/* * linux/arch/arm/mach-pxa/cpu-pxa.c * * Copyright (C) 2002,2003 Intrinsyc Software * * 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, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * History: * 31-Jul-2002 : Initial version [FB] * 29-Jan-2003 : added PXA255 support [FB] * 20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.) * * Note: * This driver may change the memory bus clock rate, but will not do any * platform specific access timing changes... for example if you have flash * memory connected to CS0, you will need to register a platform specific * notifier which will adjust the memory access strobes to maintain a * minimum strobe width. * */ #include #include #include #include #include #include #include #include #ifdef DEBUG static unsigned int freq_debug; module_param(freq_debug, uint, 0); MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0"); #else #define freq_debug 0 #endif typedef struct { unsigned int khz; unsigned int membus; unsigned int cccr; unsigned int div2; } pxa_freqs_t; /* Define the refresh period in mSec for the SDRAM and the number of rows */ #define SDRAM_TREF 64 /* standard 64ms SDRAM */ #define SDRAM_ROWS 4096 /* 64MB=8192 32MB=4096 */ #define MDREFR_DRI(x) (((x) * SDRAM_TREF) / (SDRAM_ROWS * 32)) #define CCLKCFG_TURBO 0x1 #define CCLKCFG_FCS 0x2 #define PXA25x_MIN_FREQ 99500 #define PXA25x_MAX_FREQ 398100 #define MDREFR_DB2_MASK (MDREFR_K2DB2 | MDREFR_K1DB2) #define MDREFR_DRI_MASK 0xFFF /* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */ static pxa_freqs_t pxa255_run_freqs[] = { /* CPU MEMBUS CCCR DIV2 run turbo PXbus SDRAM */ { 99500, 99500, 0x121, 1}, /* 99, 99, 50, 50 */ {132700, 132700, 0x123, 1}, /* 133, 133, 66, 66 */ {199100, 99500, 0x141, 0}, /* 199, 199, 99, 99 */ {265400, 132700, 0x143, 1}, /* 265, 265, 133, 66 */ {331800, 165900, 0x145, 1}, /* 331, 331, 166, 83 */ {398100, 99500, 0x161, 0}, /* 398, 398, 196, 99 */ {0,} }; #define NUM_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs) static struct cpufreq_frequency_table pxa255_run_freq_table[NUM_RUN_FREQS+1]; /* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */ static pxa_freqs_t pxa255_turbo_freqs[] = { /* CPU MEMBUS CCCR DIV2 run turbo PXbus SDRAM */ { 99500, 99500, 0x121, 1}, /* 99, 99, 50, 50 */ {199100, 99500, 0x221, 0}, /* 99, 199, 50, 99 */ {298500, 99500, 0x321, 0}, /* 99, 287, 50, 99 */ {298600, 99500, 0x1c1, 0}, /* 199, 287, 99, 99 */ {398100, 99500, 0x241, 0}, /* 199, 398, 99, 99 */ {0,} }; #define NUM_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs) static struct cpufreq_frequency_table pxa255_turbo_freq_table[NUM_TURBO_FREQS+1]; extern unsigned get_clk_frequency_khz(int info); /* find a valid frequency point */ static int pxa_verify_policy(struct cpufreq_policy *policy) { struct cpufreq_frequency_table *pxa_freqs_table; int ret; if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { pxa_freqs_table = pxa255_run_freq_table; } else if (policy->policy == CPUFREQ_POLICY_POWERSAVE) { pxa_freqs_table = pxa255_turbo_freq_table; } else { printk("CPU PXA: Unknown policy found. " "Using CPUFREQ_POLICY_PERFORMANCE\n"); pxa_freqs_table = pxa255_run_freq_table; } ret = cpufreq_frequency_table_verify(policy, pxa_freqs_table); if (freq_debug) pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n", policy->min, policy->max); return ret; } static int pxa_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { struct cpufreq_frequency_table *pxa_freqs_table; pxa_freqs_t *pxa_freq_settings; struct cpufreq_freqs freqs; unsigned int idx; unsigned long flags; unsigned int unused, preset_mdrefr, postset_mdrefr; void *ramstart = phys_to_virt(0xa0000000); /* Get the current policy */ if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { pxa_freq_settings = pxa255_run_freqs; pxa_freqs_table = pxa255_run_freq_table; } else if (policy->policy == CPUFREQ_POLICY_POWERSAVE) { pxa_freq_settings = pxa255_turbo_freqs; pxa_freqs_table = pxa255_turbo_freq_table; } else { printk("CPU PXA: Unknown policy found. " "Using CPUFREQ_POLICY_PERFORMANCE\n"); pxa_freq_settings = pxa255_run_freqs; pxa_freqs_table = pxa255_run_freq_table; } /* Lookup the next frequency */ if (cpufreq_frequency_table_target(policy, pxa_freqs_table, target_freq, relation, &idx)) { return -EINVAL; } freqs.old = policy->cur; freqs.new = pxa_freq_settings[idx].khz; freqs.cpu = policy->cpu; if (freq_debug) pr_debug(KERN_INFO "Changing CPU frequency to %d Mhz, " "(SDRAM %d Mhz)\n", freqs.new / 1000, (pxa_freq_settings[idx].div2) ? (pxa_freq_settings[idx].membus / 2000) : (pxa_freq_settings[idx].membus / 1000)); /* * Tell everyone what we're about to do... * you should add a notify client with any platform specific * Vcc changing capability */ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); /* Calculate the next MDREFR. If we're slowing down the SDRAM clock * we need to preset the smaller DRI before the change. If we're * speeding up we need to set the larger DRI value after the change. */ preset_mdrefr = postset_mdrefr = MDREFR; if ((MDREFR & MDREFR_DRI_MASK) > MDREFR_DRI(pxa_freq_settings[idx].membus)) { preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK) | MDREFR_DRI(pxa_freq_settings[idx].membus); } postset_mdrefr = (postset_mdrefr & ~MDREFR_DRI_MASK) | MDREFR_DRI(pxa_freq_settings[idx].membus); /* If we're dividing the memory clock by two for the SDRAM clock, this * must be set prior to the change. Clearing the divide must be done * after the change. */ if (pxa_freq_settings[idx].div2) { preset_mdrefr |= MDREFR_DB2_MASK; postset_mdrefr |= MDREFR_DB2_MASK; } else { postset_mdrefr &= ~MDREFR_DB2_MASK; } local_irq_save(flags); /* Set new the CCCR */ CCCR = pxa_freq_settings[idx].cccr; asm volatile(" \n\ ldr r4, [%1] /* load MDREFR */ \n\ b 2f \n\ .align 5 \n\ 1: \n\ str %4, [%1] /* preset the MDREFR */ \n\ mcr p14, 0, %2, c6, c0, 0 /* set CCLKCFG[FCS] */ \n\ str %5, [%1] /* postset the MDREFR */ \n\ \n\ b 3f \n\ 2: b 1b \n\ 3: nop \n\ " : "=&r" (unused) : "r" (&MDREFR), "r" (CCLKCFG_TURBO|CCLKCFG_FCS), "r" (ramstart), "r" (preset_mdrefr), "r" (postset_mdrefr) : "r4", "r5"); local_irq_restore(flags); /* * Tell everyone what we've just done... * you should add a notify client with any platform specific * SDRAM refresh timer adjustments */ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); return 0; } static unsigned int pxa_cpufreq_get(unsigned int cpu) { return get_clk_frequency_khz(0); } static int pxa_cpufreq_init(struct cpufreq_policy *policy) { int i; /* set default policy and cpuinfo */ policy->governor = CPUFREQ_DEFAULT_GOVERNOR; policy->policy = CPUFREQ_POLICY_PERFORMANCE; policy->cpuinfo.max_freq = PXA25x_MAX_FREQ; policy->cpuinfo.min_freq = PXA25x_MIN_FREQ; policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */ policy->cur = get_clk_frequency_khz(0); /* current freq */ policy->min = policy->max = policy->cur; /* Generate the run cpufreq_frequency_table struct */ for (i = 0; i < NUM_RUN_FREQS; i++) { pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz; pxa255_run_freq_table[i].index = i; } pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END; /* Generate the turbo cpufreq_frequency_table struct */ for (i = 0; i < NUM_TURBO_FREQS; i++) { pxa255_turbo_freq_table[i].frequency = pxa255_turbo_freqs[i].khz; pxa255_turbo_freq_table[i].index = i; } pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END; printk(KERN_INFO "PXA CPU frequency change support initialized\n"); return 0; } static struct cpufreq_driver pxa_cpufreq_driver = { .verify = pxa_verify_policy, .target = pxa_set_target, .init = pxa_cpufreq_init, .get = pxa_cpufreq_get, .name = "PXA25x", }; static int __init pxa_cpu_init(void) { int ret = -ENODEV; if (cpu_is_pxa25x()) ret = cpufreq_register_driver(&pxa_cpufreq_driver); return ret; } static void __exit pxa_cpu_exit(void) { if (cpu_is_pxa25x()) cpufreq_unregister_driver(&pxa_cpufreq_driver); } MODULE_AUTHOR("Intrinsyc Software Inc."); MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture"); MODULE_LICENSE("GPL"); module_init(pxa_cpu_init); module_exit(pxa_cpu_exit);