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_cpufreq_data {
  62         struct clk *clk_core;
  63 };
  64 static struct pxa_cpufreq_data  pxa_cpufreq_data;
  65
  66 struct pxa_freqs {
  67         unsigned int khz;
  68         int vmin;
  69         int vmax;
  70 };
  71
  72 /*
  73  * PXA255 definitions
  74  */
  75 static const struct pxa_freqs pxa255_run_freqs[] =
  76 {
  77         /* CPU   MEMBUS            run  turbo PXbus SDRAM */
  78         { 99500, -1, -1},       /*  99,   99,   50,   50  */
  79         {132700, -1, -1},       /* 133,  133,   66,   66  */
  80         {199100, -1, -1},       /* 199,  199,   99,   99  */
  81         {265400, -1, -1},       /* 265,  265,  133,   66  */
  82         {331800, -1, -1},       /* 331,  331,  166,   83  */
  83         {398100, -1, -1},       /* 398,  398,  196,   99  */
  84 };
  85
  86 /* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
  87 static const struct pxa_freqs pxa255_turbo_freqs[] =
  88 {
  89         /* CPU                     run  turbo PXbus SDRAM */
  90         { 99500, -1, -1},       /*  99,   99,   50,   50  */
  91         {199100, -1, -1},       /*  99,  199,   50,   99  */
  92         {298500, -1, -1},       /*  99,  287,   50,   99  */
  93         {298600, -1, -1},       /* 199,  287,   99,   99  */
  94         {398100, -1, -1},       /* 199,  398,   99,   99  */
  95 };
  96
  97 #define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
  98 #define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
  99
 100 static struct cpufreq_frequency_table
 101         pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
 102 static struct cpufreq_frequency_table
 103         pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
 104
 105 static unsigned int pxa255_turbo_table;
 106 module_param(pxa255_turbo_table, uint, 0);
 107 MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
 108
 109 static struct pxa_freqs pxa27x_freqs[] = {
 110         {104000,  900000, 1705000 },
 111         {156000, 1000000, 1705000 },
 112         {208000, 1180000, 1705000 },
 113         {312000, 1250000, 1705000 },
 114         {416000, 1350000, 1705000 },
 115         {520000, 1450000, 1705000 },
 116         {624000, 1550000, 1705000 }
 117 };
 118
 119 #define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
 120 static struct cpufreq_frequency_table
 121         pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 122
 123 extern unsigned get_clk_frequency_khz(int info);
 124
 125 #ifdef CONFIG_REGULATOR
 126
 127 static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 128 {
 129         int ret = 0;
 130         int vmin, vmax;
 131
 132         if (!cpu_is_pxa27x())
 133                 return 0;
 134
 135         vmin = pxa_freq->vmin;
 136         vmax = pxa_freq->vmax;
 137         if ((vmin == -1) || (vmax == -1))
 138                 return 0;
 139
 140         ret = regulator_set_voltage(vcc_core, vmin, vmax);
 141         if (ret)
 142                 pr_err("Failed to set vcc_core in [%dmV..%dmV]\n", vmin, vmax);
 143         return ret;
 144 }
 145
 146 static void __init pxa_cpufreq_init_voltages(void)
 147 {
 148         vcc_core = regulator_get(NULL, "vcc_core");
 149         if (IS_ERR(vcc_core)) {
 150                 pr_info("Didn't find vcc_core regulator\n");
 151                 vcc_core = NULL;
 152         } else {
 153                 pr_info("Found vcc_core regulator\n");
 154         }
 155 }
 156 #else
 157 static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 158 {
 159         return 0;
 160 }
 161
 162 static void __init pxa_cpufreq_init_voltages(void) { }
 163 #endif
 164
 165 static void find_freq_tables(struct cpufreq_frequency_table **freq_table,
 166                              const struct pxa_freqs **pxa_freqs)
 167 {
 168         if (cpu_is_pxa25x()) {
 169                 if (!pxa255_turbo_table) {
 170                         *pxa_freqs = pxa255_run_freqs;
 171                         *freq_table = pxa255_run_freq_table;
 172                 } else {
 173                         *pxa_freqs = pxa255_turbo_freqs;
 174                         *freq_table = pxa255_turbo_freq_table;
 175                 }
 176         } else if (cpu_is_pxa27x()) {
 177                 *pxa_freqs = pxa27x_freqs;
 178                 *freq_table = pxa27x_freq_table;
 179         } else {
 180                 BUG();
 181         }
 182 }
 183
 184 static void pxa27x_guess_max_freq(void)
 185 {
 186         if (!pxa27x_maxfreq) {
 187                 pxa27x_maxfreq = 416000;
 188                 pr_info("PXA CPU 27x max frequency not defined (pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
 189                         pxa27x_maxfreq);
 190         } else {
 191                 pxa27x_maxfreq *= 1000;
 192         }
 193 }
 194
 195 static unsigned int pxa_cpufreq_get(unsigned int cpu)
 196 {
 197         struct pxa_cpufreq_data *data = cpufreq_get_driver_data();
 198
 199         return (unsigned int) clk_get_rate(data->clk_core) / 1000;
 200 }
 201
 202 static int pxa_set_target(struct cpufreq_policy *policy, unsigned int idx)
 203 {
 204         struct cpufreq_frequency_table *pxa_freqs_table;
 205         const struct pxa_freqs *pxa_freq_settings;
 206         struct pxa_cpufreq_data *data = cpufreq_get_driver_data();
 207         unsigned int new_freq_cpu;
 208         int ret = 0;
 209
 210         /* Get the current policy */
 211         find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
 212
 213         new_freq_cpu = pxa_freq_settings[idx].khz;
 214
 215         if (freq_debug)
 216                 pr_debug("Changing CPU frequency from %d Mhz to %d Mhz\n",
 217                          policy->cur / 1000,  new_freq_cpu / 1000);
 218
 219         if (vcc_core && new_freq_cpu > policy->cur) {
 220                 ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 221                 if (ret)
 222                         return ret;
 223         }
 224
 225         clk_set_rate(data->clk_core, new_freq_cpu * 1000);
 226
 227         /*
 228          * Even if voltage setting fails, we don't report it, as the frequency
 229          * change succeeded. The voltage reduction is not a critical failure,
 230          * only power savings will suffer from this.
 231          *
 232          * Note: if the voltage change fails, and a return value is returned, a
 233          * bug is triggered (seems a deadlock). Should anybody find out where,
 234          * the "return 0" should become a "return ret".
 235          */
 236         if (vcc_core && new_freq_cpu < policy->cur)
 237                 ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 238
 239         return 0;
 240 }
 241
 242 static int pxa_cpufreq_init(struct cpufreq_policy *policy)
 243 {
 244         int i;
 245         unsigned int freq;
 246         struct cpufreq_frequency_table *pxa255_freq_table;
 247         const struct pxa_freqs *pxa255_freqs;
 248
 249         /* try to guess pxa27x cpu */
 250         if (cpu_is_pxa27x())
 251                 pxa27x_guess_max_freq();
 252
 253         pxa_cpufreq_init_voltages();
 254
 255         /* set default policy and cpuinfo */
 256         policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
 257
 258         /* Generate pxa25x the run cpufreq_frequency_table struct */
 259         for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
 260                 pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
 261                 pxa255_run_freq_table[i].driver_data = i;
 262         }
 263         pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
 264
 265         /* Generate pxa25x the turbo cpufreq_frequency_table struct */
 266         for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
 267                 pxa255_turbo_freq_table[i].frequency =
 268                         pxa255_turbo_freqs[i].khz;
 269                 pxa255_turbo_freq_table[i].driver_data = i;
 270         }
 271         pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
 272
 273         pxa255_turbo_table = !!pxa255_turbo_table;
 274
 275         /* Generate the pxa27x cpufreq_frequency_table struct */
 276         for (i = 0; i < NUM_PXA27x_FREQS; i++) {
 277                 freq = pxa27x_freqs[i].khz;
 278                 if (freq > pxa27x_maxfreq)
 279                         break;
 280                 pxa27x_freq_table[i].frequency = freq;
 281                 pxa27x_freq_table[i].driver_data = i;
 282         }
 283         pxa27x_freq_table[i].driver_data = i;
 284         pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
 285
 286         /*
 287          * Set the policy's minimum and maximum frequencies from the tables
 288          * just constructed.  This sets cpuinfo.mxx_freq, min and max.
 289          */
 290         if (cpu_is_pxa25x()) {
 291                 find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
 292                 pr_info("using %s frequency table\n",
 293                         pxa255_turbo_table ? "turbo" : "run");
 294
 295                 policy->freq_table = pxa255_freq_table;
 296         }
 297         else if (cpu_is_pxa27x()) {
 298                 policy->freq_table = pxa27x_freq_table;
 299         }
 300
 301         pr_info("frequency change support initialized\n");
 302
 303         return 0;
 304 }
 305
 306 static struct cpufreq_driver pxa_cpufreq_driver = {
 307         .flags  = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 308         .verify = cpufreq_generic_frequency_table_verify,
 309         .target_index = pxa_set_target,
 310         .init   = pxa_cpufreq_init,
 311         .get    = pxa_cpufreq_get,
 312         .name   = "PXA2xx",
 313         .driver_data = &pxa_cpufreq_data,
 314 };
 315
 316 static int __init pxa_cpu_init(void)
 317 {
 318         int ret = -ENODEV;
 319
 320         pxa_cpufreq_data.clk_core = clk_get_sys(NULL, "core");
 321         if (IS_ERR(pxa_cpufreq_data.clk_core))
 322                 return PTR_ERR(pxa_cpufreq_data.clk_core);
 323
 324         if (cpu_is_pxa25x() || cpu_is_pxa27x())
 325                 ret = cpufreq_register_driver(&pxa_cpufreq_driver);
 326         return ret;
 327 }
 328
 329 static void __exit pxa_cpu_exit(void)
 330 {
 331         cpufreq_unregister_driver(&pxa_cpufreq_driver);
 332 }
 333
 334
 335 MODULE_AUTHOR("Intrinsyc Software Inc.");
 336 MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 337 MODULE_LICENSE("GPL");
 338 module_init(pxa_cpu_init);
 339 module_exit(pxa_cpu_exit);