[PATCH] staging: greybus/timesync: avoid divide by zero on X86 Qemu

From: Bryan O'Donoghue
Date: Mon Sep 26 2016 - 12:57:48 EST


A system configured without CONFIG_CPUFREQ will return 0 for cpufreq_get().
greybus-timesync can subsequently then do a divide-by-zero as result. This
patch fixes by checking for a zero return value from cpufreq_get() and
setting to a default value of 19.2MHz.

Reported-by: Rui Miguel Silva <rmfrfs@xxxxxxxxx>
Signed-off-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
---
drivers/staging/greybus/timesync_platform.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/greybus/timesync_platform.c b/drivers/staging/greybus/timesync_platform.c
index 50e8883..113f3d6 100644
--- a/drivers/staging/greybus/timesync_platform.c
+++ b/drivers/staging/greybus/timesync_platform.c
@@ -20,6 +20,8 @@
#include "greybus.h"
#include "arche_platform.h"

+#define DEFAULT_FRAMETIME_CLOCK_HZ 19200000
+
static u32 gb_timesync_clock_frequency;
int (*arche_platform_change_state_cb)(enum arche_platform_state state,
struct gb_timesync_svc *pdata);
@@ -32,8 +34,11 @@ u64 gb_timesync_platform_get_counter(void)

u32 gb_timesync_platform_get_clock_rate(void)
{
- if (unlikely(!gb_timesync_clock_frequency))
- return cpufreq_get(0);
+ if (unlikely(!gb_timesync_clock_frequency)) {
+ gb_timesync_clock_frequency = cpufreq_get(0);
+ if (!gb_timesync_clock_frequency)
+ gb_timesync_clock_frequency = DEFAULT_FRAMETIME_CLOCK_HZ;
+ }

return gb_timesync_clock_frequency;
}
--
2.7.4