[U-Boot] i.MX6: Prealloc pinctrl make U-Boot hang at relocation (data abort)

[Lokesh Vutla]

+Heiko

On Tuesday 17 October 2017 04:14 AM, Jagan Teki wrote:
> Hi,
> 
> I'm trying to use SPL_OF_CONTROL with u-boot,dm-spl So I've marked
> u-boot,dm-spl with pinctrl since MMC used the pinconfig.
> 
> The issue observed here is SPL handover to U-Boot proper and before
> relocation U-Boot probed imx_thermal dm-driver through device_probe.
> But the same time device_probe unnecessary probing all u-boot,dm-spl

This statement is not entirely true. device_probe() tries to get pinctrl
for every device. So pinctrl is being probed as part of imx_thermal probe.

> marked nodes(which are strictly related for SPL) Since pinctrl marked
> as u-boot, dm-spl the same probed and this might be the show-stopper.

But then, u-boot,dm-spl marked nodes should not be probed in u-boot
proper. IMHO, this needs to be fixed.

Heiko, what is this expected behavior here?

> 
> Based on the data abort, the code hang at relocation code, relocate.S,
> eventually stop calling uclass_get_device( was called in
> arch/arm/mach-imx/cpu.c) during board_f or unmark u-boot,dm-spl make
> U-Boot boots.

So, I looked at drivers/pinctrl/nxp/pinctrl-imx6.c and observed that
there is an uninitialized global variable[1]. Before re location, BSS is
overlapped with DT area. IIUC, your dtb is being corrupted in this case.
Can you try initializing imx6_pinctrl_soc_info with some non-zero values
and see if it helps?

[1]
http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/pinctrl/nxp/pinctrl-imx6.c;h=0f767d90790a0dbeb974029a7d88cac6c03ae23f;hb=HEAD#l14


Thanks and regards,
Lokesh

> 
> Below are relocation code hang point and Log dump, request for any inputs.
> 
> Relocation code:
> ----------------------
> 
>         /* relative fix: increase location by offset */
>         add     r0, r0, r4
> 87800ac4:       e0800004        add     r0, r0, r4
>         ldr     r1, [r0]
> 87800ac8:       e5901000        ldr     r1, [r0]       /* HANG */
>         add     r1, r1, r4
> 87800acc:       e0811004        add     r1, r1, r4
>         str     r1, [r0]
> 87800ad0:       e5801000        str     r1, [r0]
> 
> 87800ad4 <fixnext>:
> 
> Log:
> -----
> U-Boot SPL 2017.11-rc1-00165-g7340683-dirty (Oct 17 2017 - 04:00:01)
> Trying to boot from MMC1
> 
> device_probe: Process pinctrl for soc
> 
> device_probe: Process pinctrl for aips-bus at 02000000
> initialized IMX pinctrl driver
> 
> device_probe: Process pinctrl for aips-bus at 02100000
> 
> device_probe: Process pinctrl for usdhc at 02190000
> 
> device_probe: Process pinctrl for usdhc1grp
> 
> device_probe: Process pinctrl for gpio at 0209c000
> Expected Linux image is not found. Trying to start U-boot
> 
> 
> U-Boot 2017.11-rc1-00165-g7340683-dirty (Oct 17 2017 - 04:00:01 +0530)
> 
> U-Boot code: 87800000 -> 8783FB38  BSS: -> 87857338
> CPU:   Freescale i.MX6UL rev1.1 528 MHz (running at 396 MHz)
> CPU:   Industrial temperature grade (-40C to 105C)
> device_probe: Process pinctrl for imx_thermal
> 
> device_probe: Process pinctrl for soc
> 
> device_probe: Process pinctrl for aips-bus at 02000000
> initialized IMX pinctrl driver
>  at 31C
> Reset cause: POR
> Model: Engicam Is.IoT MX6UL MMC Starterkit
> DRAM:  Monitor len: 00057338
> Ram size: 08000000
> Ram top: 88000000
> TLB table from 87ff0000 to 87ff4000
> Reserving 348k for U-Boot at: 87f98000
> Reserving 16384k for malloc() at: 86f98000
> Reserving 80 Bytes for Board Info at: 86f97fb0
> Reserving 240 Bytes for Global Data at: 86f97ec0
> Reserving 24448 Bytes for FDT at: 86f91f40
> 
> RAM Configuration:
> Bank #0: 80000000
> DRAM:  128 MiB
> New Stack Pointer is: 86f91f20
> Relocation Offset is: 00798000
> Relocating to 87f98000, new gd at 86f97ec0, sp at 86f91f20
> data abort
> pc : [<87800ac8>]          lr : [<87f986ac>]
> sp : 86f91f20  ip : 0000001c     fp : 00000017
> r10: 8783fa98  r9 : 86f97ec0     r8 : 00913b18
> r7 : deadbeef  r6 : 0091de88     r5 : 87800320  r4 : 00798000
> r3 : 87848848  r2 : 87843820     r1 : 00000017  r0 : 02878000
> Flags: nZCv  IRQs off  FIQs off  Mode SVC_32
> Resetting CPU ...
> 
> resetting ...
> 
> thanks!
>