Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 1 | /* |
| 2 | * drivers/cpufreq/spear-cpufreq.c |
| 3 | * |
| 4 | * CPU Frequency Scaling for SPEAr platform |
| 5 | * |
| 6 | * Copyright (C) 2012 ST Microelectronics |
| 7 | * Deepak Sikri <deepak.sikri@st.com> |
| 8 | * |
| 9 | * This file is licensed under the terms of the GNU General Public |
| 10 | * License version 2. This program is licensed "as is" without any |
| 11 | * warranty of any kind, whether express or implied. |
| 12 | */ |
| 13 | |
| 14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 15 | |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/cpufreq.h> |
| 18 | #include <linux/err.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/of.h> |
| 22 | #include <linux/slab.h> |
| 23 | #include <linux/types.h> |
| 24 | |
| 25 | /* SPEAr CPUFreq driver data structure */ |
| 26 | static struct { |
| 27 | struct clk *clk; |
| 28 | unsigned int transition_latency; |
| 29 | struct cpufreq_frequency_table *freq_tbl; |
| 30 | u32 cnt; |
| 31 | } spear_cpufreq; |
| 32 | |
Viresh Kumar | f851780 | 2013-01-12 05:12:09 +0000 | [diff] [blame] | 33 | static int spear_cpufreq_verify(struct cpufreq_policy *policy) |
Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 34 | { |
| 35 | return cpufreq_frequency_table_verify(policy, spear_cpufreq.freq_tbl); |
| 36 | } |
| 37 | |
| 38 | static unsigned int spear_cpufreq_get(unsigned int cpu) |
| 39 | { |
| 40 | return clk_get_rate(spear_cpufreq.clk) / 1000; |
| 41 | } |
| 42 | |
| 43 | static struct clk *spear1340_cpu_get_possible_parent(unsigned long newfreq) |
| 44 | { |
| 45 | struct clk *sys_pclk; |
| 46 | int pclk; |
| 47 | /* |
| 48 | * In SPEAr1340, cpu clk's parent sys clk can take input from |
| 49 | * following sources |
| 50 | */ |
| 51 | const char *sys_clk_src[] = { |
| 52 | "sys_syn_clk", |
| 53 | "pll1_clk", |
| 54 | "pll2_clk", |
| 55 | "pll3_clk", |
| 56 | }; |
| 57 | |
| 58 | /* |
| 59 | * As sys clk can have multiple source with their own range |
| 60 | * limitation so we choose possible sources accordingly |
| 61 | */ |
| 62 | if (newfreq <= 300000000) |
| 63 | pclk = 0; /* src is sys_syn_clk */ |
| 64 | else if (newfreq > 300000000 && newfreq <= 500000000) |
| 65 | pclk = 3; /* src is pll3_clk */ |
| 66 | else if (newfreq == 600000000) |
| 67 | pclk = 1; /* src is pll1_clk */ |
| 68 | else |
| 69 | return ERR_PTR(-EINVAL); |
| 70 | |
| 71 | /* Get parent to sys clock */ |
| 72 | sys_pclk = clk_get(NULL, sys_clk_src[pclk]); |
| 73 | if (IS_ERR(sys_pclk)) |
| 74 | pr_err("Failed to get %s clock\n", sys_clk_src[pclk]); |
| 75 | |
| 76 | return sys_pclk; |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * In SPEAr1340, we cannot use newfreq directly because we need to actually |
| 81 | * access a source clock (clk) which might not be ancestor of cpu at present. |
| 82 | * Hence in SPEAr1340 we would operate on source clock directly before switching |
| 83 | * cpu clock to it. |
| 84 | */ |
| 85 | static int spear1340_set_cpu_rate(struct clk *sys_pclk, unsigned long newfreq) |
| 86 | { |
| 87 | struct clk *sys_clk; |
| 88 | int ret = 0; |
| 89 | |
| 90 | sys_clk = clk_get_parent(spear_cpufreq.clk); |
| 91 | if (IS_ERR(sys_clk)) { |
| 92 | pr_err("failed to get cpu's parent (sys) clock\n"); |
| 93 | return PTR_ERR(sys_clk); |
| 94 | } |
| 95 | |
| 96 | /* Set the rate of the source clock before changing the parent */ |
| 97 | ret = clk_set_rate(sys_pclk, newfreq); |
| 98 | if (ret) { |
| 99 | pr_err("Failed to set sys clk rate to %lu\n", newfreq); |
| 100 | return ret; |
| 101 | } |
| 102 | |
| 103 | ret = clk_set_parent(sys_clk, sys_pclk); |
| 104 | if (ret) { |
| 105 | pr_err("Failed to set sys clk parent\n"); |
| 106 | return ret; |
| 107 | } |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static int spear_cpufreq_target(struct cpufreq_policy *policy, |
| 113 | unsigned int target_freq, unsigned int relation) |
| 114 | { |
| 115 | struct cpufreq_freqs freqs; |
| 116 | unsigned long newfreq; |
| 117 | struct clk *srcclk; |
| 118 | int index, ret, mult = 1; |
| 119 | |
| 120 | if (cpufreq_frequency_table_target(policy, spear_cpufreq.freq_tbl, |
| 121 | target_freq, relation, &index)) |
| 122 | return -EINVAL; |
| 123 | |
Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 124 | freqs.old = spear_cpufreq_get(0); |
| 125 | |
| 126 | newfreq = spear_cpufreq.freq_tbl[index].frequency * 1000; |
| 127 | if (of_machine_is_compatible("st,spear1340")) { |
| 128 | /* |
| 129 | * SPEAr1340 is special in the sense that due to the possibility |
| 130 | * of multiple clock sources for cpu clk's parent we can have |
| 131 | * different clock source for different frequency of cpu clk. |
| 132 | * Hence we need to choose one from amongst these possible clock |
| 133 | * sources. |
| 134 | */ |
| 135 | srcclk = spear1340_cpu_get_possible_parent(newfreq); |
| 136 | if (IS_ERR(srcclk)) { |
| 137 | pr_err("Failed to get src clk\n"); |
| 138 | return PTR_ERR(srcclk); |
| 139 | } |
| 140 | |
| 141 | /* SPEAr1340: src clk is always 2 * intended cpu clk */ |
| 142 | mult = 2; |
| 143 | } else { |
| 144 | /* |
| 145 | * src clock to be altered is ancestor of cpu clock. Hence we |
| 146 | * can directly work on cpu clk |
| 147 | */ |
| 148 | srcclk = spear_cpufreq.clk; |
| 149 | } |
| 150 | |
| 151 | newfreq = clk_round_rate(srcclk, newfreq * mult); |
| 152 | if (newfreq < 0) { |
| 153 | pr_err("clk_round_rate failed for cpu src clock\n"); |
| 154 | return newfreq; |
| 155 | } |
| 156 | |
| 157 | freqs.new = newfreq / 1000; |
| 158 | freqs.new /= mult; |
Viresh Kumar | 6f35a65 | 2013-01-31 04:53:56 +0000 | [diff] [blame] | 159 | |
Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 160 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 161 | |
| 162 | if (mult == 2) |
| 163 | ret = spear1340_set_cpu_rate(srcclk, newfreq); |
| 164 | else |
| 165 | ret = clk_set_rate(spear_cpufreq.clk, newfreq); |
| 166 | |
| 167 | /* Get current rate after clk_set_rate, in case of failure */ |
| 168 | if (ret) { |
| 169 | pr_err("CPU Freq: cpu clk_set_rate failed: %d\n", ret); |
| 170 | freqs.new = clk_get_rate(spear_cpufreq.clk) / 1000; |
| 171 | } |
| 172 | |
Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 173 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 174 | return ret; |
| 175 | } |
| 176 | |
| 177 | static int spear_cpufreq_init(struct cpufreq_policy *policy) |
| 178 | { |
| 179 | int ret; |
| 180 | |
| 181 | ret = cpufreq_frequency_table_cpuinfo(policy, spear_cpufreq.freq_tbl); |
| 182 | if (ret) { |
| 183 | pr_err("cpufreq_frequency_table_cpuinfo() failed"); |
| 184 | return ret; |
| 185 | } |
| 186 | |
| 187 | cpufreq_frequency_table_get_attr(spear_cpufreq.freq_tbl, policy->cpu); |
| 188 | policy->cpuinfo.transition_latency = spear_cpufreq.transition_latency; |
| 189 | policy->cur = spear_cpufreq_get(0); |
| 190 | |
Viresh Kumar | 4c738d0 | 2013-02-01 06:40:01 +0000 | [diff] [blame] | 191 | cpumask_setall(policy->cpus); |
Deepak Sikri | 4209932 | 2012-11-27 14:05:26 +0100 | [diff] [blame] | 192 | |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | static int spear_cpufreq_exit(struct cpufreq_policy *policy) |
| 197 | { |
| 198 | cpufreq_frequency_table_put_attr(policy->cpu); |
| 199 | return 0; |
| 200 | } |
| 201 | |
| 202 | static struct freq_attr *spear_cpufreq_attr[] = { |
| 203 | &cpufreq_freq_attr_scaling_available_freqs, |
| 204 | NULL, |
| 205 | }; |
| 206 | |
| 207 | static struct cpufreq_driver spear_cpufreq_driver = { |
| 208 | .name = "cpufreq-spear", |
| 209 | .flags = CPUFREQ_STICKY, |
| 210 | .verify = spear_cpufreq_verify, |
| 211 | .target = spear_cpufreq_target, |
| 212 | .get = spear_cpufreq_get, |
| 213 | .init = spear_cpufreq_init, |
| 214 | .exit = spear_cpufreq_exit, |
| 215 | .attr = spear_cpufreq_attr, |
| 216 | }; |
| 217 | |
| 218 | static int spear_cpufreq_driver_init(void) |
| 219 | { |
| 220 | struct device_node *np; |
| 221 | const struct property *prop; |
| 222 | struct cpufreq_frequency_table *freq_tbl; |
| 223 | const __be32 *val; |
| 224 | int cnt, i, ret; |
| 225 | |
| 226 | np = of_find_node_by_path("/cpus/cpu@0"); |
| 227 | if (!np) { |
| 228 | pr_err("No cpu node found"); |
| 229 | return -ENODEV; |
| 230 | } |
| 231 | |
| 232 | if (of_property_read_u32(np, "clock-latency", |
| 233 | &spear_cpufreq.transition_latency)) |
| 234 | spear_cpufreq.transition_latency = CPUFREQ_ETERNAL; |
| 235 | |
| 236 | prop = of_find_property(np, "cpufreq_tbl", NULL); |
| 237 | if (!prop || !prop->value) { |
| 238 | pr_err("Invalid cpufreq_tbl"); |
| 239 | ret = -ENODEV; |
| 240 | goto out_put_node; |
| 241 | } |
| 242 | |
| 243 | cnt = prop->length / sizeof(u32); |
| 244 | val = prop->value; |
| 245 | |
| 246 | freq_tbl = kmalloc(sizeof(*freq_tbl) * (cnt + 1), GFP_KERNEL); |
| 247 | if (!freq_tbl) { |
| 248 | ret = -ENOMEM; |
| 249 | goto out_put_node; |
| 250 | } |
| 251 | |
| 252 | for (i = 0; i < cnt; i++) { |
| 253 | freq_tbl[i].index = i; |
| 254 | freq_tbl[i].frequency = be32_to_cpup(val++); |
| 255 | } |
| 256 | |
| 257 | freq_tbl[i].index = i; |
| 258 | freq_tbl[i].frequency = CPUFREQ_TABLE_END; |
| 259 | |
| 260 | spear_cpufreq.freq_tbl = freq_tbl; |
| 261 | |
| 262 | of_node_put(np); |
| 263 | |
| 264 | spear_cpufreq.clk = clk_get(NULL, "cpu_clk"); |
| 265 | if (IS_ERR(spear_cpufreq.clk)) { |
| 266 | pr_err("Unable to get CPU clock\n"); |
| 267 | ret = PTR_ERR(spear_cpufreq.clk); |
| 268 | goto out_put_mem; |
| 269 | } |
| 270 | |
| 271 | ret = cpufreq_register_driver(&spear_cpufreq_driver); |
| 272 | if (!ret) |
| 273 | return 0; |
| 274 | |
| 275 | pr_err("failed register driver: %d\n", ret); |
| 276 | clk_put(spear_cpufreq.clk); |
| 277 | |
| 278 | out_put_mem: |
| 279 | kfree(freq_tbl); |
| 280 | return ret; |
| 281 | |
| 282 | out_put_node: |
| 283 | of_node_put(np); |
| 284 | return ret; |
| 285 | } |
| 286 | late_initcall(spear_cpufreq_driver_init); |
| 287 | |
| 288 | MODULE_AUTHOR("Deepak Sikri <deepak.sikri@st.com>"); |
| 289 | MODULE_DESCRIPTION("SPEAr CPUFreq driver"); |
| 290 | MODULE_LICENSE("GPL"); |