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 --- include/asm-mips/sibyte/sb1250.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/asm-mips/sibyte') diff --git a/include/asm-mips/sibyte/sb1250.h b/include/asm-mips/sibyte/sb1250.h index a474c29cd70..b09e16c93ca 100644 --- a/include/asm-mips/sibyte/sb1250.h +++ b/include/asm-mips/sibyte/sb1250.h @@ -45,8 +45,8 @@ extern unsigned int soc_type; extern unsigned int periph_rev; extern unsigned int zbbus_mhz; +extern void sb1250_hpt_setup(void); extern void sb1250_time_init(void); -extern unsigned long sb1250_gettimeoffset(void); extern void sb1250_mask_irq(int cpu, int irq); extern void sb1250_unmask_irq(int cpu, int irq); extern void sb1250_smp_finish(void); -- cgit v1.2.3