LXR linux/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
  47static unsigned int freq_debug;
  48module_param(freq_debug, uint, 0);
  49MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
  50#else
  51#define freq_debug  0
  52#endif
  53
  54static struct regulator *vcc_core;
  55
  56static unsigned int pxa27x_maxfreq;
  57module_param(pxa27x_maxfreq, uint, 0);
  58MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
  59                 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
  60
  61struct pxa_cpufreq_data {
  62        struct clk *clk_core;
  63};
  64static struct pxa_cpufreq_data  pxa_cpufreq_data;
  65
  66struct pxa_freqs {
  67        unsigned int khz;
  68        int vmin;
  69        int vmax;
  70};
  71
  72/*
  73 * PXA255 definitions
  74 */
  75static 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 */
  87static 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
 100static struct cpufreq_frequency_table
 101        pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
 102static struct cpufreq_frequency_table
 103        pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
 104
 105static unsigned int pxa255_turbo_table;
 106module_param(pxa255_turbo_table, uint, 0);
 107MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
 108
 109static 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)
 120static struct cpufreq_frequency_table
 121        pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 122
 123extern unsigned get_clk_frequency_khz(int info);
 124
 125#ifdef CONFIG_REGULATOR
 126
 127static 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
 146static 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
 157static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 158{
 159        return 0;
 160}
 161
 162static void __init pxa_cpufreq_init_voltages(void) { }
 163#endif
 164
 165static 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
 184static 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
 195static 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
 202static 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
 242static 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
 306static 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
 316static 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
 329static void __exit pxa_cpu_exit(void)
 330{
 331        cpufreq_unregister_driver(&pxa_cpufreq_driver);
 332}
 333
 334
 335MODULE_AUTHOR("Intrinsyc Software Inc.");
 336MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 337MODULE_LICENSE("GPL");
 338module_init(pxa_cpu_init);
 339module_exit(pxa_cpu_exit);
 340