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

arch/mips/kernel/cevt-r4k.c

+2 −3
Original line number Diff line number Diff line
@@ -163,7 +163,6 @@ int c0_compare_int_usable(void) 


int __cpuinit r4k_clockevent_init(void)

{

	uint64_t mips_freq = mips_hpt_frequency;

	unsigned int cpu = smp_processor_id();

	struct clock_event_device *cd;

	unsigned int irq;
@@ -188,9 +187,9 @@ int __cpuinit r4k_clockevent_init(void) 
	cd->name		= "MIPS";

	cd->features		= CLOCK_EVT_FEAT_ONESHOT;



	clockevent_set_clock(cd, mips_hpt_frequency);



	/* 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->min_delta_ns	= clockevent_delta2ns(0x300, cd);