[U-Boot] v2015.10-rc2: timer not initialized on Kirkwood

[Simon Guinot <simon.guinot@sequanux.org>]

Hi Stefan,

On Thu, Sep 03, 2015 at 07:28:01AM +0200, Stefan Roese wrote:
> Hi Simon,
> 
> On 02.09.2015 17:49, Simon Guinot wrote:
> >While testing U-Boot v2015.10-rc2 on the Kirkwood-based LaCie boards
> >I noticed that the autoboot counter is not decrementing. It stays stuck
> >at '3' endlessly. After some digging, I found out that this regression
> >is due to the commit: ade741b3896b1a3872ff74437f04b50762d05849
> >"arm: mvebu: Call timer_init early before PHY and DDR init".
> 
> Sorry about that. Unfortunately I don't have a Kirkwood target here.
> So I can't test any of the MVEBU changes on this platform.
> 
> >With this commit it appears that the timer initialization is skipped
> >on Kirkwood boards. As a consequence the timer is not ticking and then
> >all the features relying on the timer are most likely broken.
> >
> >On the Kirkwood boards, the timer_init function is only called from
> >from the ARM init_sequence. SPL support is disabled. The problem is
> >that the patch introduces a static init_done variable (to prevent
> >multiple timer initializations). But while debugging the timer_init
> >function (via JTAG), I noticed that the init_done initial value is not
> >zero. So the function exists without initializing the timer. A possible
> >explanation is that timer_init is called before the U-Boot relocation,
> >when the BSS segment is still not available...
> 
> Hmmm. I thought that BSS should be available and cleared at that
> time. But this does not seem to be the case.
> 
> >Maybe we should use an initialized variable instead ?
> 
> Could you please test the small attached patch? If this fixes the
> problem for you on your Kirkwood board?

I can confirm that the attached patch does fix the issue.

Thanks for the quick reply.

Simon

> 
> If yes, I'll submit it officially to the list for inclusion.
> 
> Thanks,
> Stefan
> 

> >From 9525d96509e36ae534a15f55afd2eae30f9e000a Mon Sep 17 00:00:00 2001
> From: Stefan Roese <sr@denx.de>
> Date: Thu, 3 Sep 2015 07:22:42 +0200
> Subject: [PATCH] arm: mvebu: timer.c: Explicitly move "init_done" var to data
>  section
> 
> As reported by Simon Guinot, commit ade741b3
> "arm: mvebu: Call timer_init early before PHY and DDR init" breaks
> Kirkwood platforms. As the static variable "init_done" is not
> available at that early boot time. This patch moves it to explicitly
> to the data section, making it available at that time.
> 
> Signed-off-by: Stefan Roese <sr@denx.de>
> Reported-by: Simon Guinot <simon.guinot@sequanux.org>
> Cc: Luka Perkov <luka.perkov@sartura.hr>
> ---
>  arch/arm/mach-mvebu/timer.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-mvebu/timer.c b/arch/arm/mach-mvebu/timer.c
> index c516c41..5449a89 100644
> --- a/arch/arm/mach-mvebu/timer.c
> +++ b/arch/arm/mach-mvebu/timer.c
> @@ -41,7 +41,7 @@
>  #define timestamp			gd->arch.tbl
>  #define lastdec				gd->arch.lastinc
>  
> -static int init_done;
> +static int init_done __attribute__((section(".data"))) = 0;
>  
>  /* Timer reload and current value registers */
>  struct kwtmr_val {
> -- 
> 2.5.1
> 

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