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authorRalf Baechle <ralf@linux-mips.org>2006-03-15 00:03:29 +0000
committerRalf Baechle <ralf@linux-mips.org>2006-03-18 16:59:30 +0000
commita904f7478561464f9fe74929b81fec237b6ff4c3 (patch)
tree6018ab25ea391aad0f4f33f0613e2b9fdbe36637 /arch/mips/sibyte/swarm
parent4308cb16286c96d980570cc5319173b524220c06 (diff)
[MIPS] Sibyte: Fix race in sb1250_gettimeoffset().
From Dave Johnson <djohnson+linuxmips@sw.starentnetworks.com>: sb1250_gettimeoffset() simply reads the current cpu 0 timer remaining value, however once this counter reaches 0 and the interrupt is raised, it immediately resets and begins to count down again. If sb1250_gettimeoffset() is called on cpu 1 via do_gettimeofday() after the timer has reset but prior to cpu 0 processing the interrupt and taking write_seqlock() in timer_interrupt() it will return a full value (or close to it) causing time to jump backwards 1ms. Once cpu 0 handles the interrupt and timer_interrupt() gets far enough along it will jump forward 1ms. Fix this problem by implementing mips_hpt_*() on sb1250 using a spare timer unrelated to the existing periodic interrupt timers. It runs at 1Mhz with a full 23bit counter. This eliminated the custom do_gettimeoffset() for sb1250 and allowed use of the generic fixed_rate_gettimeoffset() using mips_hpt_*() and timerhi/timerlo. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/sibyte/swarm')
-rw-r--r--arch/mips/sibyte/swarm/setup.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/mips/sibyte/swarm/setup.c b/arch/mips/sibyte/swarm/setup.c
index b614ca0ddb6..b661d2425a3 100644
--- a/arch/mips/sibyte/swarm/setup.c
+++ b/arch/mips/sibyte/swarm/setup.c
@@ -70,6 +70,12 @@ const char *get_system_type(void)
return "SiByte " SIBYTE_BOARD_NAME;
}
+void __init swarm_time_init(void)
+{
+ /* Setup HPT */
+ sb1250_hpt_setup();
+}
+
void __init swarm_timer_setup(struct irqaction *irq)
{
/*
@@ -109,6 +115,7 @@ void __init plat_setup(void)
panic_timeout = 5; /* For debug. */
+ board_time_init = swarm_time_init;
board_timer_setup = swarm_timer_setup;
board_be_handler = swarm_be_handler;