target/linux/xburst/patches-3.3/0012-MIPS-JZ4740-Add-cpufreq-support.patch

   1 From d0f0d5739a31c12d349980ed05a670fa1e84696d Mon Sep 17 00:00:00 2001
   2 From: Maarten ter Huurne <maarten@treewalker.org>
   3 Date: Wed, 16 Mar 2011 03:16:04 +0100
   4 Subject: [PATCH 12/21] MIPS: JZ4740: Add cpufreq support.
   5
   6 This is a squashed version of Uli's driver that was further developed in the opendingux-kernel repository.
   7 ---
   8  arch/mips/Kconfig                |    1 +
   9  arch/mips/jz4740/Makefile        |    1 +
  10  arch/mips/jz4740/cpufreq.c       |  226 ++++++++++++++++++++++++++++++++++++++
  11  arch/mips/kernel/cpufreq/Kconfig |   13 ++-
  12  4 files changed, 240 insertions(+), 1 deletions(-)
  13  create mode 100644 arch/mips/jz4740/cpufreq.c
  14
  15 --- a/arch/mips/Kconfig
  16 +++ b/arch/mips/Kconfig
  17 @@ -212,6 +212,7 @@ config MACH_JZ4740
  18         select HAVE_PWM
  19         select HAVE_CLK
  20         select GENERIC_IRQ_CHIP
  21 +       select CPU_SUPPORTS_CPUFREQ
  22
  23  config LANTIQ
  24         bool "Lantiq based platforms"
  25 --- a/arch/mips/jz4740/Makefile
  26 +++ b/arch/mips/jz4740/Makefile
  27 @@ -16,5 +16,6 @@ obj-$(CONFIG_JZ4740_QI_LB60)  += board-qi
  28  # PM support
  29
  30  obj-$(CONFIG_PM) += pm.o
  31 +obj-$(CONFIG_CPU_FREQ_JZ) += cpufreq.o
  32
  33  ccflags-y := -Werror -Wall
  34 --- /dev/null
  35 +++ b/arch/mips/jz4740/cpufreq.c
  36 @@ -0,0 +1,226 @@
  37 +/*
  38 + * linux/arch/mips/jz4740/cpufreq.c
  39 + *
  40 + * cpufreq driver for JZ4740
  41 + *
  42 + * Copyright (c) 2010       Ulrich Hecht <ulrich.hecht@gmail.com>
  43 + * Copyright (c) 2010       Maarten ter Huurne <maarten@treewalker.org>
  44 + *
  45 + * This program is free software; you can redistribute it and/or modify
  46 + * it under the terms of the GNU General Public License version 2 as
  47 + * published by the Free Software Foundation.
  48 + */
  49 +
  50 +#include <linux/kernel.h>
  51 +#include <linux/module.h>
  52 +#include <linux/init.h>
  53 +#include <linux/err.h>
  54 +
  55 +#include <linux/cpufreq.h>
  56 +
  57 +#include <linux/clk.h>
  58 +#include <asm/mach-jz4740/base.h>
  59 +
  60 +#include "clock.h"
  61 +
  62 +#define DEBUG_CPUFREQ
  63 +
  64 +#ifdef DEBUG_CPUFREQ
  65 +#define dprintk(X...) printk(KERN_INFO X)
  66 +#else
  67 +#define dprintk(X...) do { } while(0)
  68 +#endif
  69 +
  70 +#define HCLK_MIN 30000
  71 +/* TODO: The maximum MCLK most likely depends on the SDRAM chips used,
  72 +         so it is board-specific. */
  73 +#define MCLK_MAX 140000
  74 +
  75 +/* Same as jz_clk_main_divs, but with 24 and 32 removed because the hardware
  76 +   spec states those dividers must not be used for CCLK or HCLK. */
  77 +static const unsigned int jz4740_freq_cpu_divs[] = {1, 2, 3, 4, 6, 8, 12, 16};
  78 +
  79 +struct jz4740_freq_percpu_info {
  80 +       unsigned int pll_rate;
  81 +       struct cpufreq_frequency_table table[
  82 +               ARRAY_SIZE(jz4740_freq_cpu_divs) + 1];
  83 +};
  84 +
  85 +static struct clk *pll;
  86 +static struct clk *cclk;
  87 +
  88 +static struct jz4740_freq_percpu_info jz4740_freq_info;
  89 +
  90 +static struct cpufreq_driver cpufreq_jz4740_driver;
  91 +
  92 +static void jz4740_freq_fill_table(struct cpufreq_policy *policy,
  93 +                                  unsigned int pll_rate)
  94 +{
  95 +       struct cpufreq_frequency_table *table = &jz4740_freq_info.table[0];
  96 +       int i;
  97 +
  98 +#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  99 +       /* for showing /sys/devices/system/cpu/cpuX/cpufreq/stats/ */
 100 +       static bool init = false;
 101 +       if (init)
 102 +               cpufreq_frequency_table_put_attr(policy->cpu);
 103 +       else
 104 +               init = true;
 105 +#endif
 106 +
 107 +       jz4740_freq_info.pll_rate = pll_rate;
 108 +
 109 +       for (i = 0; i < ARRAY_SIZE(jz4740_freq_cpu_divs); i++) {
 110 +               unsigned int freq = pll_rate / jz4740_freq_cpu_divs[i];
 111 +               if (freq < HCLK_MIN) break;
 112 +               table[i].index = i;
 113 +               table[i].frequency = freq;
 114 +       }
 115 +       table[i].index = i;
 116 +       table[i].frequency = CPUFREQ_TABLE_END;
 117 +
 118 +       policy->min = table[i - 1].frequency;
 119 +       policy->max = table[0].frequency;
 120 +
 121 +#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 122 +       cpufreq_frequency_table_get_attr(table, policy->cpu);
 123 +#endif
 124 +}
 125 +
 126 +static unsigned int jz4740_freq_get(unsigned int cpu)
 127 +{
 128 +       return clk_get_rate(cclk) / 1000;
 129 +}
 130 +
 131 +static int jz4740_freq_verify(struct cpufreq_policy *policy)
 132 +{
 133 +       unsigned int new_pll;
 134 +
 135 +       cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 136 +                                    policy->cpuinfo.max_freq);
 137 +
 138 +       new_pll = clk_round_rate(pll, policy->max * 1000) / 1000;
 139 +       if (jz4740_freq_info.pll_rate != new_pll)
 140 +               jz4740_freq_fill_table(policy, new_pll);
 141 +
 142 +       return 0;
 143 +}
 144 +
 145 +static int jz4740_freq_target(struct cpufreq_policy *policy,
 146 +                         unsigned int target_freq,
 147 +                         unsigned int relation)
 148 +{
 149 +       struct cpufreq_frequency_table *table = &jz4740_freq_info.table[0];
 150 +       struct cpufreq_freqs freqs;
 151 +       unsigned int new_index = 0;
 152 +       unsigned int old_pll = clk_get_rate(pll) / 1000;
 153 +       unsigned int new_pll = jz4740_freq_info.pll_rate;
 154 +       int ret = 0;
 155 +
 156 +       if (cpufreq_frequency_table_target(policy, table,
 157 +                                          target_freq, relation, &new_index))
 158 +               return -EINVAL;
 159 +       freqs = (struct cpufreq_freqs) {
 160 +               .old = jz4740_freq_get(policy->cpu),
 161 +               .new = table[new_index].frequency,
 162 +               .cpu = policy->cpu,
 163 +               .flags = cpufreq_jz4740_driver.flags,
 164 +       };
 165 +       if (freqs.new != freqs.old || new_pll != old_pll) {
 166 +               unsigned int cdiv, hdiv, mdiv, pdiv;
 167 +               cdiv = jz4740_freq_cpu_divs[new_index];
 168 +               hdiv = (cdiv == 3 || cdiv == 6) ? cdiv * 2 : cdiv * 3;
 169 +               while (new_pll < HCLK_MIN * hdiv)
 170 +                       hdiv -= cdiv;
 171 +               mdiv = hdiv;
 172 +               if (new_pll > MCLK_MAX * mdiv) {
 173 +                       /* 4,4 performs better than 3,6 */
 174 +                       if (new_pll > MCLK_MAX * 4)
 175 +                               mdiv *= 2;
 176 +                       else
 177 +                               hdiv = mdiv = cdiv * 4;
 178 +               }
 179 +               pdiv = mdiv;
 180 +               dprintk(KERN_INFO "%s: cclk %p, setting from %d to %d, "
 181 +                       "dividers %d, %d, %d, %d\n",
 182 +                       __FUNCTION__, cclk, freqs.old, freqs.new,
 183 +                       cdiv, hdiv, mdiv, pdiv);
 184 +               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 185 +               ret = clk_main_set_dividers(new_pll == old_pll,
 186 +                                           cdiv, hdiv, mdiv, pdiv);
 187 +               if (ret) {
 188 +                       dprintk(KERN_INFO "failed to set dividers\n");
 189 +               } else if (new_pll != old_pll) {
 190 +                       dprintk(KERN_INFO "%s: pll %p, setting from %d to %d\n",
 191 +                               __FUNCTION__, pll, old_pll, new_pll);
 192 +                       ret = clk_set_rate(pll, new_pll * 1000);
 193 +               }
 194 +               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 195 +       }
 196 +
 197 +       return ret;
 198 +}
 199 +
 200 +static int jz4740_cpufreq_driver_init(struct cpufreq_policy *policy)
 201 +{
 202 +       int ret;
 203 +
 204 +       dprintk(KERN_INFO "Jz4740 cpufreq driver\n");
 205 +
 206 +       if (policy->cpu != 0)
 207 +               return -EINVAL;
 208 +
 209 +       pll = clk_get(NULL, "pll");
 210 +       if (IS_ERR(pll)) {
 211 +               ret = PTR_ERR(pll);
 212 +               goto err_exit;
 213 +       }
 214 +
 215 +       cclk = clk_get(NULL, "cclk");
 216 +       if (IS_ERR(cclk)) {
 217 +               ret = PTR_ERR(cclk);
 218 +               goto err_clk_put_pll;
 219 +       }
 220 +
 221 +       policy->cpuinfo.min_freq = HCLK_MIN;
 222 +       policy->cpuinfo.max_freq = 500000;
 223 +       policy->cpuinfo.transition_latency = 100000; /* in nanoseconds */
 224 +       policy->cur = jz4740_freq_get(policy->cpu);
 225 +       policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 226 +       /* min and max are set by jz4740_freq_fill_table() */
 227 +
 228 +       jz4740_freq_fill_table(policy, clk_get_rate(pll) / 1000 /* in kHz */);
 229 +
 230 +       return 0;
 231 +
 232 +err_clk_put_pll:
 233 +       clk_put(pll);
 234 +err_exit:
 235 +       return ret;
 236 +}
 237 +
 238 +static struct cpufreq_driver cpufreq_jz4740_driver = {
 239 +       .init   = jz4740_cpufreq_driver_init,
 240 +       .verify = jz4740_freq_verify,
 241 +       .target = jz4740_freq_target,
 242 +       .get    = jz4740_freq_get,
 243 +       .name   = "jz4740",
 244 +};
 245 +
 246 +static int __init jz4740_cpufreq_init(void)
 247 +{
 248 +       return cpufreq_register_driver(&cpufreq_jz4740_driver);
 249 +}
 250 +
 251 +static void __exit jz4740_cpufreq_exit(void)
 252 +{
 253 +       cpufreq_unregister_driver(&cpufreq_jz4740_driver);
 254 +}
 255 +
 256 +module_init(jz4740_cpufreq_init);
 257 +module_exit(jz4740_cpufreq_exit);
 258 +
 259 +MODULE_AUTHOR("Ulrich Hecht <ulrich.hecht@gmail.com>, "
 260 +             "Maarten ter Huurne <maarten@treewalker.org>");
 261 +MODULE_DESCRIPTION("cpufreq driver for Jz4740");
 262 +MODULE_LICENSE("GPL");
 263 --- a/arch/mips/kernel/cpufreq/Kconfig
 264 +++ b/arch/mips/kernel/cpufreq/Kconfig
 265 @@ -8,7 +8,7 @@ config MIPS_EXTERNAL_TIMER
 266  config MIPS_CPUFREQ
 267         bool
 268         default y
 269 -       depends on CPU_SUPPORTS_CPUFREQ && MIPS_EXTERNAL_TIMER
 270 +       depends on CPU_SUPPORTS_CPUFREQ
 271
 272  if MIPS_CPUFREQ
 273
 274 @@ -24,6 +24,7 @@ config LOONGSON2_CPUFREQ
 275         tristate "Loongson2 CPUFreq Driver"
 276         select CPU_FREQ_TABLE
 277         depends on MIPS_CPUFREQ
 278 +       depends on MIPS_EXTERNAL_TIMER
 279         help
 280           This option adds a CPUFreq driver for loongson processors which
 281           support software configurable cpu frequency.
 282 @@ -34,6 +35,16 @@ config LOONGSON2_CPUFREQ
 283
 284           If in doubt, say N.
 285
 286 +config CPU_FREQ_JZ
 287 +       tristate "CPUfreq driver for JZ CPUs"
 288 +       select CPU_FREQ_TABLE
 289 +       depends on MACH_JZ4740
 290 +       default n
 291 +       help
 292 +         This enables the CPUfreq driver for JZ CPUs.
 293 +
 294 +         If in doubt, say N.
 295 +
 296  endif  # CPU_FREQ
 297
 298  endmenu