[U-Boot] [PATCH] arm: ls1021a: Ensure LS1021 ARM Generic Timer CompareValue Set 64-bit

[Mark Rutland <mark.rutland@arm.com>]

Hi,

Isn't this the same patch as a couple of days ago [2], which I replied
to [3]?

On Wed, Jul 15, 2015 at 08:13:05AM +0100, Alison Wang wrote:
> This patch addresses a problem mentioned recently on this mailing list:
> [1].
> 
> In that posting a LS1021 based system was locking up at about 5 minutes
> after boot, but the problem was mysteriously related to the toolchain
> used for building u-boot.  Debugging the problem reveals a stuck
> interrupt 29 on the GIC.
> 
> It appears Freescale's LS1021 support in u-boot erroneously sets the
> 64-bit ARM generic PL1 physical time CompareValue register to all-ones
> with a 32-bit value.  This causes the timer compare to fire 344 seconds
> after u-boot configures it.  Depending on how fast u-boot gets the
> kernel booted, this amounts to about 5-minutes of Linux uptime before
> locking up.

If as in [2] this is an attempt to not generate interrupts that Linux
doesn't expect, it would be far better to simply disable the timer
interrupt before leaving U-Boot, ensuring that unexpected interrupts are
never generated regardless of the width or rate of the counter.

There are bits in CNTP_CTL to do this.

Thanks,
Mark.

[2] http://lists.denx.de/pipermail/u-boot/2015-July/218937.html
[3] http://lists.denx.de/pipermail/u-boot/2015-July/218979.html

> Apparently the bug is masked by some toolchains.  Perhaps this is
> explained by default compiler options, word sizes, or binutils versions.
> At any rate this patch makes the manipulation explicitly 64-bit which
> alleviates the issue.
> 
> [1]
> https://lists.yoctoproject.org/pipermail/meta-freescale/2015-June/014400.html
> Signed-off-by: Chris Kilgour <techie@whiterocker.com>
> Signed-off-by: Alison Wang <alison.wang@freescale.com>
> ---
>  arch/arm/cpu/armv7/ls102xa/timer.c                | 3 ++-
>  arch/arm/include/asm/arch-ls102xa/immap_ls102xa.h | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv7/ls102xa/timer.c b/arch/arm/cpu/armv7/ls102xa/timer.c
> index 11b17b2..e6a32ca 100644
> --- a/arch/arm/cpu/armv7/ls102xa/timer.c
> +++ b/arch/arm/cpu/armv7/ls102xa/timer.c
> @@ -56,7 +56,8 @@ static inline unsigned long long us_to_tick(unsigned long long usec)
>  int timer_init(void)
>  {
>  	struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR;
> -	unsigned long ctrl, val, freq;
> +	unsigned long ctrl, freq;
> +	unsigned long long val;
>  
>  	/* Enable System Counter */
>  	writel(SYS_COUNTER_CTRL_ENABLE, &sctr->cntcr);
> diff --git a/arch/arm/include/asm/arch-ls102xa/immap_ls102xa.h b/arch/arm/include/asm/arch-ls102xa/immap_ls102xa.h
> index ee547fb..34854da 100644
> --- a/arch/arm/include/asm/arch-ls102xa/immap_ls102xa.h
> +++ b/arch/arm/include/asm/arch-ls102xa/immap_ls102xa.h
> @@ -31,7 +31,7 @@
>  #define RCWSR4_SRDS1_PRTCL_SHIFT	24
>  #define RCWSR4_SRDS1_PRTCL_MASK		0xff000000
>  
> -#define TIMER_COMP_VAL			0xffffffff
> +#define TIMER_COMP_VAL			0xffffffffffffffffull
>  #define ARCH_TIMER_CTRL_ENABLE		(1 << 0)
>  #define SYS_COUNTER_CTRL_ENABLE		(1 << 24)
>  
> -- 
> 2.1.0.27.g96db324
> 
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