target/linux/generic/patches-3.3/992-mpcore_wdt_fix_watchdog_counter_loading.patch

   1 Although the commit "98af057092f8f0dabe63c5df08adc2bbfbddb1d2
   2  ARM: 6126/1: ARM mpcore_wdt: fix build failure and other fixes"
   3 resolved long standing mpcore_wdt driver build problems, it
   4 introduced an error in the relationship between the MPcore watchdog
   5 timer clock rate and mpcore_margin, "MPcore timer margin in seconds",
   6 such that watchdog timeouts are now arbitrary rather than the number
   7 of seconds specified by mpcore_margin.
   8
   9 This change restores mpcore_wdt_keepalive() to its equivalent
  10 implementation prior to commit 98af057 such that watchdog timeouts now
  11 occur as specified by mpcore_margin.
  12
  13 The variable 'mpcore_timer_rate' which caused that build failure was
  14 replaced by 'twd_timer_rate'. Adding exported function to obtain
  15 'twd_timer_rate' value in mpcore_wdt driver.
  16
  17 MPCORE_WATCHDOG needed to build 'mpcore_wdt' already depends on
  18 HAVE_ARM_TWD needed to build 'smp_twd', so from the point of view of
  19 'mpcore_wdt' driver the exported function will always exist.
  20
  21 Signed-off-by: Valentine Barshak <vbarshak@mvista.com>
  22 Signed-off-by: Vitaly Kuzmichev <vkuzmichev@mvista.com>
  23 ---
  24
  25  arch/arm/include/asm/smp_twd.h |    1 +
  26  arch/arm/kernel/smp_twd.c      |    7 +++++++
  27  drivers/watchdog/mpcore_wdt.c  |    4 +---
  28  3 files changed, 9 insertions(+), 3 deletions(-)
  29
  30 --- a/arch/arm/include/asm/smp_twd.h
  31 +++ b/arch/arm/include/asm/smp_twd.h
  32 @@ -24,5 +24,6 @@ extern void __iomem *twd_base;
  33
  34  void twd_timer_setup(struct clock_event_device *);
  35  void twd_timer_stop(struct clock_event_device *);
  36 +unsigned long twd_timer_get_rate(void);
  37
  38  #endif
  39 --- a/arch/arm/kernel/smp_twd.c
  40 +++ b/arch/arm/kernel/smp_twd.c
  41 @@ -268,3 +268,10 @@ void __cpuinit twd_timer_setup(struct cl
  42                                         0xf, 0xffffffff);
  43         enable_percpu_irq(clk->irq, 0);
  44  }
  45 +
  46 +/* Needed by mpcore_wdt */
  47 +unsigned long twd_timer_get_rate(void)
  48 +{
  49 +       return twd_timer_rate;
  50 +}
  51 +EXPORT_SYMBOL_GPL(twd_timer_get_rate);
  52 --- a/drivers/watchdog/mpcore_wdt.c
  53 +++ b/drivers/watchdog/mpcore_wdt.c
  54 @@ -99,9 +99,7 @@ static void mpcore_wdt_keepalive(struct
  55
  56         spin_lock(&wdt_lock);
  57         /* Assume prescale is set to 256 */
  58 -       count =  __raw_readl(wdt->base + TWD_WDOG_COUNTER);
  59 -       count = (0xFFFFFFFFU - count) * (HZ / 5);
  60 -       count = (count / 256) * mpcore_margin;
  61 +       count = (twd_timer_get_rate() / 256) * mpcore_margin;
  62
  63         /* Reload the counter */
  64         writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);