target/linux/brcm2708/patches-3.18/0016-Add-cpufreq-driver.patch

   1 From f8628f418651bcb52604f943c00c45d932ff3572 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 016/114] Add cpufreq driver
   5
   6 ---
   7  arch/arm/Kconfig                  |   1 +
   8  drivers/cpufreq/Kconfig.arm       |   8 ++
   9  drivers/cpufreq/Makefile          |   1 +
  10  drivers/cpufreq/bcm2835-cpufreq.c | 224 ++++++++++++++++++++++++++++++++++++++
  11  4 files changed, 234 insertions(+)
  12  create mode 100755 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 --- a/arch/arm/Kconfig
  15 +++ b/arch/arm/Kconfig
  16 @@ -390,6 +390,7 @@ config ARCH_BCM2708
  17         select NEED_MACH_GPIO_H
  18         select NEED_MACH_MEMORY_H
  19         select CLKDEV_LOOKUP
  20 +       select ARCH_HAS_CPUFREQ
  21         select GENERIC_CLOCKEVENTS
  22         select ARM_ERRATA_411920
  23         select MACH_BCM2708
  24 --- a/drivers/cpufreq/Kconfig.arm
  25 +++ b/drivers/cpufreq/Kconfig.arm
  26 @@ -241,6 +241,14 @@ config ARM_SPEAR_CPUFREQ
  27         help
  28           This adds the CPUFreq driver support for SPEAr SOCs.
  29
  30 +config ARM_BCM2835_CPUFREQ
  31 +       bool "BCM2835 Driver"
  32 +       default y
  33 +       help
  34 +         This adds the CPUFreq driver for BCM2835
  35 +
  36 +         If in doubt, say N.
  37 +
  38  config ARM_TEGRA_CPUFREQ
  39         bool "TEGRA CPUFreq support"
  40         depends on ARCH_TEGRA
  41 --- a/drivers/cpufreq/Makefile
  42 +++ b/drivers/cpufreq/Makefile
  43 @@ -75,6 +75,7 @@ obj-$(CONFIG_ARM_S5PV210_CPUFREQ)     += s5p
  44  obj-$(CONFIG_ARM_SA1100_CPUFREQ)       += sa1100-cpufreq.o
  45  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  46  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  47 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  48  obj-$(CONFIG_ARM_TEGRA_CPUFREQ)                += tegra-cpufreq.o
  49  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
  50
  51 --- /dev/null
  52 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  53 @@ -0,0 +1,224 @@
  54 +/*****************************************************************************
  55 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
  56 +*
  57 +* Unless you and Broadcom execute a separate written software license
  58 +* agreement governing use of this software, this software is licensed to you
  59 +* under the terms of the GNU General Public License version 2, available at
  60 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  61 +*
  62 +* Notwithstanding the above, under no circumstances may you combine this
  63 +* software in any way with any other Broadcom software provided under a
  64 +* license other than the GPL, without Broadcom's express prior written
  65 +* consent.
  66 +*****************************************************************************/
  67 +
  68 +/*****************************************************************************
  69 +* FILENAME: bcm2835-cpufreq.h
  70 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  71 +* processor. Messages are sent to Videocore either setting or requesting the
  72 +* frequency of the ARM in order to match an appropiate frequency to the current
  73 +* usage of the processor. The policy which selects the frequency to use is
  74 +* defined in the kernel .config file, but can be changed during runtime.
  75 +*****************************************************************************/
  76 +
  77 +/* ---------- INCLUDES ---------- */
  78 +#include <linux/kernel.h>
  79 +#include <linux/init.h>
  80 +#include <linux/module.h>
  81 +#include <linux/cpufreq.h>
  82 +#include <mach/vcio.h>
  83 +
  84 +/* ---------- DEFINES ---------- */
  85 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  86 +#define MODULE_NAME "bcm2835-cpufreq"
  87 +
  88 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  89 +
  90 +/* debug printk macros */
  91 +#ifdef CPUFREQ_DEBUG_ENABLE
  92 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  93 +#else
  94 +#define print_debug(fmt,...)
  95 +#endif
  96 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
  97 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
  98 +
  99 +/* tag part of the message */
 100 +struct vc_msg_tag {
 101 +       uint32_t tag_id;                /* the message id */
 102 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
 103 +       uint32_t data_size;             /* amount of data being sent or received */
 104 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
 105 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
 106 +};
 107 +
 108 +/* message structure to be sent to videocore */
 109 +struct vc_msg {
 110 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
 111 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
 112 +       struct vc_msg_tag tag;          /* the tag structure above to make */
 113 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
 114 +};
 115 +
 116 +/* ---------- GLOBALS ---------- */
 117 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
 118 +
 119 +static struct cpufreq_frequency_table bcm2835_freq_table[] = {
 120 +       {0, 0, 0},
 121 +       {0, 0, 0},
 122 +       {0, 0, CPUFREQ_TABLE_END},
 123 +};
 124 +
 125 +/*
 126 + ===============================================
 127 +  clk_rate either gets or sets the clock rates.
 128 + ===============================================
 129 +*/
 130 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 131 +{
 132 +       int s, actual_rate=0;
 133 +       struct vc_msg msg;
 134 +
 135 +       /* wipe all previous message data */
 136 +       memset(&msg, 0, sizeof msg);
 137 +
 138 +       msg.msg_size = sizeof msg;
 139 +
 140 +       msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
 141 +       msg.tag.buffer_size = 8;
 142 +       msg.tag.data_size = 8;   /* we're sending the clock ID and the new rates which is a total of 2 words */
 143 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 144 +       msg.tag.val = arm_rate * 1000;
 145 +
 146 +       /* send the message */
 147 +       s = bcm_mailbox_property(&msg, sizeof msg);
 148 +
 149 +       /* check if it was all ok and return the rate in KHz */
 150 +       if (s == 0 && (msg.request_code & 0x80000000))
 151 +               actual_rate = msg.tag.val/1000;
 152 +
 153 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
 154 +       return actual_rate;
 155 +}
 156 +
 157 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 158 +{
 159 +       int s;
 160 +       int arm_rate = 0;
 161 +       struct vc_msg msg;
 162 +
 163 +       /* wipe all previous message data */
 164 +       memset(&msg, 0, sizeof msg);
 165 +
 166 +       msg.msg_size = sizeof msg;
 167 +       msg.tag.tag_id = tag;
 168 +       msg.tag.buffer_size = 8;
 169 +       msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
 170 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 171 +
 172 +       /* send the message */
 173 +       s = bcm_mailbox_property(&msg, sizeof msg);
 174 +
 175 +       /* check if it was all ok and return the rate in KHz */
 176 +       if (s == 0 && (msg.request_code & 0x80000000))
 177 +               arm_rate = msg.tag.val/1000;
 178 +
 179 +       print_debug("%s frequency = %d\n",
 180 +               tag == VCMSG_GET_CLOCK_RATE ? "Current":
 181 +               tag == VCMSG_GET_MIN_CLOCK ? "Min":
 182 +               tag == VCMSG_GET_MAX_CLOCK ? "Max":
 183 +               "Unexpected", arm_rate);
 184 +
 185 +       return arm_rate;
 186 +}
 187 +
 188 +/*
 189 + ====================================================
 190 +  Module Initialisation registers the cpufreq driver
 191 + ====================================================
 192 +*/
 193 +static int __init bcm2835_cpufreq_module_init(void)
 194 +{
 195 +       print_debug("IN\n");
 196 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 197 +}
 198 +
 199 +/*
 200 + =============
 201 +  Module exit
 202 + =============
 203 +*/
 204 +static void __exit bcm2835_cpufreq_module_exit(void)
 205 +{
 206 +       print_debug("IN\n");
 207 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 208 +       return;
 209 +}
 210 +
 211 +/*
 212 + ==============================================================
 213 +  Initialisation function sets up the CPU policy for first use
 214 + ==============================================================
 215 +*/
 216 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 217 +{
 218 +       /* measured value of how long it takes to change frequency */
 219 +       const unsigned int transition_latency = 355000; /* ns */
 220 +
 221 +       /* now find out what the maximum and minimum frequencies are */
 222 +       bcm2835_freq_table[0].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 223 +       bcm2835_freq_table[1].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 224 +
 225 +       print_info("min=%d max=%d\n", bcm2835_freq_table[0].frequency, bcm2835_freq_table[1].frequency);
 226 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 227 +}
 228 +
 229 +/*
 230 + =====================================================================
 231 +  Target index function chooses the requested frequency from the table
 232 + =====================================================================
 233 +*/
 234 +
 235 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 236 +{
 237 +       unsigned int target_freq = bcm2835_freq_table[state].frequency;
 238 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 239 +
 240 +       if (!cur)
 241 +       {
 242 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 243 +               return -EINVAL;
 244 +       }
 245 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 246 +       return 0;
 247 +}
 248 +
 249 +/*
 250 + ======================================================
 251 +  Get function returns the current frequency from table
 252 + ======================================================
 253 +*/
 254 +
 255 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 256 +{
 257 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 258 +       print_debug("%d: freq=%d\n", cpu, actual_rate);
 259 +       return actual_rate <= bcm2835_freq_table[0].frequency ? bcm2835_freq_table[0].frequency : bcm2835_freq_table[1].frequency;
 260 +}
 261 +
 262 +/* the CPUFreq driver */
 263 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 264 +       .name         = "BCM2835 CPUFreq",
 265 +       .init         = bcm2835_cpufreq_driver_init,
 266 +       .verify       = cpufreq_generic_frequency_table_verify,
 267 +       .target_index = bcm2835_cpufreq_driver_target_index,
 268 +       .get          = bcm2835_cpufreq_driver_get,
 269 +       .attr         = cpufreq_generic_attr,
 270 +};
 271 +
 272 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 273 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 274 +MODULE_LICENSE("GPL");
 275 +
 276 +module_init(bcm2835_cpufreq_module_init);
 277 +module_exit(bcm2835_cpufreq_module_exit);