hi Fabio,

> Subject: Re: Cannot boot mx6qsabred with 2019.07-rc2
> 
> Hi Peng,
> 
> On Thu, May 16, 2019 at 11:29 PM Peng Fan <peng.fan at nxp.com> wrote:
> 
> > You could enable DEBUG in SPL, and disable SPL_SDP because of size will
> exceeds.
> > Then see what happends.
> > I have no idea, then. My board is REV C4, chip 1.5
> 
> My mx6qsabresd is revC2, with a i.MX6Q rev 1.2 populated.
> 
> After further investigation we can confirm that the problem is caused by SPL
> size being greater than the 68kB limit (4KB header + 64KB max size)as
> explained in include/configs/imx6_spl.h:
> 
> ---------------
> #ifndef __IMX6_SPL_CONFIG_H
> #define __IMX6_SPL_CONFIG_H
> 
> #ifdef CONFIG_SPL
> /*
>  * see Figure 8-3 in IMX6DQ/IMX6SDL Reference manuals:
>  *  - IMX6SDL OCRAM (IRAM) is from 0x00907000 to 0x0091FFFF
>  *  - IMX6DQ has 2x IRAM of IMX6SDL but we intend to support IMX6SDL as
> well
>  *  - BOOT ROM stack is at 0x0091FFB8
>  *  - if icache/dcache is enabled (eFuse/strapping controlled) then the
>  *    IMX BOOT ROM will setup MMU table at 0x00918000, therefore we
> need to
>  *    fit between 0x00907000 and 0x00918000.
>  *  - Additionally the BOOT ROM loads what they consider the firmware
> image
>  *    which consists of a 4K header in front of us that contains the IVT, DCD
>  *    and some padding thus 'our' max size is really 0x00908000 -
> 0x00918000
>  *    or 64KB
>  */
> #define CONFIG_SPL_MAX_SIZE             0x10000
> #define CONFIG_SPL_STACK                0x0091FFB8
> /*
>  * Pad SPL to 68KB (4KB header + 64KB max size). This allows to write the
>  * SPL/U-Boot combination generated with u-boot-with-spl.imx directly to a
>  * boot media (given that boot media specific offset is configured properly).
>  */
> #define CONFIG_SPL_PAD_TO               0x11000
> ---------------
> 
> Here are the tests I ran:
> 
> Test 1: Original U-Boot 2019.07-rc2
> -----------------------------------------------
> 
> SPL: 76800 (75 kB)
> Result: does not boot
> 
> Test 2: Removing extra dtbs
> -------------------------------------
> 
> --- a/configs/mx6sabresd_defconfig
> +++ b/configs/mx6sabresd_defconfig
> @@ -59,10 +59,10 @@ CONFIG_EFI_PARTITION=y
> CONFIG_OF_CONTROL=y  CONFIG_SPL_OF_CONTROL=y
> CONFIG_DEFAULT_DEVICE_TREE="imx6q-sabresd"
> -CONFIG_OF_LIST="imx6q-sabresd imx6qp-sabresd imx6dl-sabresd"
> +CONFIG_OF_LIST="imx6q-sabresd"
>  CONFIG_MULTI_DTB_FIT=y
>  CONFIG_SPL_MULTI_DTB_FIT=y
> -CONFIG_SPL_OF_LIST="imx6dl-sabresd imx6q-sabresd imx6qp-sabresd"
> +CONFIG_SPL_OF_LIST="imx6q-sabresd"
>  CONFIG_ENV_IS_IN_MMC=y
>  CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
>  CONFIG_SPL_DM=y
> 
> SPL:68608 (67 kB)
> Result: boots correctly
> 
> Test 3: Removing SPL_DM
> ------------------------------------
> 
> --- a/configs/mx6sabresd_defconfig
> +++ b/configs/mx6sabresd_defconfig
> @@ -65,7 +65,6 @@ CONFIG_SPL_MULTI_DTB_FIT=y
> CONFIG_SPL_OF_LIST="imx6dl-sabresd imx6q-sabresd imx6qp-sabresd"
>  CONFIG_ENV_IS_IN_MMC=y
>  CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
> -CONFIG_SPL_DM=y
>  CONFIG_USB_FUNCTION_FASTBOOT=y
>  CONFIG_FASTBOOT_BUF_ADDR=0x12000000
>  CONFIG_FASTBOOT_BUF_SIZE=0x10000000
> 
> SPL: 68608 (67 kB)
> Result: boots correctly
> 
> I will send a v2 removing CONFIG_SPL_DM.

So what is the real direction moving to use SPL driver, non-dm is allowed in future?

> 
> Also, the SPL size check should be really done after the multi fit image is
> concatenated so that we can have a chance to detect such size overflow in
> build time.

Agree. I also meet that SPL size is too large on i.MX8/8M, although still have OCRAM for it.

Regards,
Peng.

> 
> Thanks