From: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Date: Thu, 23 Oct 2008 09:23:08 +0000 (+0200)
Subject: avr32: Scale loops_per_jiffy when cpu frequency changes
X-Git-Tag: v3.12-rc1~17528^2^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e3f91ca48162c3eb70450314a4d09384fccb92fa;p=kernel%2Fkernel-generic.git

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>
---

diff --git a/arch/avr32/mach-at32ap/cpufreq.c b/arch/avr32/mach-at32ap/cpufreq.c
index d84efe4..024c586 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);