drivers/cpufreq/pxa2xx-cpufreq.c

   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  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 #include <linux/io.h>
  42
  43 #include <mach/pxa2xx-regs.h>
  44 #include <mach/smemc.h>
  45
  46 #ifdef DEBUG
  47 static unsigned int freq_debug;
  48 module_param(freq_debug, uint, 0);
  49 MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
  50 #else
  51 #define freq_debug  0
  52 #endif
  53
  54 static struct regulator *vcc_core;
  55
  56 static unsigned int pxa27x_maxfreq;
  57 module_param(pxa27x_maxfreq, uint, 0);
  58 MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
  59                  "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
  60
  61 struct pxa_freqs {
  62         unsigned int khz;
  63         unsigned int membus;
  64         unsigned int cccr;
  65         unsigned int div2;
  66         unsigned int cclkcfg;
  67         int vmin;
  68         int vmax;
  69 };
  70
  71 /* Define the refresh period in mSec for the SDRAM and the number of rows */
  72 #define SDRAM_TREF      64      /* standard 64ms SDRAM */
  73 static unsigned int sdram_rows;
  74
  75 #define CCLKCFG_TURBO           0x1
  76 #define CCLKCFG_FCS             0x2
  77 #define CCLKCFG_HALFTURBO       0x4
  78 #define CCLKCFG_FASTBUS         0x8
  79 #define MDREFR_DB2_MASK         (MDREFR_K2DB2 | MDREFR_K1DB2)
  80 #define MDREFR_DRI_MASK         0xFFF
  81
  82 #define MDCNFG_DRAC2(mdcnfg) (((mdcnfg) >> 21) & 0x3)
  83 #define MDCNFG_DRAC0(mdcnfg) (((mdcnfg) >> 5) & 0x3)
  84
  85 /*
  86  * PXA255 definitions
  87  */
  88 /* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */
  89 #define CCLKCFG                 CCLKCFG_TURBO | CCLKCFG_FCS
  90
  91 static const struct pxa_freqs pxa255_run_freqs[] =
  92 {
  93         /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG                run  turbo PXbus SDRAM */
  94         { 99500,  99500, 0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
  95         {132700, 132700, 0x123, 1,  CCLKCFG, -1, -1},   /* 133,  133,   66,   66  */
  96         {199100,  99500, 0x141, 0,  CCLKCFG, -1, -1},   /* 199,  199,   99,   99  */
  97         {265400, 132700, 0x143, 1,  CCLKCFG, -1, -1},   /* 265,  265,  133,   66  */
  98         {331800, 165900, 0x145, 1,  CCLKCFG, -1, -1},   /* 331,  331,  166,   83  */
  99         {398100,  99500, 0x161, 0,  CCLKCFG, -1, -1},   /* 398,  398,  196,   99  */
 100 };
 101
 102 /* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
 103 static const struct pxa_freqs pxa255_turbo_freqs[] =
 104 {
 105         /* CPU   MEMBUS  CCCR  DIV2 CCLKCFG        run  turbo PXbus SDRAM */
 106         { 99500, 99500,  0x121, 1,  CCLKCFG, -1, -1},   /*  99,   99,   50,   50  */
 107         {199100, 99500,  0x221, 0,  CCLKCFG, -1, -1},   /*  99,  199,   50,   99  */
 108         {298500, 99500,  0x321, 0,  CCLKCFG, -1, -1},   /*  99,  287,   50,   99  */
 109         {298600, 99500,  0x1c1, 0,  CCLKCFG, -1, -1},   /* 199,  287,   99,   99  */
 110         {398100, 99500,  0x241, 0,  CCLKCFG, -1, -1},   /* 199,  398,   99,   99  */
 111 };
 112
 113 #define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
 114 #define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
 115
 116 static struct cpufreq_frequency_table
 117         pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
 118 static struct cpufreq_frequency_table
 119         pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
 120
 121 static unsigned int pxa255_turbo_table;
 122 module_param(pxa255_turbo_table, uint, 0);
 123 MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
 124
 125 /*
 126  * PXA270 definitions
 127  *
 128  * For the PXA27x:
 129  * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
 130  *
 131  * A = 0 => memory controller clock from table 3-7,
 132  * A = 1 => memory controller clock = system bus clock
 133  * Run mode frequency   = 13 MHz * L
 134  * Turbo mode frequency = 13 MHz * L * N
 135  * System bus frequency = 13 MHz * L / (B + 1)
 136  *
 137  * In CCCR:
 138  * A = 1
 139  * L = 16         oscillator to run mode ratio
 140  * 2N = 6         2 * (turbo mode to run mode ratio)
 141  *
 142  * In CCLKCFG:
 143  * B = 1          Fast bus mode
 144  * HT = 0         Half-Turbo mode
 145  * T = 1          Turbo mode
 146  *
 147  * For now, just support some of the combinations in table 3-7 of
 148  * PXA27x Processor Family Developer's Manual to simplify frequency
 149  * change sequences.
 150  */
 151 #define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
 152 #define CCLKCFG2(B, HT, T) \
 153   (CCLKCFG_FCS | \
 154    ((B)  ? CCLKCFG_FASTBUS : 0) | \
 155    ((HT) ? CCLKCFG_HALFTURBO : 0) | \
 156    ((T)  ? CCLKCFG_TURBO : 0))
 157
 158 static struct pxa_freqs pxa27x_freqs[] = {
 159         {104000, 104000, PXA27x_CCCR(1,  8, 2), 0, CCLKCFG2(1, 0, 1),  900000, 1705000 },
 160         {156000, 104000, PXA27x_CCCR(1,  8, 3), 0, CCLKCFG2(1, 0, 1), 1000000, 1705000 },
 161         {208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1), 1180000, 1705000 },
 162         {312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1), 1250000, 1705000 },
 163         {416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1), 1350000, 1705000 },
 164         {520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1), 1450000, 1705000 },
 165         {624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1), 1550000, 1705000 }
 166 };
 167
 168 #define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
 169 static struct cpufreq_frequency_table
 170         pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 171
 172 extern unsigned get_clk_frequency_khz(int info);
 173
 174 #ifdef CONFIG_REGULATOR
 175
 176 static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 177 {
 178         int ret = 0;
 179         int vmin, vmax;
 180
 181         if (!cpu_is_pxa27x())
 182                 return 0;
 183
 184         vmin = pxa_freq->vmin;
 185         vmax = pxa_freq->vmax;
 186         if ((vmin == -1) || (vmax == -1))
 187                 return 0;
 188
 189         ret = regulator_set_voltage(vcc_core, vmin, vmax);
 190         if (ret)
 191                 pr_err("Failed to set vcc_core in [%dmV..%dmV]\n", vmin, vmax);
 192         return ret;
 193 }
 194
 195 static void __init pxa_cpufreq_init_voltages(void)
 196 {
 197         vcc_core = regulator_get(NULL, "vcc_core");
 198         if (IS_ERR(vcc_core)) {
 199                 pr_info("Didn't find vcc_core regulator\n");
 200                 vcc_core = NULL;
 201         } else {
 202                 pr_info("Found vcc_core regulator\n");
 203         }
 204 }
 205 #else
 206 static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 207 {
 208         return 0;
 209 }
 210
 211 static void __init pxa_cpufreq_init_voltages(void) { }
 212 #endif
 213
 214 static void find_freq_tables(struct cpufreq_frequency_table **freq_table,
 215                              const struct pxa_freqs **pxa_freqs)
 216 {
 217         if (cpu_is_pxa25x()) {
 218                 if (!pxa255_turbo_table) {
 219                         *pxa_freqs = pxa255_run_freqs;
 220                         *freq_table = pxa255_run_freq_table;
 221                 } else {
 222                         *pxa_freqs = pxa255_turbo_freqs;
 223                         *freq_table = pxa255_turbo_freq_table;
 224                 }
 225         } else if (cpu_is_pxa27x()) {
 226                 *pxa_freqs = pxa27x_freqs;
 227                 *freq_table = pxa27x_freq_table;
 228         } else {
 229                 BUG();
 230         }
 231 }
 232
 233 static void pxa27x_guess_max_freq(void)
 234 {
 235         if (!pxa27x_maxfreq) {
 236                 pxa27x_maxfreq = 416000;
 237                 pr_info("PXA CPU 27x max frequency not defined (pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
 238                         pxa27x_maxfreq);
 239         } else {
 240                 pxa27x_maxfreq *= 1000;
 241         }
 242 }
 243
 244 static 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
 258 static 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 static unsigned int pxa_cpufreq_get(unsigned int cpu)
 266 {
 267         return get_clk_frequency_khz(0);
 268 }
 269
 270 static int pxa_set_target(struct cpufreq_policy *policy, unsigned int idx)
 271 {
 272         struct cpufreq_frequency_table *pxa_freqs_table;
 273         const struct pxa_freqs *pxa_freq_settings;
 274         unsigned long flags;
 275         unsigned int new_freq_cpu, new_freq_mem;
 276         unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg;
 277         int ret = 0;
 278
 279         /* Get the current policy */
 280         find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
 281
 282         new_freq_cpu = pxa_freq_settings[idx].khz;
 283         new_freq_mem = pxa_freq_settings[idx].membus;
 284
 285         if (freq_debug)
 286                 pr_debug("Changing CPU frequency to %d Mhz, (SDRAM %d Mhz)\n",
 287                          new_freq_cpu / 1000, (pxa_freq_settings[idx].div2) ?
 288                          (new_freq_mem / 2000) : (new_freq_mem / 1000));
 289
 290         if (vcc_core && new_freq_cpu > policy->cur) {
 291                 ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 292                 if (ret)
 293                         return ret;
 294         }
 295
 296         /* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
 297          * we need to preset the smaller DRI before the change.  If we're
 298          * speeding up we need to set the larger DRI value after the change.
 299          */
 300         preset_mdrefr = postset_mdrefr = __raw_readl(MDREFR);
 301         if ((preset_mdrefr & MDREFR_DRI_MASK) > mdrefr_dri(new_freq_mem)) {
 302                 preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
 303                 preset_mdrefr |= mdrefr_dri(new_freq_mem);
 304         }
 305         postset_mdrefr =
 306                 (postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem);
 307
 308         /* If we're dividing the memory clock by two for the SDRAM clock, this
 309          * must be set prior to the change.  Clearing the divide must be done
 310          * after the change.
 311          */
 312         if (pxa_freq_settings[idx].div2) {
 313                 preset_mdrefr  |= MDREFR_DB2_MASK;
 314                 postset_mdrefr |= MDREFR_DB2_MASK;
 315         } else {
 316                 postset_mdrefr &= ~MDREFR_DB2_MASK;
 317         }
 318
 319         local_irq_save(flags);
 320
 321         /* Set new the CCCR and prepare CCLKCFG */
 322         writel(pxa_freq_settings[idx].cccr, CCCR);
 323         cclkcfg = pxa_freq_settings[idx].cclkcfg;
 324
 325         asm volatile("                                                  \n\
 326                 ldr     r4, [%1]                /* load MDREFR */       \n\
 327                 b       2f                                              \n\
 328                 .align  5                                               \n\
 329 1:                                                                      \n\
 330                 str     %3, [%1]                /* preset the MDREFR */ \n\
 331                 mcr     p14, 0, %2, c6, c0, 0   /* set CCLKCFG[FCS] */  \n\
 332                 str     %4, [%1]                /* postset the MDREFR */ \n\
 333                                                                         \n\
 334                 b       3f                                              \n\
 335 2:              b       1b                                              \n\
 336 3:              nop                                                     \n\
 337           "
 338                      : "=&r" (unused)
 339                      : "r" (MDREFR), "r" (cclkcfg),
 340                        "r" (preset_mdrefr), "r" (postset_mdrefr)
 341                      : "r4", "r5");
 342         local_irq_restore(flags);
 343
 344         /*
 345          * Even if voltage setting fails, we don't report it, as the frequency
 346          * change succeeded. The voltage reduction is not a critical failure,
 347          * only power savings will suffer from this.
 348          *
 349          * Note: if the voltage change fails, and a return value is returned, a
 350          * bug is triggered (seems a deadlock). Should anybody find out where,
 351          * the "return 0" should become a "return ret".
 352          */
 353         if (vcc_core && new_freq_cpu < policy->cur)
 354                 ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 355
 356         return 0;
 357 }
 358
 359 static int pxa_cpufreq_init(struct cpufreq_policy *policy)
 360 {
 361         int i;
 362         unsigned int freq;
 363         struct cpufreq_frequency_table *pxa255_freq_table;
 364         const struct pxa_freqs *pxa255_freqs;
 365
 366         /* try to guess pxa27x cpu */
 367         if (cpu_is_pxa27x())
 368                 pxa27x_guess_max_freq();
 369
 370         pxa_cpufreq_init_voltages();
 371
 372         init_sdram_rows();
 373
 374         /* set default policy and cpuinfo */
 375         policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
 376
 377         /* Generate pxa25x the run cpufreq_frequency_table struct */
 378         for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
 379                 pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
 380                 pxa255_run_freq_table[i].driver_data = i;
 381         }
 382         pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
 383
 384         /* Generate pxa25x the turbo cpufreq_frequency_table struct */
 385         for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
 386                 pxa255_turbo_freq_table[i].frequency =
 387                         pxa255_turbo_freqs[i].khz;
 388                 pxa255_turbo_freq_table[i].driver_data = i;
 389         }
 390         pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
 391
 392         pxa255_turbo_table = !!pxa255_turbo_table;
 393
 394         /* Generate the pxa27x cpufreq_frequency_table struct */
 395         for (i = 0; i < NUM_PXA27x_FREQS; i++) {
 396                 freq = pxa27x_freqs[i].khz;
 397                 if (freq > pxa27x_maxfreq)
 398                         break;
 399                 pxa27x_freq_table[i].frequency = freq;
 400                 pxa27x_freq_table[i].driver_data = i;
 401         }
 402         pxa27x_freq_table[i].driver_data = i;
 403         pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
 404
 405         /*
 406          * Set the policy's minimum and maximum frequencies from the tables
 407          * just constructed.  This sets cpuinfo.mxx_freq, min and max.
 408          */
 409         if (cpu_is_pxa25x()) {
 410                 find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
 411                 pr_info("using %s frequency table\n",
 412                         pxa255_turbo_table ? "turbo" : "run");
 413
 414                 cpufreq_table_validate_and_show(policy, pxa255_freq_table);
 415         }
 416         else if (cpu_is_pxa27x()) {
 417                 cpufreq_table_validate_and_show(policy, pxa27x_freq_table);
 418         }
 419
 420         pr_info("frequency change support initialized\n");
 421
 422         return 0;
 423 }
 424
 425 static struct cpufreq_driver pxa_cpufreq_driver = {
 426         .flags  = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 427         .verify = cpufreq_generic_frequency_table_verify,
 428         .target_index = pxa_set_target,
 429         .init   = pxa_cpufreq_init,
 430         .get    = pxa_cpufreq_get,
 431         .name   = "PXA2xx",
 432 };
 433
 434 static int __init pxa_cpu_init(void)
 435 {
 436         int ret = -ENODEV;
 437         if (cpu_is_pxa25x() || cpu_is_pxa27x())
 438                 ret = cpufreq_register_driver(&pxa_cpufreq_driver);
 439         return ret;
 440 }
 441
 442 static void __exit pxa_cpu_exit(void)
 443 {
 444         cpufreq_unregister_driver(&pxa_cpufreq_driver);
 445 }
 446
 447
 448 MODULE_AUTHOR("Intrinsyc Software Inc.");
 449 MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 450 MODULE_LICENSE("GPL");
 451 module_init(pxa_cpu_init);
 452 module_exit(pxa_cpu_exit);