AMD Elan SC520 cpufreq driver

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diff -urpN linux-2.6.9/arch/i386/kernel/cpu/cpufreq/sc520_freq.c /tmp/linux-2.6.9/arch/i386/kernel/cpu/cpufreq/sc520_freq.c
@@ -17,7 +17,6 @@
 #include <linux/module.h>
 #include <linux/init.h>
 
-#include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/cpufreq.h>
 

@@ -25,11 +24,13 @@
 #include <asm/timex.h>
 #include <asm/io.h>
 
-#define MMCR_BASE       0xfffef000      /* The default base address */
+#define MMCR_BASE	0xfffef000	/* The default base address */
 #define OFFS_CPUCTL	0x2   /* CPU Control Register */
 
 static __u8 __iomem *cpuctl;
 
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "sc520_freq", msg)
+
 static struct cpufreq_frequency_table sc520_freq_table[] = {
 	{0x01,	100000},
 	{0x02,	133000},

@@ -53,7 +54,8 @@ static unsigned int sc520_freq_get_cpu_f
 static void sc520_freq_set_cpu_state (unsigned int state)
 {
 
-	struct cpufreq_freqs    freqs;
+	struct cpufreq_freqs	freqs;
+	u8 clockspeed_reg;
 
 	freqs.old = sc520_freq_get_cpu_frequency(0);
 	freqs.new = sc520_freq_table[state].frequency;

@@ -61,10 +63,15 @@ static void sc520_freq_set_cpu_state (un
 
 	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 
-	printk(KERN_INFO "sc520_freq: attempting to set frequency to %i kHz\n",
+	dprintk("attempting to set frequency to %i kHz\n",
 			sc520_freq_table[state].frequency);
 
-	*cpuctl = sc520_freq_table[state].index;
+	local_irq_disable();
+
+	clockspeed_reg = *cpuctl & ~0x03;
+	*cpuctl = clockspeed_reg | sc520_freq_table[state].index;
+
+	local_irq_enable();
 
 	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 };

@@ -105,14 +112,14 @@ static int sc520_freq_cpu_init(struct cp
 
 	/* cpuinfo and default policy values */
 	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
-	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+	policy->cpuinfo.transition_latency = 1000; /* 1ms */
 	policy->cur = sc520_freq_get_cpu_frequency(0);
 
 	result = cpufreq_frequency_table_cpuinfo(policy, sc520_freq_table);
 	if (result)
 		return (result);
 
-        cpufreq_frequency_table_get_attr(sc520_freq_table, policy->cpu);
+	cpufreq_frequency_table_get_attr(sc520_freq_table, policy->cpu);
 
 	return 0;
 }

@@ -148,10 +155,10 @@ static int __init sc520_freq_init(void)
 	struct cpuinfo_x86 *c = cpu_data;
 
 	/* Test if we have the right hardware */
-	if (c->x86_vendor != X86_VENDOR_AMD ||
-		c->x86 != 4 || c->x86_model != 9) {
-		printk(KERN_INFO "sc520_freq: error: no Elan SC520 processor found!\n");
-                return -ENODEV;
+	if(c->x86_vendor != X86_VENDOR_AMD ||
+				c->x86 != 4 || c->x86_model != 9) {
+		dprintk("no Elan SC520 processor found!\n");
+		return -ENODEV;
 	}
 	cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
 	if(!cpuctl) {

Index: 2.6.12-rc2/include/linux/cpufreq.h
===================================================================
@@ -49,7 +49,7 @@
 /* Frequency values here are CPU kHz so that hardware which doesn't run 
  * with some frequencies can complain without having to guess what per 
  * cent / per mille means. 
- * Maximum transition latency is in microseconds - if it's unknown,
+ * Maximum transition latency is in nanoseconds - if it's unknown,
  * CPUFREQ_ETERNAL shall be used.
  */