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