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authorLennert Buytenhek <buytenh@org.rmk.(none)>2005-06-20 18:51:07 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-06-20 18:51:07 +0100
commite4fe19819ef32950541503042f32e71b67edffc7 (patch)
tree57c68008ba8c3b3a9f6ab8950c620175e9405569 /drivers/char
parentc0da085ad2e6b1419b8a7439538f7f15eb5c4777 (diff)
[PATCH] ARM: 2701/1: free up ixp2000 timer 4 for the watchdog
Patch from Lennert Buytenhek The IXP2000 has four timers, but if we're on an A-step IXP2800, timer 2 and 3 don't work. We need two timers for timekeeping (one for the timer interrupt and one for tracking missed jiffies), so on early IXP2800s we have no other choice but to use timer 1 and 4 for that, but on all other IXP2000s we'd rather leave timer 4 free since that's the only timer we can use for the watchdog. So, on buggy IXP2000s (i.e. the A-step IXP2800) we use timer 4 for tracking missed jiffies, and on all all non-buggy IXP2000s (i.e. everything but the A-step IXP2800) we use timer 2. On a pre-production IXP2800, this patch should print these messages on boot: Enabling IXP2800 erratum #25 workaround Unable to use IXP2000 watchdog due to IXP2800 erratum #25 On any non-buggy IXP2800 (as well as on IXP2400s) you shouldn't see anything at all, and the watchdog should be usable again. Signed-off-by: Lennert Buytenhek Signed-off-by: Deepak Saxena Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/watchdog/ixp2000_wdt.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/char/watchdog/ixp2000_wdt.c b/drivers/char/watchdog/ixp2000_wdt.c
index ab659d37b4d..4e98c215e5b 100644
--- a/drivers/char/watchdog/ixp2000_wdt.c
+++ b/drivers/char/watchdog/ixp2000_wdt.c
@@ -192,7 +192,12 @@ static struct miscdevice ixp2000_wdt_miscdev =
static int __init ixp2000_wdt_init(void)
{
- wdt_tick_rate = (*IXP2000_T1_CLD * HZ)/ 256;;
+ if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
+ printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
+ return -EIO;
+ }
+
+ wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
return misc_register(&ixp2000_wdt_miscdev);
}