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 struct cpufreq_frequency_table *freq_table;
  52 static unsigned int max_freq;
  53 static unsigned int transition_latency;
  54
  55 static u32 *imx6_soc_volt;
  56 static u32 soc_opp_count;
  57
  58 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
  59 {
  60         struct dev_pm_opp *opp;
  61         unsigned long freq_hz, volt, volt_old;
  62         unsigned int old_freq, new_freq;
  63         bool pll1_sys_temp_enabled = false;
  64         int ret;
  65
  66         new_freq = freq_table[index].frequency;
  67         freq_hz = new_freq * 1000;
  68         old_freq = clk_get_rate(clks[ARM].clk) / 1000;
  69
  70         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
  71         if (IS_ERR(opp)) {
  72                 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
  73                 return PTR_ERR(opp);
  74         }
  75
  76         volt = dev_pm_opp_get_voltage(opp);
  77         dev_pm_opp_put(opp);
  78
  79         volt_old = regulator_get_voltage(arm_reg);
  80
  81         dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
  82                 old_freq / 1000, volt_old / 1000,
  83                 new_freq / 1000, volt / 1000);
  84
  85         /* scaling up?  scale voltage before frequency */
  86         if (new_freq > old_freq) {
  87                 if (!IS_ERR(pu_reg)) {
  88                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
  89                         if (ret) {
  90                                 dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
  91                                 return ret;
  92                         }
  93                 }
  94                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
  95                 if (ret) {
  96                         dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
  97                         return ret;
  98                 }
  99                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 100                 if (ret) {
 101                         dev_err(cpu_dev,
 102                                 "failed to scale vddarm up: %d\n", ret);
 103                         return ret;
 104                 }
 105         }
 106
 107         /*
 108          * The setpoints are selected per PLL/PDF frequencies, so we need to
 109          * reprogram PLL for frequency scaling.  The procedure of reprogramming
 110          * PLL1 is as below.
 111          * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
 112          * flow is slightly different from other i.MX6 OSC.
 113          * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
 114          *  - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
 115          *  - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
 116          *  - Disable pll2_pfd2_396m_clk
 117          */
 118         if (of_machine_is_compatible("fsl,imx6ul") ||
 119             of_machine_is_compatible("fsl,imx6ull")) {
 120                 /*
 121                  * When changing pll1_sw_clk's parent to pll1_sys_clk,
 122                  * CPU may run at higher than 528MHz, this will lead to
 123                  * the system unstable if the voltage is lower than the
 124                  * voltage of 528MHz, so lower the CPU frequency to one
 125                  * half before changing CPU frequency.
 126                  */
 127                 clk_set_rate(clks[ARM].clk, (old_freq >> 1) * 1000);
 128                 clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 129                 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk))
 130                         clk_set_parent(clks[SECONDARY_SEL].clk,
 131                                        clks[PLL2_BUS].clk);
 132                 else
 133                         clk_set_parent(clks[SECONDARY_SEL].clk,
 134                                        clks[PLL2_PFD2_396M].clk);
 135                 clk_set_parent(clks[STEP].clk, clks[SECONDARY_SEL].clk);
 136                 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 137                 if (freq_hz > clk_get_rate(clks[PLL2_BUS].clk)) {
 138                         clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 139                         clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 140                 }
 141         } else {
 142                 clk_set_parent(clks[STEP].clk, clks[PLL2_PFD2_396M].clk);
 143                 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
 144                 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk)) {
 145                         clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
 146                         clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
 147                 } else {
 148                         /* pll1_sys needs to be enabled for divider rate change to work. */
 149                         pll1_sys_temp_enabled = true;
 150                         clk_prepare_enable(clks[PLL1_SYS].clk);
 151                 }
 152         }
 153
 154         /* Ensure the arm clock divider is what we expect */
 155         ret = clk_set_rate(clks[ARM].clk, new_freq * 1000);
 156         if (ret) {
 157                 int ret1;
 158
 159                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 160                 ret1 = regulator_set_voltage_tol(arm_reg, volt_old, 0);
 161                 if (ret1)
 162                         dev_warn(cpu_dev,
 163                                  "failed to restore vddarm voltage: %d\n", ret1);
 164                 return ret;
 165         }
 166
 167         /* PLL1 is only needed until after ARM-PODF is set. */
 168         if (pll1_sys_temp_enabled)
 169                 clk_disable_unprepare(clks[PLL1_SYS].clk);
 170
 171         /* scaling down?  scale voltage after frequency */
 172         if (new_freq < old_freq) {
 173                 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
 174                 if (ret)
 175                         dev_warn(cpu_dev,
 176                                  "failed to scale vddarm down: %d\n", ret);
 177                 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
 178                 if (ret)
 179                         dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
 180                 if (!IS_ERR(pu_reg)) {
 181                         ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
 182                         if (ret)
 183                                 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
 184                 }
 185         }
 186
 187         return 0;
 188 }
 189
 190 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 191 {
 192         policy->clk = clks[ARM].clk;
 193         cpufreq_generic_init(policy, freq_table, transition_latency);
 194         policy->suspend_freq = max_freq;
 195         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 196
 197         return 0;
 198 }
 199
 200 static struct cpufreq_driver imx6q_cpufreq_driver = {
 201         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 202                  CPUFREQ_IS_COOLING_DEV,
 203         .verify = cpufreq_generic_frequency_table_verify,
 204         .target_index = imx6q_set_target,
 205         .get = cpufreq_generic_get,
 206         .init = imx6q_cpufreq_init,
 207         .name = "imx6q-cpufreq",
 208         .attr = cpufreq_generic_attr,
 209         .suspend = cpufreq_generic_suspend,
 210 };
 211
 212 static void imx6x_disable_freq_in_opp(struct device *dev, unsigned long freq)
 213 {
 214         int ret = dev_pm_opp_disable(dev, freq);
 215
 216         if (ret < 0 && ret != -ENODEV)
 217                 dev_warn(dev, "failed to disable %ldMHz OPP\n", freq / 1000000);
 218 }
 219
 220 #define OCOTP_CFG3                      0x440
 221 #define OCOTP_CFG3_SPEED_SHIFT          16
 222 #define OCOTP_CFG3_SPEED_1P2GHZ         0x3
 223 #define OCOTP_CFG3_SPEED_996MHZ         0x2
 224 #define OCOTP_CFG3_SPEED_852MHZ         0x1
 225
 226 static int imx6q_opp_check_speed_grading(struct device *dev)
 227 {
 228         struct device_node *np;
 229         void __iomem *base;
 230         u32 val;
 231         int ret;
 232
 233         if (of_property_present(dev->of_node, "nvmem-cells")) {
 234                 ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 235                 if (ret)
 236                         return ret;
 237         } else {
 238                 np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp");
 239                 if (!np)
 240                         return -ENOENT;
 241
 242                 base = of_iomap(np, 0);
 243                 of_node_put(np);
 244                 if (!base) {
 245                         dev_err(dev, "failed to map ocotp\n");
 246                         return -EFAULT;
 247                 }
 248
 249                 /*
 250                  * SPEED_GRADING[1:0] defines the max speed of ARM:
 251                  * 2b'11: 1200000000Hz;
 252                  * 2b'10: 996000000Hz;
 253                  * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
 254                  * 2b'00: 792000000Hz;
 255                  * We need to set the max speed of ARM according to fuse map.
 256                  */
 257                 val = readl_relaxed(base + OCOTP_CFG3);
 258                 iounmap(base);
 259         }
 260
 261         val >>= OCOTP_CFG3_SPEED_SHIFT;
 262         val &= 0x3;
 263
 264         if (val < OCOTP_CFG3_SPEED_996MHZ)
 265                 imx6x_disable_freq_in_opp(dev, 996000000);
 266
 267         if (of_machine_is_compatible("fsl,imx6q") ||
 268             of_machine_is_compatible("fsl,imx6qp")) {
 269                 if (val != OCOTP_CFG3_SPEED_852MHZ)
 270                         imx6x_disable_freq_in_opp(dev, 852000000);
 271
 272                 if (val != OCOTP_CFG3_SPEED_1P2GHZ)
 273                         imx6x_disable_freq_in_opp(dev, 1200000000);
 274         }
 275
 276         return 0;
 277 }
 278
 279 #define OCOTP_CFG3_6UL_SPEED_696MHZ     0x2
 280 #define OCOTP_CFG3_6ULL_SPEED_792MHZ    0x2
 281 #define OCOTP_CFG3_6ULL_SPEED_900MHZ    0x3
 282
 283 static int imx6ul_opp_check_speed_grading(struct device *dev)
 284 {
 285         u32 val;
 286         int ret = 0;
 287
 288         if (of_property_present(dev->of_node, "nvmem-cells")) {
 289                 ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
 290                 if (ret)
 291                         return ret;
 292         } else {
 293                 struct device_node *np;
 294                 void __iomem *base;
 295
 296                 np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
 297                 if (!np)
 298                         np = of_find_compatible_node(NULL, NULL,
 299                                                      "fsl,imx6ull-ocotp");
 300                 if (!np)
 301                         return -ENOENT;
 302
 303                 base = of_iomap(np, 0);
 304                 of_node_put(np);
 305                 if (!base) {
 306                         dev_err(dev, "failed to map ocotp\n");
 307                         return -EFAULT;
 308                 }
 309
 310                 val = readl_relaxed(base + OCOTP_CFG3);
 311                 iounmap(base);
 312         }
 313
 314         /*
 315          * Speed GRADING[1:0] defines the max speed of ARM:
 316          * 2b'00: Reserved;
 317          * 2b'01: 528000000Hz;
 318          * 2b'10: 696000000Hz on i.MX6UL, 792000000Hz on i.MX6ULL;
 319          * 2b'11: 900000000Hz on i.MX6ULL only;
 320          * We need to set the max speed of ARM according to fuse map.
 321          */
 322         val >>= OCOTP_CFG3_SPEED_SHIFT;
 323         val &= 0x3;
 324
 325         if (of_machine_is_compatible("fsl,imx6ul"))
 326                 if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
 327                         imx6x_disable_freq_in_opp(dev, 696000000);
 328
 329         if (of_machine_is_compatible("fsl,imx6ull")) {
 330                 if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
 331                         imx6x_disable_freq_in_opp(dev, 792000000);
 332
 333                 if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
 334                         imx6x_disable_freq_in_opp(dev, 900000000);
 335         }
 336
 337         return ret;
 338 }
 339
 340 static int imx6q_cpufreq_probe(struct platform_device *pdev)
 341 {
 342         struct device_node *np;
 343         struct dev_pm_opp *opp;
 344         unsigned long min_volt, max_volt;
 345         int num, ret;
 346         const struct property *prop;
 347         const __be32 *val;
 348         u32 nr, i, j;
 349
 350         cpu_dev = get_cpu_device(0);
 351         if (!cpu_dev) {
 352                 pr_err("failed to get cpu0 device\n");
 353                 return -ENODEV;
 354         }
 355
 356         np = of_node_get(cpu_dev->of_node);
 357         if (!np) {
 358                 dev_err(cpu_dev, "failed to find cpu0 node\n");
 359                 return -ENOENT;
 360         }
 361
 362         if (of_machine_is_compatible("fsl,imx6ul") ||
 363             of_machine_is_compatible("fsl,imx6ull"))
 364                 num_clks = IMX6UL_CPUFREQ_CLK_NUM;
 365         else
 366                 num_clks = IMX6Q_CPUFREQ_CLK_NUM;
 367
 368         ret = clk_bulk_get(cpu_dev, num_clks, clks);
 369         if (ret)
 370                 goto put_node;
 371
 372         arm_reg = regulator_get(cpu_dev, "arm");
 373         pu_reg = regulator_get_optional(cpu_dev, "pu");
 374         soc_reg = regulator_get(cpu_dev, "soc");
 375         if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
 376                         PTR_ERR(soc_reg) == -EPROBE_DEFER ||
 377                         PTR_ERR(pu_reg) == -EPROBE_DEFER) {
 378                 ret = -EPROBE_DEFER;
 379                 dev_dbg(cpu_dev, "regulators not ready, defer\n");
 380                 goto put_reg;
 381         }
 382         if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
 383                 dev_err(cpu_dev, "failed to get regulators\n");
 384                 ret = -ENOENT;
 385                 goto put_reg;
 386         }
 387
 388         ret = dev_pm_opp_of_add_table(cpu_dev);
 389         if (ret < 0) {
 390                 dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
 391                 goto put_reg;
 392         }
 393
 394         if (of_machine_is_compatible("fsl,imx6ul") ||
 395             of_machine_is_compatible("fsl,imx6ull")) {
 396                 ret = imx6ul_opp_check_speed_grading(cpu_dev);
 397         } else {
 398                 ret = imx6q_opp_check_speed_grading(cpu_dev);
 399         }
 400         if (ret) {
 401                 if (ret != -EPROBE_DEFER)
 402                         dev_err(cpu_dev, "failed to read ocotp: %d\n",
 403                                 ret);
 404                 goto out_free_opp;
 405         }
 406
 407         num = dev_pm_opp_get_opp_count(cpu_dev);
 408         if (num < 0) {
 409                 ret = num;
 410                 dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
 411                 goto out_free_opp;
 412         }
 413
 414         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 415         if (ret) {
 416                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 417                 goto out_free_opp;
 418         }
 419
 420         /* Make imx6_soc_volt array's size same as arm opp number */
 421         imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
 422                                      GFP_KERNEL);
 423         if (imx6_soc_volt == NULL) {
 424                 ret = -ENOMEM;
 425                 goto free_freq_table;
 426         }
 427
 428         prop = of_find_property(np, "fsl,soc-operating-points", NULL);
 429         if (!prop || !prop->value)
 430                 goto soc_opp_out;
 431
 432         /*
 433          * Each OPP is a set of tuples consisting of frequency and
 434          * voltage like <freq-kHz vol-uV>.
 435          */
 436         nr = prop->length / sizeof(u32);
 437         if (nr % 2 || (nr / 2) < num)
 438                 goto soc_opp_out;
 439
 440         for (j = 0; j < num; j++) {
 441                 val = prop->value;
 442                 for (i = 0; i < nr / 2; i++) {
 443                         unsigned long freq = be32_to_cpup(val++);
 444                         unsigned long volt = be32_to_cpup(val++);
 445                         if (freq_table[j].frequency == freq) {
 446                                 imx6_soc_volt[soc_opp_count++] = volt;
 447                                 break;
 448                         }
 449                 }
 450         }
 451
 452 soc_opp_out:
 453         /* use fixed soc opp volt if no valid soc opp info found in dtb */
 454         if (soc_opp_count != num) {
 455                 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
 456                 for (j = 0; j < num; j++)
 457                         imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
 458                 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
 459                         imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
 460         }
 461
 462         if (of_property_read_u32(np, "clock-latency", &transition_latency))
 463                 transition_latency = CPUFREQ_ETERNAL;
 464
 465         /*
 466          * Calculate the ramp time for max voltage change in the
 467          * VDDSOC and VDDPU regulators.
 468          */
 469         ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 470         if (ret > 0)
 471                 transition_latency += ret * 1000;
 472         if (!IS_ERR(pu_reg)) {
 473                 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
 474                 if (ret > 0)
 475                         transition_latency += ret * 1000;
 476         }
 477
 478         /*
 479          * OPP is maintained in order of increasing frequency, and
 480          * freq_table initialised from OPP is therefore sorted in the
 481          * same order.
 482          */
 483         max_freq = freq_table[--num].frequency;
 484         opp = dev_pm_opp_find_freq_exact(cpu_dev,
 485                                   freq_table[0].frequency * 1000, true);
 486         min_volt = dev_pm_opp_get_voltage(opp);
 487         dev_pm_opp_put(opp);
 488         opp = dev_pm_opp_find_freq_exact(cpu_dev, max_freq * 1000, true);
 489         max_volt = dev_pm_opp_get_voltage(opp);
 490         dev_pm_opp_put(opp);
 491
 492         ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
 493         if (ret > 0)
 494                 transition_latency += ret * 1000;
 495
 496         ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
 497         if (ret) {
 498                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 499                 goto free_freq_table;
 500         }
 501
 502         of_node_put(np);
 503         return 0;
 504
 505 free_freq_table:
 506         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 507 out_free_opp:
 508         dev_pm_opp_of_remove_table(cpu_dev);
 509 put_reg:
 510         if (!IS_ERR(arm_reg))
 511                 regulator_put(arm_reg);
 512         if (!IS_ERR(pu_reg))
 513                 regulator_put(pu_reg);
 514         if (!IS_ERR(soc_reg))
 515                 regulator_put(soc_reg);
 516
 517         clk_bulk_put(num_clks, clks);
 518 put_node:
 519         of_node_put(np);
 520
 521         return ret;
 522 }
 523
 524 static int imx6q_cpufreq_remove(struct platform_device *pdev)
 525 {
 526         cpufreq_unregister_driver(&imx6q_cpufreq_driver);
 527         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 528         dev_pm_opp_of_remove_table(cpu_dev);
 529         regulator_put(arm_reg);
 530         if (!IS_ERR(pu_reg))
 531                 regulator_put(pu_reg);
 532         regulator_put(soc_reg);
 533
 534         clk_bulk_put(num_clks, clks);
 535
 536         return 0;
 537 }
 538
 539 static struct platform_driver imx6q_cpufreq_platdrv = {
 540         .driver = {
 541                 .name   = "imx6q-cpufreq",
 542         },
 543         .probe          = imx6q_cpufreq_probe,
 544         .remove         = imx6q_cpufreq_remove,
 545 };
 546 module_platform_driver(imx6q_cpufreq_platdrv);
 547
 548 MODULE_ALIAS("platform:imx6q-cpufreq");
 549 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 550 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
 551 MODULE_LICENSE("GPL");