linux/drivers/cpufreq/pxa2xx-cpufreq.c
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   1/*
   2 *  Copyright (C) 2002,2003 Intrinsyc Software
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 *
  18 * History:
  19 *   31-Jul-2002 : Initial version [FB]
  20 *   29-Jan-2003 : added PXA255 support [FB]
  21 *   20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
  22 *
  23 * Note:
  24 *   This driver may change the memory bus clock rate, but will not do any
  25 *   platform specific access timing changes... for example if you have flash
  26 *   memory connected to CS0, you will need to register a platform specific
  27 *   notifier which will adjust the memory access strobes to maintain a
  28 *   minimum strobe width.
  29 *
  30 */
  31
  32#include <linux/kernel.h>
  33#include <linux/module.h>
  34#include <linux/sched.h>
  35#include <linux/init.h>
  36#include <linux/cpufreq.h>
  37#include <linux/err.h>
  38#include <linux/regulator/consumer.h>
  39#include <linux/io.h>
  40
  41#include <mach/pxa2xx-regs.h>
  42#include <mach/smemc.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        } else if (cpu_is_pxa27x()) {
 225                *pxa_freqs = pxa27x_freqs;
 226                *freq_table = pxa27x_freq_table;
 227        } else {
 228                BUG();
 229        }
 230}
 231
 232static void pxa27x_guess_max_freq(void)
 233{
 234        if (!pxa27x_maxfreq) {
 235                pxa27x_maxfreq = 416000;
 236                printk(KERN_INFO "PXA CPU 27x max frequency not defined "
 237                       "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
 238                       pxa27x_maxfreq);
 239        } else {
 240                pxa27x_maxfreq *= 1000;
 241        }
 242}
 243
 244static void init_sdram_rows(void)
 245{
 246        uint32_t mdcnfg = __raw_readl(MDCNFG);
 247        unsigned int drac2 = 0, drac0 = 0;
 248
 249        if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3))
 250                drac2 = MDCNFG_DRAC2(mdcnfg);
 251
 252        if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1))
 253                drac0 = MDCNFG_DRAC0(mdcnfg);
 254
 255        sdram_rows = 1 << (11 + max(drac0, drac2));
 256}
 257
 258static u32 mdrefr_dri(unsigned int freq)
 259{
 260        u32 interval = freq * SDRAM_TREF / sdram_rows;
 261
 262        return (interval - (cpu_is_pxa27x() ? 31 : 0)) / 32;
 263}
 264
 265/* find a valid frequency point */
 266static int pxa_verify_policy(struct cpufreq_policy *policy)
 267{
 268        struct cpufreq_frequency_table *pxa_freqs_table;
 269        pxa_freqs_t *pxa_freqs;
 270        int ret;
 271
 272        find_freq_tables(&pxa_freqs_table, &pxa_freqs);
 273        ret = cpufreq_frequency_table_verify(policy, pxa_freqs_table);
 274
 275        if (freq_debug)
 276                pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n",
 277                         policy->min, policy->max);
 278
 279        return ret;
 280}
 281
 282static unsigned int pxa_cpufreq_get(unsigned int cpu)
 283{
 284        return get_clk_frequency_khz(0);
 285}
 286
 287static int pxa_set_target(struct cpufreq_policy *policy,
 288                          unsigned int target_freq,
 289                          unsigned int relation)
 290{
 291        struct cpufreq_frequency_table *pxa_freqs_table;
 292        pxa_freqs_t *pxa_freq_settings;
 293        struct cpufreq_freqs freqs;
 294        unsigned int idx;
 295        unsigned long flags;
 296        unsigned int new_freq_cpu, new_freq_mem;
 297        unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg;
 298        int ret = 0;
 299
 300        /* Get the current policy */
 301        find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
 302
 303        /* Lookup the next frequency */
 304        if (cpufreq_frequency_table_target(policy, pxa_freqs_table,
 305                                           target_freq, relation, &idx)) {
 306                return -EINVAL;
 307        }
 308
 309        new_freq_cpu = pxa_freq_settings[idx].khz;
 310        new_freq_mem = pxa_freq_settings[idx].membus;
 311        freqs.old = policy->cur;
 312        freqs.new = new_freq_cpu;
 313
 314        if (freq_debug)
 315                pr_debug("Changing CPU frequency to %d Mhz, (SDRAM %d Mhz)\n",
 316                         freqs.new / 1000, (pxa_freq_settings[idx].div2) ?
 317                         (new_freq_mem / 2000) : (new_freq_mem / 1000));
 318
 319        if (vcc_core && freqs.new > freqs.old)
 320                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 321        if (ret)
 322                return ret;
 323        /*
 324         * Tell everyone what we're about to do...
 325         * you should add a notify client with any platform specific
 326         * Vcc changing capability
 327         */
 328        cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 329
 330        /* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
 331         * we need to preset the smaller DRI before the change.  If we're
 332         * speeding up we need to set the larger DRI value after the change.
 333         */
 334        preset_mdrefr = postset_mdrefr = __raw_readl(MDREFR);
 335        if ((preset_mdrefr & MDREFR_DRI_MASK) > mdrefr_dri(new_freq_mem)) {
 336                preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
 337                preset_mdrefr |= mdrefr_dri(new_freq_mem);
 338        }
 339        postset_mdrefr =
 340                (postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem);
 341
 342        /* If we're dividing the memory clock by two for the SDRAM clock, this
 343         * must be set prior to the change.  Clearing the divide must be done
 344         * after the change.
 345         */
 346        if (pxa_freq_settings[idx].div2) {
 347                preset_mdrefr  |= MDREFR_DB2_MASK;
 348                postset_mdrefr |= MDREFR_DB2_MASK;
 349        } else {
 350                postset_mdrefr &= ~MDREFR_DB2_MASK;
 351        }
 352
 353        local_irq_save(flags);
 354
 355        /* Set new the CCCR and prepare CCLKCFG */
 356        CCCR = pxa_freq_settings[idx].cccr;
 357        cclkcfg = pxa_freq_settings[idx].cclkcfg;
 358
 359        asm volatile("                                                  \n\
 360                ldr     r4, [%1]                /* load MDREFR */       \n\
 361                b       2f                                              \n\
 362                .align  5                                               \n\
 3631:                                                                      \n\
 364                str     %3, [%1]                /* preset the MDREFR */ \n\
 365                mcr     p14, 0, %2, c6, c0, 0   /* set CCLKCFG[FCS] */  \n\
 366                str     %4, [%1]                /* postset the MDREFR */ \n\
 367                                                                        \n\
 368                b       3f                                              \n\
 3692:              b       1b                                              \n\
 3703:              nop                                                     \n\
 371          "
 372                     : "=&r" (unused)
 373                     : "r" (MDREFR), "r" (cclkcfg),
 374                       "r" (preset_mdrefr), "r" (postset_mdrefr)
 375                     : "r4", "r5");
 376        local_irq_restore(flags);
 377
 378        /*
 379         * Tell everyone what we've just done...
 380         * you should add a notify client with any platform specific
 381         * SDRAM refresh timer adjustments
 382         */
 383        cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 384
 385        /*
 386         * Even if voltage setting fails, we don't report it, as the frequency
 387         * change succeeded. The voltage reduction is not a critical failure,
 388         * only power savings will suffer from this.
 389         *
 390         * Note: if the voltage change fails, and a return value is returned, a
 391         * bug is triggered (seems a deadlock). Should anybody find out where,
 392         * the "return 0" should become a "return ret".
 393         */
 394        if (vcc_core && freqs.new < freqs.old)
 395                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 396
 397        return 0;
 398}
 399
 400static int pxa_cpufreq_init(struct cpufreq_policy *policy)
 401{
 402        int i;
 403        unsigned int freq;
 404        struct cpufreq_frequency_table *pxa255_freq_table;
 405        pxa_freqs_t *pxa255_freqs;
 406
 407        /* try to guess pxa27x cpu */
 408        if (cpu_is_pxa27x())
 409                pxa27x_guess_max_freq();
 410
 411        pxa_cpufreq_init_voltages();
 412
 413        init_sdram_rows();
 414
 415        /* set default policy and cpuinfo */
 416        policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
 417        policy->cur = get_clk_frequency_khz(0);    /* current freq */
 418        policy->min = policy->max = policy->cur;
 419
 420        /* Generate pxa25x the run cpufreq_frequency_table struct */
 421        for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
 422                pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
 423                pxa255_run_freq_table[i].driver_data = i;
 424        }
 425        pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
 426
 427        /* Generate pxa25x the turbo cpufreq_frequency_table struct */
 428        for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
 429                pxa255_turbo_freq_table[i].frequency =
 430                        pxa255_turbo_freqs[i].khz;
 431                pxa255_turbo_freq_table[i].driver_data = i;
 432        }
 433        pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
 434
 435        pxa255_turbo_table = !!pxa255_turbo_table;
 436
 437        /* Generate the pxa27x cpufreq_frequency_table struct */
 438        for (i = 0; i < NUM_PXA27x_FREQS; i++) {
 439                freq = pxa27x_freqs[i].khz;
 440                if (freq > pxa27x_maxfreq)
 441                        break;
 442                pxa27x_freq_table[i].frequency = freq;
 443                pxa27x_freq_table[i].driver_data = i;
 444        }
 445        pxa27x_freq_table[i].driver_data = i;
 446        pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
 447
 448        /*
 449         * Set the policy's minimum and maximum frequencies from the tables
 450         * just constructed.  This sets cpuinfo.mxx_freq, min and max.
 451         */
 452        if (cpu_is_pxa25x()) {
 453                find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
 454                pr_info("PXA255 cpufreq using %s frequency table\n",
 455                        pxa255_turbo_table ? "turbo" : "run");
 456                cpufreq_frequency_table_cpuinfo(policy, pxa255_freq_table);
 457        }
 458        else if (cpu_is_pxa27x())
 459                cpufreq_frequency_table_cpuinfo(policy, pxa27x_freq_table);
 460
 461        printk(KERN_INFO "PXA CPU frequency change support initialized\n");
 462
 463        return 0;
 464}
 465
 466static struct cpufreq_driver pxa_cpufreq_driver = {
 467        .verify = pxa_verify_policy,
 468        .target = pxa_set_target,
 469        .init   = pxa_cpufreq_init,
 470        .get    = pxa_cpufreq_get,
 471        .name   = "PXA2xx",
 472};
 473
 474static int __init pxa_cpu_init(void)
 475{
 476        int ret = -ENODEV;
 477        if (cpu_is_pxa25x() || cpu_is_pxa27x())
 478                ret = cpufreq_register_driver(&pxa_cpufreq_driver);
 479        return ret;
 480}
 481
 482static void __exit pxa_cpu_exit(void)
 483{
 484        cpufreq_unregister_driver(&pxa_cpufreq_driver);
 485}
 486
 487
 488MODULE_AUTHOR("Intrinsyc Software Inc.");
 489MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 490MODULE_LICENSE("GPL");
 491module_init(pxa_cpu_init);
 492module_exit(pxa_cpu_exit);
 493
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