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
  33 static unsigned int freq_debug;
  34 module_param(freq_debug, uint, 0);
  35 MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
  36 #else
  37 #define freq_debug  0
  38 #endif
  39
  40 static struct regulator *vcc_core;
  41
  42 static unsigned int pxa27x_maxfreq;
  43 module_param(pxa27x_maxfreq, uint, 0);
  44 MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
  45                  "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
  46
  47 struct pxa_cpufreq_data {
  48         struct clk *clk_core;
  49 };
  50 static struct pxa_cpufreq_data  pxa_cpufreq_data;
  51
  52 struct pxa_freqs {
  53         unsigned int khz;
  54         int vmin;
  55         int vmax;
  56 };
  57
  58 /*
  59  * PXA255 definitions
  60  */
  61 static 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 */
  73 static 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
  86 static struct cpufreq_frequency_table
  87         pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
  88 static struct cpufreq_frequency_table
  89         pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];
  90
  91 static unsigned int pxa255_turbo_table;
  92 module_param(pxa255_turbo_table, uint, 0);
  93 MODULE_PARM_DESC(pxa255_turbo_table, "Selects the frequency table (0 = run table, !0 = turbo table)");
  94
  95 static 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)
 106 static struct cpufreq_frequency_table
 107         pxa27x_freq_table[NUM_PXA27x_FREQS+1];
 108
 109 extern unsigned get_clk_frequency_khz(int info);
 110
 111 #ifdef CONFIG_REGULATOR
 112
 113 static 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
 132 static 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
 143 static int pxa_cpufreq_change_voltage(const struct pxa_freqs *pxa_freq)
 144 {
 145         return 0;
 146 }
 147
 148 static void pxa_cpufreq_init_voltages(void) { }
 149 #endif
 150
 151 static 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
 170 static 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
 181 static 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
 188 static 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
 228 static 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
 292 static 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
 302 static 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
 315 static void __exit pxa_cpu_exit(void)
 316 {
 317         cpufreq_unregister_driver(&pxa_cpufreq_driver);
 318 }
 319
 320
 321 MODULE_AUTHOR("Intrinsyc Software Inc.");
 322 MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
 323 MODULE_LICENSE("GPL");
 324 module_init(pxa_cpu_init);
 325 module_exit(pxa_cpu_exit);