diff options
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/elanfreq.c')
| -rw-r--r-- | arch/i386/kernel/cpu/cpufreq/elanfreq.c | 312 |
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); + |