/* * elanfreq: cpufreq driver for the AMD ELAN family * * (c) Copyright 2002 Robert Schwebel * * Parts of this code are (c) Sven Geggus * * 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 * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #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, 0, 1000}, {0, 1, 2000}, {0, 2, 4000}, {0, 3, 8000}, {0, 4, 16000}, {0, 5, 33000}, {0, 6, 66000}, {0, 7, 99000}, {0, 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; } static int elanfreq_target(struct cpufreq_policy *policy, unsigned int state) { /* * 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(); return 0; } /* * Module init and exit code */ static int elanfreq_cpu_init(struct cpufreq_policy *policy) { struct cpuinfo_x86 *c = &cpu_data(0); struct cpufreq_frequency_table *pos; /* 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 */ cpufreq_for_each_entry(pos, elanfreq_table) if (pos->frequency > max_freq) pos->frequency = CPUFREQ_ENTRY_INVALID; return cpufreq_table_validate_and_show(policy, elanfreq_table); } #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); pr_warn("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 cpufreq_driver elanfreq_driver = { .get = elanfreq_get_cpu_frequency, .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, .verify = cpufreq_generic_frequency_table_verify, .target_index = elanfreq_target, .init = elanfreq_cpu_init, .name = "elanfreq", .attr = cpufreq_generic_attr, }; static const struct x86_cpu_id elan_id[] = { { X86_VENDOR_AMD, 4, 10, }, {} }; MODULE_DEVICE_TABLE(x86cpu, elan_id); static int __init elanfreq_init(void) { if (!x86_match_cpu(elan_id)) 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 , " "Sven Geggus "); MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs"); module_init(elanfreq_init); module_exit(elanfreq_exit);