target/linux/brcm2708/patches-4.1/0017-Add-cpufreq-driver.patch

   1 From ccdc49f30be0caec97b9b7e4352b8c63eb45acdd 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 017/121] 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 | 224 ++++++++++++++++++++++++++++++++++++++
  11  3 files changed, 234 insertions(+)
  12  create mode 100644 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 --- a/drivers/cpufreq/Kconfig.arm
  15 +++ b/drivers/cpufreq/Kconfig.arm
  16 @@ -258,6 +258,15 @@ 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 BCM2708_MBOX
  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_TEGRA_CPUFREQ
  30         bool "TEGRA CPUFreq support"
  31         depends on ARCH_TEGRA
  32 --- a/drivers/cpufreq/Makefile
  33 +++ b/drivers/cpufreq/Makefile
  34 @@ -77,6 +77,7 @@ obj-$(CONFIG_ARM_S5PV210_CPUFREQ)     += s5p
  35  obj-$(CONFIG_ARM_SA1100_CPUFREQ)       += sa1100-cpufreq.o
  36  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  37  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  38 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  39  obj-$(CONFIG_ARM_TEGRA_CPUFREQ)                += tegra-cpufreq.o
  40  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
  41
  42 --- /dev/null
  43 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  44 @@ -0,0 +1,224 @@
  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 <linux/platform_data/mailbox-bcm2708.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 +/* tag part of the message */
  91 +struct vc_msg_tag {
  92 +       uint32_t tag_id;                /* the message id */
  93 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
  94 +       uint32_t data_size;             /* amount of data being sent or received */
  95 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
  96 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
  97 +};
  98 +
  99 +/* message structure to be sent to videocore */
 100 +struct vc_msg {
 101 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
 102 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
 103 +       struct vc_msg_tag tag;          /* the tag structure above to make */
 104 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
 105 +};
 106 +
 107 +/* ---------- GLOBALS ---------- */
 108 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
 109 +
 110 +static struct cpufreq_frequency_table bcm2835_freq_table[] = {
 111 +       {0, 0, 0},
 112 +       {0, 0, 0},
 113 +       {0, 0, CPUFREQ_TABLE_END},
 114 +};
 115 +
 116 +/*
 117 + ===============================================
 118 +  clk_rate either gets or sets the clock rates.
 119 + ===============================================
 120 +*/
 121 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 122 +{
 123 +       int s, actual_rate=0;
 124 +       struct vc_msg msg;
 125 +
 126 +       /* wipe all previous message data */
 127 +       memset(&msg, 0, sizeof msg);
 128 +
 129 +       msg.msg_size = sizeof msg;
 130 +
 131 +       msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
 132 +       msg.tag.buffer_size = 8;
 133 +       msg.tag.data_size = 8;   /* we're sending the clock ID and the new rates which is a total of 2 words */
 134 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 135 +       msg.tag.val = arm_rate * 1000;
 136 +
 137 +       /* send the message */
 138 +       s = bcm_mailbox_property(&msg, sizeof msg);
 139 +
 140 +       /* check if it was all ok and return the rate in KHz */
 141 +       if (s == 0 && (msg.request_code & 0x80000000))
 142 +               actual_rate = msg.tag.val/1000;
 143 +
 144 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
 145 +       return actual_rate;
 146 +}
 147 +
 148 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 149 +{
 150 +       int s;
 151 +       int arm_rate = 0;
 152 +       struct vc_msg msg;
 153 +
 154 +       /* wipe all previous message data */
 155 +       memset(&msg, 0, sizeof msg);
 156 +
 157 +       msg.msg_size = sizeof msg;
 158 +       msg.tag.tag_id = tag;
 159 +       msg.tag.buffer_size = 8;
 160 +       msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
 161 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 162 +
 163 +       /* send the message */
 164 +       s = bcm_mailbox_property(&msg, sizeof msg);
 165 +
 166 +       /* check if it was all ok and return the rate in KHz */
 167 +       if (s == 0 && (msg.request_code & 0x80000000))
 168 +               arm_rate = msg.tag.val/1000;
 169 +
 170 +       print_debug("%s frequency = %d\n",
 171 +               tag == VCMSG_GET_CLOCK_RATE ? "Current":
 172 +               tag == VCMSG_GET_MIN_CLOCK ? "Min":
 173 +               tag == VCMSG_GET_MAX_CLOCK ? "Max":
 174 +               "Unexpected", arm_rate);
 175 +
 176 +       return arm_rate;
 177 +}
 178 +
 179 +/*
 180 + ====================================================
 181 +  Module Initialisation registers the cpufreq driver
 182 + ====================================================
 183 +*/
 184 +static int __init bcm2835_cpufreq_module_init(void)
 185 +{
 186 +       print_debug("IN\n");
 187 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 188 +}
 189 +
 190 +/*
 191 + =============
 192 +  Module exit
 193 + =============
 194 +*/
 195 +static void __exit bcm2835_cpufreq_module_exit(void)
 196 +{
 197 +       print_debug("IN\n");
 198 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 199 +       return;
 200 +}
 201 +
 202 +/*
 203 + ==============================================================
 204 +  Initialisation function sets up the CPU policy for first use
 205 + ==============================================================
 206 +*/
 207 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 208 +{
 209 +       /* measured value of how long it takes to change frequency */
 210 +       const unsigned int transition_latency = 355000; /* ns */
 211 +
 212 +       /* now find out what the maximum and minimum frequencies are */
 213 +       bcm2835_freq_table[0].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 214 +       bcm2835_freq_table[1].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 215 +
 216 +       print_info("min=%d max=%d\n", bcm2835_freq_table[0].frequency, bcm2835_freq_table[1].frequency);
 217 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 218 +}
 219 +
 220 +/*
 221 + =====================================================================
 222 +  Target index function chooses the requested frequency from the table
 223 + =====================================================================
 224 +*/
 225 +
 226 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 227 +{
 228 +       unsigned int target_freq = bcm2835_freq_table[state].frequency;
 229 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 230 +
 231 +       if (!cur)
 232 +       {
 233 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 234 +               return -EINVAL;
 235 +       }
 236 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 237 +       return 0;
 238 +}
 239 +
 240 +/*
 241 + ======================================================
 242 +  Get function returns the current frequency from table
 243 + ======================================================
 244 +*/
 245 +
 246 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 247 +{
 248 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 249 +       print_debug("%d: freq=%d\n", cpu, actual_rate);
 250 +       return actual_rate <= bcm2835_freq_table[0].frequency ? bcm2835_freq_table[0].frequency : bcm2835_freq_table[1].frequency;
 251 +}
 252 +
 253 +/* the CPUFreq driver */
 254 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 255 +       .name         = "BCM2835 CPUFreq",
 256 +       .init         = bcm2835_cpufreq_driver_init,
 257 +       .verify       = cpufreq_generic_frequency_table_verify,
 258 +       .target_index = bcm2835_cpufreq_driver_target_index,
 259 +       .get          = bcm2835_cpufreq_driver_get,
 260 +       .attr         = cpufreq_generic_attr,
 261 +};
 262 +
 263 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 264 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 265 +MODULE_LICENSE("GPL");
 266 +
 267 +module_init(bcm2835_cpufreq_module_init);
 268 +module_exit(bcm2835_cpufreq_module_exit);