/* * File: arch/blackfin/mach-common/cpufreq.c * Based on: * Author: * * Created: * Description: Blackfin core clock scaling * * Modified: * Copyright 2004-2008 Analog Devices Inc. * * Bugs: Enter bugs at http://blackfin.uclinux.org/ * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see the file COPYING, or write * to the Free Software Foundation, Inc., * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include <linux/kernel.h> #include <linux/types.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/fs.h> #include <asm/blackfin.h> #include <asm/time.h> /* this is the table of CCLK frequencies, in Hz */ /* .index is the entry in the auxillary dpm_state_table[] */ static struct cpufreq_frequency_table bfin_freq_table[] = { { .frequency = CPUFREQ_TABLE_END, .index = 0, }, { .frequency = CPUFREQ_TABLE_END, .index = 1, }, { .frequency = CPUFREQ_TABLE_END, .index = 2, }, { .frequency = CPUFREQ_TABLE_END, .index = 0, }, }; static struct bfin_dpm_state { unsigned int csel; /* system clock divider */ unsigned int tscale; /* change the divider on the core timer interrupt */ } dpm_state_table[3]; /* normalized to maximum frequncy offset for CYCLES, used in time-ts cycles clock source, but could be used somewhere also. */ unsigned long long __bfin_cycles_off; unsigned int __bfin_cycles_mod; /**************************************************************************/ static unsigned int bfin_getfreq(unsigned int cpu) { /* The driver only support single cpu */ if (cpu != 0) return -1; return get_cclk(); } static int bfin_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { unsigned int index, plldiv, tscale; unsigned long flags, cclk_hz; struct cpufreq_freqs freqs; cycles_t cycles; if (cpufreq_frequency_table_target(policy, bfin_freq_table, target_freq, relation, &index)) return -EINVAL; cclk_hz = bfin_freq_table[index].frequency; freqs.old = bfin_getfreq(0); freqs.new = cclk_hz; freqs.cpu = 0; pr_debug("cpufreq: changing cclk to %lu; target = %u, oldfreq = %u\n", cclk_hz, target_freq, freqs.old); cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); local_irq_save(flags); plldiv = (bfin_read_PLL_DIV() & SSEL) | dpm_state_table[index].csel; tscale = dpm_state_table[index].tscale; bfin_write_PLL_DIV(plldiv); /* we have to adjust the core timer, because it is using cclk */ bfin_write_TSCALE(tscale); cycles = get_cycles(); SSYNC(); cycles += 10; /* ~10 cycles we loose after get_cycles() */ __bfin_cycles_off += (cycles << __bfin_cycles_mod) - (cycles << index); __bfin_cycles_mod = index; local_irq_restore(flags); /* TODO: just test case for cycles clock source, remove later */ pr_debug("cpufreq: done\n"); cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); return 0; } static int bfin_verify_speed(struct cpufreq_policy *policy) { return cpufreq_frequency_table_verify(policy, bfin_freq_table); } static int __init __bfin_cpu_init(struct cpufreq_policy *policy) { unsigned long cclk, sclk, csel, min_cclk; int index; if (policy->cpu != 0) return -EINVAL; cclk = get_cclk(); sclk = get_sclk(); #if ANOMALY_05000273 || (!defined(CONFIG_BF54x) && defined(CONFIG_BFIN_DCACHE)) min_cclk = sclk * 2; #else min_cclk = sclk; #endif csel = ((bfin_read_PLL_DIV() & CSEL) >> 4); for (index = 0; (cclk >> index) >= min_cclk && csel <= 3; index++, csel++) { bfin_freq_table[index].frequency = cclk >> index; dpm_state_table[index].csel = csel << 4; /* Shift now into PLL_DIV bitpos */ dpm_state_table[index].tscale = (TIME_SCALE / (1 << csel)) - 1; pr_debug("cpufreq: freq:%d csel:%d tscale:%d\n", bfin_freq_table[index].frequency, dpm_state_table[index].csel, dpm_state_table[index].tscale); } policy->governor = CPUFREQ_DEFAULT_GOVERNOR; policy->cpuinfo.transition_latency = (bfin_read_PLL_LOCKCNT() / (sclk / 1000000)) * 1000; /*Now ,only support one cpu */ policy->cur = cclk; cpufreq_frequency_table_get_attr(bfin_freq_table, policy->cpu); return cpufreq_frequency_table_cpuinfo(policy, bfin_freq_table); } static struct freq_attr *bfin_freq_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, NULL, }; static struct cpufreq_driver bfin_driver = { .verify = bfin_verify_speed, .target = bfin_target, .get = bfin_getfreq, .init = __bfin_cpu_init, .name = "bfin cpufreq", .owner = THIS_MODULE, .attr = bfin_freq_attr, }; static int __init bfin_cpu_init(void) { return cpufreq_register_driver(&bfin_driver); } static void __exit bfin_cpu_exit(void) { cpufreq_unregister_driver(&bfin_driver); } MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); MODULE_DESCRIPTION("cpufreq driver for Blackfin"); MODULE_LICENSE("GPL"); module_init(bfin_cpu_init); module_exit(bfin_cpu_exit);