target/linux/ipq806x/patches/0172-cpufreq-Add-a-cpufreq-krait-based-on-cpufreq-cpu0.patch

   1 From 5cf343c60d7557aefb468603065cac5062f11b8d Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <sboyd@codeaurora.org>
   3 Date: Fri, 30 May 2014 16:36:11 -0700
   4 Subject: [PATCH 172/182] cpufreq: Add a cpufreq-krait based on cpufreq-cpu0
   5
   6 Krait processors have individual clocks for each CPU that can
   7 scale independently from one another. cpufreq-cpu0 is fairly
   8 close to this, but assumes that there is only one clock for all
   9 CPUs. Add a driver to support the Krait configuration.
  10
  11 TODO: Merge into cpufreq-cpu0? Or make generic?
  12
  13 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  14 ---
  15  drivers/cpufreq/Kconfig         |   13 +++
  16  drivers/cpufreq/Makefile        |    1 +
  17  drivers/cpufreq/cpufreq-krait.c |  190 +++++++++++++++++++++++++++++++++++++++
  18  3 files changed, 204 insertions(+)
  19  create mode 100644 drivers/cpufreq/cpufreq-krait.c
  20
  21 --- a/drivers/cpufreq/Kconfig
  22 +++ b/drivers/cpufreq/Kconfig
  23 @@ -194,6 +194,19 @@ config GENERIC_CPUFREQ_CPU0
  24
  25           If in doubt, say N.
  26
  27 +config GENERIC_CPUFREQ_KRAIT
  28 +       tristate "Krait cpufreq driver"
  29 +       depends on HAVE_CLK && OF
  30 +       # if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y:
  31 +       depends on !CPU_THERMAL || THERMAL
  32 +       select PM_OPP
  33 +       help
  34 +         This adds a generic cpufreq driver for CPU0 frequency management.
  35 +         It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
  36 +         systems which share clock and voltage across all CPUs.
  37 +
  38 +         If in doubt, say N.
  39 +
  40  menu "x86 CPU frequency scaling drivers"
  41  depends on X86
  42  source "drivers/cpufreq/Kconfig.x86"
  43 --- a/drivers/cpufreq/Makefile
  44 +++ b/drivers/cpufreq/Makefile
  45 @@ -12,6 +12,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)
  46  obj-$(CONFIG_CPU_FREQ_GOV_COMMON)              += cpufreq_governor.o
  47
  48  obj-$(CONFIG_GENERIC_CPUFREQ_CPU0)     += cpufreq-cpu0.o
  49 +obj-$(CONFIG_GENERIC_CPUFREQ_KRAIT)    += cpufreq-krait.o
  50
  51  ##################################################################################
  52  # x86 drivers.
  53 --- /dev/null
  54 +++ b/drivers/cpufreq/cpufreq-krait.c
  55 @@ -0,0 +1,190 @@
  56 +/*
  57 + * Copyright (C) 2012 Freescale Semiconductor, Inc.
  58 + * Copyright (c) 2014, The Linux Foundation. All rights reserved.
  59 + *
  60 + * The OPP code in function krait_set_target() is reused from
  61 + * drivers/cpufreq/omap-cpufreq.c
  62 + *
  63 + * This program is free software; you can redistribute it and/or modify
  64 + * it under the terms of the GNU General Public License version 2 as
  65 + * published by the Free Software Foundation.
  66 + */
  67 +
  68 +#include <linux/clk.h>
  69 +#include <linux/cpu.h>
  70 +#include <linux/cpu_cooling.h>
  71 +#include <linux/cpufreq.h>
  72 +#include <linux/cpumask.h>
  73 +#include <linux/err.h>
  74 +#include <linux/module.h>
  75 +#include <linux/of.h>
  76 +#include <linux/pm_opp.h>
  77 +#include <linux/platform_device.h>
  78 +#include <linux/slab.h>
  79 +#include <linux/thermal.h>
  80 +
  81 +static unsigned int transition_latency;
  82 +
  83 +static struct device *cpu_dev;
  84 +static DEFINE_PER_CPU(struct clk *, krait_cpu_clks);
  85 +static struct cpufreq_frequency_table *freq_table;
  86 +static struct thermal_cooling_device *cdev;
  87 +
  88 +static int krait_set_target(struct cpufreq_policy *policy, unsigned int index)
  89 +{
  90 +       unsigned long volt = 0, volt_old = 0;
  91 +       unsigned int old_freq, new_freq;
  92 +       long freq_Hz, freq_exact;
  93 +       int ret;
  94 +       struct clk *cpu_clk;
  95 +
  96 +       cpu_clk = per_cpu(krait_cpu_clks, policy->cpu);
  97 +
  98 +       freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
  99 +       if (freq_Hz <= 0)
 100 +               freq_Hz = freq_table[index].frequency * 1000;
 101 +
 102 +       freq_exact = freq_Hz;
 103 +       new_freq = freq_Hz / 1000;
 104 +       old_freq = clk_get_rate(cpu_clk) / 1000;
 105 +
 106 +       pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
 107 +                old_freq / 1000, volt_old ? volt_old / 1000 : -1,
 108 +                new_freq / 1000, volt ? volt / 1000 : -1);
 109 +
 110 +       ret = clk_set_rate(cpu_clk, freq_exact);
 111 +       if (ret)
 112 +               pr_err("failed to set clock rate: %d\n", ret);
 113 +
 114 +       return ret;
 115 +}
 116 +
 117 +static int krait_cpufreq_init(struct cpufreq_policy *policy)
 118 +{
 119 +       int ret;
 120 +
 121 +       policy->clk = per_cpu(krait_cpu_clks, policy->cpu);
 122 +
 123 +       ret = cpufreq_table_validate_and_show(policy, freq_table);
 124 +       if (ret) {
 125 +               pr_err("%s: invalid frequency table: %d\n", __func__, ret);
 126 +               return ret;
 127 +       }
 128 +
 129 +       policy->cpuinfo.transition_latency = transition_latency;
 130 +
 131 +       return 0;
 132 +}
 133 +
 134 +static struct cpufreq_driver krait_cpufreq_driver = {
 135 +       .flags = CPUFREQ_STICKY,
 136 +       .verify = cpufreq_generic_frequency_table_verify,
 137 +       .target_index = krait_set_target,
 138 +       .get = cpufreq_generic_get,
 139 +       .init = krait_cpufreq_init,
 140 +       .name = "generic_krait",
 141 +       .attr = cpufreq_generic_attr,
 142 +};
 143 +
 144 +static int krait_cpufreq_probe(struct platform_device *pdev)
 145 +{
 146 +       struct device_node *np;
 147 +       int ret;
 148 +       unsigned int cpu;
 149 +       struct device *dev;
 150 +       struct clk *clk;
 151 +
 152 +       cpu_dev = get_cpu_device(0);
 153 +       if (!cpu_dev) {
 154 +               pr_err("failed to get krait device\n");
 155 +               return -ENODEV;
 156 +       }
 157 +
 158 +       np = of_node_get(cpu_dev->of_node);
 159 +       if (!np) {
 160 +               pr_err("failed to find krait node\n");
 161 +               return -ENOENT;
 162 +       }
 163 +
 164 +       for_each_possible_cpu(cpu) {
 165 +               dev = get_cpu_device(cpu);
 166 +               if (!dev) {
 167 +                       pr_err("failed to get krait device\n");
 168 +                       ret = -ENOENT;
 169 +                       goto out_put_node;
 170 +               }
 171 +               per_cpu(krait_cpu_clks, cpu) = clk = devm_clk_get(dev, NULL);
 172 +               if (IS_ERR(clk)) {
 173 +                       ret = PTR_ERR(clk);
 174 +                       goto out_put_node;
 175 +               }
 176 +       }
 177 +
 178 +       ret = of_init_opp_table(cpu_dev);
 179 +       if (ret) {
 180 +               pr_err("failed to init OPP table: %d\n", ret);
 181 +               goto out_put_node;
 182 +       }
 183 +
 184 +       ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 185 +       if (ret) {
 186 +               pr_err("failed to init cpufreq table: %d\n", ret);
 187 +               goto out_put_node;
 188 +       }
 189 +
 190 +       if (of_property_read_u32(np, "clock-latency", &transition_latency))
 191 +               transition_latency = CPUFREQ_ETERNAL;
 192 +
 193 +       ret = cpufreq_register_driver(&krait_cpufreq_driver);
 194 +       if (ret) {
 195 +               pr_err("failed register driver: %d\n", ret);
 196 +               goto out_free_table;
 197 +       }
 198 +       of_node_put(np);
 199 +
 200 +       /*
 201 +        * For now, just loading the cooling device;
 202 +        * thermal DT code takes care of matching them.
 203 +        */
 204 +       for_each_possible_cpu(cpu) {
 205 +               dev = get_cpu_device(cpu);
 206 +               np = of_node_get(dev->of_node);
 207 +               if (of_find_property(np, "#cooling-cells", NULL)) {
 208 +                       cdev = of_cpufreq_cooling_register(np, cpumask_of(cpu));
 209 +                       if (IS_ERR(cdev))
 210 +                               pr_err("running cpufreq without cooling device: %ld\n",
 211 +                                      PTR_ERR(cdev));
 212 +               }
 213 +               of_node_put(np);
 214 +       }
 215 +
 216 +       return 0;
 217 +
 218 +out_free_table:
 219 +       dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 220 +out_put_node:
 221 +       of_node_put(np);
 222 +       return ret;
 223 +}
 224 +
 225 +static int krait_cpufreq_remove(struct platform_device *pdev)
 226 +{
 227 +       cpufreq_cooling_unregister(cdev);
 228 +       cpufreq_unregister_driver(&krait_cpufreq_driver);
 229 +       dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 230 +
 231 +       return 0;
 232 +}
 233 +
 234 +static struct platform_driver krait_cpufreq_platdrv = {
 235 +       .driver = {
 236 +               .name   = "cpufreq-krait",
 237 +               .owner  = THIS_MODULE,
 238 +       },
 239 +       .probe          = krait_cpufreq_probe,
 240 +       .remove         = krait_cpufreq_remove,
 241 +};
 242 +module_platform_driver(krait_cpufreq_platdrv);
 243 +
 244 +MODULE_DESCRIPTION("Krait CPUfreq driver");
 245 +MODULE_LICENSE("GPL v2");