[U-Boot] [PATCH] arm: socfpga: dm: Fix DM initialization failure after warm reset

[Simon Glass]

Hi Marek,

On 29 August 2015 at 08:46, Marek Vasut <marex at denx.de> wrote:
> On Saturday, August 29, 2015 at 04:39:43 PM, Simon Glass wrote:
>> Hi Marek,
>>
>> On 29 August 2015 at 01:56, Marek Vasut <marex at denx.de> wrote:
>> > On Saturday, August 29, 2015 at 01:21:31 AM, Simon Glass wrote:
>> > > Hi,
>> > >
>> > > On 28 August 2015 at 02:41, Jian Luo <Jian.Luo4 at boschrexroth.de> wrote:
>> > > > gd->dm_root is not cleared in SPL after warm reset.
>> > > > This might cause DM initilazation failure.
>> > > >
>> > > > Signed-off-by: Jian Luo <jian.luo4 at boschrexroth.de>
>> > > > ---
>> > > >
>> > > >  arch/arm/mach-socfpga/spl.c | 6 ++++++
>> > > >  1 file changed, 6 insertions(+)
>> > > >
>> > > > diff --git a/arch/arm/mach-socfpga/spl.c
>> > > > b/arch/arm/mach-socfpga/spl.c index 13ec24b..59fe1f2 100644
>> > > > --- a/arch/arm/mach-socfpga/spl.c
>> > > > +++ b/arch/arm/mach-socfpga/spl.c
>> > > > @@ -181,5 +181,11 @@ void board_init_f(ulong dummy)
>> > > >
>> > > >         /* Configure simple malloc base pointer into RAM. */
>> > > >         gd->malloc_base = CONFIG_SYS_TEXT_BASE + (1024 * 1024);
>> > > >
>> > > > +       /*
>> > > > +        * gd->dm_root might contain non-zero value after warm reset.
>> > > > +        * Clear it to avoid dm_init error
>> > > > +        */
>> > > > +       gd->dm_root = NULL;
>> > > > +
>> > > >
>> > > >         board_init_r(NULL, 0);
>> > > >
>> > > >  }
>> > > >
>> > > > --
>> > > > 1.9.1
>> > >
>> > > This does not look like the root cause to me. global_data is zeroed by
>> > > crt0.S if CONFIG_SPL_FRAMEWORK is set, which it seems to be for
>> > > socfpga.
>> > >
>> > > What boot path does 'warm reset' take?
>> >
>> > Warm reset resets the CPU core(s) and jumps to 0x0 in SRAM (without
>> > re-reading anything from the boot media).
>>
>> Does that mean it skips crt0.S? How come global_data is not zeroed there?
>
> No, it does not mean it skips crt0.S . After the warm reset, the bootrom
> jumps onto the reset vector, so crt0.S (_main) must be executed.

Then I don't understand the need for this patch.

>
>> > > Also BTW it would be better if board_init_f() returned rather than
>> > > calling board_init_r() directly.
>> >
>> > I'm all for it, it'd trim down the stack utilisation slightly too.
>>
>> Sound good.
>
> Done ;-)

 :-)

>
> Best regards,
> Marek Vasut

Regards,
Simon