[U-Boot] QSPI XIP boot on am437x

[Vignesh R <vigneshr@ti.com>]

On 11/13/2015 11:58 AM, Albert ARIBAUD wrote:
> Hello Vignesh,
> 
> On Fri, 13 Nov 2015 11:22:19 +0530, Vignesh R <vigneshr@ti.com> wrote:
>> Hi,
>>
>> On 11/11/2015 02:33 PM, Albert ARIBAUD wrote:
>>
>> [...]
>>
>>> Alternatively, you could test the patch at
>>>
>>> 	http://patchwork.ozlabs.org/patch/542558/
>>>
>>> Let us know if this solves your issue. If it does, then it will confirm
>>> the issue is with arch_setup_gd not being able to set up your GD for
>>> some reason.
>>>
>>> IMPORTANT: patch 542558 is *not* a final patch (there will be at least
>>> a v3), and may even never land in u-boot/master; but some equivalent will
>>> eventually do. Right now, patch 542558 is only a way to test if your
>>> issue is a GD one.
>>>
>>
>> The above patch affects the code that executes after s_init(), therefore
>> I don't think above patch matters (_main is run after s_init()).
> 
> See (1) below.
> 
>> As you said in your first reply "If s_init() runs before
>> board_init_f_mem(), then you must move it to
>> run after board_init_f_mem().", this is the problem with my case.
>> s_init() is running *before* setting up of global_data in
>> arch/arm/lib/crt0.S (in _main), hence IMO, calling serial_init() in
>> s_init() is wrong. This has to be moved to board_init_f() (in
>> arch/arm/cpu/armv7/am33xx/board.c).
>> The comment in arch/arm/cpu/armv7/lowlevel_init.S that calls s_init()
>> also says *not* to access global_data and not to try to start console.
>> Therefore, I intend to do something like this:
>>
>> diff --git a/arch/arm/cpu/armv7/am33xx/board.c
>> b/arch/arm/cpu/armv7/am33xx/board.c
>> index bd14326cf479..351fc37b0483 100644
>> --- a/arch/arm/cpu/armv7/am33xx/board.c
>> +++ b/arch/arm/cpu/armv7/am33xx/board.c
>> @@ -256,6 +256,11 @@ void board_init_f(ulong dummy)
>>  {
>>         board_early_init_f();
>>         sdram_init();
>> +#if defined(CONFIG_NOR_BOOT) || defined(CONFIG_QSPI_BOOT)
>> +       gd->baudrate = CONFIG_BAUDRATE;
>> +       serial_init();
>> +       gd->have_console = 1;
>> +#endif
>>  }
>>  #endif /* end  CONFIG_SPL_BUILD */
>>
>> @@ -273,12 +278,6 @@ void s_init(void)
>>         set_uart_mux_conf();
>>         setup_clocks_for_console();
>>         uart_soft_reset();
>> -#if defined(CONFIG_NOR_BOOT) || defined(CONFIG_QSPI_BOOT)
>> -       /* TODO: This does not work, gd is not available yet */
>> -       gd->baudrate = CONFIG_BAUDRATE;
>> -       serial_init();
>> -       gd->have_console = 1;
>> -#endif
>>  #if defined(CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC)
>>         /* Enable RTC32K clock */
>>         rtc32k_enable();
>>
>> Do you see any issues with above change?
> 
> (1) So your s_init runs even before board_init_f_mem(), right?
> 
> Your working fix seems to imply that as long as s_init() is run after
> board_init_f_mem (and any time before board_init_f) it will work. If
> so, then another, fix, preferable to the above, would be that the call
> to s_init be moved between those to board_init_f_mem and board_init_f.
> Can you test that?

Yes, gd area gets initialized to 0 in board_init_f_mem(). Initializing
the console thereafter fixes the issue. There is nothing between call to
board_init_f_mem and board_init_f. board_init_f gets called right after
board_init_f_mem (in arch/arm/lib/crt0.S), therefore I thought of moved
in serial_init call to board_init_f as above.

-- 
Regards
Vignesh