drivers/cpufreq/imx6q-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2013 Freescale Semiconductor, Inc.
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/cpu.h>
   8 #include <linux/cpufreq.h>
   9 #include <linux/err.h>
  10 #include <linux/module.h>
  11 #include <linux/nvmem-consumer.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/pm_opp.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regulator/consumer.h>
  17
  18 #define PU_SOC_VOLTAGE_NORMAL   1250000
  19 #define PU_SOC_VOLTAGE_HIGH     1275000
  20 #define FREQ_1P2_GHZ            1200000000
  21
  22 static struct regulator *arm_reg;
  23 static struct regulator *pu_reg;
  24 static struct regulator *soc_reg;
  25
  26 enum IMX6_CPUFREQ_CLKS {
  27         ARM,
  28         PLL1_SYS,
  29         STEP,
  30         PLL1_SW,
  31         PLL2_PFD2_396M,
  32         /* MX6UL requires two more clks */
  33         PLL2_BUS,
  34         SECONDARY_SEL,
  35 };
  36 #define IMX6Q_CPUFREQ_CLK_NUM           5
  37 #define IMX6UL_CPUFREQ_CLK_NUM          7
  38
  39 static int num_clks;
  40 static struct clk_bulk_data clks[] = {
  41         { .id = "arm" },
  42         { .id = "pll1_sys" },
  43         { .id = "step" },
  44         { .id = "pll1_sw" },
  45         { .id = "pll2_pfd2_396m" },
  46         { .id = "pll2_bus" },
  47         { .id = "secondary_sel" },
  48 };
  49
  50 static struct device *cpu_dev;
  51 static bool free_opp;
  52 static struct cpufreq_frequency_table *freq_table;
  53 static unsigned int max_freq;
  54 static unsigned int transition_latency;
  55
  56 static u32 *imx6_soc_volt;
  57 static u32 soc_opp_count;
  58
  59 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
  60 {
  61         struct dev_pm_opp *opp;
  62         unsigned long freq_hz, volt, volt_old;
  63         unsigned int old_freq, new_freq;
  64         bool pll1_sys_temp_enabled = false;
  65         int ret;
  66
  67         new_freq = freq_table[index].frequency;
  68         freq_hz = new_freq * 1000;
  69         old_freq = clk_get_rate(clks[ARM].clk) / 1000;
  70
  71         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
  72         if (IS_ERR(opp)) {
  73                 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
  74                 return PTR_ERR(opp);
  75         }
  76
  77         volt = dev_pm_opp_get_voltage(opp);
  78         dev_pm_opp_put(opp);
  79
  80         volt_old = regulator_get_voltage(arm_reg);
  81
  82         dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
  83                 old_freq / 1000, volt_old / 1000,
  84                 new_freq / 1000, volt / 1000);
  85
  86         /* scaling up?  scale voltage before frequency */
  87         if (new_freq > old_freq) {
  88                 if (!IS_ERR(pu_reg)) {
  89                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
  90                         if (ret) {
  91                                 dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
  92                                 return ret;
  93                         }
  94                 }
  95                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
  96                 if (ret) {
  97                         dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
  98                         return ret;
  99                 }
 100                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 101                 if (ret) {
 102                         dev_err(cpu_dev,
 103                                 "failed to scale vddarm up: %d\n", ret);
 104                         return ret;
 105                 }
 106         }
 107
 108         /*
 109          * The setpoints are selected per PLL/PDF frequencies, so we need to
 110          * reprogram PLL for frequency scaling.  The procedure of reprogramming
 111          * PLL1 is as below.
 112          * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
 113          * flow is slightly different from other i.MX6 OSC.
 114          * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
 115          *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
 116          *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
 117          *  - Disable pll2_pfd2_396m_clk
 118          */
 119         if (of_machine_is_compatible("fsl,imx6ul") ||
 120             of_machine_is_compatible("fsl,imx6ull")) {
 121                 /*
 122                  * When changing pll1_sw_clk's parent to pll1_sys_clk,
 123                  * CPU may run at higher than 528MHz, this will lead to
 124                  * the system unstable if the voltage is lower than the
 125                  * voltage of 528MHz, so lower the CPU frequency to one
 126                  * half before changing CPU frequency.
 127                  */
 128                 clk_set_rate(clks[ARM].clk, (old_freq >> 1) * 1000);
 129                 clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 130                 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk))
 131                         clk_set_parent(clks[SECONDARY_SEL].clk,
 132                                        clks[PLL2_BUS].clk);
 133                 else
 134                         clk_set_parent(clks[SECONDARY_SEL].clk,
 135                                        clks[PLL2_PFD2_396M].clk);
 136                 clk_set_parent(clks[STEP].clk, clks[SECONDARY_SEL].clk);
 137                 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 138                 if (freq_hz > clk_get_rate(clks[PLL2_BUS].clk)) {
 139                         clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 140                         clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 141                 }
 142         } else {
 143                 clk_set_parent(clks[STEP].clk, clks[PLL2_PFD2_396M].clk);
 144                 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 145                 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk)) {
 146                         clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 147                         clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 148                 } else {
 149                         /* pll1_sys needs to be enabled for divider rate change to work. */
 150                         pll1_sys_temp_enabled = true;
 151                         clk_prepare_enable(clks[PLL1_SYS].clk);
 152                 }
 153         }
 154
 155         /* Ensure the arm clock divider is what we expect */
 156         ret = clk_set_rate(clks[ARM].clk, new_freq * 1000);
 157         if (ret) {
 158                 int ret1;
 159
 160                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 161                 ret1 = regulator_set_voltage_tol(arm_reg, volt_old, 0);
 162                 if (ret1)
 163                         dev_warn(cpu_dev,
 164                                  "failed to restore vddarm voltage: %d\n", ret1);
 165                 return ret;
 166         }
 167
 168         /* PLL1 is only needed until after ARM-PODF is set. */
 169         if (pll1_sys_temp_enabled)
 170                 clk_disable_unprepare(clks[PLL1_SYS].clk);
 171
 172         /* scaling down?  scale voltage after frequency */
 173         if (new_freq < old_freq) {
 174                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 175                 if (ret)
 176                         dev_warn(cpu_dev,
 177                                  "failed to scale vddarm down: %d\n", ret);
 178                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 179                 if (ret)
 180                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 181                 if (!IS_ERR(pu_reg)) {
 182                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 183                         if (ret)
 184                                 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 185                 }
 186         }
 187
 188         return 0;
 189 }
 190
 191 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 192 {
 193         policy->clk = clks[ARM].clk;
 194         cpufreq_generic_init(policy, freq_table, transition_latency);
 195         policy->suspend_freq = max_freq;
 196         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 197
 198         return 0;
 199 }
 200
 201 static struct cpufreq_driver imx6q_cpufreq_driver = {
 202         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 203                  CPUFREQ_IS_COOLING_DEV,
 204         .verify = cpufreq_generic_frequency_table_verify,
 205         .target_index = imx6q_set_target,
 206         .get = cpufreq_generic_get,
 207         .init = imx6q_cpufreq_init,
 208         .name = "imx6q-cpufreq",
 209         .attr = cpufreq_generic_attr,
 210         .suspend = cpufreq_generic_suspend,
 211 };
 212
 213 #define OCOTP_CFG3                      0x440
 214 #define OCOTP_CFG3_SPEED_SHIFT          16
 215 #define OCOTP_CFG3_SPEED_1P2GHZ         0x3
 216 #define OCOTP_CFG3_SPEED_996MHZ         0x2
 217 #define OCOTP_CFG3_SPEED_852MHZ         0x1
 218
 219 static int imx6q_opp_check_speed_grading(struct device *dev)
 220 {
 221         struct device_node *np;
 222         void __iomem *base;
 223         u32 val;
 224         int ret;
 225
 226         if (of_find_property(dev->of_node, "nvmem-cells", NULL)) {
 227                 ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 228                 if (ret)
 229                         return ret;
 230         } else {
 231                 np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp");
 232                 if (!np)
 233                         return -ENOENT;
 234
 235                 base = of_iomap(np, 0);
 236                 of_node_put(np);
 237                 if (!base) {
 238                         dev_err(dev, "failed to map ocotp\n");
 239                         return -EFAULT;
 240                 }
 241
 242                 /*
 243                  * SPEED_GRADING[1:0] defines the max speed of ARM:
 244                  * 2b'11: 1200000000Hz;
 245                  * 2b'10: 996000000Hz;
 246                  * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
 247                  * 2b'00: 792000000Hz;
 248                  * We need to set the max speed of ARM according to fuse map.
 249                  */
 250                 val = readl_relaxed(base + OCOTP_CFG3);
 251                 iounmap(base);
 252         }
 253
 254         val >>= OCOTP_CFG3_SPEED_SHIFT;
 255         val &= 0x3;
 256
 257         if (val < OCOTP_CFG3_SPEED_996MHZ)
 258                 if (dev_pm_opp_disable(dev, 996000000))
 259                         dev_warn(dev, "failed to disable 996MHz OPP\n");
 260
 261         if (of_machine_is_compatible("fsl,imx6q") ||
 262             of_machine_is_compatible("fsl,imx6qp")) {
 263                 if (val != OCOTP_CFG3_SPEED_852MHZ)
 264                         if (dev_pm_opp_disable(dev, 852000000))
 265                                 dev_warn(dev, "failed to disable 852MHz OPP\n");
 266                 if (val != OCOTP_CFG3_SPEED_1P2GHZ)
 267                         if (dev_pm_opp_disable(dev, 1200000000))
 268                                 dev_warn(dev, "failed to disable 1.2GHz OPP\n");
 269         }
 270
 271         return 0;
 272 }
 273
 274 #define OCOTP_CFG3_6UL_SPEED_696MHZ     0x2
 275 #define OCOTP_CFG3_6ULL_SPEED_792MHZ    0x2
 276 #define OCOTP_CFG3_6ULL_SPEED_900MHZ    0x3
 277
 278 static int imx6ul_opp_check_speed_grading(struct device *dev)
 279 {
 280         u32 val;
 281         int ret = 0;
 282
 283         if (of_find_property(dev->of_node, "nvmem-cells", NULL)) {
 284                 ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 285                 if (ret)
 286                         return ret;
 287         } else {
 288                 struct device_node *np;
 289                 void __iomem *base;
 290
 291                 np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
 292                 if (!np)
 293                         np = of_find_compatible_node(NULL, NULL,
 294                                                      "fsl,imx6ull-ocotp");
 295                 if (!np)
 296                         return -ENOENT;
 297
 298                 base = of_iomap(np, 0);
 299                 of_node_put(np);
 300                 if (!base) {
 301                         dev_err(dev, "failed to map ocotp\n");
 302                         return -EFAULT;
 303                 }
 304
 305                 val = readl_relaxed(base + OCOTP_CFG3);
 306                 iounmap(base);
 307         }
 308
 309         /*
 310          * Speed GRADING[1:0] defines the max speed of ARM:
 311          * 2b'00: Reserved;
 312          * 2b'01: 528000000Hz;
 313          * 2b'10: 696000000Hz on i.MX6UL, 792000000Hz on i.MX6ULL;
 314          * 2b'11: 900000000Hz on i.MX6ULL only;
 315          * We need to set the max speed of ARM according to fuse map.
 316          */
 317         val >>= OCOTP_CFG3_SPEED_SHIFT;
 318         val &= 0x3;
 319
 320         if (of_machine_is_compatible("fsl,imx6ul")) {
 321                 if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
 322                         if (dev_pm_opp_disable(dev, 696000000))
 323                                 dev_warn(dev, "failed to disable 696MHz OPP\n");
 324         }
 325
 326         if (of_machine_is_compatible("fsl,imx6ull")) {
 327                 if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
 328                         if (dev_pm_opp_disable(dev, 792000000))
 329                                 dev_warn(dev, "failed to disable 792MHz OPP\n");
 330
 331                 if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
 332                         if (dev_pm_opp_disable(dev, 900000000))
 333                                 dev_warn(dev, "failed to disable 900MHz OPP\n");
 334         }
 335
 336         return ret;
 337 }
 338
 339 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 340 {
 341         struct device_node *np;
 342         struct dev_pm_opp *opp;
 343         unsigned long min_volt, max_volt;
 344         int num, ret;
 345         const struct property *prop;
 346         const __be32 *val;
 347         u32 nr, i, j;
 348
 349         cpu_dev = get_cpu_device(0);
 350         if (!cpu_dev) {
 351                 pr_err("failed to get cpu0 device\n");
 352                 return -ENODEV;
 353         }
 354
 355         np = of_node_get(cpu_dev->of_node);
 356         if (!np) {
 357                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 358                 return -ENOENT;
 359         }
 360
 361         if (of_machine_is_compatible("fsl,imx6ul") ||
 362             of_machine_is_compatible("fsl,imx6ull"))
 363                 num_clks = IMX6UL_CPUFREQ_CLK_NUM;
 364         else
 365                 num_clks = IMX6Q_CPUFREQ_CLK_NUM;
 366
 367         ret = clk_bulk_get(cpu_dev, num_clks, clks);
 368         if (ret)
 369                 goto put_node;
 370
 371         arm_reg = regulator_get(cpu_dev, "arm");
 372         pu_reg = regulator_get_optional(cpu_dev, "pu");
 373         soc_reg = regulator_get(cpu_dev, "soc");
 374         if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
 375                         PTR_ERR(soc_reg) == -EPROBE_DEFER ||
 376                         PTR_ERR(pu_reg) == -EPROBE_DEFER) {
 377                 ret = -EPROBE_DEFER;
 378                 dev_dbg(cpu_dev, "regulators not ready, defer\n");
 379                 goto put_reg;
 380         }
 381         if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 382                 dev_err(cpu_dev, "failed to get regulators\n");
 383                 ret = -ENOENT;
 384                 goto put_reg;
 385         }
 386
 387         ret = dev_pm_opp_of_add_table(cpu_dev);
 388         if (ret < 0) {
 389                 dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 390                 goto put_reg;
 391         }
 392
 393         /* Because we have added the OPPs here, we must free them */
 394         free_opp = true;
 395
 396         if (of_machine_is_compatible("fsl,imx6ul") ||
 397             of_machine_is_compatible("fsl,imx6ull")) {
 398                 ret = imx6ul_opp_check_speed_grading(cpu_dev);
 399         } else {
 400                 ret = imx6q_opp_check_speed_grading(cpu_dev);
 401         }
 402         if (ret) {
 403                 if (ret != -EPROBE_DEFER)
 404                         dev_err(cpu_dev, "failed to read ocotp: %d\n",
 405                                 ret);
 406                 goto out_free_opp;
 407         }
 408
 409         num = dev_pm_opp_get_opp_count(cpu_dev);
 410         if (num < 0) {
 411                 ret = num;
 412                 dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 413                 goto out_free_opp;
 414         }
 415
 416         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 417         if (ret) {
 418                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 419                 goto out_free_opp;
 420         }
 421
 422         /* Make imx6_soc_volt array's size same as arm opp number */
 423         imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
 424                                      GFP_KERNEL);
 425         if (imx6_soc_volt == NULL) {
 426                 ret = -ENOMEM;
 427                 goto free_freq_table;
 428         }
 429
 430         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 431         if (!prop || !prop->value)
 432                 goto soc_opp_out;
 433
 434         /*
 435          * Each OPP is a set of tuples consisting of frequency and
 436          * voltage like <freq-kHz vol-uV>.
 437          */
 438         nr = prop->length / sizeof(u32);
 439         if (nr % 2 || (nr / 2) < num)
 440                 goto soc_opp_out;
 441
 442         for (j = 0; j < num; j++) {
 443                 val = prop->value;
 444                 for (i = 0; i < nr / 2; i++) {
 445                         unsigned long freq = be32_to_cpup(val++);
 446                         unsigned long volt = be32_to_cpup(val++);
 447                         if (freq_table[j].frequency == freq) {
 448                                 imx6_soc_volt[soc_opp_count++] = volt;
 449                                 break;
 450                         }
 451                 }
 452         }
 453
 454 soc_opp_out:
 455         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 456         if (soc_opp_count != num) {
 457                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 458                 for (j = 0; j < num; j++)
 459                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 460                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 461                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 462         }
 463
 464         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 465                 transition_latency = CPUFREQ_ETERNAL;
 466
 467         /*
 468          * Calculate the ramp time for max voltage change in the
 469          * VDDSOC and VDDPU regulators.
 470          */
 471         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 472         if (ret > 0)
 473                 transition_latency += ret * 1000;
 474         if (!IS_ERR(pu_reg)) {
 475                 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 476                 if (ret > 0)
 477                         transition_latency += ret * 1000;
 478         }
 479
 480         /*
 481          * OPP is maintained in order of increasing frequency, and
 482          * freq_table initialised from OPP is therefore sorted in the
 483          * same order.
 484          */
 485         max_freq = freq_table[--num].frequency;
 486         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 487                                   freq_table[0].frequency * 1000, true);
 488         min_volt = dev_pm_opp_get_voltage(opp);
 489         dev_pm_opp_put(opp);
 490         opp = dev_pm_opp_find_freq_exact(cpu_dev, max_freq * 1000, true);
 491         max_volt = dev_pm_opp_get_voltage(opp);
 492         dev_pm_opp_put(opp);
 493
 494         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 495         if (ret > 0)
 496                 transition_latency += ret * 1000;
 497
 498         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 499         if (ret) {
 500                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 501                 goto free_freq_table;
 502         }
 503
 504         of_node_put(np);
 505         return 0;
 506
 507 free_freq_table:
 508         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 509 out_free_opp:
 510         if (free_opp)
 511                 dev_pm_opp_of_remove_table(cpu_dev);
 512 put_reg:
 513         if (!IS_ERR(arm_reg))
 514                 regulator_put(arm_reg);
 515         if (!IS_ERR(pu_reg))
 516                 regulator_put(pu_reg);
 517         if (!IS_ERR(soc_reg))
 518                 regulator_put(soc_reg);
 519
 520         clk_bulk_put(num_clks, clks);
 521 put_node:
 522         of_node_put(np);
 523
 524         return ret;
 525 }
 526
 527 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 528 {
 529         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 530         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 531         if (free_opp)
 532                 dev_pm_opp_of_remove_table(cpu_dev);
 533         regulator_put(arm_reg);
 534         if (!IS_ERR(pu_reg))
 535                 regulator_put(pu_reg);
 536         regulator_put(soc_reg);
 537
 538         clk_bulk_put(num_clks, clks);
 539
 540         return 0;
 541 }
 542
 543 static struct platform_driver imx6q_cpufreq_platdrv = {
 544         .driver = {
 545                 .name   = "imx6q-cpufreq",
 546         },
 547         .probe          = imx6q_cpufreq_probe,
 548         .remove         = imx6q_cpufreq_remove,
 549 };
 550 module_platform_driver(imx6q_cpufreq_platdrv);
 551
 552 MODULE_ALIAS("platform:imx6q-cpufreq");
 553 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 554 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 555 MODULE_LICENSE("GPL");