LXR linux/arch/arm/mach-pxa/cpufreq-pxa2xx.c

   1/*
   2 *  linux/arch/arm/mach-pxa/cpufreq-pxa2xx.c
   3 *
   4 *  Copyright (C) 2002,2003 Intrinsyc Software
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 *
  20 * History:
  21 *   31-Jul-2002 : Initial version [FB]
  22 *   29-Jan-2003 : added PXA255 support [FB]
  23 *   20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
  24 *
  25 * Note:
  26 *   This driver may change the memory bus clock rate, but will not do any
  27 *   platform specific access timing changes... for example if you have flash
  28 *   memory connected to CS0, you will need to register a platform specific
  29 *   notifier which will adjust the memory access strobes to maintain a
  30 *   minimum strobe width.
  31 *
  32 */
  33
  34#include <linux/kernel.h>
  35#include <linux/module.h>
  36#include <linux/sched.h>
  37#include <linux/init.h>
  38#include <linux/cpufreq.h>
  39#include <linux/err.h>
  40#include <linux/regulator/consumer.h>
  41
  42#include <mach/pxa2xx-regs.h>
  43
  44#ifdef DEBUG
  45static unsigned int freq_debug;
  46module_param(freq_debug, uint, 0);
  47MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
  48#else
  49#define freq_debug  0
  50#endif
  51
  52static struct regulator *vcc_core;
  53
  54static unsigned int pxa27x_maxfreq;
  55module_param(pxa27x_maxfreq, uint, 0);
  56MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
  57                 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
  58
  59typedef struct {
  60        unsigned int khz;
  61        unsigned int membus;
  62        unsigned int cccr;
  63        unsigned int div2;
  64        unsigned int cclkcfg;
  65        int vmin;
  66        int vmax;
  67} pxa_freqs_t;
  68
  69/* Define the refresh period in mSec for the SDRAM and the number of rows */
  70#define SDRAM_TREF      64      /* standard 64ms SDRAM */
  71static unsigned int sdram_rows;
  72
  73#define CCLKCFG_TURBO           0x1
  74#define CCLKCFG_FCS             0x2
  75#define CCLKCFG_HALFTURBO       0x4
  76#define CCLKCFG_FASTBUS         0x8
  77#define MDREFR_DB2_MASK         (MDREFR_K2DB2 | MDREFR_K1DB2)
  78#define MDREFR_DRI_MASK         0xFFF
  79
  80#define MDCNFG_DRAC2(mdcnfg) (((mdcnfg) >> 21) & 0x3)
  81#define MDCNFG_DRAC0(mdcnfg) (((mdcnfg) >> 5) & 0x3)
  82
  83/*
  84 * PXA255 definitions
  85 */
  86/* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */
  87#define CCLKCFG                 CCLKCFG_TURBO | CCLKCFG_FCS
  88
  89static pxa_freqs_t pxa255_run_freqs[] =
  90{
  91        /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG                run  turbo PXbus SDRAM */
  92        { 99500,  99500, 0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
  93        {132700, 132700, 0x123, 1,  CCLKCFG, -1, -1},   /* 133,  133,   66,   66  */
  94        {199100,  99500, 0x141, 0,  CCLKCFG, -1, -1},   /* 199,  199,   99,   99  */
  95        {265400, 132700, 0x143, 1,  CCLKCFG, -1, -1},   /* 265,  265,  133,   66  */
  96        {331800, 165900, 0x145, 1,  CCLKCFG, -1, -1},   /* 331,  331,  166,   83  */
  97        {398100,  99500, 0x161, 0,  CCLKCFG, -1, -1},   /* 398,  398,  196,   99  */
  98};
  99
 100/* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
 101static pxa_freqs_t pxa255_turbo_freqs[] =
 102{
 103        /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG        run  turbo PXbus SDRAM */
 104        { 99500, 99500,  0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
 105        {199100, 99500,  0x221, 0,  CCLKCFG, -1, -1},   /*  99,  199,   50,   99  */
 106        {298500, 99500,  0x321, 0,  CCLKCFG, -1, -1},   /*  99,  287,   50,   99  */
 107        {298600, 99500,  0x1c1, 0,  CCLKCFG, -1, -1},   /* 199,  287,   99,   99  */
 108        {398100, 99500,  0x241, 0,  CCLKCFG, -1, -1},   /* 199,  398,   99,   99  */
 109};
 110
 111#define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
 112#define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
 113
 114static struct cpufreq_frequency_table
 115        pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
 116static struct cpufreq_frequency_table
 117        pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
 118
 119static unsigned int pxa255_turbo_table;
 120module_param(pxa255_turbo_table, uint, 0);
 121MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
 122
 123/*
 124 * PXA270 definitions
 125 *
 126 * For the PXA27x:
 127 * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
 128 *
 129 * A = 0 => memory controller clock from table 3-7,
 130 * A = 1 => memory controller clock = system bus clock
 131 * Run mode frequency   = 13 MHz * L
 132 * Turbo mode frequency = 13 MHz * L * N
 133 * System bus frequency = 13 MHz * L / (B + 1)
 134 *
 135 * In CCCR:
 136 * A = 1
 137 * L = 16         oscillator to run mode ratio
 138 * 2N = 6         2 * (turbo mode to run mode ratio)
 139 *
 140 * In CCLKCFG:
 141 * B = 1          Fast bus mode
 142 * HT = 0         Half-Turbo mode
 143 * T = 1          Turbo mode
 144 *
 145 * For now, just support some of the combinations in table 3-7 of
 146 * PXA27x Processor Family Developer's Manual to simplify frequency
 147 * change sequences.
 148 */
 149#define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
 150#define CCLKCFG2(B, HT, T) \
 151  (CCLKCFG_FCS | \
 152   ((B)  ? CCLKCFG_FASTBUS : 0) | \
 153   ((HT) ? CCLKCFG_HALFTURBO : 0) | \
 154   ((T)  ? CCLKCFG_TURBO : 0))
 155
 156static pxa_freqs_t pxa27x_freqs[] = {
 157        {104000, 104000, PXA27x_CCCR(1,  8, 2), 0, CCLKCFG2(1, 0, 1),  900000, 1705000 },
 158        {156000, 104000, PXA27x_CCCR(1,  8, 3), 0, CCLKCFG2(1, 0, 1), 1000000, 1705000 },
 159        {208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1), 1180000, 1705000 },
 160        {312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1), 1250000, 1705000 },
 161        {416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1), 1350000, 1705000 },
 162        {520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1), 1450000, 1705000 },
 163        {624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1), 1550000, 1705000 }
 164};
 165
 166#define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
 167static struct cpufreq_frequency_table
 168        pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 169
 170extern unsigned get_clk_frequency_khz(int info);
 171
 172#ifdef CONFIG_REGULATOR
 173
 174static int pxa_cpufreq_change_voltage(pxa_freqs_t *pxa_freq)
 175{
 176        int ret = 0;
 177        int vmin, vmax;
 178
 179        if (!cpu_is_pxa27x())
 180                return 0;
 181
 182        vmin = pxa_freq->vmin;
 183        vmax = pxa_freq->vmax;
 184        if ((vmin == -1) || (vmax == -1))
 185                return 0;
 186
 187        ret = regulator_set_voltage(vcc_core, vmin, vmax);
 188        if (ret)
 189                pr_err("cpufreq: Failed to set vcc_core in [%dmV..%dmV]\n",
 190                       vmin, vmax);
 191        return ret;
 192}
 193
 194static __init void pxa_cpufreq_init_voltages(void)
 195{
 196        vcc_core = regulator_get(NULL, "vcc_core");
 197        if (IS_ERR(vcc_core)) {
 198                pr_info("cpufreq: Didn't find vcc_core regulator\n");
 199                vcc_core = NULL;
 200        } else {
 201                pr_info("cpufreq: Found vcc_core regulator\n");
 202        }
 203}
 204#else
 205static int pxa_cpufreq_change_voltage(pxa_freqs_t *pxa_freq)
 206{
 207        return 0;
 208}
 209
 210static __init void pxa_cpufreq_init_voltages(void) { }
 211#endif
 212
 213static void find_freq_tables(struct cpufreq_frequency_table **freq_table,
 214                             pxa_freqs_t **pxa_freqs)
 215{
 216        if (cpu_is_pxa25x()) {
 217                if (!pxa255_turbo_table) {
 218                        *pxa_freqs = pxa255_run_freqs;
 219                        *freq_table = pxa255_run_freq_table;
 220                } else {
 221                        *pxa_freqs = pxa255_turbo_freqs;
 222                        *freq_table = pxa255_turbo_freq_table;
 223                }
 224        }
 225        if (cpu_is_pxa27x()) {
 226                *pxa_freqs = pxa27x_freqs;
 227                *freq_table = pxa27x_freq_table;
 228        }
 229}
 230
 231static void pxa27x_guess_max_freq(void)
 232{
 233        if (!pxa27x_maxfreq) {
 234                pxa27x_maxfreq = 416000;
 235                printk(KERN_INFO "PXA CPU 27x max frequency not defined "
 236                       "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
 237                       pxa27x_maxfreq);
 238        } else {
 239                pxa27x_maxfreq *= 1000;
 240        }
 241}
 242
 243static void init_sdram_rows(void)
 244{
 245        uint32_t mdcnfg = MDCNFG;
 246        unsigned int drac2 = 0, drac0 = 0;
 247
 248        if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3))
 249                drac2 = MDCNFG_DRAC2(mdcnfg);
 250
 251        if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1))
 252                drac0 = MDCNFG_DRAC0(mdcnfg);
 253
 254        sdram_rows = 1 << (11 + max(drac0, drac2));
 255}
 256
 257static u32 mdrefr_dri(unsigned int freq)
 258{
 259        u32 dri = 0;
 260
 261        if (cpu_is_pxa25x())
 262                dri = ((freq * SDRAM_TREF) / (sdram_rows * 32));
 263        if (cpu_is_pxa27x())
 264                dri = ((freq * SDRAM_TREF) / (sdram_rows - 31)) / 32;
 265        return dri;
 266}
 267
 268/* find a valid frequency point */
 269static int pxa_verify_policy(struct cpufreq_policy *policy)
 270{
 271        struct cpufreq_frequency_table *pxa_freqs_table;
 272        pxa_freqs_t *pxa_freqs;
 273        int ret;
 274
 275        find_freq_tables(&pxa_freqs_table, &pxa_freqs);
 276        ret = cpufreq_frequency_table_verify(policy, pxa_freqs_table);
 277
 278        if (freq_debug)
 279                pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n",
 280                         policy->min, policy->max);
 281
 282        return ret;
 283}
 284
 285static unsigned int pxa_cpufreq_get(unsigned int cpu)
 286{
 287        return get_clk_frequency_khz(0);
 288}
 289
 290static int pxa_set_target(struct cpufreq_policy *policy,
 291                          unsigned int target_freq,
 292                          unsigned int relation)
 293{
 294        struct cpufreq_frequency_table *pxa_freqs_table;
 295        pxa_freqs_t *pxa_freq_settings;
 296        struct cpufreq_freqs freqs;
 297        unsigned int idx;
 298        unsigned long flags;
 299        unsigned int new_freq_cpu, new_freq_mem;
 300        unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg;
 301        int ret = 0;
 302
 303        /* Get the current policy */
 304        find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
 305
 306        /* Lookup the next frequency */
 307        if (cpufreq_frequency_table_target(policy, pxa_freqs_table,
 308                                           target_freq, relation, &idx)) {
 309                return -EINVAL;
 310        }
 311
 312        new_freq_cpu = pxa_freq_settings[idx].khz;
 313        new_freq_mem = pxa_freq_settings[idx].membus;
 314        freqs.old = policy->cur;
 315        freqs.new = new_freq_cpu;
 316        freqs.cpu = policy->cpu;
 317
 318        if (freq_debug)
 319                pr_debug(KERN_INFO "Changing CPU frequency to %d Mhz, "
 320                         "(SDRAM %d Mhz)\n",
 321                         freqs.new / 1000, (pxa_freq_settings[idx].div2) ?
 322                         (new_freq_mem / 2000) : (new_freq_mem / 1000));
 323
 324        if (vcc_core && freqs.new > freqs.old)
 325                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 326        if (ret)
 327                return ret;
 328        /*
 329         * Tell everyone what we're about to do...
 330         * you should add a notify client with any platform specific
 331         * Vcc changing capability
 332         */
 333        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 334
 335        /* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
 336         * we need to preset the smaller DRI before the change.  If we're
 337         * speeding up we need to set the larger DRI value after the change.
 338         */
 339        preset_mdrefr = postset_mdrefr = MDREFR;
 340        if ((MDREFR & MDREFR_DRI_MASK) > mdrefr_dri(new_freq_mem)) {
 341                preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
 342                preset_mdrefr |= mdrefr_dri(new_freq_mem);
 343        }
 344        postset_mdrefr =
 345                (postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem);
 346
 347        /* If we're dividing the memory clock by two for the SDRAM clock, this
 348         * must be set prior to the change.  Clearing the divide must be done
 349         * after the change.
 350         */
 351        if (pxa_freq_settings[idx].div2) {
 352                preset_mdrefr  |= MDREFR_DB2_MASK;
 353                postset_mdrefr |= MDREFR_DB2_MASK;
 354        } else {
 355                postset_mdrefr &= ~MDREFR_DB2_MASK;
 356        }
 357
 358        local_irq_save(flags);
 359
 360        /* Set new the CCCR and prepare CCLKCFG */
 361        CCCR = pxa_freq_settings[idx].cccr;
 362        cclkcfg = pxa_freq_settings[idx].cclkcfg;
 363
 364        asm volatile("                                                  \n\
 365                ldr     r4, [%1]                /* load MDREFR */       \n\
 366                b       2f                                              \n\
 367                .align  5                                               \n\
 3681:                                                                      \n\
 369                str     %3, [%1]                /* preset the MDREFR */ \n\
 370                mcr     p14, 0, %2, c6, c0, 0   /* set CCLKCFG[FCS] */  \n\
 371                str     %4, [%1]                /* postset the MDREFR */ \n\
 372                                                                        \n\
 373                b       3f                                              \n\
 3742:              b       1b                                              \n\
 3753:              nop                                                     \n\
 376          "
 377                     : "=&r" (unused)
 378                     : "r" (&MDREFR), "r" (cclkcfg),
 379                       "r" (preset_mdrefr), "r" (postset_mdrefr)
 380                     : "r4", "r5");
 381        local_irq_restore(flags);
 382
 383        /*
 384         * Tell everyone what we've just done...
 385         * you should add a notify client with any platform specific
 386         * SDRAM refresh timer adjustments
 387         */
 388        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 389
 390        /*
 391         * Even if voltage setting fails, we don't report it, as the frequency
 392         * change succeeded. The voltage reduction is not a critical failure,
 393         * only power savings will suffer from this.
 394         *
 395         * Note: if the voltage change fails, and a return value is returned, a
 396         * bug is triggered (seems a deadlock). Should anybody find out where,
 397         * the "return 0" should become a "return ret".
 398         */
 399        if (vcc_core && freqs.new < freqs.old)
 400                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 401
 402        return 0;
 403}
 404
 405static __init int pxa_cpufreq_init(struct cpufreq_policy *policy)
 406{
 407        int i;
 408        unsigned int freq;
 409        struct cpufreq_frequency_table *pxa255_freq_table;
 410        pxa_freqs_t *pxa255_freqs;
 411
 412        /* try to guess pxa27x cpu */
 413        if (cpu_is_pxa27x())
 414                pxa27x_guess_max_freq();
 415
 416        pxa_cpufreq_init_voltages();
 417
 418        init_sdram_rows();
 419
 420        /* set default policy and cpuinfo */
 421        policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
 422        policy->cur = get_clk_frequency_khz(0);    /* current freq */
 423        policy->min = policy->max = policy->cur;
 424
 425        /* Generate pxa25x the run cpufreq_frequency_table struct */
 426        for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
 427                pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
 428                pxa255_run_freq_table[i].index = i;
 429        }
 430        pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
 431
 432        /* Generate pxa25x the turbo cpufreq_frequency_table struct */
 433        for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
 434                pxa255_turbo_freq_table[i].frequency =
 435                        pxa255_turbo_freqs[i].khz;
 436                pxa255_turbo_freq_table[i].index = i;
 437        }
 438        pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
 439
 440        pxa255_turbo_table = !!pxa255_turbo_table;
 441
 442        /* Generate the pxa27x cpufreq_frequency_table struct */
 443        for (i = 0; i < NUM_PXA27x_FREQS; i++) {
 444                freq = pxa27x_freqs[i].khz;
 445                if (freq > pxa27x_maxfreq)
 446                        break;
 447                pxa27x_freq_table[i].frequency = freq;
 448                pxa27x_freq_table[i].index = i;
 449        }
 450        pxa27x_freq_table[i].index = i;
 451        pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
 452
 453        /*
 454         * Set the policy's minimum and maximum frequencies from the tables
 455         * just constructed.  This sets cpuinfo.mxx_freq, min and max.
 456         */
 457        if (cpu_is_pxa25x()) {
 458                find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
 459                pr_info("PXA255 cpufreq using %s frequency table\n",
 460                        pxa255_turbo_table ? "turbo" : "run");
 461                cpufreq_frequency_table_cpuinfo(policy, pxa255_freq_table);
 462        }
 463        else if (cpu_is_pxa27x())
 464                cpufreq_frequency_table_cpuinfo(policy, pxa27x_freq_table);
 465
 466        printk(KERN_INFO "PXA CPU frequency change support initialized\n");
 467
 468        return 0;
 469}
 470
 471static struct cpufreq_driver pxa_cpufreq_driver = {
 472        .verify = pxa_verify_policy,
 473        .target = pxa_set_target,
 474        .init   = pxa_cpufreq_init,
 475        .get    = pxa_cpufreq_get,
 476        .name   = "PXA2xx",
 477};
 478
 479static int __init pxa_cpu_init(void)
 480{
 481        int ret = -ENODEV;
 482        if (cpu_is_pxa25x() || cpu_is_pxa27x())
 483                ret = cpufreq_register_driver(&pxa_cpufreq_driver);
 484        return ret;
 485}
 486
 487static void __exit pxa_cpu_exit(void)
 488{
 489        cpufreq_unregister_driver(&pxa_cpufreq_driver);
 490}
 491
 492
 493MODULE_AUTHOR("Intrinsyc Software Inc.");
 494MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 495MODULE_LICENSE("GPL");
 496module_init(pxa_cpu_init);
 497module_exit(pxa_cpu_exit);
 498