Commit 4d2b1125 authored by David Daney's avatar David Daney Committed by Ralf Baechle
Browse files

MIPS: Don't overflow cevt-r4k.c calculations at high clock rates.



The 'mult' element of struct clock_event_device must never be wider
than 32-bits.  If it were, it would get truncated when used by
clockevent_delta2ns() when this calls do_div().

We can meet this requirement by using clockevent_set_clock() to set
the MULT and SHIFT values.
Signed-off-by: default avatarDavid Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1253/

Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 6165df98
...@@ -163,7 +163,6 @@ int c0_compare_int_usable(void) ...@@ -163,7 +163,6 @@ int c0_compare_int_usable(void)
int __cpuinit r4k_clockevent_init(void) int __cpuinit r4k_clockevent_init(void)
{ {
uint64_t mips_freq = mips_hpt_frequency;
unsigned int cpu = smp_processor_id(); unsigned int cpu = smp_processor_id();
struct clock_event_device *cd; struct clock_event_device *cd;
unsigned int irq; unsigned int irq;
...@@ -188,9 +187,9 @@ int __cpuinit r4k_clockevent_init(void) ...@@ -188,9 +187,9 @@ int __cpuinit r4k_clockevent_init(void)
cd->name = "MIPS"; cd->name = "MIPS";
cd->features = CLOCK_EVT_FEAT_ONESHOT; cd->features = CLOCK_EVT_FEAT_ONESHOT;
clockevent_set_clock(cd, mips_hpt_frequency);
/* Calculate the min / max delta */ /* Calculate the min / max delta */
cd->mult = div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32);
cd->shift = 32;
cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
cd->min_delta_ns = clockevent_delta2ns(0x300, cd); cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
......
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