target/linux/atheros/patches-2.6.30/002-mips_clocksource_init_war.patch

   1 --- a/arch/mips/kernel/cevt-r4k.c
   2 +++ b/arch/mips/kernel/cevt-r4k.c
   3 @@ -15,6 +15,22 @@
   4  #include <asm/cevt-r4k.h>
   5
   6  /*
   7 + * Compare interrupt can be routed and latched outside the core,
   8 + * so a single execution hazard barrier may not be enough to give
   9 + * it time to clear as seen in the Cause register.  4 time the
  10 + * pipeline depth seems reasonably conservative, and empirically
  11 + * works better in configurations with high CPU/bus clock ratios.
  12 + */
  13 +
  14 +#define compare_change_hazard() \
  15 +       do { \
  16 +               irq_disable_hazard(); \
  17 +               irq_disable_hazard(); \
  18 +               irq_disable_hazard(); \
  19 +               irq_disable_hazard(); \
  20 +       } while (0)
  21 +
  22 +/*
  23   * The SMTC Kernel for the 34K, 1004K, et. al. replaces several
  24   * of these routines with SMTC-specific variants.
  25   */
  26 @@ -30,6 +46,7 @@ static int mips_next_event(unsigned long
  27         cnt = read_c0_count();
  28         cnt += delta;
  29         write_c0_compare(cnt);
  30 +       compare_change_hazard();
  31         res = ((int)(read_c0_count() - cnt) > 0) ? -ETIME : 0;
  32         return res;
  33  }
  34 @@ -99,22 +116,6 @@ static int c0_compare_int_pending(void)
  35         return (read_c0_cause() >> cp0_compare_irq) & 0x100;
  36  }
  37
  38 -/*
  39 - * Compare interrupt can be routed and latched outside the core,
  40 - * so a single execution hazard barrier may not be enough to give
  41 - * it time to clear as seen in the Cause register.  4 time the
  42 - * pipeline depth seems reasonably conservative, and empirically
  43 - * works better in configurations with high CPU/bus clock ratios.
  44 - */
  45 -
  46 -#define compare_change_hazard() \
  47 -       do { \
  48 -               irq_disable_hazard(); \
  49 -               irq_disable_hazard(); \
  50 -               irq_disable_hazard(); \
  51 -               irq_disable_hazard(); \
  52 -       } while (0)
  53 -
  54  int c0_compare_int_usable(void)
  55  {
  56         unsigned int delta;