[U-Boot] [PATCH] time: fix usec_to_tick()

[Rob Herring]

On Thu, Dec 5, 2013 at 1:08 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> From: Stephen Warren <swarren at nvidia.com>
>
> Commit 8dfafdde88eb ("Introduce common timer functions") created a
> common definition of usec_to_tick() which had a couple problems:
>
> static unsigned long long usec_to_tick(unsigned long usec)
> {
>        uint64_t tick = usec * get_tbclk();
>
> That likely overflows.
>
>        usec *= get_tbclk();
>
> That was an attempt to fix it by performing the multiply after the
> promotion of usec to 64-bit, but was applied to the wrong variable,
> which was never used.
>
> This patch fixes these issues. A user-visible symptom of the problem was
> the e.g. "dhcp zImage" using an ASIX USB Ethernet dongle would print:
>
> Waiting for Ethernet connection... unable to connect.
>
> ... with no delay before "unable to connect". There are likely other
> symptoms.
>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>

Acked-by: Rob Herring <rob.herring at calxeda.com>

Tom,

Can you please merge this and VExpress timer fix [1] ASAP. Multiple
fixes keep getting sent to the list.

Rob

[1] http://patchwork.ozlabs.org/patch/294336/

> ---
>  lib/time.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/time.c b/lib/time.c
> index 09bb05a24d33..8085aa40d1c9 100644
> --- a/lib/time.c
> +++ b/lib/time.c
> @@ -71,8 +71,8 @@ unsigned long __weak notrace timer_get_us(void)
>  }
>  static unsigned long long usec_to_tick(unsigned long usec)
>  {
> -       uint64_t tick = usec * get_tbclk();
> -       usec *= get_tbclk();
> +       uint64_t tick = usec;
> +       tick *= get_tbclk();
>         do_div(tick, 1000000);
>         return tick;
>  }
> --
> 1.8.1.5
>
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