target/linux/brcm2708/patches-4.4/0043-Add-cpufreq-driver.patch

   1 From f3f2bddacba23cab954a421d490bd17364e69d2d 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 | 213 ++++++++++++++++++++++++++++++++++++++
  11  3 files changed, 223 insertions(+)
  12  create mode 100644 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 --- a/drivers/cpufreq/Kconfig.arm
  15 +++ b/drivers/cpufreq/Kconfig.arm
  16 @@ -217,6 +217,15 @@ config ARM_SPEAR_CPUFREQ
  17         help
  18           This adds the CPUFreq driver support for SPEAr 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 @@ -73,6 +73,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)      += sa11
  35  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  36  obj-$(CONFIG_ARM_SCPI_CPUFREQ)         += scpi-cpufreq.o
  37  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-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 +1,213 @@
  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 +
  93 +static struct cpufreq_frequency_table bcm2835_freq_table[] = {
  94 +       {0, 0, 0},
  95 +       {0, 0, 0},
  96 +       {0, 0, CPUFREQ_TABLE_END},
  97 +};
  98 +
  99 +/*
 100 + ===============================================
 101 +  clk_rate either gets or sets the clock rates.
 102 + ===============================================
 103 +*/
 104 +
 105 +static int bcm2835_cpufreq_clock_property(u32 tag, u32 id, u32 *val)
 106 +{
 107 +       struct rpi_firmware *fw = rpi_firmware_get(NULL);
 108 +       struct {
 109 +               u32 id;
 110 +               u32 val;
 111 +       } packet;
 112 +       int ret;
 113 +
 114 +       packet.id = id;
 115 +       packet.val = *val;
 116 +       ret = rpi_firmware_property(fw, tag, &packet, sizeof(packet));
 117 +       if (ret)
 118 +               return ret;
 119 +
 120 +       *val = packet.val;
 121 +
 122 +       return 0;
 123 +}
 124 +
 125 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 126 +{
 127 +       u32 rate = arm_rate * 1000;
 128 +       int ret;
 129 +
 130 +       ret = bcm2835_cpufreq_clock_property(RPI_FIRMWARE_SET_CLOCK_RATE, VCMSG_ID_ARM_CLOCK, &rate);
 131 +       if (ret) {
 132 +               print_err("Failed to set clock: %d (%d)\n", arm_rate, ret);
 133 +               return 0;
 134 +       }
 135 +
 136 +       rate /= 1000;
 137 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, rate);
 138 +
 139 +       return rate;
 140 +}
 141 +
 142 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 143 +{
 144 +       u32 rate;
 145 +       int ret;
 146 +
 147 +       ret = bcm2835_cpufreq_clock_property(tag, VCMSG_ID_ARM_CLOCK, &rate);
 148 +       if (ret) {
 149 +               print_err("Failed to get clock (%d)\n", ret);
 150 +               return 0;
 151 +       }
 152 +
 153 +       rate /= 1000;
 154 +       print_debug("%s frequency = %u\n",
 155 +               tag == RPI_FIRMWARE_GET_CLOCK_RATE ? "Current":
 156 +               tag == RPI_FIRMWARE_GET_MIN_CLOCK_RATE ? "Min":
 157 +               tag == RPI_FIRMWARE_GET_MAX_CLOCK_RATE ? "Max":
 158 +               "Unexpected", rate);
 159 +
 160 +       return rate;
 161 +}
 162 +
 163 +/*
 164 + ====================================================
 165 +  Module Initialisation registers the cpufreq driver
 166 + ====================================================
 167 +*/
 168 +static int __init bcm2835_cpufreq_module_init(void)
 169 +{
 170 +       print_debug("IN\n");
 171 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 172 +}
 173 +
 174 +/*
 175 + =============
 176 +  Module exit
 177 + =============
 178 +*/
 179 +static void __exit bcm2835_cpufreq_module_exit(void)
 180 +{
 181 +       print_debug("IN\n");
 182 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 183 +       return;
 184 +}
 185 +
 186 +/*
 187 + ==============================================================
 188 +  Initialisation function sets up the CPU policy for first use
 189 + ==============================================================
 190 +*/
 191 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 192 +{
 193 +       /* measured value of how long it takes to change frequency */
 194 +       const unsigned int transition_latency = 355000; /* ns */
 195 +
 196 +       if (!rpi_firmware_get(NULL)) {
 197 +               print_err("Firmware is not available\n");
 198 +               return -ENODEV;
 199 +       }
 200 +
 201 +       /* now find out what the maximum and minimum frequencies are */
 202 +       bcm2835_freq_table[0].frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 203 +       bcm2835_freq_table[1].frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
 204 +
 205 +       print_info("min=%d max=%d\n", bcm2835_freq_table[0].frequency, bcm2835_freq_table[1].frequency);
 206 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 207 +}
 208 +
 209 +/*
 210 + =====================================================================
 211 +  Target index function chooses the requested frequency from the table
 212 + =====================================================================
 213 +*/
 214 +
 215 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 216 +{
 217 +       unsigned int target_freq = bcm2835_freq_table[state].frequency;
 218 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 219 +
 220 +       if (!cur)
 221 +       {
 222 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 223 +               return -EINVAL;
 224 +       }
 225 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 226 +       return 0;
 227 +}
 228 +
 229 +/*
 230 + ======================================================
 231 +  Get function returns the current frequency from table
 232 + ======================================================
 233 +*/
 234 +
 235 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 236 +{
 237 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 238 +       print_debug("cpu%d: freq=%d\n", cpu, actual_rate);
 239 +       return actual_rate <= bcm2835_freq_table[0].frequency ? bcm2835_freq_table[0].frequency : bcm2835_freq_table[1].frequency;
 240 +}
 241 +
 242 +/* the CPUFreq driver */
 243 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 244 +       .name         = "BCM2835 CPUFreq",
 245 +       .init         = bcm2835_cpufreq_driver_init,
 246 +       .verify       = cpufreq_generic_frequency_table_verify,
 247 +       .target_index = bcm2835_cpufreq_driver_target_index,
 248 +       .get          = bcm2835_cpufreq_driver_get,
 249 +       .attr         = cpufreq_generic_attr,
 250 +};
 251 +
 252 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 253 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 254 +MODULE_LICENSE("GPL");
 255 +
 256 +module_init(bcm2835_cpufreq_module_init);
 257 +module_exit(bcm2835_cpufreq_module_exit);