diff options
Diffstat (limited to 'arch/arm/mach-ixp2000/core.c')
| -rw-r--r-- | arch/arm/mach-ixp2000/core.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/arch/arm/mach-ixp2000/core.c b/arch/arm/mach-ixp2000/core.c index 4f3c3d5c781..fc0555596d6 100644 --- a/arch/arm/mach-ixp2000/core.c +++ b/arch/arm/mach-ixp2000/core.c @@ -162,12 +162,13 @@ void __init ixp2000_map_io(void) static unsigned ticks_per_jiffy; static unsigned ticks_per_usec; static unsigned next_jiffy_time; +static volatile unsigned long *missing_jiffy_timer_csr; unsigned long ixp2000_gettimeoffset (void) { unsigned long offset; - offset = next_jiffy_time - *IXP2000_T4_CSR; + offset = next_jiffy_time - *missing_jiffy_timer_csr; return offset / ticks_per_usec; } @@ -179,7 +180,7 @@ static int ixp2000_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) /* clear timer 1 */ ixp2000_reg_write(IXP2000_T1_CLR, 1); - while ((next_jiffy_time - *IXP2000_T4_CSR) > ticks_per_jiffy) { + while ((next_jiffy_time - *missing_jiffy_timer_csr) > ticks_per_jiffy) { timer_tick(regs); next_jiffy_time -= ticks_per_jiffy; } @@ -197,20 +198,37 @@ static struct irqaction ixp2000_timer_irq = { void __init ixp2000_init_time(unsigned long tick_rate) { - ixp2000_reg_write(IXP2000_T1_CLR, 0); - ixp2000_reg_write(IXP2000_T4_CLR, 0); - ticks_per_jiffy = (tick_rate + HZ/2) / HZ; ticks_per_usec = tick_rate / 1000000; + /* + * We use timer 1 as our timer interrupt. + */ + ixp2000_reg_write(IXP2000_T1_CLR, 0); ixp2000_reg_write(IXP2000_T1_CLD, ticks_per_jiffy - 1); ixp2000_reg_write(IXP2000_T1_CTL, (1 << 7)); /* - * We use T4 as a monotonic counter to track missed jiffies + * We use a second timer as a monotonic counter for tracking + * missed jiffies. The IXP2000 has four timers, but if we're + * on an A-step IXP2800, timer 2 and 3 don't work, so on those + * chips we use timer 4. Timer 4 is the only timer that can + * be used for the watchdog, so we use timer 2 if we're on a + * non-buggy chip. */ - ixp2000_reg_write(IXP2000_T4_CLD, -1); - ixp2000_reg_write(IXP2000_T4_CTL, (1 << 7)); + if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) { + printk(KERN_INFO "Enabling IXP2800 erratum #25 workaround\n"); + + ixp2000_reg_write(IXP2000_T4_CLR, 0); + ixp2000_reg_write(IXP2000_T4_CLD, -1); + ixp2000_reg_write(IXP2000_T4_CTL, (1 << 7)); + missing_jiffy_timer_csr = IXP2000_T4_CSR; + } else { + ixp2000_reg_write(IXP2000_T2_CLR, 0); + ixp2000_reg_write(IXP2000_T2_CLD, -1); + ixp2000_reg_write(IXP2000_T2_CTL, (1 << 7)); + missing_jiffy_timer_csr = IXP2000_T2_CSR; + } next_jiffy_time = 0xffffffff; /* register for interrupt */ |