From 78d81f2f844b739b377817cfd279fb6067e191a7 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 6 Oct 2009 10:34:04 +0200 Subject: [S390] Fix enabled udelay for short delays. When udelay() gets called with a delay that would expire before the next clock event it reprograms the clock comparator. When the interrupt happens the clock comparator won't be resetted therefore the interrupt condition doesn't get cleared. The result is an endless timer interrupt loop until the next clock event would expire (stored in lowcore). So udelay() usually would wait much longer for small delays than it should. Fix this by disabling the local tick which makes sure that the clock comparator will be resetted when a timer interrupt happens. Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/lib/delay.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'arch/s390/lib/delay.c') diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index 97c1eca83cc2..2c3094342789 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -49,17 +49,22 @@ static void __udelay_disabled(unsigned long usecs) static void __udelay_enabled(unsigned long usecs) { unsigned long mask; - u64 end, time; + u64 clock_saved; + u64 end; mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT | PSW_MASK_IO; end = get_clock() + ((u64) usecs << 12); do { - time = end < S390_lowcore.clock_comparator ? - end : S390_lowcore.clock_comparator; - set_clock_comparator(time); + clock_saved = 0; + if (end < S390_lowcore.clock_comparator) { + clock_saved = local_tick_disable(); + set_clock_comparator(end); + } trace_hardirqs_on(); __load_psw_mask(mask); local_irq_disable(); + if (clock_saved) + local_tick_enable(clock_saved); } while (get_clock() < end); set_clock_comparator(S390_lowcore.clock_comparator); } -- cgit v1.2.2 From 0cd6a403e8f86bb24975e4c16ce640a063475515 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 6 Oct 2009 10:34:05 +0200 Subject: [S390] Provide arch specific mdelay implementation. Use an own implementation instead of the common code udelay loop. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/lib/delay.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'arch/s390/lib/delay.c') diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index 2c3094342789..752b362bf651 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -25,13 +25,13 @@ void __delay(unsigned long loops) asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); } -static void __udelay_disabled(unsigned long usecs) +static void __udelay_disabled(unsigned long long usecs) { unsigned long mask, cr0, cr0_saved; u64 clock_saved; clock_saved = local_tick_disable(); - set_clock_comparator(get_clock() + ((u64) usecs << 12)); + set_clock_comparator(get_clock() + (usecs << 12)); __ctl_store(cr0_saved, 0, 0); cr0 = (cr0_saved & 0xffff00e0) | 0x00000800; __ctl_load(cr0 , 0, 0); @@ -46,14 +46,14 @@ static void __udelay_disabled(unsigned long usecs) set_clock_comparator(S390_lowcore.clock_comparator); } -static void __udelay_enabled(unsigned long usecs) +static void __udelay_enabled(unsigned long long usecs) { unsigned long mask; u64 clock_saved; u64 end; mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT | PSW_MASK_IO; - end = get_clock() + ((u64) usecs << 12); + end = get_clock() + (usecs << 12); do { clock_saved = 0; if (end < S390_lowcore.clock_comparator) { @@ -72,7 +72,7 @@ static void __udelay_enabled(unsigned long usecs) /* * Waits for 'usecs' microseconds using the TOD clock comparator. */ -void __udelay(unsigned long usecs) +void __udelay(unsigned long long usecs) { unsigned long flags; @@ -106,11 +106,11 @@ EXPORT_SYMBOL(__udelay); * Simple udelay variant. To be used on startup and reboot * when the interrupt handler isn't working. */ -void udelay_simple(unsigned long usecs) +void udelay_simple(unsigned long long usecs) { u64 end; - end = get_clock() + ((u64) usecs << 12); + end = get_clock() + (usecs << 12); while (get_clock() < end) cpu_relax(); } -- cgit v1.2.2