1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2013 Freescale Semiconductor, Inc. 4 * 5 * CPU Frequency Scaling driver for Freescale QorIQ SoCs. 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/clk.h> 11 #include <linux/clk-provider.h> 12 #include <linux/cpufreq.h> 13 #include <linux/errno.h> 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/mutex.h> 18 #include <linux/of.h> 19 #include <linux/slab.h> 20 #include <linux/smp.h> 21 #include <linux/platform_device.h> 22 23 /** 24 * struct cpu_data 25 * @pclk: the parent clock of cpu 26 * @table: frequency table 27 */ 28 struct cpu_data { 29 struct clk **pclk; 30 struct cpufreq_frequency_table *table; 31 }; 32 33 /** 34 * struct soc_data - SoC specific data 35 * @flags: SOC_xxx 36 */ 37 struct soc_data { 38 u32 flags; 39 }; 40 41 static u32 get_bus_freq(void) 42 { 43 struct device_node *soc; 44 u32 sysfreq; 45 struct clk *pltclk; 46 int ret; 47 48 /* get platform freq by searching bus-frequency property */ 49 soc = of_find_node_by_type(NULL, "soc"); 50 if (soc) { 51 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq); 52 of_node_put(soc); 53 if (!ret) 54 return sysfreq; 55 } 56 57 /* get platform freq by its clock name */ 58 pltclk = clk_get(NULL, "cg-pll0-div1"); 59 if (IS_ERR(pltclk)) { 60 pr_err("%s: can't get bus frequency %ld\n", 61 __func__, PTR_ERR(pltclk)); 62 return PTR_ERR(pltclk); 63 } 64 65 return clk_get_rate(pltclk); 66 } 67 68 static struct clk *cpu_to_clk(int cpu) 69 { 70 struct device_node *np; 71 struct clk *clk; 72 73 if (!cpu_present(cpu)) 74 return NULL; 75 76 np = of_get_cpu_node(cpu, NULL); 77 if (!np) 78 return NULL; 79 80 clk = of_clk_get(np, 0); 81 of_node_put(np); 82 return clk; 83 } 84 85 /* traverse cpu nodes to get cpu mask of sharing clock wire */ 86 static void set_affected_cpus(struct cpufreq_policy *policy) 87 { 88 struct cpumask *dstp = policy->cpus; 89 struct clk *clk; 90 int i; 91 92 for_each_present_cpu(i) { 93 clk = cpu_to_clk(i); 94 if (IS_ERR(clk)) { 95 pr_err("%s: no clock for cpu %d\n", __func__, i); 96 continue; 97 } 98 99 if (clk_is_match(policy->clk, clk)) 100 cpumask_set_cpu(i, dstp); 101 } 102 } 103 104 /* reduce the duplicated frequencies in frequency table */ 105 static void freq_table_redup(struct cpufreq_frequency_table *freq_table, 106 int count) 107 { 108 int i, j; 109 110 for (i = 1; i < count; i++) { 111 for (j = 0; j < i; j++) { 112 if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID || 113 freq_table[j].frequency != 114 freq_table[i].frequency) 115 continue; 116 117 freq_table[i].frequency = CPUFREQ_ENTRY_INVALID; 118 break; 119 } 120 } 121 } 122 123 /* sort the frequencies in frequency table in descenting order */ 124 static void freq_table_sort(struct cpufreq_frequency_table *freq_table, 125 int count) 126 { 127 int i, j, ind; 128 unsigned int freq, max_freq; 129 struct cpufreq_frequency_table table; 130 131 for (i = 0; i < count - 1; i++) { 132 max_freq = freq_table[i].frequency; 133 ind = i; 134 for (j = i + 1; j < count; j++) { 135 freq = freq_table[j].frequency; 136 if (freq == CPUFREQ_ENTRY_INVALID || 137 freq <= max_freq) 138 continue; 139 ind = j; 140 max_freq = freq; 141 } 142 143 if (ind != i) { 144 /* exchange the frequencies */ 145 table.driver_data = freq_table[i].driver_data; 146 table.frequency = freq_table[i].frequency; 147 freq_table[i].driver_data = freq_table[ind].driver_data; 148 freq_table[i].frequency = freq_table[ind].frequency; 149 freq_table[ind].driver_data = table.driver_data; 150 freq_table[ind].frequency = table.frequency; 151 } 152 } 153 } 154 155 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy) 156 { 157 struct device_node *np; 158 int i, count; 159 u32 freq; 160 struct clk *clk; 161 const struct clk_hw *hwclk; 162 struct cpufreq_frequency_table *table; 163 struct cpu_data *data; 164 unsigned int cpu = policy->cpu; 165 u64 u64temp; 166 167 np = of_get_cpu_node(cpu, NULL); 168 if (!np) 169 return -ENODEV; 170 171 data = kzalloc(sizeof(*data), GFP_KERNEL); 172 if (!data) 173 goto err_np; 174 175 policy->clk = of_clk_get(np, 0); 176 if (IS_ERR(policy->clk)) { 177 pr_err("%s: no clock information\n", __func__); 178 goto err_nomem2; 179 } 180 181 hwclk = __clk_get_hw(policy->clk); 182 count = clk_hw_get_num_parents(hwclk); 183 184 data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL); 185 if (!data->pclk) 186 goto err_nomem2; 187 188 table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL); 189 if (!table) 190 goto err_pclk; 191 192 for (i = 0; i < count; i++) { 193 clk = clk_hw_get_parent_by_index(hwclk, i)->clk; 194 data->pclk[i] = clk; 195 freq = clk_get_rate(clk); 196 table[i].frequency = freq / 1000; 197 table[i].driver_data = i; 198 } 199 freq_table_redup(table, count); 200 freq_table_sort(table, count); 201 table[i].frequency = CPUFREQ_TABLE_END; 202 policy->freq_table = table; 203 data->table = table; 204 205 /* update ->cpus if we have cluster, no harm if not */ 206 set_affected_cpus(policy); 207 policy->driver_data = data; 208 209 /* Minimum transition latency is 12 platform clocks */ 210 u64temp = 12ULL * NSEC_PER_SEC; 211 do_div(u64temp, get_bus_freq()); 212 policy->cpuinfo.transition_latency = u64temp + 1; 213 214 of_node_put(np); 215 216 return 0; 217 218 err_pclk: 219 kfree(data->pclk); 220 err_nomem2: 221 kfree(data); 222 err_np: 223 of_node_put(np); 224 225 return -ENODEV; 226 } 227 228 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy) 229 { 230 struct cpu_data *data = policy->driver_data; 231 232 kfree(data->pclk); 233 kfree(data->table); 234 kfree(data); 235 policy->driver_data = NULL; 236 237 return 0; 238 } 239 240 static int qoriq_cpufreq_target(struct cpufreq_policy *policy, 241 unsigned int index) 242 { 243 struct clk *parent; 244 struct cpu_data *data = policy->driver_data; 245 246 parent = data->pclk[data->table[index].driver_data]; 247 return clk_set_parent(policy->clk, parent); 248 } 249 250 static struct cpufreq_driver qoriq_cpufreq_driver = { 251 .name = "qoriq_cpufreq", 252 .flags = CPUFREQ_CONST_LOOPS | 253 CPUFREQ_IS_COOLING_DEV, 254 .init = qoriq_cpufreq_cpu_init, 255 .exit = qoriq_cpufreq_cpu_exit, 256 .verify = cpufreq_generic_frequency_table_verify, 257 .target_index = qoriq_cpufreq_target, 258 .get = cpufreq_generic_get, 259 .attr = cpufreq_generic_attr, 260 }; 261 262 static const struct of_device_id qoriq_cpufreq_blacklist[] = { 263 /* e6500 cannot use cpufreq due to erratum A-008083 */ 264 { .compatible = "fsl,b4420-clockgen", }, 265 { .compatible = "fsl,b4860-clockgen", }, 266 { .compatible = "fsl,t2080-clockgen", }, 267 { .compatible = "fsl,t4240-clockgen", }, 268 {} 269 }; 270 271 static int qoriq_cpufreq_probe(struct platform_device *pdev) 272 { 273 int ret; 274 struct device_node *np; 275 276 np = of_find_matching_node(NULL, qoriq_cpufreq_blacklist); 277 if (np) { 278 dev_info(&pdev->dev, "Disabling due to erratum A-008083"); 279 return -ENODEV; 280 } 281 282 ret = cpufreq_register_driver(&qoriq_cpufreq_driver); 283 if (ret) 284 return ret; 285 286 dev_info(&pdev->dev, "Freescale QorIQ CPU frequency scaling driver\n"); 287 return 0; 288 } 289 290 static int qoriq_cpufreq_remove(struct platform_device *pdev) 291 { 292 cpufreq_unregister_driver(&qoriq_cpufreq_driver); 293 294 return 0; 295 } 296 297 static struct platform_driver qoriq_cpufreq_platform_driver = { 298 .driver = { 299 .name = "qoriq-cpufreq", 300 }, 301 .probe = qoriq_cpufreq_probe, 302 .remove = qoriq_cpufreq_remove, 303 }; 304 module_platform_driver(qoriq_cpufreq_platform_driver); 305 306 MODULE_ALIAS("platform:qoriq-cpufreq"); 307 MODULE_LICENSE("GPL"); 308 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>"); 309 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs"); 310