diff options
Diffstat (limited to 'arch/arm/mach-pxa/cpufreq-pxa2xx.c')
| -rw-r--r-- | arch/arm/mach-pxa/cpufreq-pxa2xx.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/cpufreq-pxa2xx.c b/arch/arm/mach-pxa/cpufreq-pxa2xx.c new file mode 100644 index 00000000000..d82528e74bd --- /dev/null +++ b/arch/arm/mach-pxa/cpufreq-pxa2xx.c @@ -0,0 +1,410 @@ +/* + * linux/arch/arm/mach-pxa/cpufreq-pxa2xx.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 <linux/kernel.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/cpufreq.h> + +#include <mach/hardware.h> +#include <mach/pxa-regs.h> +#include <mach/pxa2xx-regs.h> + +#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 + +static unsigned int pxa27x_maxfreq; +module_param(pxa27x_maxfreq, uint, 0); +MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz" + "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)"); + +typedef struct { + unsigned int khz; + unsigned int membus; + unsigned int cccr; + unsigned int div2; + unsigned int cclkcfg; +} 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 CCLKCFG_TURBO 0x1 +#define CCLKCFG_FCS 0x2 +#define CCLKCFG_HALFTURBO 0x4 +#define CCLKCFG_FASTBUS 0x8 +#define MDREFR_DB2_MASK (MDREFR_K2DB2 | MDREFR_K1DB2) +#define MDREFR_DRI_MASK 0xFFF + +/* + * PXA255 definitions + */ +/* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */ +#define CCLKCFG CCLKCFG_TURBO | CCLKCFG_FCS + +static pxa_freqs_t pxa255_run_freqs[] = +{ + /* CPU MEMBUS CCCR DIV2 CCLKCFG run turbo PXbus SDRAM */ + { 99500, 99500, 0x121, 1, CCLKCFG}, /* 99, 99, 50, 50 */ + {132700, 132700, 0x123, 1, CCLKCFG}, /* 133, 133, 66, 66 */ + {199100, 99500, 0x141, 0, CCLKCFG}, /* 199, 199, 99, 99 */ + {265400, 132700, 0x143, 1, CCLKCFG}, /* 265, 265, 133, 66 */ + {331800, 165900, 0x145, 1, CCLKCFG}, /* 331, 331, 166, 83 */ + {398100, 99500, 0x161, 0, CCLKCFG}, /* 398, 398, 196, 99 */ +}; + +/* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */ +static pxa_freqs_t pxa255_turbo_freqs[] = +{ + /* CPU MEMBUS CCCR DIV2 CCLKCFG run turbo PXbus SDRAM */ + { 99500, 99500, 0x121, 1, CCLKCFG}, /* 99, 99, 50, 50 */ + {199100, 99500, 0x221, 0, CCLKCFG}, /* 99, 199, 50, 99 */ + {298500, 99500, 0x321, 0, CCLKCFG}, /* 99, 287, 50, 99 */ + {298600, 99500, 0x1c1, 0, CCLKCFG}, /* 199, 287, 99, 99 */ + {398100, 99500, 0x241, 0, CCLKCFG}, /* 199, 398, 99, 99 */ +}; + +#define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs) +#define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs) + +static struct cpufreq_frequency_table + pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1]; +static struct cpufreq_frequency_table + pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1]; + +/* + * PXA270 definitions + * + * For the PXA27x: + * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG. + * + * A = 0 => memory controller clock from table 3-7, + * A = 1 => memory controller clock = system bus clock + * Run mode frequency = 13 MHz * L + * Turbo mode frequency = 13 MHz * L * N + * System bus frequency = 13 MHz * L / (B + 1) + * + * In CCCR: + * A = 1 + * L = 16 oscillator to run mode ratio + * 2N = 6 2 * (turbo mode to run mode ratio) + * + * In CCLKCFG: + * B = 1 Fast bus mode + * HT = 0 Half-Turbo mode + * T = 1 Turbo mode + * + * For now, just support some of the combinations in table 3-7 of + * PXA27x Processor Family Developer's Manual to simplify frequency + * change sequences. + */ +#define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L) +#define CCLKCFG2(B, HT, T) \ + (CCLKCFG_FCS | \ + ((B) ? CCLKCFG_FASTBUS : 0) | \ + ((HT) ? CCLKCFG_HALFTURBO : 0) | \ + ((T) ? CCLKCFG_TURBO : 0)) + +static pxa_freqs_t pxa27x_freqs[] = { + {104000, 104000, PXA27x_CCCR(1, 8, 2), 0, CCLKCFG2(1, 0, 1)}, + {156000, 104000, PXA27x_CCCR(1, 8, 6), 0, CCLKCFG2(1, 1, 1)}, + {208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1)}, + {312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1)}, + {416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1)}, + {520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1)}, + {624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1)} +}; + +#define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs) +static struct cpufreq_frequency_table + pxa27x_freq_table[NUM_PXA27x_FREQS+1]; + +extern unsigned get_clk_frequency_khz(int info); + +static void find_freq_tables(struct cpufreq_policy *policy, + struct cpufreq_frequency_table **freq_table, + pxa_freqs_t **pxa_freqs) +{ + if (cpu_is_pxa25x()) { + if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { + *pxa_freqs = pxa255_run_freqs; + *freq_table = pxa255_run_freq_table; + } else if (policy->policy == CPUFREQ_POLICY_POWERSAVE) { + *pxa_freqs = pxa255_turbo_freqs; + *freq_table = pxa255_turbo_freq_table; + } else { + printk("CPU PXA: Unknown policy found. " + "Using CPUFREQ_POLICY_PERFORMANCE\n"); + *pxa_freqs = pxa255_run_freqs; + *freq_table = pxa255_run_freq_table; + } + } + if (cpu_is_pxa27x()) { + *pxa_freqs = pxa27x_freqs; + *freq_table = pxa27x_freq_table; + } +} + +static void pxa27x_guess_max_freq(void) +{ + if (!pxa27x_maxfreq) { + pxa27x_maxfreq = 416000; + printk(KERN_INFO "PXA CPU 27x max frequency not defined " + "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n", + pxa27x_maxfreq); + } else { + pxa27x_maxfreq *= 1000; + } +} + +static u32 mdrefr_dri(unsigned int freq) +{ + u32 dri = 0; + + if (cpu_is_pxa25x()) + dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS * 32)); + if (cpu_is_pxa27x()) + dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS - 31)) / 32; + return dri; +} + +/* find a valid frequency point */ +static int pxa_verify_policy(struct cpufreq_policy *policy) +{ + struct cpufreq_frequency_table *pxa_freqs_table; + pxa_freqs_t *pxa_freqs; + int ret; + + find_freq_tables(policy, &pxa_freqs_table, &pxa_freqs); + 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 unsigned int pxa_cpufreq_get(unsigned int cpu) +{ + return get_clk_frequency_khz(0); +} + +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 new_freq_cpu, new_freq_mem; + unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg; + + /* Get the current policy */ + find_freq_tables(policy, &pxa_freqs_table, &pxa_freq_settings); + + /* Lookup the next frequency */ + if (cpufreq_frequency_table_target(policy, pxa_freqs_table, + target_freq, relation, &idx)) { + return -EINVAL; + } + + new_freq_cpu = pxa_freq_settings[idx].khz; + new_freq_mem = pxa_freq_settings[idx].membus; + freqs.old = policy->cur; + freqs.new = new_freq_cpu; + 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) ? + (new_freq_mem / 2000) : (new_freq_mem / 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(new_freq_mem)) { + preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK); + preset_mdrefr |= mdrefr_dri(new_freq_mem); + } + postset_mdrefr = + (postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem); + + /* 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 and prepare CCLKCFG */ + CCCR = pxa_freq_settings[idx].cccr; + cclkcfg = pxa_freq_settings[idx].cclkcfg; + + asm volatile(" \n\ + ldr r4, [%1] /* load MDREFR */ \n\ + b 2f \n\ + .align 5 \n\ +1: \n\ + str %3, [%1] /* preset the MDREFR */ \n\ + mcr p14, 0, %2, c6, c0, 0 /* set CCLKCFG[FCS] */ \n\ + str %4, [%1] /* postset the MDREFR */ \n\ + \n\ + b 3f \n\ +2: b 1b \n\ +3: nop \n\ + " + : "=&r" (unused) + : "r" (&MDREFR), "r" (cclkcfg), + "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 __init int pxa_cpufreq_init(struct cpufreq_policy *policy) +{ + int i; + unsigned int freq; + + /* try to guess pxa27x cpu */ + if (cpu_is_pxa27x()) + pxa27x_guess_max_freq(); + + /* set default policy and cpuinfo */ + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + if (cpu_is_pxa25x()) + policy->policy = CPUFREQ_POLICY_PERFORMANCE; + 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 pxa25x the run cpufreq_frequency_table struct */ + for (i = 0; i < NUM_PXA25x_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 pxa25x the turbo cpufreq_frequency_table struct */ + for (i = 0; i < NUM_PXA25x_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; + + /* Generate the pxa27x cpufreq_frequency_table struct */ + for (i = 0; i < NUM_PXA27x_FREQS; i++) { + freq = pxa27x_freqs[i].khz; + if (freq > pxa27x_maxfreq) + break; + pxa27x_freq_table[i].frequency = freq; + pxa27x_freq_table[i].index = i; + } + pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END; + + /* + * Set the policy's minimum and maximum frequencies from the tables + * just constructed. This sets cpuinfo.mxx_freq, min and max. + */ + if (cpu_is_pxa25x()) + cpufreq_frequency_table_cpuinfo(policy, pxa255_run_freq_table); + else if (cpu_is_pxa27x()) + cpufreq_frequency_table_cpuinfo(policy, pxa27x_freq_table); + + 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 = "PXA2xx", +}; + +static int __init pxa_cpu_init(void) +{ + int ret = -ENODEV; + if (cpu_is_pxa25x() || cpu_is_pxa27x()) + ret = cpufreq_register_driver(&pxa_cpufreq_driver); + return ret; +} + +static void __exit pxa_cpu_exit(void) +{ + 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); |