aboutsummaryrefslogtreecommitdiff
path: root/arch/i386/kernel/cpu/cpufreq/elanfreq.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/cpu/cpufreq/elanfreq.c
downloadlinux-stericsson-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/elanfreq.c')
-rw-r--r--arch/i386/kernel/cpu/cpufreq/elanfreq.c312
1 files changed, 312 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/elanfreq.c b/arch/i386/kernel/cpu/cpufreq/elanfreq.c
new file mode 100644
index 000000000000..3f7caa4ae6d6
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/elanfreq.c
@@ -0,0 +1,312 @@
+/*
+ * 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/slab.h>
+#include <linux/delay.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <asm/timex.h>
+#include <asm/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!
+ */
+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;
+ 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->governor = CPUFREQ_DEFAULT_GOVERNOR;
+ 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;
+
+ /* 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);
+