target/linux/brcm2708/patches-4.19/950-0052-Add-cpufreq-driver.patch

   1 From 0a248af6e18d7f1ad57fffa7f588bc8a5851832e 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 052/806] Add cpufreq driver
   5
   6 Signed-off-by: popcornmix <popcornmix@gmail.com>
   7
   8 bcm2835-cpufreq: Change licence to GPLv2
   9
  10 Signed-off-by: Eben Upton <eben.upton@broadcom.com>
  11 Signed-off-by: Dom Cobley <dom@raspberrypi.com>
  12 ---
  13  drivers/cpufreq/Kconfig.arm       |   9 ++
  14  drivers/cpufreq/Makefile          |   1 +
  15  drivers/cpufreq/bcm2835-cpufreq.c | 210 ++++++++++++++++++++++++++++++
  16  3 files changed, 220 insertions(+)
  17  create mode 100644 drivers/cpufreq/bcm2835-cpufreq.c
  18
  19 --- a/drivers/cpufreq/Kconfig.arm
  20 +++ b/drivers/cpufreq/Kconfig.arm
  21 @@ -260,6 +260,15 @@ config ARM_TANGO_CPUFREQ
  22         depends on CPUFREQ_DT && ARCH_TANGO
  23         default y
  24
  25 +config ARM_BCM2835_CPUFREQ
  26 +       depends on RASPBERRYPI_FIRMWARE
  27 +       bool "BCM2835 Driver"
  28 +       default y
  29 +       help
  30 +         This adds the CPUFreq driver for BCM2835
  31 +
  32 +         If in doubt, say N.
  33 +
  34  config ARM_TEGRA20_CPUFREQ
  35         tristate "Tegra20 CPUFreq support"
  36         depends on ARCH_TEGRA
  37 --- a/drivers/cpufreq/Makefile
  38 +++ b/drivers/cpufreq/Makefile
  39 @@ -80,6 +80,7 @@ obj-$(CONFIG_ARM_SCPI_CPUFREQ)                += scpi-
  40  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  41  obj-$(CONFIG_ARM_STI_CPUFREQ)          += sti-cpufreq.o
  42  obj-$(CONFIG_ARM_TANGO_CPUFREQ)                += tango-cpufreq.o
  43 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  44  obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)      += tegra20-cpufreq.o
  45  obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)     += tegra124-cpufreq.o
  46  obj-$(CONFIG_ARM_TEGRA186_CPUFREQ)     += tegra186-cpufreq.o
  47 --- /dev/null
  48 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  49 @@ -0,0 +1,210 @@
  50 +/*
  51 + * Copyright 2011 Broadcom Corporation.
  52 + *
  53 + * This program is free software; you can redistribute it and/or
  54 + * modify it under the terms of the GNU General Public License
  55 + * as published by the Free Software Foundation; version 2
  56 + * of the License.
  57 + *
  58 + * This driver dynamically manages the CPU Frequency of the ARM
  59 + * processor. Messages are sent to Videocore either setting or requesting the
  60 + * frequency of the ARM in order to match an appropiate frequency to the current
  61 + * usage of the processor. The policy which selects the frequency to use is
  62 + * defined in the kernel .config file, but can be changed during runtime.
  63 + */
  64 +
  65 +/* ---------- INCLUDES ---------- */
  66 +#include <linux/kernel.h>
  67 +#include <linux/init.h>
  68 +#include <linux/module.h>
  69 +#include <linux/cpufreq.h>
  70 +#include <soc/bcm2835/raspberrypi-firmware.h>
  71 +
  72 +/* ---------- DEFINES ---------- */
  73 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  74 +#define MODULE_NAME "bcm2835-cpufreq"
  75 +
  76 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  77 +
  78 +/* debug printk macros */
  79 +#ifdef CPUFREQ_DEBUG_ENABLE
  80 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  81 +#else
  82 +#define print_debug(fmt,...)
  83 +#endif
  84 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
  85 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
  86 +
  87 +/* ---------- GLOBALS ---------- */
  88 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
  89 +static unsigned int min_frequency, max_frequency;
  90 +static struct cpufreq_frequency_table bcm2835_freq_table[3];
  91 +
  92 +/*
  93 + ===============================================
  94 +  clk_rate either gets or sets the clock rates.
  95 + ===============================================
  96 +*/
  97 +
  98 +static int bcm2835_cpufreq_clock_property(u32 tag, u32 id, u32 *val)
  99 +{
 100 +       struct rpi_firmware *fw = rpi_firmware_get(NULL);
 101 +       struct {
 102 +               u32 id;
 103 +               u32 val;
 104 +       } packet;
 105 +       int ret;
 106 +
 107 +       packet.id = id;
 108 +       packet.val = *val;
 109 +       ret = rpi_firmware_property(fw, tag, &packet, sizeof(packet));
 110 +       if (ret)
 111 +               return ret;
 112 +
 113 +       *val = packet.val;
 114 +
 115 +       return 0;
 116 +}
 117 +
 118 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 119 +{
 120 +       u32 rate = arm_rate * 1000;
 121 +       int ret;
 122 +
 123 +       ret = bcm2835_cpufreq_clock_property(RPI_FIRMWARE_SET_CLOCK_RATE, VCMSG_ID_ARM_CLOCK, &rate);
 124 +       if (ret) {
 125 +               print_err("Failed to set clock: %d (%d)\n", arm_rate, ret);
 126 +               return 0;
 127 +       }
 128 +
 129 +       rate /= 1000;
 130 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, rate);
 131 +
 132 +       return rate;
 133 +}
 134 +
 135 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 136 +{
 137 +       u32 rate;
 138 +       int ret;
 139 +
 140 +       ret = bcm2835_cpufreq_clock_property(tag, VCMSG_ID_ARM_CLOCK, &rate);
 141 +       if (ret) {
 142 +               print_err("Failed to get clock (%d)\n", ret);
 143 +               return 0;
 144 +       }
 145 +
 146 +       rate /= 1000;
 147 +       print_debug("%s frequency = %u\n",
 148 +               tag == RPI_FIRMWARE_GET_CLOCK_RATE ? "Current":
 149 +               tag == RPI_FIRMWARE_GET_MIN_CLOCK_RATE ? "Min":
 150 +               tag == RPI_FIRMWARE_GET_MAX_CLOCK_RATE ? "Max":
 151 +               "Unexpected", rate);
 152 +
 153 +       return rate;
 154 +}
 155 +
 156 +/*
 157 + ====================================================
 158 +  Module Initialisation registers the cpufreq driver
 159 + ====================================================
 160 +*/
 161 +static int __init bcm2835_cpufreq_module_init(void)
 162 +{
 163 +       print_debug("IN\n");
 164 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 165 +}
 166 +
 167 +/*
 168 + =============
 169 +  Module exit
 170 + =============
 171 +*/
 172 +static void __exit bcm2835_cpufreq_module_exit(void)
 173 +{
 174 +       print_debug("IN\n");
 175 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 176 +       return;
 177 +}
 178 +
 179 +/*
 180 + ==============================================================
 181 +  Initialisation function sets up the CPU policy for first use
 182 + ==============================================================
 183 +*/
 184 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 185 +{
 186 +       /* measured value of how long it takes to change frequency */
 187 +       const unsigned int transition_latency = 355000; /* ns */
 188 +
 189 +       if (!rpi_firmware_get(NULL)) {
 190 +               print_err("Firmware is not available\n");
 191 +               return -ENODEV;
 192 +       }
 193 +
 194 +       /* now find out what the maximum and minimum frequencies are */
 195 +       min_frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 196 +       max_frequency = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
 197 +
 198 +       if (min_frequency == max_frequency) {
 199 +               bcm2835_freq_table[0].frequency = min_frequency;
 200 +               bcm2835_freq_table[1].frequency = CPUFREQ_TABLE_END;
 201 +       } else {
 202 +               bcm2835_freq_table[0].frequency = min_frequency;
 203 +               bcm2835_freq_table[1].frequency = max_frequency;
 204 +               bcm2835_freq_table[2].frequency = CPUFREQ_TABLE_END;
 205 +       }
 206 +
 207 +       print_info("min=%d max=%d\n", min_frequency, max_frequency);
 208 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 209 +}
 210 +
 211 +/*
 212 + =====================================================================
 213 +  Target index function chooses the requested frequency from the table
 214 + =====================================================================
 215 +*/
 216 +
 217 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 218 +{
 219 +       unsigned int target_freq = state == 0 ? min_frequency : max_frequency;
 220 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 221 +
 222 +       if (!cur)
 223 +       {
 224 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 225 +               return -EINVAL;
 226 +       }
 227 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 228 +       return 0;
 229 +}
 230 +
 231 +/*
 232 + ======================================================
 233 +  Get function returns the current frequency from table
 234 + ======================================================
 235 +*/
 236 +
 237 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 238 +{
 239 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 240 +       print_debug("cpu%d: freq=%d\n", cpu, actual_rate);
 241 +       return actual_rate <= min_frequency ? min_frequency : max_frequency;
 242 +}
 243 +
 244 +/* the CPUFreq driver */
 245 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 246 +       .name         = "BCM2835 CPUFreq",
 247 +       .init         = bcm2835_cpufreq_driver_init,
 248 +       .verify       = cpufreq_generic_frequency_table_verify,
 249 +       .target_index = bcm2835_cpufreq_driver_target_index,
 250 +       .get          = bcm2835_cpufreq_driver_get,
 251 +       .attr         = cpufreq_generic_attr,
 252 +};
 253 +
 254 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 255 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 256 +MODULE_LICENSE("GPL");
 257 +
 258 +module_init(bcm2835_cpufreq_module_init);
 259 +module_exit(bcm2835_cpufreq_module_exit);