diff options
Diffstat (limited to 'drivers/cpufreq/powernow-k6.c')
| -rw-r--r-- | drivers/cpufreq/powernow-k6.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c new file mode 100644 index 00000000000..b3379d6a5c5 --- /dev/null +++ b/drivers/cpufreq/powernow-k6.c @@ -0,0 +1,261 @@ +/* + * This file was based upon code in Powertweak Linux (http://powertweak.sf.net) + * (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä, + * Dominik Brodowski. + * + * Licensed under the terms of the GNU GPL License version 2. + * + * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/cpufreq.h> +#include <linux/ioport.h> +#include <linux/timex.h> +#include <linux/io.h> + +#include <asm/msr.h> + +#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long + as it is unused */ + +#define PFX "powernow-k6: " +static unsigned int busfreq; /* FSB, in 10 kHz */ +static unsigned int max_multiplier; + + +/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */ +static struct cpufreq_frequency_table clock_ratio[] = { + {45, /* 000 -> 4.5x */ 0}, + {50, /* 001 -> 5.0x */ 0}, + {40, /* 010 -> 4.0x */ 0}, + {55, /* 011 -> 5.5x */ 0}, + {20, /* 100 -> 2.0x */ 0}, + {30, /* 101 -> 3.0x */ 0}, + {60, /* 110 -> 6.0x */ 0}, + {35, /* 111 -> 3.5x */ 0}, + {0, CPUFREQ_TABLE_END} +}; + + +/** + * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier + * + * Returns the current setting of the frequency multiplier. Core clock + * speed is frequency of the Front-Side Bus multiplied with this value. + */ +static int powernow_k6_get_cpu_multiplier(void) +{ + u64 invalue = 0; + u32 msrval; + + msrval = POWERNOW_IOPORT + 0x1; + wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ + invalue = inl(POWERNOW_IOPORT + 0x8); + msrval = POWERNOW_IOPORT + 0x0; + wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ + + return clock_ratio[(invalue >> 5)&7].index; +} + + +/** + * powernow_k6_set_state - set the PowerNow! multiplier + * @best_i: clock_ratio[best_i] is the target multiplier + * + * Tries to change the PowerNow! multiplier + */ +static void powernow_k6_set_state(unsigned int best_i) +{ + unsigned long outvalue = 0, invalue = 0; + unsigned long msrval; + struct cpufreq_freqs freqs; + + if (clock_ratio[best_i].index > max_multiplier) { + printk(KERN_ERR PFX "invalid target frequency\n"); + return; + } + + freqs.old = busfreq * powernow_k6_get_cpu_multiplier(); + freqs.new = busfreq * clock_ratio[best_i].index; + freqs.cpu = 0; /* powernow-k6.c is UP only driver */ + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + /* we now need to transform best_i to the BVC format, see AMD#23446 */ + + outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5); + + msrval = POWERNOW_IOPORT + 0x1; + wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ + invalue = inl(POWERNOW_IOPORT + 0x8); + invalue = invalue & 0xf; + outvalue = outvalue | invalue; + outl(outvalue , (POWERNOW_IOPORT + 0x8)); + msrval = POWERNOW_IOPORT + 0x0; + wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return; +} + + +/** + * powernow_k6_verify - verifies a new CPUfreq policy + * @policy: new policy + * + * Policy must be within lowest and highest possible CPU Frequency, + * and at least one possible state must be within min and max. + */ +static int powernow_k6_verify(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, &clock_ratio[0]); +} + + +/** + * powernow_k6_setpolicy - sets a new CPUFreq policy + * @policy: new policy + * @target_freq: the target frequency + * @relation: how that frequency relates to achieved frequency + * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H) + * + * sets a new CPUFreq policy + */ +static int powernow_k6_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + unsigned int newstate = 0; + + if (cpufreq_frequency_table_target(policy, &clock_ratio[0], + target_freq, relation, &newstate)) + return -EINVAL; + + powernow_k6_set_state(newstate); + + return 0; +} + + +static int powernow_k6_cpu_init(struct cpufreq_policy *policy) +{ + unsigned int i, f; + int result; + + if (policy->cpu != 0) + return -ENODEV; + + /* get frequencies */ + max_multiplier = powernow_k6_get_cpu_multiplier(); + busfreq = cpu_khz / max_multiplier; + + /* table init */ + for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { + f = clock_ratio[i].index; + if (f > max_multiplier) + clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID; + else + clock_ratio[i].frequency = busfreq * f; + } + + /* cpuinfo and default policy values */ + policy->cpuinfo.transition_latency = 200000; + policy->cur = busfreq * max_multiplier; + + result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio); + if (result) + return result; + + cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu); + + return 0; +} + + +static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) +{ + unsigned int i; + for (i = 0; i < 8; i++) { + if (i == max_multiplier) + powernow_k6_set_state(i); + } + cpufreq_frequency_table_put_attr(policy->cpu); + return 0; +} + +static unsigned int powernow_k6_get(unsigned int cpu) +{ + unsigned int ret; + ret = (busfreq * powernow_k6_get_cpu_multiplier()); + return ret; +} + +static struct freq_attr *powernow_k6_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + +static struct cpufreq_driver powernow_k6_driver = { + .verify = powernow_k6_verify, + .target = powernow_k6_target, + .init = powernow_k6_cpu_init, + .exit = powernow_k6_cpu_exit, + .get = powernow_k6_get, + .name = "powernow-k6", + .owner = THIS_MODULE, + .attr = powernow_k6_attr, +}; + + +/** + * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver + * + * Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported + * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero + * on success. + */ +static int __init powernow_k6_init(void) +{ + struct cpuinfo_x86 *c = &cpu_data(0); + + if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) || + ((c->x86_model != 12) && (c->x86_model != 13))) + return -ENODEV; + + if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) { + printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n"); + return -EIO; + } + + if (cpufreq_register_driver(&powernow_k6_driver)) { + release_region(POWERNOW_IOPORT, 16); + return -EINVAL; + } + + return 0; +} + + +/** + * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support + * + * Unregisters AMD K6-2+ / K6-3+ PowerNow! support. + */ +static void __exit powernow_k6_exit(void) +{ + cpufreq_unregister_driver(&powernow_k6_driver); + release_region(POWERNOW_IOPORT, 16); +} + + +MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, " + "Dominik Brodowski <linux@brodo.de>"); +MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors."); +MODULE_LICENSE("GPL"); + +module_init(powernow_k6_init); +module_exit(powernow_k6_exit); |