target/linux/brcm2708/patches-4.9/0046-Add-cpufreq-driver.patch

   1 From 91eeb6693671b5ae0220f4a276b84e6597266cb9 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Wed, 3 Jul 2013 00:49:20 +0100
   4 Subject: [PATCH] Add cpufreq driver
   5
   6 Signed-off-by: popcornmix <popcornmix@gmail.com>
   7 ---
   8  drivers/cpufreq/Kconfig.arm       |   9 ++
   9  drivers/cpufreq/Makefile          |   1 +
  10  drivers/cpufreq/bcm2835-cpufreq.c | 218 ++++++++++++++++++++++++++++++++++++++
  11  3 files changed, 228 insertions(+)
  12  create mode 100644 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 --- a/drivers/cpufreq/Kconfig.arm
  15 +++ b/drivers/cpufreq/Kconfig.arm
  16 @@ -220,6 +220,15 @@ config ARM_STI_CPUFREQ
  17           this config option if you wish to add CPUFreq support for STi based
  18           SoCs.
  19
  20 +config ARM_BCM2835_CPUFREQ
  21 +       depends on RASPBERRYPI_FIRMWARE
  22 +       bool "BCM2835 Driver"
  23 +       default y
  24 +       help
  25 +         This adds the CPUFreq driver for BCM2835
  26 +
  27 +         If in doubt, say N.
  28 +
  29  config ARM_TEGRA20_CPUFREQ
  30         bool "Tegra20 CPUFreq support"
  31         depends on ARCH_TEGRA
  32 --- a/drivers/cpufreq/Makefile
  33 +++ b/drivers/cpufreq/Makefile
  34 @@ -75,6 +75,7 @@ obj-$(CONFIG_ARM_SA1110_CPUFREQ)      += sa11
  35  obj-$(CONFIG_ARM_SCPI_CPUFREQ)         += scpi-cpufreq.o
  36  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  37  obj-$(CONFIG_ARM_STI_CPUFREQ)          += sti-cpufreq.o
  38 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  39  obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)      += tegra20-cpufreq.o
  40  obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)     += tegra124-cpufreq.o
  41  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
  42 --- /dev/null
  43 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  44 @@ -0,0 +1,218 @@
  45 +/*****************************************************************************
  46 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
  47 +*
  48 +* Unless you and Broadcom execute a separate written software license
  49 +* agreement governing use of this software, this software is licensed to you
  50 +* under the terms of the GNU General Public License version 2, available at
  51 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  52 +*
  53 +* Notwithstanding the above, under no circumstances may you combine this
  54 +* software in any way with any other Broadcom software provided under a
  55 +* license other than the GPL, without Broadcom's express prior written
  56 +* consent.
  57 +*****************************************************************************/
  58 +
  59 +/*****************************************************************************
  60 +* FILENAME: bcm2835-cpufreq.h
  61 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  62 +* processor. Messages are sent to Videocore either setting or requesting the
  63 +* frequency of the ARM in order to match an appropiate frequency to the current
  64 +* usage of the processor. The policy which selects the frequency to use is
  65 +* defined in the kernel .config file, but can be changed during runtime.
  66 +*****************************************************************************/
  67 +
  68 +/* ---------- INCLUDES ---------- */
  69 +#include <linux/kernel.h>
  70 +#include <linux/init.h>
  71 +#include <linux/module.h>
  72 +#include <linux/cpufreq.h>
  73 +#include <soc/bcm2835/raspberrypi-firmware.h>
  74 +
  75 +/* ---------- DEFINES ---------- */
  76 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  77 +#define MODULE_NAME "bcm2835-cpufreq"
  78 +
  79 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  80 +
  81 +/* debug printk macros */
  82 +#ifdef CPUFREQ_DEBUG_ENABLE
  83 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  84 +#else
  85 +#define print_debug(fmt,...)
  86 +#endif
  87 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
  88 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
  89 +
  90 +/* ---------- GLOBALS ---------- */
  91 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
  92 +static unsigned int min_frequency, max_frequency;
  93 +static struct cpufreq_frequency_table bcm2835_freq_table[3];
  94 +
  95 +/*
  96 + ===============================================
  97 +  clk_rate either gets or sets the clock rates.
  98 + ===============================================
  99 +*/
 100 +
 101 +static int bcm2835_cpufreq_clock_property(u32 tag, u32 id, u32 *val)
 102 +{
 103 +       struct rpi_firmware *fw = rpi_firmware_get(NULL);
 104 +       struct {
 105 +               u32 id;
 106 +               u32 val;
 107 +       } packet;
 108 +       int ret;
 109 +
 110 +       packet.id = id;
 111 +       packet.val = *val;
 112 +       ret = rpi_firmware_property(fw, tag, &packet, sizeof(packet));
 113 +       if (ret)
 114 +               return ret;
 115 +
 116 +       *val = packet.val;
 117 +
 118 +       return 0;
 119 +}
 120 +
 121 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 122 +{
 123 +       u32 rate = arm_rate * 1000;
 124 +       int ret;
 125 +
 126 +       ret = bcm2835_cpufreq_clock_property(RPI_FIRMWARE_SET_CLOCK_RATE, VCMSG_ID_ARM_CLOCK, &rate);
 127 +       if (ret) {
 128 +               print_err("Failed to set clock: %d (%d)\n", arm_rate, ret);
 129 +               return 0;
 130 +       }
 131 +
 132 +       rate /= 1000;
 133 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, rate);
 134 +
 135 +       return rate;
 136 +}
 137 +
 138 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 139 +{
 140 +       u32 rate;
 141 +       int ret;
 142 +
 143 +       ret = bcm2835_cpufreq_clock_property(tag, VCMSG_ID_ARM_CLOCK, &rate);
 144 +       if (ret) {
 145 +               print_err("Failed to get clock (%d)\n", ret);
 146 +               return 0;
 147 +       }
 148 +
 149 +       rate /= 1000;
 150 +       print_debug("%s frequency = %u\n",
 151 +               tag == RPI_FIRMWARE_GET_CLOCK_RATE ? "Current":
 152 +               tag == RPI_FIRMWARE_GET_MIN_CLOCK_RATE ? "Min":
 153 +               tag == RPI_FIRMWARE_GET_MAX_CLOCK_RATE ? "Max":
 154 +               "Unexpected", rate);
 155 +
 156 +       return rate;
 157 +}
 158 +
 159 +/*
 160 + ====================================================
 161 +  Module Initialisation registers the cpufreq driver
 162 + ====================================================
 163 +*/
 164 +static int __init bcm2835_cpufreq_module_init(void)
 165 +{
 166 +       print_debug("IN\n");
 167 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 168 +}
 169 +
 170 +/*
 171 + =============
 172 +  Module exit
 173 + =============
 174 +*/
 175 +static void __exit bcm2835_cpufreq_module_exit(void)
 176 +{
 177 +       print_debug("IN\n");
 178 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 179 +       return;
 180 +}
 181 +
 182 +/*
 183 + ==============================================================
 184 +  Initialisation function sets up the CPU policy for first use
 185 + ==============================================================
 186 +*/
 187 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 188 +{
 189 +       /* measured value of how long it takes to change frequency */
 190 +       const unsigned int transition_latency = 355000; /* ns */
 191 +
 192 +       if (!rpi_firmware_get(NULL)) {
 193 +               print_err("Firmware is not available\n");
 194 +               return -ENODEV;
 195 +       }
 196 +
 197 +       /* now find out what the maximum and minimum frequencies are */
 198 +       min_frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 199 +       max_frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
 200 +
 201 +       if (min_frequency == max_frequency) {
 202 +               bcm2835_freq_table[0].frequency = min_frequency;
 203 +               bcm2835_freq_table[1].frequency = CPUFREQ_TABLE_END;
 204 +       } else {
 205 +               bcm2835_freq_table[0].frequency = min_frequency;
 206 +               bcm2835_freq_table[1].frequency = max_frequency;
 207 +               bcm2835_freq_table[2].frequency = CPUFREQ_TABLE_END;
 208 +       }
 209 +
 210 +       print_info("min=%d max=%d\n", min_frequency, max_frequency);
 211 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 212 +}
 213 +
 214 +/*
 215 + =====================================================================
 216 +  Target index function chooses the requested frequency from the table
 217 + =====================================================================
 218 +*/
 219 +
 220 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 221 +{
 222 +       unsigned int target_freq = state == 0 ? min_frequency : max_frequency;
 223 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 224 +
 225 +       if (!cur)
 226 +       {
 227 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 228 +               return -EINVAL;
 229 +       }
 230 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 231 +       return 0;
 232 +}
 233 +
 234 +/*
 235 + ======================================================
 236 +  Get function returns the current frequency from table
 237 + ======================================================
 238 +*/
 239 +
 240 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 241 +{
 242 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 243 +       print_debug("cpu%d: freq=%d\n", cpu, actual_rate);
 244 +       return actual_rate <= min_frequency ? min_frequency : max_frequency;
 245 +}
 246 +
 247 +/* the CPUFreq driver */
 248 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 249 +       .name         = "BCM2835 CPUFreq",
 250 +       .init         = bcm2835_cpufreq_driver_init,
 251 +       .verify       = cpufreq_generic_frequency_table_verify,
 252 +       .target_index = bcm2835_cpufreq_driver_target_index,
 253 +       .get          = bcm2835_cpufreq_driver_get,
 254 +       .attr         = cpufreq_generic_attr,
 255 +};
 256 +
 257 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 258 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 259 +MODULE_LICENSE("GPL");
 260 +
 261 +module_init(bcm2835_cpufreq_module_init);
 262 +module_exit(bcm2835_cpufreq_module_exit);