1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * CPU frequency scaling support for Armada 37xx platform. 4 * 5 * Copyright (C) 2017 Marvell 6 * 7 * Gregory CLEMENT <gregory.clement@free-electrons.com> 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/cpu.h> 12 #include <linux/cpufreq.h> 13 #include <linux/err.h> 14 #include <linux/interrupt.h> 15 #include <linux/io.h> 16 #include <linux/mfd/syscon.h> 17 #include <linux/module.h> 18 #include <linux/of_address.h> 19 #include <linux/of_device.h> 20 #include <linux/of_irq.h> 21 #include <linux/platform_device.h> 22 #include <linux/pm_opp.h> 23 #include <linux/regmap.h> 24 #include <linux/slab.h> 25 26 #include "cpufreq-dt.h" 27 28 /* Power management in North Bridge register set */ 29 #define ARMADA_37XX_NB_L0L1 0x18 30 #define ARMADA_37XX_NB_L2L3 0x1C 31 #define ARMADA_37XX_NB_TBG_DIV_OFF 13 32 #define ARMADA_37XX_NB_TBG_DIV_MASK 0x7 33 #define ARMADA_37XX_NB_CLK_SEL_OFF 11 34 #define ARMADA_37XX_NB_CLK_SEL_MASK 0x1 35 #define ARMADA_37XX_NB_CLK_SEL_TBG 0x1 36 #define ARMADA_37XX_NB_TBG_SEL_OFF 9 37 #define ARMADA_37XX_NB_TBG_SEL_MASK 0x3 38 #define ARMADA_37XX_NB_VDD_SEL_OFF 6 39 #define ARMADA_37XX_NB_VDD_SEL_MASK 0x3 40 #define ARMADA_37XX_NB_CONFIG_SHIFT 16 41 #define ARMADA_37XX_NB_DYN_MOD 0x24 42 #define ARMADA_37XX_NB_CLK_SEL_EN BIT(26) 43 #define ARMADA_37XX_NB_TBG_EN BIT(28) 44 #define ARMADA_37XX_NB_DIV_EN BIT(29) 45 #define ARMADA_37XX_NB_VDD_EN BIT(30) 46 #define ARMADA_37XX_NB_DFS_EN BIT(31) 47 #define ARMADA_37XX_NB_CPU_LOAD 0x30 48 #define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3 49 #define ARMADA_37XX_DVFS_LOAD_0 0 50 #define ARMADA_37XX_DVFS_LOAD_1 1 51 #define ARMADA_37XX_DVFS_LOAD_2 2 52 #define ARMADA_37XX_DVFS_LOAD_3 3 53 54 /* AVS register set */ 55 #define ARMADA_37XX_AVS_CTL0 0x0 56 #define ARMADA_37XX_AVS_ENABLE BIT(30) 57 #define ARMADA_37XX_AVS_HIGH_VDD_LIMIT 16 58 #define ARMADA_37XX_AVS_LOW_VDD_LIMIT 22 59 #define ARMADA_37XX_AVS_VDD_MASK 0x3F 60 #define ARMADA_37XX_AVS_CTL2 0x8 61 #define ARMADA_37XX_AVS_LOW_VDD_EN BIT(6) 62 #define ARMADA_37XX_AVS_VSET(x) (0x1C + 4 * (x)) 63 64 /* 65 * On Armada 37xx the Power management manages 4 level of CPU load, 66 * each level can be associated with a CPU clock source, a CPU 67 * divider, a VDD level, etc... 68 */ 69 #define LOAD_LEVEL_NR 4 70 71 #define MIN_VOLT_MV 1000 72 73 /* AVS value for the corresponding voltage (in mV) */ 74 static int avs_map[] = { 75 747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898, 76 910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050, 77 1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190, 78 1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330, 79 1342 80 }; 81 82 struct armada37xx_cpufreq_state { 83 struct regmap *regmap; 84 u32 nb_l0l1; 85 u32 nb_l2l3; 86 u32 nb_dyn_mod; 87 u32 nb_cpu_load; 88 }; 89 90 static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state; 91 92 struct armada_37xx_dvfs { 93 u32 cpu_freq_max; 94 u8 divider[LOAD_LEVEL_NR]; 95 u32 avs[LOAD_LEVEL_NR]; 96 }; 97 98 static struct armada_37xx_dvfs armada_37xx_dvfs[] = { 99 {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, 100 {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} }, 101 {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} }, 102 {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} }, 103 }; 104 105 static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq) 106 { 107 int i; 108 109 for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) { 110 if (freq == armada_37xx_dvfs[i].cpu_freq_max) 111 return &armada_37xx_dvfs[i]; 112 } 113 114 pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000); 115 return NULL; 116 } 117 118 /* 119 * Setup the four level managed by the hardware. Once the four level 120 * will be configured then the DVFS will be enabled. 121 */ 122 static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base, 123 struct clk *clk, u8 *divider) 124 { 125 int load_lvl; 126 struct clk *parent; 127 128 for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) { 129 unsigned int reg, mask, val, offset = 0; 130 131 if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1) 132 reg = ARMADA_37XX_NB_L0L1; 133 else 134 reg = ARMADA_37XX_NB_L2L3; 135 136 if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 || 137 load_lvl == ARMADA_37XX_DVFS_LOAD_2) 138 offset += ARMADA_37XX_NB_CONFIG_SHIFT; 139 140 /* Set cpu clock source, for all the level we use TBG */ 141 val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF; 142 mask = (ARMADA_37XX_NB_CLK_SEL_MASK 143 << ARMADA_37XX_NB_CLK_SEL_OFF); 144 145 /* 146 * Set cpu divider based on the pre-computed array in 147 * order to have balanced step. 148 */ 149 val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF; 150 mask |= (ARMADA_37XX_NB_TBG_DIV_MASK 151 << ARMADA_37XX_NB_TBG_DIV_OFF); 152 153 /* Set VDD divider which is actually the load level. */ 154 val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF; 155 mask |= (ARMADA_37XX_NB_VDD_SEL_MASK 156 << ARMADA_37XX_NB_VDD_SEL_OFF); 157 158 val <<= offset; 159 mask <<= offset; 160 161 regmap_update_bits(base, reg, mask, val); 162 } 163 164 /* 165 * Set cpu clock source, for all the level we keep the same 166 * clock source that the one already configured. For this one 167 * we need to use the clock framework 168 */ 169 parent = clk_get_parent(clk); 170 clk_set_parent(clk, parent); 171 } 172 173 /* 174 * Find out the armada 37x supported AVS value whose voltage value is 175 * the round-up closest to the target voltage value. 176 */ 177 static u32 armada_37xx_avs_val_match(int target_vm) 178 { 179 u32 avs; 180 181 /* Find out the round-up closest supported voltage value */ 182 for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++) 183 if (avs_map[avs] >= target_vm) 184 break; 185 186 /* 187 * If all supported voltages are smaller than target one, 188 * choose the largest supported voltage 189 */ 190 if (avs == ARRAY_SIZE(avs_map)) 191 avs = ARRAY_SIZE(avs_map) - 1; 192 193 return avs; 194 } 195 196 /* 197 * For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision 198 * value or a default value when SVC is not supported. 199 * - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage 200 * can be got from the mapping table of avs_map. 201 * - L1 voltage should be about 100mv smaller than L0 voltage 202 * - L2 & L3 voltage should be about 150mv smaller than L0 voltage. 203 * This function calculates L1 & L2 & L3 AVS values dynamically based 204 * on L0 voltage and fill all AVS values to the AVS value table. 205 */ 206 static void __init armada37xx_cpufreq_avs_configure(struct regmap *base, 207 struct armada_37xx_dvfs *dvfs) 208 { 209 unsigned int target_vm; 210 int load_level = 0; 211 u32 l0_vdd_min; 212 213 if (base == NULL) 214 return; 215 216 /* Get L0 VDD min value */ 217 regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min); 218 l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) & 219 ARMADA_37XX_AVS_VDD_MASK; 220 if (l0_vdd_min >= ARRAY_SIZE(avs_map)) { 221 pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min); 222 return; 223 } 224 dvfs->avs[0] = l0_vdd_min; 225 226 if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) { 227 /* 228 * If L0 voltage is smaller than 1000mv, then all VDD sets 229 * use L0 voltage; 230 */ 231 u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV); 232 233 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) 234 dvfs->avs[load_level] = avs_min; 235 236 return; 237 } 238 239 /* 240 * L1 voltage is equal to L0 voltage - 100mv and it must be 241 * larger than 1000mv 242 */ 243 244 target_vm = avs_map[l0_vdd_min] - 100; 245 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV; 246 dvfs->avs[1] = armada_37xx_avs_val_match(target_vm); 247 248 /* 249 * L2 & L3 voltage is equal to L0 voltage - 150mv and it must 250 * be larger than 1000mv 251 */ 252 target_vm = avs_map[l0_vdd_min] - 150; 253 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV; 254 dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm); 255 } 256 257 static void __init armada37xx_cpufreq_avs_setup(struct regmap *base, 258 struct armada_37xx_dvfs *dvfs) 259 { 260 unsigned int avs_val = 0, freq; 261 int load_level = 0; 262 263 if (base == NULL) 264 return; 265 266 /* Disable AVS before the configuration */ 267 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0, 268 ARMADA_37XX_AVS_ENABLE, 0); 269 270 271 /* Enable low voltage mode */ 272 regmap_update_bits(base, ARMADA_37XX_AVS_CTL2, 273 ARMADA_37XX_AVS_LOW_VDD_EN, 274 ARMADA_37XX_AVS_LOW_VDD_EN); 275 276 277 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) { 278 freq = dvfs->cpu_freq_max / dvfs->divider[load_level]; 279 280 avs_val = dvfs->avs[load_level]; 281 regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1), 282 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT | 283 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT, 284 avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT | 285 avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT); 286 } 287 288 /* Enable AVS after the configuration */ 289 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0, 290 ARMADA_37XX_AVS_ENABLE, 291 ARMADA_37XX_AVS_ENABLE); 292 293 } 294 295 static void armada37xx_cpufreq_disable_dvfs(struct regmap *base) 296 { 297 unsigned int reg = ARMADA_37XX_NB_DYN_MOD, 298 mask = ARMADA_37XX_NB_DFS_EN; 299 300 regmap_update_bits(base, reg, mask, 0); 301 } 302 303 static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base) 304 { 305 unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD, 306 mask = ARMADA_37XX_NB_CPU_LOAD_MASK; 307 308 /* Start with the highest load (0) */ 309 val = ARMADA_37XX_DVFS_LOAD_0; 310 regmap_update_bits(base, reg, mask, val); 311 312 /* Now enable DVFS for the CPUs */ 313 reg = ARMADA_37XX_NB_DYN_MOD; 314 mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN | 315 ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN | 316 ARMADA_37XX_NB_DFS_EN; 317 318 regmap_update_bits(base, reg, mask, mask); 319 } 320 321 static int armada37xx_cpufreq_suspend(struct cpufreq_policy *policy) 322 { 323 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state; 324 325 regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1); 326 regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3); 327 regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD, 328 &state->nb_cpu_load); 329 regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod); 330 331 return 0; 332 } 333 334 static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy) 335 { 336 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state; 337 338 /* Ensure DVFS is disabled otherwise the following registers are RO */ 339 armada37xx_cpufreq_disable_dvfs(state->regmap); 340 341 regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1); 342 regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3); 343 regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD, 344 state->nb_cpu_load); 345 346 /* 347 * NB_DYN_MOD register is the one that actually enable back DVFS if it 348 * was enabled before the suspend operation. This must be done last 349 * otherwise other registers are not writable. 350 */ 351 regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod); 352 353 return 0; 354 } 355 356 static int __init armada37xx_cpufreq_driver_init(void) 357 { 358 struct cpufreq_dt_platform_data pdata; 359 struct armada_37xx_dvfs *dvfs; 360 struct platform_device *pdev; 361 unsigned long freq; 362 unsigned int cur_frequency; 363 struct regmap *nb_pm_base, *avs_base; 364 struct device *cpu_dev; 365 int load_lvl, ret; 366 struct clk *clk; 367 368 nb_pm_base = 369 syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm"); 370 371 if (IS_ERR(nb_pm_base)) 372 return -ENODEV; 373 374 avs_base = 375 syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs"); 376 377 /* if AVS is not present don't use it but still try to setup dvfs */ 378 if (IS_ERR(avs_base)) { 379 pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n"); 380 avs_base = NULL; 381 } 382 /* Before doing any configuration on the DVFS first, disable it */ 383 armada37xx_cpufreq_disable_dvfs(nb_pm_base); 384 385 /* 386 * On CPU 0 register the operating points supported (which are 387 * the nominal CPU frequency and full integer divisions of 388 * it). 389 */ 390 cpu_dev = get_cpu_device(0); 391 if (!cpu_dev) { 392 dev_err(cpu_dev, "Cannot get CPU\n"); 393 return -ENODEV; 394 } 395 396 clk = clk_get(cpu_dev, 0); 397 if (IS_ERR(clk)) { 398 dev_err(cpu_dev, "Cannot get clock for CPU0\n"); 399 return PTR_ERR(clk); 400 } 401 402 /* Get nominal (current) CPU frequency */ 403 cur_frequency = clk_get_rate(clk); 404 if (!cur_frequency) { 405 dev_err(cpu_dev, "Failed to get clock rate for CPU\n"); 406 clk_put(clk); 407 return -EINVAL; 408 } 409 410 dvfs = armada_37xx_cpu_freq_info_get(cur_frequency); 411 if (!dvfs) { 412 clk_put(clk); 413 return -EINVAL; 414 } 415 416 armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state), 417 GFP_KERNEL); 418 if (!armada37xx_cpufreq_state) { 419 clk_put(clk); 420 return -ENOMEM; 421 } 422 423 armada37xx_cpufreq_state->regmap = nb_pm_base; 424 425 armada37xx_cpufreq_avs_configure(avs_base, dvfs); 426 armada37xx_cpufreq_avs_setup(avs_base, dvfs); 427 428 armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider); 429 clk_put(clk); 430 431 for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR; 432 load_lvl++) { 433 unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000; 434 freq = cur_frequency / dvfs->divider[load_lvl]; 435 ret = dev_pm_opp_add(cpu_dev, freq, u_volt); 436 if (ret) 437 goto remove_opp; 438 439 440 } 441 442 /* Now that everything is setup, enable the DVFS at hardware level */ 443 armada37xx_cpufreq_enable_dvfs(nb_pm_base); 444 445 pdata.suspend = armada37xx_cpufreq_suspend; 446 pdata.resume = armada37xx_cpufreq_resume; 447 448 pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata, 449 sizeof(pdata)); 450 ret = PTR_ERR_OR_ZERO(pdev); 451 if (ret) 452 goto disable_dvfs; 453 454 return 0; 455 456 disable_dvfs: 457 armada37xx_cpufreq_disable_dvfs(nb_pm_base); 458 remove_opp: 459 /* clean-up the already added opp before leaving */ 460 while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) { 461 freq = cur_frequency / dvfs->divider[load_lvl]; 462 dev_pm_opp_remove(cpu_dev, freq); 463 } 464 465 kfree(armada37xx_cpufreq_state); 466 467 return ret; 468 } 469 /* late_initcall, to guarantee the driver is loaded after A37xx clock driver */ 470 late_initcall(armada37xx_cpufreq_driver_init); 471 472 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>"); 473 MODULE_DESCRIPTION("Armada 37xx cpufreq driver"); 474 MODULE_LICENSE("GPL"); 475