1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Allwinner CPUFreq nvmem based driver 4 * 5 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to 6 * provide the OPP framework with required information. 7 * 8 * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com> 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/arm-smccc.h> 14 #include <linux/cpu.h> 15 #include <linux/module.h> 16 #include <linux/nvmem-consumer.h> 17 #include <linux/of.h> 18 #include <linux/platform_device.h> 19 #include <linux/pm_opp.h> 20 #include <linux/slab.h> 21 22 #define NVMEM_MASK 0x7 23 #define NVMEM_SHIFT 5 24 25 static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev; 26 27 struct sunxi_cpufreq_data { 28 u32 (*efuse_xlate)(u32 speedbin); 29 }; 30 31 static u32 sun50i_h6_efuse_xlate(u32 speedbin) 32 { 33 u32 efuse_value; 34 35 efuse_value = (speedbin >> NVMEM_SHIFT) & NVMEM_MASK; 36 37 /* 38 * We treat unexpected efuse values as if the SoC was from 39 * the slowest bin. Expected efuse values are 1-3, slowest 40 * to fastest. 41 */ 42 if (efuse_value >= 1 && efuse_value <= 3) 43 return efuse_value - 1; 44 else 45 return 0; 46 } 47 48 static int get_soc_id_revision(void) 49 { 50 #ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY 51 return arm_smccc_get_soc_id_revision(); 52 #else 53 return SMCCC_RET_NOT_SUPPORTED; 54 #endif 55 } 56 57 /* 58 * Judging by the OPP tables in the vendor BSP, the quality order of the 59 * returned speedbin index is 4 -> 0/2 -> 3 -> 1, from worst to best. 60 * 0 and 2 seem identical from the OPP tables' point of view. 61 */ 62 static u32 sun50i_h616_efuse_xlate(u32 speedbin) 63 { 64 int ver_bits = get_soc_id_revision(); 65 u32 value = 0; 66 67 switch (speedbin & 0xffff) { 68 case 0x2000: 69 value = 0; 70 break; 71 case 0x2400: 72 case 0x7400: 73 case 0x2c00: 74 case 0x7c00: 75 if (ver_bits != SMCCC_RET_NOT_SUPPORTED && ver_bits <= 1) { 76 /* ic version A/B */ 77 value = 1; 78 } else { 79 /* ic version C and later version */ 80 value = 2; 81 } 82 break; 83 case 0x5000: 84 case 0x5400: 85 case 0x6000: 86 value = 3; 87 break; 88 case 0x5c00: 89 value = 4; 90 break; 91 case 0x5d00: 92 value = 0; 93 break; 94 default: 95 pr_warn("sun50i-cpufreq-nvmem: unknown speed bin 0x%x, using default bin 0\n", 96 speedbin & 0xffff); 97 value = 0; 98 break; 99 } 100 101 return value; 102 } 103 104 static struct sunxi_cpufreq_data sun50i_h6_cpufreq_data = { 105 .efuse_xlate = sun50i_h6_efuse_xlate, 106 }; 107 108 static struct sunxi_cpufreq_data sun50i_h616_cpufreq_data = { 109 .efuse_xlate = sun50i_h616_efuse_xlate, 110 }; 111 112 static const struct of_device_id cpu_opp_match_list[] = { 113 { .compatible = "allwinner,sun50i-h6-operating-points", 114 .data = &sun50i_h6_cpufreq_data, 115 }, 116 { .compatible = "allwinner,sun50i-h616-operating-points", 117 .data = &sun50i_h616_cpufreq_data, 118 }, 119 {} 120 }; 121 122 /** 123 * dt_has_supported_hw() - Check if any OPPs use opp-supported-hw 124 * 125 * If we ask the cpufreq framework to use the opp-supported-hw feature, it 126 * will ignore every OPP node without that DT property. If none of the OPPs 127 * have it, the driver will fail probing, due to the lack of OPPs. 128 * 129 * Returns true if we have at least one OPP with the opp-supported-hw property. 130 */ 131 static bool dt_has_supported_hw(void) 132 { 133 bool has_opp_supported_hw = false; 134 struct device_node *np, *opp; 135 struct device *cpu_dev; 136 137 cpu_dev = get_cpu_device(0); 138 if (!cpu_dev) 139 return false; 140 141 np = dev_pm_opp_of_get_opp_desc_node(cpu_dev); 142 if (!np) 143 return false; 144 145 for_each_child_of_node(np, opp) { 146 if (of_find_property(opp, "opp-supported-hw", NULL)) { 147 has_opp_supported_hw = true; 148 break; 149 } 150 } 151 152 of_node_put(np); 153 154 return has_opp_supported_hw; 155 } 156 157 /** 158 * sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value 159 * 160 * Returns non-negative speed bin index on success, a negative error 161 * value otherwise. 162 */ 163 static int sun50i_cpufreq_get_efuse(void) 164 { 165 const struct sunxi_cpufreq_data *opp_data; 166 struct nvmem_cell *speedbin_nvmem; 167 const struct of_device_id *match; 168 struct device_node *np; 169 struct device *cpu_dev; 170 u32 *speedbin; 171 int ret; 172 173 cpu_dev = get_cpu_device(0); 174 if (!cpu_dev) 175 return -ENODEV; 176 177 np = dev_pm_opp_of_get_opp_desc_node(cpu_dev); 178 if (!np) 179 return -ENOENT; 180 181 match = of_match_node(cpu_opp_match_list, np); 182 if (!match) { 183 of_node_put(np); 184 return -ENOENT; 185 } 186 opp_data = match->data; 187 188 speedbin_nvmem = of_nvmem_cell_get(np, NULL); 189 of_node_put(np); 190 if (IS_ERR(speedbin_nvmem)) 191 return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem), 192 "Could not get nvmem cell\n"); 193 194 speedbin = nvmem_cell_read(speedbin_nvmem, NULL); 195 nvmem_cell_put(speedbin_nvmem); 196 if (IS_ERR(speedbin)) 197 return PTR_ERR(speedbin); 198 199 ret = opp_data->efuse_xlate(*speedbin); 200 201 kfree(speedbin); 202 203 return ret; 204 }; 205 206 static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev) 207 { 208 int *opp_tokens; 209 char name[] = "speedXXXXXXXXXXX"; /* Integers can take 11 chars max */ 210 unsigned int cpu, supported_hw; 211 struct dev_pm_opp_config config = {}; 212 int speed; 213 int ret; 214 215 opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens), 216 GFP_KERNEL); 217 if (!opp_tokens) 218 return -ENOMEM; 219 220 speed = sun50i_cpufreq_get_efuse(); 221 if (speed < 0) { 222 kfree(opp_tokens); 223 return speed; 224 } 225 226 /* 227 * We need at least one OPP with the "opp-supported-hw" property, 228 * or else the upper layers will ignore every OPP and will bail out. 229 */ 230 if (dt_has_supported_hw()) { 231 supported_hw = 1U << speed; 232 config.supported_hw = &supported_hw; 233 config.supported_hw_count = 1; 234 } 235 236 snprintf(name, sizeof(name), "speed%d", speed); 237 config.prop_name = name; 238 239 for_each_possible_cpu(cpu) { 240 struct device *cpu_dev = get_cpu_device(cpu); 241 242 if (!cpu_dev) { 243 ret = -ENODEV; 244 goto free_opp; 245 } 246 247 ret = dev_pm_opp_set_config(cpu_dev, &config); 248 if (ret < 0) 249 goto free_opp; 250 251 opp_tokens[cpu] = ret; 252 } 253 254 cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1, 255 NULL, 0); 256 if (!IS_ERR(cpufreq_dt_pdev)) { 257 platform_set_drvdata(pdev, opp_tokens); 258 return 0; 259 } 260 261 ret = PTR_ERR(cpufreq_dt_pdev); 262 pr_err("Failed to register platform device\n"); 263 264 free_opp: 265 for_each_possible_cpu(cpu) 266 dev_pm_opp_clear_config(opp_tokens[cpu]); 267 kfree(opp_tokens); 268 269 return ret; 270 } 271 272 static void sun50i_cpufreq_nvmem_remove(struct platform_device *pdev) 273 { 274 int *opp_tokens = platform_get_drvdata(pdev); 275 unsigned int cpu; 276 277 platform_device_unregister(cpufreq_dt_pdev); 278 279 for_each_possible_cpu(cpu) 280 dev_pm_opp_clear_config(opp_tokens[cpu]); 281 282 kfree(opp_tokens); 283 } 284 285 static struct platform_driver sun50i_cpufreq_driver = { 286 .probe = sun50i_cpufreq_nvmem_probe, 287 .remove_new = sun50i_cpufreq_nvmem_remove, 288 .driver = { 289 .name = "sun50i-cpufreq-nvmem", 290 }, 291 }; 292 293 static const struct of_device_id sun50i_cpufreq_match_list[] = { 294 { .compatible = "allwinner,sun50i-h6" }, 295 { .compatible = "allwinner,sun50i-h616" }, 296 { .compatible = "allwinner,sun50i-h618" }, 297 { .compatible = "allwinner,sun50i-h700" }, 298 {} 299 }; 300 MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list); 301 302 static const struct of_device_id *sun50i_cpufreq_match_node(void) 303 { 304 const struct of_device_id *match; 305 struct device_node *np; 306 307 np = of_find_node_by_path("/"); 308 match = of_match_node(sun50i_cpufreq_match_list, np); 309 of_node_put(np); 310 311 return match; 312 } 313 314 /* 315 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER, 316 * all the real activity is done in the probe, which may be defered as well. 317 * The init here is only registering the driver and the platform device. 318 */ 319 static int __init sun50i_cpufreq_init(void) 320 { 321 const struct of_device_id *match; 322 int ret; 323 324 match = sun50i_cpufreq_match_node(); 325 if (!match) 326 return -ENODEV; 327 328 ret = platform_driver_register(&sun50i_cpufreq_driver); 329 if (unlikely(ret < 0)) 330 return ret; 331 332 sun50i_cpufreq_pdev = 333 platform_device_register_simple("sun50i-cpufreq-nvmem", 334 -1, NULL, 0); 335 ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev); 336 if (ret == 0) 337 return 0; 338 339 platform_driver_unregister(&sun50i_cpufreq_driver); 340 return ret; 341 } 342 module_init(sun50i_cpufreq_init); 343 344 static void __exit sun50i_cpufreq_exit(void) 345 { 346 platform_device_unregister(sun50i_cpufreq_pdev); 347 platform_driver_unregister(&sun50i_cpufreq_driver); 348 } 349 module_exit(sun50i_cpufreq_exit); 350 351 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver"); 352 MODULE_LICENSE("GPL v2"); 353