[PATCH v4] ARM: ep93xx: use more reliable CPLD watchdog for reset on ts72xx

[Olof Johansson]

Hi,

On Fri, Jun 3, 2011 at 11:28 AM, Petr Štetiar <ynezz at true.cz> wrote:
> On all ep93xx based boards from Technologic Systems, there's CPLD watchdog
> available, so use this one to reset the board instead of the soft reset in
> CPU.  I've seen some weird lockups with the soft reset on ep93xx in the past,
> while the reset via CPLD watchdog seems to be rock solid (tm) and works fine
> so far.
>
> Cc: Ryan Mallon <ryan at bluewatersys.com>
> Acked-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> Signed-off-by: Petr Štetiar <ynezz at true.cz>
> ---
>  arch/arm/mach-ep93xx/include/mach/system.h |   18 +++++++++++++-----
>  1 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mach-ep93xx/include/mach/system.h b/arch/arm/mach-ep93xx/include/mach/system.h
> index 6d661fe..67ec430 100644
> --- a/arch/arm/mach-ep93xx/include/mach/system.h
> +++ b/arch/arm/mach-ep93xx/include/mach/system.h
> @@ -2,7 +2,10 @@
>  * arch/arm/mach-ep93xx/include/mach/system.h
>  */
>
> +#include <linux/io.h>
> +
>  #include <mach/hardware.h>
> +#include <mach/ts72xx.h>
>
>  static inline void arch_idle(void)
>  {
> @@ -13,11 +16,16 @@ static inline void arch_reset(char mode, const char *cmd)
>  {
>        local_irq_disable();
>
> -       /*
> -        * Set then clear the SWRST bit to initiate a software reset
> -        */
> -       ep93xx_devcfg_set_bits(EP93XX_SYSCON_DEVCFG_SWRST);
> -       ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_SWRST);
> +       if (board_is_ts7200() || board_is_ts7250() || board_is_ts7260() ||
> +           board_is_ts7300() || board_is_ts7400()) {
> +               /* We use more reliable CPLD watchdog to perform the reset */
> +               __raw_writeb(0x5, TS72XX_WDT_FEED_PHYS_BASE);
> +               __raw_writeb(0x1, TS72XX_WDT_CONTROL_PHYS_BASE);
> +       } else {
> +               /* Set then clear the SWRST bit to initiate a software reset */
> +               ep93xx_devcfg_set_bits(EP93XX_SYSCON_DEVCFG_SWRST);
> +               ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_SWRST);
> +       }

It would be nicer to introduce a function pointer here, that's filled
in by the ts72xx.c machine_init function but NULL by default:


extern void (*ep93xx_reset)(void);
...

arch_reset():

   local_irq_disable();

   if (ep93xx_reset) {
      ep93xx_reset();
   } else {
      ... current SWRST code ...
   }
...



Otherwise, other boards would add another if statement, any new ts72xx
board would need to modify the soc-common header, etc.


-Olof