From a904f7478561464f9fe74929b81fec237b6ff4c3 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Wed, 15 Mar 2006 00:03:29 +0000 Subject: [MIPS] Sibyte: Fix race in sb1250_gettimeoffset(). From Dave Johnson : 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 --- arch/mips/sibyte/swarm/setup.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/mips/sibyte/swarm') diff --git a/arch/mips/sibyte/swarm/setup.c b/arch/mips/sibyte/swarm/setup.c index b614ca0..b661d24 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; -- cgit v1.1