1 files changed, 309 insertions, 0 deletions
diff --git a/drivers/cpufreq/elanfreq.c b/drivers/cpufreq/elanfreq.c
new file mode 100644
index 000000000000..c587db472a75
--- /dev/null
+++ b/drivers/cpufreq/elanfreq.c
@@ -0,0 +1,309 @@
+/*
+ *	elanfreq:	cpufreq driver for the AMD ELAN family
+ *
+ *	(c) Copyright 2002 Robert Schwebel <r.schwebel@pengutronix.de>
+ *
+ *	Parts of this code are (c) Sven Geggus <sven@geggus.net>
+ *
+ *      All Rights Reserved.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *	2002-02-13: - initial revision for 2.4.18-pre9 by Robert Schwebel
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/delay.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <linux/timex.h>
+#include <linux/io.h>
+
+#define REG_CSCIR 0x22		/* Chip Setup and Control Index Register    */
+#define REG_CSCDR 0x23		/* Chip Setup and Control Data  Register    */
+
+/* Module parameter */
+static int max_freq;
+
+struct s_elan_multiplier {
+	int clock;		/* frequency in kHz                         */
+	int val40h;		/* PMU Force Mode register                  */
+	int val80h;		/* CPU Clock Speed Register                 */
+};
+
+/*
+ * It is important that the frequencies
+ * are listed in ascending order here!
+ */
+static struct s_elan_multiplier elan_multiplier[] = {
+	{1000,	0x02,	0x18},
+	{2000,	0x02,	0x10},
+	{4000,	0x02,	0x08},
+	{8000,	0x00,	0x00},
+	{16000,	0x00,	0x02},
+	{33000,	0x00,	0x04},
+	{66000,	0x01,	0x04},
+	{99000,	0x01,	0x05}
+};
+
+static struct cpufreq_frequency_table elanfreq_table[] = {
+	{0,	1000},
+	{1,	2000},
+	{2,	4000},
+	{3,	8000},
+	{4,	16000},
+	{5,	33000},
+	{6,	66000},
+	{7,	99000},
+	{0,	CPUFREQ_TABLE_END},
+};
+
+
+/**
+ *	elanfreq_get_cpu_frequency: determine current cpu speed
+ *
+ *	Finds out at which frequency the CPU of the Elan SOC runs
+ *	at the moment. Frequencies from 1 to 33 MHz are generated
+ *	the normal way, 66 and 99 MHz are called "Hyperspeed Mode"
+ *	and have the rest of the chip running with 33 MHz.
+ */
+
+static unsigned int elanfreq_get_cpu_frequency(unsigned int cpu)
+{
+	u8 clockspeed_reg;    /* Clock Speed Register */
+
+	local_irq_disable();
+	outb_p(0x80, REG_CSCIR);
+	clockspeed_reg = inb_p(REG_CSCDR);
+	local_irq_enable();
+
+	if ((clockspeed_reg & 0xE0) == 0xE0)
+		return 0;
+
+	/* Are we in CPU clock multiplied mode (66/99 MHz)? */
+	if ((clockspeed_reg & 0xE0) == 0xC0) {
+		if ((clockspeed_reg & 0x01) == 0)
+			return 66000;
+		else
+			return 99000;
+	}
+
+	/* 33 MHz is not 32 MHz... */
+	if ((clockspeed_reg & 0xE0) == 0xA0)
+		return 33000;
+
+	return (1<<((clockspeed_reg & 0xE0) >> 5)) * 1000;
+}
+
+
+/**
+ *	elanfreq_set_cpu_frequency: Change the CPU core frequency
+ *	@cpu: cpu number
+ *	@freq: frequency in kHz
+ *
+ *	This function takes a frequency value and changes the CPU frequency
+ *	according to this. Note that the frequency has to be checked by
+ *	elanfreq_validatespeed() for correctness!
+ *
+ *	There is no return value.
+ */
+
+static void elanfreq_set_cpu_state(unsigned int state)
+{
+	struct cpufreq_freqs    freqs;
+
+	freqs.old = elanfreq_get_cpu_frequency(0);
+	freqs.new = elan_multiplier[state].clock;
+	freqs.cpu = 0; /* elanfreq.c is UP only driver */
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	printk(KERN_INFO "elanfreq: attempting to set frequency to %i kHz\n",
+			elan_multiplier[state].clock);
+
+
+	/*
+	 * Access to the Elan's internal registers is indexed via
+	 * 0x22: Chip Setup & Control Register Index Register (CSCI)
+	 * 0x23: Chip Setup & Control Register Data  Register (CSCD)
+	 *
+	 */
+
+	/*
+	 * 0x40 is the Power Management Unit's Force Mode Register.
+	 * Bit 6 enables Hyperspeed Mode (66/100 MHz core frequency)
+	 */
+
+	local_irq_disable();
+	outb_p(0x40, REG_CSCIR);		/* Disable hyperspeed mode */
+	outb_p(0x00, REG_CSCDR);
+	local_irq_enable();		/* wait till internal pipelines and */
+	udelay(1000);			/* buffers have cleaned up          */
+
+	local_irq_disable();
+
+	/* now, set the CPU clock speed register (0x80) */
+	outb_p(0x80, REG_CSCIR);
+	outb_p(elan_multiplier[state].val80h, REG_CSCDR);
+
+	/* now, the hyperspeed bit in PMU Force Mode Register (0x40) */
+	outb_p(0x40, REG_CSCIR);
+	outb_p(elan_multiplier[state].val40h, REG_CSCDR);
+	udelay(10000);
+	local_irq_enable();
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+};
+
+
+/**
+ *	elanfreq_validatespeed: test if frequency range is valid
+ *	@policy: the policy to validate
+ *
+ *	This function checks if a given frequency range in kHz is valid
+ *	for the hardware supported by the driver.
+ */
+
+static int elanfreq_verify(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, &elanfreq_table[0]);
+}
+
+static int elanfreq_target(struct cpufreq_policy *policy,
+			    unsigned int target_freq,
+			    unsigned int relation)
+{
+	unsigned int newstate = 0;
+
+	if (cpufreq_frequency_table_target(policy, &elanfreq_table[0],
+				target_freq, relation, &newstate))
+		return -EINVAL;
+
+	elanfreq_set_cpu_state(newstate);
+
+	return 0;
+}
+
+
+/*
+ *	Module init and exit code
+ */
+
+static int elanfreq_cpu_init(struct cpufreq_policy *policy)
+{
+	struct cpuinfo_x86 *c = &cpu_data(0);
+	unsigned int i;
+	int result;
+
+	/* capability check */
+	if ((c->x86_vendor != X86_VENDOR_AMD) ||
+	    (c->x86 != 4) || (c->x86_model != 10))
+		return -ENODEV;
+
+	/* max freq */
+	if (!max_freq)
+		max_freq = elanfreq_get_cpu_frequency(0);
+
+	/* table init */
+	for (i = 0; (elanfreq_table[i].frequency != CPUFREQ_TABLE_END); i++) {
+		if (elanfreq_table[i].frequency > max_freq)
+			elanfreq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+	}
+
+	/* cpuinfo and default policy values */
+	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+	policy->cur = elanfreq_get_cpu_frequency(0);
+
+	result = cpufreq_frequency_table_cpuinfo(policy, elanfreq_table);
+	if (result)
+		return result;
+
+	cpufreq_frequency_table_get_attr(elanfreq_table, policy->cpu);
+	return 0;
+}
+
+
+static int elanfreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	return 0;
+}
+
+
+#ifndef MODULE
+/**
+ * elanfreq_setup - elanfreq command line parameter parsing
+ *
+ * elanfreq command line parameter.  Use:
+ *  elanfreq=66000
+ * to set the maximum CPU frequency to 66 MHz. Note that in
+ * case you do not give this boot parameter, the maximum
+ * frequency will fall back to _current_ CPU frequency which
+ * might be lower. If you build this as a module, use the
+ * max_freq module parameter instead.
+ */
+static int __init elanfreq_setup(char *str)
+{
+	max_freq = simple_strtoul(str, &str, 0);
+	printk(KERN_WARNING "You're using the deprecated elanfreq command line option. Use elanfreq.max_freq instead, please!\n");
+	return 1;
+}
+__setup("elanfreq=", elanfreq_setup);
+#endif
+
+
+static struct freq_attr *elanfreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+
+static struct cpufreq_driver elanfreq_driver = {
+	.get		= elanfreq_get_cpu_frequency,
+	.verify		= elanfreq_verify,
+	.target		= elanfreq_target,
+	.init		= elanfreq_cpu_init,
+	.exit		= elanfreq_cpu_exit,
+	.name		= "elanfreq",
+	.owner		= THIS_MODULE,
+	.attr		= elanfreq_attr,
+};
+
+
+static int __init elanfreq_init(void)
+{
+	struct cpuinfo_x86 *c = &cpu_data(0);
+
+	/* Test if we have the right hardware */
+	if ((c->x86_vendor != X86_VENDOR_AMD) ||
+		(c->x86 != 4) || (c->x86_model != 10)) {
+		printk(KERN_INFO "elanfreq: error: no Elan processor found!\n");
+		return -ENODEV;
+	}
+	return cpufreq_register_driver(&elanfreq_driver);
+}
+
+
+static void __exit elanfreq_exit(void)
+{
+	cpufreq_unregister_driver(&elanfreq_driver);
+}
+
+
+module_param(max_freq, int, 0444);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, "
+		"Sven Geggus <sven@geggus.net>");
+MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
+
+module_init(elanfreq_init);
+module_exit(elanfreq_exit);