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1// SPDX-License-Identifier: GPL-2.02/*3 * Allwinner CPUFreq nvmem based driver4 *5 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to6 * 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 ": " fmt12 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 0x723#define NVMEM_SHIFT 524 25static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;26 27struct sunxi_cpufreq_data {28 u32 (*efuse_xlate)(u32 speedbin);29};30 31static 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 from39 * the slowest bin. Expected efuse values are 1-3, slowest40 * to fastest.41 */42 if (efuse_value >= 1 && efuse_value <= 3)43 return efuse_value - 1;44 else45 return 0;46}47 48static int get_soc_id_revision(void)49{50#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY51 return arm_smccc_get_soc_id_revision();52#else53 return SMCCC_RET_NOT_SUPPORTED;54#endif55}56 57/*58 * Judging by the OPP tables in the vendor BSP, the quality order of the59 * 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 */62static 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 107static struct sunxi_cpufreq_data sun50i_h6_cpufreq_data = {108 .efuse_xlate = sun50i_h6_efuse_xlate,109};110 111static struct sunxi_cpufreq_data sun50i_h616_cpufreq_data = {112 .efuse_xlate = sun50i_h616_efuse_xlate,113};114 115static 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-hw127 *128 * If we ask the cpufreq framework to use the opp-supported-hw feature, it129 * will ignore every OPP node without that DT property. If none of the OPPs130 * 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 */134static 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 value160 *161 * Returns non-negative speed bin index on success, a negative error162 * value otherwise.163 */164static 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 205static 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 263free_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 271static 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 284static 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 292static 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};299MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list);300 301static 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 */313static 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}336module_init(sun50i_cpufreq_init);337 338static void __exit sun50i_cpufreq_exit(void)339{340 platform_device_unregister(sun50i_cpufreq_pdev);341 platform_driver_unregister(&sun50i_cpufreq_driver);342}343module_exit(sun50i_cpufreq_exit);344 345MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");346MODULE_LICENSE("GPL v2");347