LXR linux/drivers/cpufreq/pxa2xx-cpufreq.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  Copyright (C) 2002,2003 Intrinsyc Software
   4 *
   5 * History:
   6 *   31-Jul-2002 : Initial version [FB]
   7 *   29-Jan-2003 : added PXA255 support [FB]
   8 *   20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
   9 *
  10 * Note:
  11 *   This driver may change the memory bus clock rate, but will not do any
  12 *   platform specific access timing changes... for example if you have flash
  13 *   memory connected to CS0, you will need to register a platform specific
  14 *   notifier which will adjust the memory access strobes to maintain a
  15 *   minimum strobe width.
  16 */
  17
  18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20#include <linux/kernel.h>
  21#include <linux/module.h>
  22#include <linux/sched.h>
  23#include <linux/init.h>
  24#include <linux/cpufreq.h>
  25#include <linux/err.h>
  26#include <linux/regulator/consumer.h>
  27#include <linux/io.h>
  28
  29#include <mach/pxa2xx-regs.h>
  30#include <mach/smemc.h>
  31
  32#ifdef DEBUG
  33static unsigned int freq_debug;
  34module_param(freq_debug, uint, 0);
  35MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
  36#else
  37#define freq_debug  0
  38#endif
  39
  40static struct regulator *vcc_core;
  41
  42static unsigned int pxa27x_maxfreq;
  43module_param(pxa27x_maxfreq, uint, 0);
  44MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
  45                 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
  46
  47struct pxa_cpufreq_data {
  48        struct clk *clk_core;
  49};
  50static struct pxa_cpufreq_data  pxa_cpufreq_data;
  51
  52struct pxa_freqs {
  53        unsigned int khz;
  54        int vmin;
  55        int vmax;
  56};
  57
  58/*
  59 * PXA255 definitions
  60 */
  61static const struct pxa_freqs pxa255_run_freqs[] =
  62{
  63        /* CPU   MEMBUS            run  turbo PXbus SDRAM */
  64        { 99500, -1, -1},       /*  99,   99,   50,   50  */
  65        {132700, -1, -1},       /* 133,  133,   66,   66  */
  66        {199100, -1, -1},       /* 199,  199,   99,   99  */
  67        {265400, -1, -1},       /* 265,  265,  133,   66  */
  68        {331800, -1, -1},       /* 331,  331,  166,   83  */
  69        {398100, -1, -1},       /* 398,  398,  196,   99  */
  70};
  71
  72/* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
  73static const struct pxa_freqs pxa255_turbo_freqs[] =
  74{
  75        /* CPU                     run  turbo PXbus SDRAM */
  76        { 99500, -1, -1},       /*  99,   99,   50,   50  */
  77        {199100, -1, -1},       /*  99,  199,   50,   99  */
  78        {298500, -1, -1},       /*  99,  287,   50,   99  */
  79        {298600, -1, -1},       /* 199,  287,   99,   99  */
  80        {398100, -1, -1},       /* 199,  398,   99,   99  */
  81};
  82
  83#define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
  84#define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
  85
  86static struct cpufreq_frequency_table
  87        pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
  88static struct cpufreq_frequency_table
  89        pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
  90
  91static unsigned int pxa255_turbo_table;
  92module_param(pxa255_turbo_table, uint, 0);
  93MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
  94
  95static struct pxa_freqs pxa27x_freqs[] = {
  96        {104000,  900000, 1705000 },
  97        {156000, 1000000, 1705000 },
  98        {208000, 1180000, 1705000 },
  99        {312000, 1250000, 1705000 },
 100        {416000, 1350000, 1705000 },
 101        {520000, 1450000, 1705000 },
 102        {624000, 1550000, 1705000 }
 103};
 104
 105#define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
 106static struct cpufreq_frequency_table
 107        pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 108
 109extern unsigned get_clk_frequency_khz(int info);
 110
 111#ifdef CONFIG_REGULATOR
 112
 113static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 114{
 115        int ret = 0;
 116        int vmin, vmax;
 117
 118        if (!cpu_is_pxa27x())
 119                return 0;
 120
 121        vmin = pxa_freq->vmin;
 122        vmax = pxa_freq->vmax;
 123        if ((vmin == -1) || (vmax == -1))
 124                return 0;
 125
 126        ret = regulator_set_voltage(vcc_core, vmin, vmax);
 127        if (ret)
 128                pr_err("Failed to set vcc_core in [%dmV..%dmV]\n", vmin, vmax);
 129        return ret;
 130}
 131
 132static void pxa_cpufreq_init_voltages(void)
 133{
 134        vcc_core = regulator_get(NULL, "vcc_core");
 135        if (IS_ERR(vcc_core)) {
 136                pr_info("Didn't find vcc_core regulator\n");
 137                vcc_core = NULL;
 138        } else {
 139                pr_info("Found vcc_core regulator\n");
 140        }
 141}
 142#else
 143static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 144{
 145        return 0;
 146}
 147
 148static void pxa_cpufreq_init_voltages(void) { }
 149#endif
 150
 151static void find_freq_tables(struct cpufreq_frequency_table **freq_table,
 152                             const struct pxa_freqs **pxa_freqs)
 153{
 154        if (cpu_is_pxa25x()) {
 155                if (!pxa255_turbo_table) {
 156                        *pxa_freqs = pxa255_run_freqs;
 157                        *freq_table = pxa255_run_freq_table;
 158                } else {
 159                        *pxa_freqs = pxa255_turbo_freqs;
 160                        *freq_table = pxa255_turbo_freq_table;
 161                }
 162        } else if (cpu_is_pxa27x()) {
 163                *pxa_freqs = pxa27x_freqs;
 164                *freq_table = pxa27x_freq_table;
 165        } else {
 166                BUG();
 167        }
 168}
 169
 170static void pxa27x_guess_max_freq(void)
 171{
 172        if (!pxa27x_maxfreq) {
 173                pxa27x_maxfreq = 416000;
 174                pr_info("PXA CPU 27x max frequency not defined (pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
 175                        pxa27x_maxfreq);
 176        } else {
 177                pxa27x_maxfreq *= 1000;
 178        }
 179}
 180
 181static unsigned int pxa_cpufreq_get(unsigned int cpu)
 182{
 183        struct pxa_cpufreq_data *data = cpufreq_get_driver_data();
 184
 185        return (unsigned int) clk_get_rate(data->clk_core) / 1000;
 186}
 187
 188static int pxa_set_target(struct cpufreq_policy *policy, unsigned int idx)
 189{
 190        struct cpufreq_frequency_table *pxa_freqs_table;
 191        const struct pxa_freqs *pxa_freq_settings;
 192        struct pxa_cpufreq_data *data = cpufreq_get_driver_data();
 193        unsigned int new_freq_cpu;
 194        int ret = 0;
 195
 196        /* Get the current policy */
 197        find_freq_tables(&pxa_freqs_table, &pxa_freq_settings);
 198
 199        new_freq_cpu = pxa_freq_settings[idx].khz;
 200
 201        if (freq_debug)
 202                pr_debug("Changing CPU frequency from %d Mhz to %d Mhz\n",
 203                         policy->cur / 1000,  new_freq_cpu / 1000);
 204
 205        if (vcc_core && new_freq_cpu > policy->cur) {
 206                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 207                if (ret)
 208                        return ret;
 209        }
 210
 211        clk_set_rate(data->clk_core, new_freq_cpu * 1000);
 212
 213        /*
 214         * Even if voltage setting fails, we don't report it, as the frequency
 215         * change succeeded. The voltage reduction is not a critical failure,
 216         * only power savings will suffer from this.
 217         *
 218         * Note: if the voltage change fails, and a return value is returned, a
 219         * bug is triggered (seems a deadlock). Should anybody find out where,
 220         * the "return 0" should become a "return ret".
 221         */
 222        if (vcc_core && new_freq_cpu < policy->cur)
 223                ret = pxa_cpufreq_change_voltage(&pxa_freq_settings[idx]);
 224
 225        return 0;
 226}
 227
 228static int pxa_cpufreq_init(struct cpufreq_policy *policy)
 229{
 230        int i;
 231        unsigned int freq;
 232        struct cpufreq_frequency_table *pxa255_freq_table;
 233        const struct pxa_freqs *pxa255_freqs;
 234
 235        /* try to guess pxa27x cpu */
 236        if (cpu_is_pxa27x())
 237                pxa27x_guess_max_freq();
 238
 239        pxa_cpufreq_init_voltages();
 240
 241        /* set default policy and cpuinfo */
 242        policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
 243
 244        /* Generate pxa25x the run cpufreq_frequency_table struct */
 245        for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
 246                pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
 247                pxa255_run_freq_table[i].driver_data = i;
 248        }
 249        pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;
 250
 251        /* Generate pxa25x the turbo cpufreq_frequency_table struct */
 252        for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
 253                pxa255_turbo_freq_table[i].frequency =
 254                        pxa255_turbo_freqs[i].khz;
 255                pxa255_turbo_freq_table[i].driver_data = i;
 256        }
 257        pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;
 258
 259        pxa255_turbo_table = !!pxa255_turbo_table;
 260
 261        /* Generate the pxa27x cpufreq_frequency_table struct */
 262        for (i = 0; i < NUM_PXA27x_FREQS; i++) {
 263                freq = pxa27x_freqs[i].khz;
 264                if (freq > pxa27x_maxfreq)
 265                        break;
 266                pxa27x_freq_table[i].frequency = freq;
 267                pxa27x_freq_table[i].driver_data = i;
 268        }
 269        pxa27x_freq_table[i].driver_data = i;
 270        pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;
 271
 272        /*
 273         * Set the policy's minimum and maximum frequencies from the tables
 274         * just constructed.  This sets cpuinfo.mxx_freq, min and max.
 275         */
 276        if (cpu_is_pxa25x()) {
 277                find_freq_tables(&pxa255_freq_table, &pxa255_freqs);
 278                pr_info("using %s frequency table\n",
 279                        pxa255_turbo_table ? "turbo" : "run");
 280
 281                policy->freq_table = pxa255_freq_table;
 282        }
 283        else if (cpu_is_pxa27x()) {
 284                policy->freq_table = pxa27x_freq_table;
 285        }
 286
 287        pr_info("frequency change support initialized\n");
 288
 289        return 0;
 290}
 291
 292static struct cpufreq_driver pxa_cpufreq_driver = {
 293        .flags  = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 294        .verify = cpufreq_generic_frequency_table_verify,
 295        .target_index = pxa_set_target,
 296        .init   = pxa_cpufreq_init,
 297        .get    = pxa_cpufreq_get,
 298        .name   = "PXA2xx",
 299        .driver_data = &pxa_cpufreq_data,
 300};
 301
 302static int __init pxa_cpu_init(void)
 303{
 304        int ret = -ENODEV;
 305
 306        pxa_cpufreq_data.clk_core = clk_get_sys(NULL, "core");
 307        if (IS_ERR(pxa_cpufreq_data.clk_core))
 308                return PTR_ERR(pxa_cpufreq_data.clk_core);
 309
 310        if (cpu_is_pxa25x() || cpu_is_pxa27x())
 311                ret = cpufreq_register_driver(&pxa_cpufreq_driver);
 312        return ret;
 313}
 314
 315static void __exit pxa_cpu_exit(void)
 316{
 317        cpufreq_unregister_driver(&pxa_cpufreq_driver);
 318}
 319
 320
 321MODULE_AUTHOR("Intrinsyc Software Inc.");
 322MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 323MODULE_LICENSE("GPL");
 324module_init(pxa_cpu_init);
 325module_exit(pxa_cpu_exit);
 326