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>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/avr32/mach-at32ap/cpufreq.c b/arch/avr32/mach-at32ap/cpufreq.c
index d84efe4984ab..024c586e936c 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);