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

[Marek Vasut]

On Friday, August 28, 2015 at 12:27:18 PM, Jian Luo wrote:
> Hi Marek,
> 
> On 28.08.2015 11:24, Marek Vasut wrote:
> > On Friday, August 28, 2015 at 10:41:50 AM, Jian Luo 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>
> > 
> > Hi!
> > 
> >> ---
> >> 
> >>    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;
> > 
> > Nit: The indent should be done with tabs, not spaces. I think the email
> > got messed up somewhere along the way.
> 
> Yes, sorry. I can't setup git send-email in our company network.
> Thunderbird messed the indent up.

Why not ?

> > The bigger concern I have is that if you look into arch/arm/lib/crt0.S ,
> > you will see that the entire global data are cleared there (_main, label
> > clr_gd: ) and this code is executed before the board_init_f() .
> 
> This was my first assumption, it should be cleared in crt0.S.
> I was using U-Boot to load a VxWorks image.
> And wrote 1 to rstmgr ctrl in VxWorks to do a warm reset.
> Afterwards the SPL hangs.

Hangs in which way ? Can you share the output please ?

> It did not happen if I do reset direct in U-Boot.
> I'll attach a JTAG Debug to dig deeper.

Neat, that'd be really awesome, thanks for looking into this !

> > Can you try tracking it down a bit more? I suspect that you might see
> > dm_init_and_scan() returned error -22 , is that what you observe please?
> 
> Yes, in dm_init() where gd->dm_root will be checked.

But if you get -ENOMEM, that means somehow the malloc is broken here.
I wonder if this explicit setting of gd->malloc_area is screwing something
up ?

Best regards,
Marek Vasut