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 case 0x6c00: 95 value = 5; 96 break; 97 default: 98 pr_warn("sun50i-cpufreq-nvmem: unknown speed bin 0x%x, using default bin 0\n", 99 speedbin & 0xffff); 100 value = 0; 101 break; 102 } 103 104 return value; 105 } 106 107 static struct sunxi_cpufreq_data sun50i_h6_cpufreq_data = { 108 .efuse_xlate = sun50i_h6_efuse_xlate, 109 }; 110 111 static struct sunxi_cpufreq_data sun50i_h616_cpufreq_data = { 112 .efuse_xlate = sun50i_h616_efuse_xlate, 113 }; 114 115 static const struct of_device_id cpu_opp_match_list[] = { 116 { .compatible = "allwinner,sun50i-h6-operating-points", 117 .data = &sun50i_h6_cpufreq_data, 118 }, 119 { .compatible = "allwinner,sun50i-h616-operating-points", 120 .data = &sun50i_h616_cpufreq_data, 121 }, 122 {} 123 }; 124 125 /** 126 * dt_has_supported_hw() - Check if any OPPs use opp-supported-hw 127 * 128 * If we ask the cpufreq framework to use the opp-supported-hw feature, it 129 * will ignore every OPP node without that DT property. If none of the OPPs 130 * have it, the driver will fail probing, due to the lack of OPPs. 131 * 132 * Returns true if we have at least one OPP with the opp-supported-hw property. 133 */ 134 static bool dt_has_supported_hw(void) 135 { 136 bool has_opp_supported_hw = false; 137 struct device *cpu_dev; 138 139 cpu_dev = get_cpu_device(0); 140 if (!cpu_dev) 141 return false; 142 143 struct device_node *np __free(device_node) = 144 dev_pm_opp_of_get_opp_desc_node(cpu_dev); 145 if (!np) 146 return false; 147 148 for_each_child_of_node_scoped(np, opp) { 149 if (of_property_present(opp, "opp-supported-hw")) { 150 has_opp_supported_hw = true; 151 break; 152 } 153 } 154 155 return has_opp_supported_hw; 156 } 157 158 /** 159 * sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value 160 * 161 * Returns non-negative speed bin index on success, a negative error 162 * value otherwise. 163 */ 164 static int sun50i_cpufreq_get_efuse(void) 165 { 166 const struct sunxi_cpufreq_data *opp_data; 167 struct nvmem_cell *speedbin_nvmem; 168 const struct of_device_id *match; 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 struct device_node *np __free(device_node) = 178 dev_pm_opp_of_get_opp_desc_node(cpu_dev); 179 if (!np) 180 return -ENOENT; 181 182 match = of_match_node(cpu_opp_match_list, np); 183 if (!match) 184 return -ENOENT; 185 186 opp_data = match->data; 187 188 speedbin_nvmem = of_nvmem_cell_get(np, NULL); 189 if (IS_ERR(speedbin_nvmem)) 190 return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem), 191 "Could not get nvmem cell\n"); 192 193 speedbin = nvmem_cell_read(speedbin_nvmem, NULL); 194 nvmem_cell_put(speedbin_nvmem); 195 if (IS_ERR(speedbin)) 196 return PTR_ERR(speedbin); 197 198 ret = opp_data->efuse_xlate(*speedbin); 199 200 kfree(speedbin); 201 202 return ret; 203 }; 204 205 static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev) 206 { 207 int *opp_tokens; 208 char name[] = "speedXXXXXXXXXXX"; /* Integers can take 11 chars max */ 209 unsigned int cpu, supported_hw; 210 struct dev_pm_opp_config config = {}; 211 int speed; 212 int ret; 213 214 opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens), 215 GFP_KERNEL); 216 if (!opp_tokens) 217 return -ENOMEM; 218 219 speed = sun50i_cpufreq_get_efuse(); 220 if (speed < 0) { 221 kfree(opp_tokens); 222 return speed; 223 } 224 225 /* 226 * We need at least one OPP with the "opp-supported-hw" property, 227 * or else the upper layers will ignore every OPP and will bail out. 228 */ 229 if (dt_has_supported_hw()) { 230 supported_hw = 1U << speed; 231 config.supported_hw = &supported_hw; 232 config.supported_hw_count = 1; 233 } 234 235 snprintf(name, sizeof(name), "speed%d", speed); 236 config.prop_name = name; 237 238 for_each_possible_cpu(cpu) { 239 struct device *cpu_dev = get_cpu_device(cpu); 240 241 if (!cpu_dev) { 242 ret = -ENODEV; 243 goto free_opp; 244 } 245 246 ret = dev_pm_opp_set_config(cpu_dev, &config); 247 if (ret < 0) 248 goto free_opp; 249 250 opp_tokens[cpu] = ret; 251 } 252 253 cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1, 254 NULL, 0); 255 if (!IS_ERR(cpufreq_dt_pdev)) { 256 platform_set_drvdata(pdev, opp_tokens); 257 return 0; 258 } 259 260 ret = PTR_ERR(cpufreq_dt_pdev); 261 pr_err("Failed to register platform device\n"); 262 263 free_opp: 264 for_each_possible_cpu(cpu) 265 dev_pm_opp_clear_config(opp_tokens[cpu]); 266 kfree(opp_tokens); 267 268 return ret; 269 } 270 271 static void sun50i_cpufreq_nvmem_remove(struct platform_device *pdev) 272 { 273 int *opp_tokens = platform_get_drvdata(pdev); 274 unsigned int cpu; 275 276 platform_device_unregister(cpufreq_dt_pdev); 277 278 for_each_possible_cpu(cpu) 279 dev_pm_opp_clear_config(opp_tokens[cpu]); 280 281 kfree(opp_tokens); 282 } 283 284 static struct platform_driver sun50i_cpufreq_driver = { 285 .probe = sun50i_cpufreq_nvmem_probe, 286 .remove_new = sun50i_cpufreq_nvmem_remove, 287 .driver = { 288 .name = "sun50i-cpufreq-nvmem", 289 }, 290 }; 291 292 static const struct of_device_id sun50i_cpufreq_match_list[] = { 293 { .compatible = "allwinner,sun50i-h6" }, 294 { .compatible = "allwinner,sun50i-h616" }, 295 { .compatible = "allwinner,sun50i-h618" }, 296 { .compatible = "allwinner,sun50i-h700" }, 297 {} 298 }; 299 MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list); 300 301 static const struct of_device_id *sun50i_cpufreq_match_node(void) 302 { 303 struct device_node *np __free(device_node) = of_find_node_by_path("/"); 304 305 return of_match_node(sun50i_cpufreq_match_list, np); 306 } 307 308 /* 309 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER, 310 * all the real activity is done in the probe, which may be defered as well. 311 * The init here is only registering the driver and the platform device. 312 */ 313 static int __init sun50i_cpufreq_init(void) 314 { 315 const struct of_device_id *match; 316 int ret; 317 318 match = sun50i_cpufreq_match_node(); 319 if (!match) 320 return -ENODEV; 321 322 ret = platform_driver_register(&sun50i_cpufreq_driver); 323 if (unlikely(ret < 0)) 324 return ret; 325 326 sun50i_cpufreq_pdev = 327 platform_device_register_simple("sun50i-cpufreq-nvmem", 328 -1, NULL, 0); 329 ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev); 330 if (ret == 0) 331 return 0; 332 333 platform_driver_unregister(&sun50i_cpufreq_driver); 334 return ret; 335 } 336 module_init(sun50i_cpufreq_init); 337 338 static void __exit sun50i_cpufreq_exit(void) 339 { 340 platform_device_unregister(sun50i_cpufreq_pdev); 341 platform_driver_unregister(&sun50i_cpufreq_driver); 342 } 343 module_exit(sun50i_cpufreq_exit); 344 345 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver"); 346 MODULE_LICENSE("GPL v2"); 347