root/drivers/cpufreq/qoriq-cpufreq.c

DEFINITIONS

1. get_bus_freq
2. cpu_to_clk
3. set_affected_cpus
4. freq_table_redup
5. freq_table_sort
6. qoriq_cpufreq_cpu_init
7. qoriq_cpufreq_cpu_exit
8. qoriq_cpufreq_target
9. qoriq_cpufreq_init
10. qoriq_cpufreq_exit

   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 
  22 /**
  23  * struct cpu_data
  24  * @pclk: the parent clock of cpu
  25  * @table: frequency table
  26  */
  27 struct cpu_data {
  28         struct clk **pclk;
  29         struct cpufreq_frequency_table *table;
  30 };
  31 
  32 /*
  33  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
  34  * matched a more generic compatible.
  35  */
  36 #define SOC_BLACKLIST           1
  37 
  38 /**
  39  * struct soc_data - SoC specific data
  40  * @flags: SOC_xxx
  41  */
  42 struct soc_data {
  43         u32 flags;
  44 };
  45 
  46 static u32 get_bus_freq(void)
  47 {
  48         struct device_node *soc;
  49         u32 sysfreq;
  50         struct clk *pltclk;
  51         int ret;
  52 
  53         /* get platform freq by searching bus-frequency property */
  54         soc = of_find_node_by_type(NULL, "soc");
  55         if (soc) {
  56                 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
  57                 of_node_put(soc);
  58                 if (!ret)
  59                         return sysfreq;
  60         }
  61 
  62         /* get platform freq by its clock name */
  63         pltclk = clk_get(NULL, "cg-pll0-div1");
  64         if (IS_ERR(pltclk)) {
  65                 pr_err("%s: can't get bus frequency %ld\n",
  66                        __func__, PTR_ERR(pltclk));
  67                 return PTR_ERR(pltclk);
  68         }
  69 
  70         return clk_get_rate(pltclk);
  71 }
  72 
  73 static struct clk *cpu_to_clk(int cpu)
  74 {
  75         struct device_node *np;
  76         struct clk *clk;
  77 
  78         if (!cpu_present(cpu))
  79                 return NULL;
  80 
  81         np = of_get_cpu_node(cpu, NULL);
  82         if (!np)
  83                 return NULL;
  84 
  85         clk = of_clk_get(np, 0);
  86         of_node_put(np);
  87         return clk;
  88 }
  89 
  90 /* traverse cpu nodes to get cpu mask of sharing clock wire */
  91 static void set_affected_cpus(struct cpufreq_policy *policy)
  92 {
  93         struct cpumask *dstp = policy->cpus;
  94         struct clk *clk;
  95         int i;
  96 
  97         for_each_present_cpu(i) {
  98                 clk = cpu_to_clk(i);
  99                 if (IS_ERR(clk)) {
 100                         pr_err("%s: no clock for cpu %d\n", __func__, i);
 101                         continue;
 102                 }
 103 
 104                 if (clk_is_match(policy->clk, clk))
 105                         cpumask_set_cpu(i, dstp);
 106         }
 107 }
 108 
 109 /* reduce the duplicated frequencies in frequency table */
 110 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 111                 int count)
 112 {
 113         int i, j;
 114 
 115         for (i = 1; i < count; i++) {
 116                 for (j = 0; j < i; j++) {
 117                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 118                                         freq_table[j].frequency !=
 119                                         freq_table[i].frequency)
 120                                 continue;
 121 
 122                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 123                         break;
 124                 }
 125         }
 126 }
 127 
 128 /* sort the frequencies in frequency table in descenting order */
 129 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 130                 int count)
 131 {
 132         int i, j, ind;
 133         unsigned int freq, max_freq;
 134         struct cpufreq_frequency_table table;
 135 
 136         for (i = 0; i < count - 1; i++) {
 137                 max_freq = freq_table[i].frequency;
 138                 ind = i;
 139                 for (j = i + 1; j < count; j++) {
 140                         freq = freq_table[j].frequency;
 141                         if (freq == CPUFREQ_ENTRY_INVALID ||
 142                                         freq <= max_freq)
 143                                 continue;
 144                         ind = j;
 145                         max_freq = freq;
 146                 }
 147 
 148                 if (ind != i) {
 149                         /* exchange the frequencies */
 150                         table.driver_data = freq_table[i].driver_data;
 151                         table.frequency = freq_table[i].frequency;
 152                         freq_table[i].driver_data = freq_table[ind].driver_data;
 153                         freq_table[i].frequency = freq_table[ind].frequency;
 154                         freq_table[ind].driver_data = table.driver_data;
 155                         freq_table[ind].frequency = table.frequency;
 156                 }
 157         }
 158 }
 159 
 160 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 161 {
 162         struct device_node *np;
 163         int i, count;
 164         u32 freq;
 165         struct clk *clk;
 166         const struct clk_hw *hwclk;
 167         struct cpufreq_frequency_table *table;
 168         struct cpu_data *data;
 169         unsigned int cpu = policy->cpu;
 170         u64 u64temp;
 171 
 172         np = of_get_cpu_node(cpu, NULL);
 173         if (!np)
 174                 return -ENODEV;
 175 
 176         data = kzalloc(sizeof(*data), GFP_KERNEL);
 177         if (!data)
 178                 goto err_np;
 179 
 180         policy->clk = of_clk_get(np, 0);
 181         if (IS_ERR(policy->clk)) {
 182                 pr_err("%s: no clock information\n", __func__);
 183                 goto err_nomem2;
 184         }
 185 
 186         hwclk = __clk_get_hw(policy->clk);
 187         count = clk_hw_get_num_parents(hwclk);
 188 
 189         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 190         if (!data->pclk)
 191                 goto err_nomem2;
 192 
 193         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 194         if (!table)
 195                 goto err_pclk;
 196 
 197         for (i = 0; i < count; i++) {
 198                 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
 199                 data->pclk[i] = clk;
 200                 freq = clk_get_rate(clk);
 201                 table[i].frequency = freq / 1000;
 202                 table[i].driver_data = i;
 203         }
 204         freq_table_redup(table, count);
 205         freq_table_sort(table, count);
 206         table[i].frequency = CPUFREQ_TABLE_END;
 207         policy->freq_table = table;
 208         data->table = table;
 209 
 210         /* update ->cpus if we have cluster, no harm if not */
 211         set_affected_cpus(policy);
 212         policy->driver_data = data;
 213 
 214         /* Minimum transition latency is 12 platform clocks */
 215         u64temp = 12ULL * NSEC_PER_SEC;
 216         do_div(u64temp, get_bus_freq());
 217         policy->cpuinfo.transition_latency = u64temp + 1;
 218 
 219         of_node_put(np);
 220 
 221         return 0;
 222 
 223 err_pclk:
 224         kfree(data->pclk);
 225 err_nomem2:
 226         kfree(data);
 227 err_np:
 228         of_node_put(np);
 229 
 230         return -ENODEV;
 231 }
 232 
 233 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 234 {
 235         struct cpu_data *data = policy->driver_data;
 236 
 237         kfree(data->pclk);
 238         kfree(data->table);
 239         kfree(data);
 240         policy->driver_data = NULL;
 241 
 242         return 0;
 243 }
 244 
 245 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 246                 unsigned int index)
 247 {
 248         struct clk *parent;
 249         struct cpu_data *data = policy->driver_data;
 250 
 251         parent = data->pclk[data->table[index].driver_data];
 252         return clk_set_parent(policy->clk, parent);
 253 }
 254 
 255 static struct cpufreq_driver qoriq_cpufreq_driver = {
 256         .name           = "qoriq_cpufreq",
 257         .flags          = CPUFREQ_CONST_LOOPS |
 258                           CPUFREQ_IS_COOLING_DEV,
 259         .init           = qoriq_cpufreq_cpu_init,
 260         .exit           = qoriq_cpufreq_cpu_exit,
 261         .verify         = cpufreq_generic_frequency_table_verify,
 262         .target_index   = qoriq_cpufreq_target,
 263         .get            = cpufreq_generic_get,
 264         .attr           = cpufreq_generic_attr,
 265 };
 266 
 267 static const struct soc_data blacklist = {
 268         .flags = SOC_BLACKLIST,
 269 };
 270 
 271 static const struct of_device_id node_matches[] __initconst = {
 272         /* e6500 cannot use cpufreq due to erratum A-008083 */
 273         { .compatible = "fsl,b4420-clockgen", &blacklist },
 274         { .compatible = "fsl,b4860-clockgen", &blacklist },
 275         { .compatible = "fsl,t2080-clockgen", &blacklist },
 276         { .compatible = "fsl,t4240-clockgen", &blacklist },
 277 
 278         { .compatible = "fsl,ls1012a-clockgen", },
 279         { .compatible = "fsl,ls1021a-clockgen", },
 280         { .compatible = "fsl,ls1028a-clockgen", },
 281         { .compatible = "fsl,ls1043a-clockgen", },
 282         { .compatible = "fsl,ls1046a-clockgen", },
 283         { .compatible = "fsl,ls1088a-clockgen", },
 284         { .compatible = "fsl,ls2080a-clockgen", },
 285         { .compatible = "fsl,lx2160a-clockgen", },
 286         { .compatible = "fsl,p4080-clockgen", },
 287         { .compatible = "fsl,qoriq-clockgen-1.0", },
 288         { .compatible = "fsl,qoriq-clockgen-2.0", },
 289         {}
 290 };
 291 
 292 static int __init qoriq_cpufreq_init(void)
 293 {
 294         int ret;
 295         struct device_node  *np;
 296         const struct of_device_id *match;
 297         const struct soc_data *data;
 298 
 299         np = of_find_matching_node(NULL, node_matches);
 300         if (!np)
 301                 return -ENODEV;
 302 
 303         match = of_match_node(node_matches, np);
 304         data = match->data;
 305 
 306         of_node_put(np);
 307 
 308         if (data && data->flags & SOC_BLACKLIST)
 309                 return -ENODEV;
 310 
 311         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 312         if (!ret)
 313                 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
 314 
 315         return ret;
 316 }
 317 module_init(qoriq_cpufreq_init);
 318 
 319 static void __exit qoriq_cpufreq_exit(void)
 320 {
 321         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 322 }
 323 module_exit(qoriq_cpufreq_exit);
 324 
 325 MODULE_LICENSE("GPL");
 326 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 327 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");