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| 1 | /* |
| 2 | * Copyright (C) STMicroelectronics 2009 |
| 3 | * Copyright (C) ST-Ericsson SA 2010 |
| 4 | * |
| 5 | * License Terms: GNU General Public License v2 |
| 6 | * Author: Sundar Iyer <sundar.iyer@stericsson.com> |
| 7 | * Author: Martin Persson <martin.persson@stericsson.com> |
| 8 | * Author: Jonas Aaberg <jonas.aberg@stericsson.com> |
| 9 | * |
| 10 | */ |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/cpufreq.h> |
| 13 | #include <linux/delay.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/mfd/dbx500-prcmu.h> |
| 16 | #include <mach/id.h> |
| 17 | |
| 18 | static struct cpufreq_frequency_table freq_table[] = { |
| 19 | [0] = { |
| 20 | .index = 0, |
| 21 | .frequency = 200000, |
| 22 | }, |
| 23 | [1] = { |
| 24 | .index = 1, |
| 25 | .frequency = 400000, |
| 26 | }, |
| 27 | [2] = { |
| 28 | .index = 2, |
| 29 | .frequency = 800000, |
| 30 | }, |
| 31 | [3] = { |
| 32 | /* Used for MAX_OPP, if available */ |
| 33 | .index = 3, |
| 34 | .frequency = CPUFREQ_TABLE_END, |
| 35 | }, |
| 36 | [4] = { |
| 37 | .index = 4, |
| 38 | .frequency = CPUFREQ_TABLE_END, |
| 39 | }, |
| 40 | }; |
| 41 | |
| 42 | static enum arm_opp idx2opp[] = { |
| 43 | ARM_EXTCLK, |
| 44 | ARM_50_OPP, |
| 45 | ARM_100_OPP, |
| 46 | ARM_MAX_OPP |
| 47 | }; |
| 48 | |
| 49 | static struct freq_attr *db8500_cpufreq_attr[] = { |
| 50 | &cpufreq_freq_attr_scaling_available_freqs, |
| 51 | NULL, |
| 52 | }; |
| 53 | |
| 54 | static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy) |
| 55 | { |
| 56 | return cpufreq_frequency_table_verify(policy, freq_table); |
| 57 | } |
| 58 | |
| 59 | static int db8500_cpufreq_target(struct cpufreq_policy *policy, |
| 60 | unsigned int target_freq, |
| 61 | unsigned int relation) |
| 62 | { |
| 63 | struct cpufreq_freqs freqs; |
| 64 | unsigned int idx; |
| 65 | |
| 66 | /* scale the target frequency to one of the extremes supported */ |
| 67 | if (target_freq < policy->cpuinfo.min_freq) |
| 68 | target_freq = policy->cpuinfo.min_freq; |
| 69 | if (target_freq > policy->cpuinfo.max_freq) |
| 70 | target_freq = policy->cpuinfo.max_freq; |
| 71 | |
| 72 | /* Lookup the next frequency */ |
| 73 | if (cpufreq_frequency_table_target |
| 74 | (policy, freq_table, target_freq, relation, &idx)) { |
| 75 | return -EINVAL; |
| 76 | } |
| 77 | |
| 78 | freqs.old = policy->cur; |
| 79 | freqs.new = freq_table[idx].frequency; |
| 80 | |
| 81 | if (freqs.old == freqs.new) |
| 82 | return 0; |
| 83 | |
| 84 | /* pre-change notification */ |
| 85 | for_each_cpu(freqs.cpu, policy->cpus) |
| 86 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| 87 | |
| 88 | /* request the PRCM unit for opp change */ |
| 89 | if (prcmu_set_arm_opp(idx2opp[idx])) { |
| 90 | pr_err("db8500-cpufreq: Failed to set OPP level\n"); |
| 91 | return -EINVAL; |
| 92 | } |
| 93 | |
| 94 | /* post change notification */ |
| 95 | for_each_cpu(freqs.cpu, policy->cpus) |
| 96 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| 97 | |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | static unsigned int db8500_cpufreq_getspeed(unsigned int cpu) |
| 102 | { |
| 103 | int i; |
| 104 | /* request the prcm to get the current ARM opp */ |
| 105 | for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++) |
| 106 | ; |
| 107 | return freq_table[i].frequency; |
| 108 | } |
| 109 | |
| 110 | static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy) |
| 111 | { |
| 112 | int i, res; |
| 113 | |
| 114 | BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table)); |
| 115 | |
| 116 | if (prcmu_has_arm_maxopp()) |
| 117 | freq_table[3].frequency = 1000000; |
| 118 | |
| 119 | pr_info("db8500-cpufreq : Available frequencies:\n"); |
| 120 | for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) |
| 121 | pr_info(" %d Mhz\n", freq_table[i].frequency/1000); |
| 122 | |
| 123 | /* get policy fields based on the table */ |
| 124 | res = cpufreq_frequency_table_cpuinfo(policy, freq_table); |
| 125 | if (!res) |
| 126 | cpufreq_frequency_table_get_attr(freq_table, policy->cpu); |
| 127 | else { |
| 128 | pr_err("db8500-cpufreq : Failed to read policy table\n"); |
| 129 | return res; |
| 130 | } |
| 131 | |
| 132 | policy->min = policy->cpuinfo.min_freq; |
| 133 | policy->max = policy->cpuinfo.max_freq; |
| 134 | policy->cur = db8500_cpufreq_getspeed(policy->cpu); |
| 135 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; |
| 136 | |
| 137 | /* |
| 138 | * FIXME : Need to take time measurement across the target() |
| 139 | * function with no/some/all drivers in the notification |
| 140 | * list. |
| 141 | */ |
| 142 | policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */ |
| 143 | |
| 144 | /* policy sharing between dual CPUs */ |
| 145 | cpumask_copy(policy->cpus, cpu_present_mask); |
| 146 | |
| 147 | policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static struct cpufreq_driver db8500_cpufreq_driver = { |
| 153 | .flags = CPUFREQ_STICKY, |
| 154 | .verify = db8500_cpufreq_verify_speed, |
| 155 | .target = db8500_cpufreq_target, |
| 156 | .get = db8500_cpufreq_getspeed, |
| 157 | .init = db8500_cpufreq_init, |
| 158 | .name = "DB8500", |
| 159 | .attr = db8500_cpufreq_attr, |
| 160 | }; |
| 161 | |
| 162 | static int __init db8500_cpufreq_register(void) |
| 163 | { |
| 164 | if (!cpu_is_u8500_family()) |
| 165 | return -ENODEV; |
| 166 | |
| 167 | pr_info("cpufreq for DB8500 started\n"); |
| 168 | return cpufreq_register_driver(&db8500_cpufreq_driver); |
| 169 | } |
| 170 | device_initcall(db8500_cpufreq_register); |
| 171 |
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