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authorHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-10-23 11:23:08 +0200
committerHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-10-23 15:18:33 +0200
commite3f91ca48162c3eb70450314a4d09384fccb92fa (patch)
tree07da27300068cb64fcc7e79bcdb502359b668ff7 /arch
parent6090065663ba5daab82d116d3040dc924e8cf79f (diff)
avr32: Scale loops_per_jiffy when cpu frequency changes
The loops_per_jiffy variable isn't updated when cpufreq changes the CPU frequency. This could cause udelay() and friends to produce wrong delays. Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/avr32/mach-at32ap/cpufreq.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/avr32/mach-at32ap/cpufreq.c b/arch/avr32/mach-at32ap/cpufreq.c
index d84efe4984a..024c586e936 100644
--- a/arch/avr32/mach-at32ap/cpufreq.c
+++ b/arch/avr32/mach-at32ap/cpufreq.c
@@ -40,6 +40,9 @@ static unsigned int at32_get_speed(unsigned int cpu)
return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
}
+static unsigned int ref_freq;
+static unsigned long loops_per_jiffy_ref;
+
static int at32_set_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
@@ -61,8 +64,19 @@ static int at32_set_target(struct cpufreq_policy *policy,
freqs.cpu = 0;
freqs.flags = 0;
+ if (!ref_freq) {
+ ref_freq = freqs.old;
+ loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
+ }
+
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ if (freqs.old < freqs.new)
+ boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+ loops_per_jiffy_ref, ref_freq, freqs.new);
clk_set_rate(cpuclk, freq);
+ if (freqs.new < freqs.old)
+ boot_cpu_data.loops_per_jiffy = cpufreq_scale(
+ loops_per_jiffy_ref, ref_freq, freqs.new);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
pr_debug("cpufreq: set frequency %lu Hz\n", freq);