drivers/cpufreq/imx6q-cpufreq.c

   1 /*
   2  * Copyright (C) 2013 Freescale Semiconductor, Inc.
   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 version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/cpu.h>
  11 #include <linux/cpufreq.h>
  12 #include <linux/err.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16 #include <linux/pm_opp.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regulator/consumer.h>
  19
  20 #define PU_SOC_VOLTAGE_NORMAL   1250000
  21 #define PU_SOC_VOLTAGE_HIGH     1275000
  22 #define FREQ_1P2_GHZ            1200000000
  23
  24 static struct regulator *arm_reg;
  25 static struct regulator *pu_reg;
  26 static struct regulator *soc_reg;
  27
  28 static struct clk *arm_clk;
  29 static struct clk *pll1_sys_clk;
  30 static struct clk *pll1_sw_clk;
  31 static struct clk *step_clk;
  32 static struct clk *pll2_pfd2_396m_clk;
  33
  34 /* clk used by i.MX6UL */
  35 static struct clk *pll2_bus_clk;
  36 static struct clk *secondary_sel_clk;
  37
  38 static struct device *cpu_dev;
  39 static bool free_opp;
  40 static struct cpufreq_frequency_table *freq_table;
  41 static unsigned int transition_latency;
  42
  43 static u32 *imx6_soc_volt;
  44 static u32 soc_opp_count;
  45
  46 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
  47 {
  48         struct dev_pm_opp *opp;
  49         unsigned long freq_hz, volt, volt_old;
  50         unsigned int old_freq, new_freq;
  51         bool pll1_sys_temp_enabled = false;
  52         int ret;
  53
  54         new_freq = freq_table[index].frequency;
  55         freq_hz = new_freq * 1000;
  56         old_freq = clk_get_rate(arm_clk) / 1000;
  57
  58         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
  59         if (IS_ERR(opp)) {
  60                 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
  61                 return PTR_ERR(opp);
  62         }
  63
  64         volt = dev_pm_opp_get_voltage(opp);
  65         dev_pm_opp_put(opp);
  66
  67         volt_old = regulator_get_voltage(arm_reg);
  68
  69         dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
  70                 old_freq / 1000, volt_old / 1000,
  71                 new_freq / 1000, volt / 1000);
  72
  73         /* scaling up?  scale voltage before frequency */
  74         if (new_freq > old_freq) {
  75                 if (!IS_ERR(pu_reg)) {
  76                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
  77                         if (ret) {
  78                                 dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
  79                                 return ret;
  80                         }
  81                 }
  82                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
  83                 if (ret) {
  84                         dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
  85                         return ret;
  86                 }
  87                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
  88                 if (ret) {
  89                         dev_err(cpu_dev,
  90                                 "failed to scale vddarm up: %d\n", ret);
  91                         return ret;
  92                 }
  93         }
  94
  95         /*
  96          * The setpoints are selected per PLL/PDF frequencies, so we need to
  97          * reprogram PLL for frequency scaling.  The procedure of reprogramming
  98          * PLL1 is as below.
  99          * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
 100          * flow is slightly different from other i.MX6 OSC.
 101          * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
 102          *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
 103          *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
 104          *  - Disable pll2_pfd2_396m_clk
 105          */
 106         if (of_machine_is_compatible("fsl,imx6ul") ||
 107             of_machine_is_compatible("fsl,imx6ull")) {
 108                 /*
 109                  * When changing pll1_sw_clk's parent to pll1_sys_clk,
 110                  * CPU may run at higher than 528MHz, this will lead to
 111                  * the system unstable if the voltage is lower than the
 112                  * voltage of 528MHz, so lower the CPU frequency to one
 113                  * half before changing CPU frequency.
 114                  */
 115                 clk_set_rate(arm_clk, (old_freq >> 1) * 1000);
 116                 clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 117                 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
 118                         clk_set_parent(secondary_sel_clk, pll2_bus_clk);
 119                 else
 120                         clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
 121                 clk_set_parent(step_clk, secondary_sel_clk);
 122                 clk_set_parent(pll1_sw_clk, step_clk);
 123         } else {
 124                 clk_set_parent(step_clk, pll2_pfd2_396m_clk);
 125                 clk_set_parent(pll1_sw_clk, step_clk);
 126                 if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
 127                         clk_set_rate(pll1_sys_clk, new_freq * 1000);
 128                         clk_set_parent(pll1_sw_clk, pll1_sys_clk);
 129                 } else {
 130                         /* pll1_sys needs to be enabled for divider rate change to work. */
 131                         pll1_sys_temp_enabled = true;
 132                         clk_prepare_enable(pll1_sys_clk);
 133                 }
 134         }
 135
 136         /* Ensure the arm clock divider is what we expect */
 137         ret = clk_set_rate(arm_clk, new_freq * 1000);
 138         if (ret) {
 139                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 140                 regulator_set_voltage_tol(arm_reg, volt_old, 0);
 141                 return ret;
 142         }
 143
 144         /* PLL1 is only needed until after ARM-PODF is set. */
 145         if (pll1_sys_temp_enabled)
 146                 clk_disable_unprepare(pll1_sys_clk);
 147
 148         /* scaling down?  scale voltage after frequency */
 149         if (new_freq < old_freq) {
 150                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 151                 if (ret) {
 152                         dev_warn(cpu_dev,
 153                                  "failed to scale vddarm down: %d\n", ret);
 154                         ret = 0;
 155                 }
 156                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 157                 if (ret) {
 158                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 159                         ret = 0;
 160                 }
 161                 if (!IS_ERR(pu_reg)) {
 162                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 163                         if (ret) {
 164                                 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 165                                 ret = 0;
 166                         }
 167                 }
 168         }
 169
 170         return 0;
 171 }
 172
 173 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 174 {
 175         int ret;
 176
 177         policy->clk = arm_clk;
 178         ret = cpufreq_generic_init(policy, freq_table, transition_latency);
 179         policy->suspend_freq = policy->max;
 180
 181         return ret;
 182 }
 183
 184 static struct cpufreq_driver imx6q_cpufreq_driver = {
 185         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 186         .verify = cpufreq_generic_frequency_table_verify,
 187         .target_index = imx6q_set_target,
 188         .get = cpufreq_generic_get,
 189         .init = imx6q_cpufreq_init,
 190         .name = "imx6q-cpufreq",
 191         .attr = cpufreq_generic_attr,
 192         .suspend = cpufreq_generic_suspend,
 193 };
 194
 195 #define OCOTP_CFG3                      0x440
 196 #define OCOTP_CFG3_SPEED_SHIFT          16
 197 #define OCOTP_CFG3_SPEED_1P2GHZ         0x3
 198 #define OCOTP_CFG3_SPEED_996MHZ         0x2
 199 #define OCOTP_CFG3_SPEED_852MHZ         0x1
 200
 201 static void imx6q_opp_check_speed_grading(struct device *dev)
 202 {
 203         struct device_node *np;
 204         void __iomem *base;
 205         u32 val;
 206
 207         np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp");
 208         if (!np)
 209                 return;
 210
 211         base = of_iomap(np, 0);
 212         if (!base) {
 213                 dev_err(dev, "failed to map ocotp\n");
 214                 goto put_node;
 215         }
 216
 217         /*
 218          * SPEED_GRADING[1:0] defines the max speed of ARM:
 219          * 2b'11: 1200000000Hz;
 220          * 2b'10: 996000000Hz;
 221          * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
 222          * 2b'00: 792000000Hz;
 223          * We need to set the max speed of ARM according to fuse map.
 224          */
 225         val = readl_relaxed(base + OCOTP_CFG3);
 226         val >>= OCOTP_CFG3_SPEED_SHIFT;
 227         val &= 0x3;
 228
 229         if ((val != OCOTP_CFG3_SPEED_1P2GHZ) &&
 230              of_machine_is_compatible("fsl,imx6q"))
 231                 if (dev_pm_opp_disable(dev, 1200000000))
 232                         dev_warn(dev, "failed to disable 1.2GHz OPP\n");
 233         if (val < OCOTP_CFG3_SPEED_996MHZ)
 234                 if (dev_pm_opp_disable(dev, 996000000))
 235                         dev_warn(dev, "failed to disable 996MHz OPP\n");
 236         if (of_machine_is_compatible("fsl,imx6q")) {
 237                 if (val != OCOTP_CFG3_SPEED_852MHZ)
 238                         if (dev_pm_opp_disable(dev, 852000000))
 239                                 dev_warn(dev, "failed to disable 852MHz OPP\n");
 240         }
 241         iounmap(base);
 242 put_node:
 243         of_node_put(np);
 244 }
 245
 246 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 247 {
 248         struct device_node *np;
 249         struct dev_pm_opp *opp;
 250         unsigned long min_volt, max_volt;
 251         int num, ret;
 252         const struct property *prop;
 253         const __be32 *val;
 254         u32 nr, i, j;
 255
 256         cpu_dev = get_cpu_device(0);
 257         if (!cpu_dev) {
 258                 pr_err("failed to get cpu0 device\n");
 259                 return -ENODEV;
 260         }
 261
 262         np = of_node_get(cpu_dev->of_node);
 263         if (!np) {
 264                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 265                 return -ENOENT;
 266         }
 267
 268         arm_clk = clk_get(cpu_dev, "arm");
 269         pll1_sys_clk = clk_get(cpu_dev, "pll1_sys");
 270         pll1_sw_clk = clk_get(cpu_dev, "pll1_sw");
 271         step_clk = clk_get(cpu_dev, "step");
 272         pll2_pfd2_396m_clk = clk_get(cpu_dev, "pll2_pfd2_396m");
 273         if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
 274             IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
 275                 dev_err(cpu_dev, "failed to get clocks\n");
 276                 ret = -ENOENT;
 277                 goto put_clk;
 278         }
 279
 280         if (of_machine_is_compatible("fsl,imx6ul") ||
 281             of_machine_is_compatible("fsl,imx6ull")) {
 282                 pll2_bus_clk = clk_get(cpu_dev, "pll2_bus");
 283                 secondary_sel_clk = clk_get(cpu_dev, "secondary_sel");
 284                 if (IS_ERR(pll2_bus_clk) || IS_ERR(secondary_sel_clk)) {
 285                         dev_err(cpu_dev, "failed to get clocks specific to imx6ul\n");
 286                         ret = -ENOENT;
 287                         goto put_clk;
 288                 }
 289         }
 290
 291         arm_reg = regulator_get(cpu_dev, "arm");
 292         pu_reg = regulator_get_optional(cpu_dev, "pu");
 293         soc_reg = regulator_get(cpu_dev, "soc");
 294         if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
 295                         PTR_ERR(soc_reg) == -EPROBE_DEFER ||
 296                         PTR_ERR(pu_reg) == -EPROBE_DEFER) {
 297                 ret = -EPROBE_DEFER;
 298                 dev_dbg(cpu_dev, "regulators not ready, defer\n");
 299                 goto put_reg;
 300         }
 301         if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 302                 dev_err(cpu_dev, "failed to get regulators\n");
 303                 ret = -ENOENT;
 304                 goto put_reg;
 305         }
 306
 307         ret = dev_pm_opp_of_add_table(cpu_dev);
 308         if (ret < 0) {
 309                 dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 310                 goto put_reg;
 311         }
 312
 313         imx6q_opp_check_speed_grading(cpu_dev);
 314
 315         /* Because we have added the OPPs here, we must free them */
 316         free_opp = true;
 317         num = dev_pm_opp_get_opp_count(cpu_dev);
 318         if (num < 0) {
 319                 ret = num;
 320                 dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 321                 goto out_free_opp;
 322         }
 323
 324         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 325         if (ret) {
 326                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 327                 goto out_free_opp;
 328         }
 329
 330         /* Make imx6_soc_volt array's size same as arm opp number */
 331         imx6_soc_volt = devm_kzalloc(cpu_dev, sizeof(*imx6_soc_volt) * num, GFP_KERNEL);
 332         if (imx6_soc_volt == NULL) {
 333                 ret = -ENOMEM;
 334                 goto free_freq_table;
 335         }
 336
 337         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 338         if (!prop || !prop->value)
 339                 goto soc_opp_out;
 340
 341         /*
 342          * Each OPP is a set of tuples consisting of frequency and
 343          * voltage like <freq-kHz vol-uV>.
 344          */
 345         nr = prop->length / sizeof(u32);
 346         if (nr % 2 || (nr / 2) < num)
 347                 goto soc_opp_out;
 348
 349         for (j = 0; j < num; j++) {
 350                 val = prop->value;
 351                 for (i = 0; i < nr / 2; i++) {
 352                         unsigned long freq = be32_to_cpup(val++);
 353                         unsigned long volt = be32_to_cpup(val++);
 354                         if (freq_table[j].frequency == freq) {
 355                                 imx6_soc_volt[soc_opp_count++] = volt;
 356                                 break;
 357                         }
 358                 }
 359         }
 360
 361 soc_opp_out:
 362         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 363         if (soc_opp_count != num) {
 364                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 365                 for (j = 0; j < num; j++)
 366                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 367                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 368                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 369         }
 370
 371         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 372                 transition_latency = CPUFREQ_ETERNAL;
 373
 374         /*
 375          * Calculate the ramp time for max voltage change in the
 376          * VDDSOC and VDDPU regulators.
 377          */
 378         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 379         if (ret > 0)
 380                 transition_latency += ret * 1000;
 381         if (!IS_ERR(pu_reg)) {
 382                 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 383                 if (ret > 0)
 384                         transition_latency += ret * 1000;
 385         }
 386
 387         /*
 388          * OPP is maintained in order of increasing frequency, and
 389          * freq_table initialised from OPP is therefore sorted in the
 390          * same order.
 391          */
 392         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 393                                   freq_table[0].frequency * 1000, true);
 394         min_volt = dev_pm_opp_get_voltage(opp);
 395         dev_pm_opp_put(opp);
 396         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 397                                   freq_table[--num].frequency * 1000, true);
 398         max_volt = dev_pm_opp_get_voltage(opp);
 399         dev_pm_opp_put(opp);
 400
 401         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 402         if (ret > 0)
 403                 transition_latency += ret * 1000;
 404
 405         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 406         if (ret) {
 407                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 408                 goto free_freq_table;
 409         }
 410
 411         of_node_put(np);
 412         return 0;
 413
 414 free_freq_table:
 415         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 416 out_free_opp:
 417         if (free_opp)
 418                 dev_pm_opp_of_remove_table(cpu_dev);
 419 put_reg:
 420         if (!IS_ERR(arm_reg))
 421                 regulator_put(arm_reg);
 422         if (!IS_ERR(pu_reg))
 423                 regulator_put(pu_reg);
 424         if (!IS_ERR(soc_reg))
 425                 regulator_put(soc_reg);
 426 put_clk:
 427         if (!IS_ERR(arm_clk))
 428                 clk_put(arm_clk);
 429         if (!IS_ERR(pll1_sys_clk))
 430                 clk_put(pll1_sys_clk);
 431         if (!IS_ERR(pll1_sw_clk))
 432                 clk_put(pll1_sw_clk);
 433         if (!IS_ERR(step_clk))
 434                 clk_put(step_clk);
 435         if (!IS_ERR(pll2_pfd2_396m_clk))
 436                 clk_put(pll2_pfd2_396m_clk);
 437         if (!IS_ERR(pll2_bus_clk))
 438                 clk_put(pll2_bus_clk);
 439         if (!IS_ERR(secondary_sel_clk))
 440                 clk_put(secondary_sel_clk);
 441         of_node_put(np);
 442         return ret;
 443 }
 444
 445 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 446 {
 447         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 448         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 449         if (free_opp)
 450                 dev_pm_opp_of_remove_table(cpu_dev);
 451         regulator_put(arm_reg);
 452         if (!IS_ERR(pu_reg))
 453                 regulator_put(pu_reg);
 454         regulator_put(soc_reg);
 455         clk_put(arm_clk);
 456         clk_put(pll1_sys_clk);
 457         clk_put(pll1_sw_clk);
 458         clk_put(step_clk);
 459         clk_put(pll2_pfd2_396m_clk);
 460         clk_put(pll2_bus_clk);
 461         clk_put(secondary_sel_clk);
 462
 463         return 0;
 464 }
 465
 466 static struct platform_driver imx6q_cpufreq_platdrv = {
 467         .driver = {
 468                 .name   = "imx6q-cpufreq",
 469         },
 470         .probe          = imx6q_cpufreq_probe,
 471         .remove         = imx6q_cpufreq_remove,
 472 };
 473 module_platform_driver(imx6q_cpufreq_platdrv);
 474
 475 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 476 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 477 MODULE_LICENSE("GPL");