target/linux/brcm2708/patches-3.14/0014-Add-cpufreq-driver.patch

   1 From 4882beaf73302c162f08620d770f020211bf0acb 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 14/54] 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 | 239 ++++++++++++++++++++++++++++++++++++++
  11  4 files changed, 249 insertions(+)
  12  create mode 100755 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
  15 index 9e23417..be8a752 100644
  16 --- a/arch/arm/Kconfig
  17 +++ b/arch/arm/Kconfig
  18 @@ -389,6 +389,7 @@ config ARCH_BCM2708
  19         select NEED_MACH_GPIO_H
  20         select NEED_MACH_MEMORY_H
  21         select CLKDEV_LOOKUP
  22 +       select ARCH_HAS_CPUFREQ
  23         select GENERIC_CLOCKEVENTS
  24         select ARM_ERRATA_411920
  25         select MACH_BCM2708
  26 diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
  27 index 3129749..d12c80d 100644
  28 --- a/drivers/cpufreq/Kconfig.arm
  29 +++ b/drivers/cpufreq/Kconfig.arm
  30 @@ -235,6 +235,14 @@ config ARM_SPEAR_CPUFREQ
  31         help
  32           This adds the CPUFreq driver support for SPEAr SOCs.
  33
  34 +config ARM_BCM2835_CPUFREQ
  35 +       bool "BCM2835 Driver"
  36 +       default y
  37 +       help
  38 +         This adds the CPUFreq driver for BCM2835
  39 +
  40 +         If in doubt, say N.
  41 +
  42  config ARM_TEGRA_CPUFREQ
  43         bool "TEGRA CPUFreq support"
  44         depends on ARCH_TEGRA
  45 diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
  46 index dac58f6..d8ded24 100644
  47 --- a/drivers/cpufreq/Makefile
  48 +++ b/drivers/cpufreq/Makefile
  49 @@ -73,6 +73,7 @@ obj-$(CONFIG_ARM_S5PV210_CPUFREQ)     += s5pv210-cpufreq.o
  50  obj-$(CONFIG_ARM_SA1100_CPUFREQ)       += sa1100-cpufreq.o
  51  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  52  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  53 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  54  obj-$(CONFIG_ARM_TEGRA_CPUFREQ)                += tegra-cpufreq.o
  55  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
  56
  57 diff --git a/drivers/cpufreq/bcm2835-cpufreq.c b/drivers/cpufreq/bcm2835-cpufreq.c
  58 new file mode 100755
  59 index 0000000..7bc55bd
  60 --- /dev/null
  61 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  62 @@ -0,0 +1,239 @@
  63 +/*****************************************************************************
  64 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
  65 +*
  66 +* Unless you and Broadcom execute a separate written software license
  67 +* agreement governing use of this software, this software is licensed to you
  68 +* under the terms of the GNU General Public License version 2, available at
  69 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  70 +*
  71 +* Notwithstanding the above, under no circumstances may you combine this
  72 +* software in any way with any other Broadcom software provided under a
  73 +* license other than the GPL, without Broadcom's express prior written
  74 +* consent.
  75 +*****************************************************************************/
  76 +
  77 +/*****************************************************************************
  78 +* FILENAME: bcm2835-cpufreq.h
  79 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  80 +* processor. Messages are sent to Videocore either setting or requesting the
  81 +* frequency of the ARM in order to match an appropiate frequency to the current
  82 +* usage of the processor. The policy which selects the frequency to use is
  83 +* defined in the kernel .config file, but can be changed during runtime.
  84 +*****************************************************************************/
  85 +
  86 +/* ---------- INCLUDES ---------- */
  87 +#include <linux/kernel.h>
  88 +#include <linux/init.h>
  89 +#include <linux/module.h>
  90 +#include <linux/cpufreq.h>
  91 +#include <mach/vcio.h>
  92 +
  93 +/* ---------- DEFINES ---------- */
  94 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  95 +#define MODULE_NAME "bcm2835-cpufreq"
  96 +
  97 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  98 +
  99 +/* debug printk macros */
 100 +#ifdef CPUFREQ_DEBUG_ENABLE
 101 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
 102 +#else
 103 +#define print_debug(fmt,...)
 104 +#endif
 105 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
 106 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
 107 +
 108 +/* tag part of the message */
 109 +struct vc_msg_tag {
 110 +       uint32_t tag_id;                /* the message id */
 111 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
 112 +       uint32_t data_size;             /* amount of data being sent or received */
 113 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
 114 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
 115 +};
 116 +
 117 +/* message structure to be sent to videocore */
 118 +struct vc_msg {
 119 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
 120 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
 121 +       struct vc_msg_tag tag;          /* the tag structure above to make */
 122 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
 123 +};
 124 +
 125 +/* ---------- GLOBALS ---------- */
 126 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
 127 +
 128 +/*
 129 + ===============================================
 130 +  clk_rate either gets or sets the clock rates.
 131 + ===============================================
 132 +*/
 133 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 134 +{
 135 +       int s, actual_rate=0;
 136 +       struct vc_msg msg;
 137 +
 138 +       /* wipe all previous message data */
 139 +       memset(&msg, 0, sizeof msg);
 140 +
 141 +       msg.msg_size = sizeof msg;
 142 +
 143 +       msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
 144 +       msg.tag.buffer_size = 8;
 145 +       msg.tag.data_size = 8;   /* we're sending the clock ID and the new rates which is a total of 2 words */
 146 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 147 +       msg.tag.val = arm_rate * 1000;
 148 +
 149 +       /* send the message */
 150 +       s = bcm_mailbox_property(&msg, sizeof msg);
 151 +
 152 +       /* check if it was all ok and return the rate in KHz */
 153 +       if (s == 0 && (msg.request_code & 0x80000000))
 154 +               actual_rate = msg.tag.val/1000;
 155 +
 156 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
 157 +       return actual_rate;
 158 +}
 159 +
 160 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 161 +{
 162 +       int s;
 163 +       int arm_rate = 0;
 164 +       struct vc_msg msg;
 165 +
 166 +       /* wipe all previous message data */
 167 +       memset(&msg, 0, sizeof msg);
 168 +
 169 +       msg.msg_size = sizeof msg;
 170 +       msg.tag.tag_id = tag;
 171 +       msg.tag.buffer_size = 8;
 172 +       msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
 173 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 174 +
 175 +       /* send the message */
 176 +       s = bcm_mailbox_property(&msg, sizeof msg);
 177 +
 178 +       /* check if it was all ok and return the rate in KHz */
 179 +       if (s == 0 && (msg.request_code & 0x80000000))
 180 +               arm_rate = msg.tag.val/1000;
 181 +
 182 +       print_debug("%s frequency = %d\n",
 183 +               tag == VCMSG_GET_CLOCK_RATE ? "Current":
 184 +               tag == VCMSG_GET_MIN_CLOCK ? "Min":
 185 +               tag == VCMSG_GET_MAX_CLOCK ? "Max":
 186 +               "Unexpected", arm_rate);
 187 +
 188 +       return arm_rate;
 189 +}
 190 +
 191 +/*
 192 + ====================================================
 193 +  Module Initialisation registers the cpufreq driver
 194 + ====================================================
 195 +*/
 196 +static int __init bcm2835_cpufreq_module_init(void)
 197 +{
 198 +       print_debug("IN\n");
 199 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 200 +}
 201 +
 202 +/*
 203 + =============
 204 +  Module exit
 205 + =============
 206 +*/
 207 +static void __exit bcm2835_cpufreq_module_exit(void)
 208 +{
 209 +       print_debug("IN\n");
 210 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 211 +       return;
 212 +}
 213 +
 214 +/*
 215 + ==============================================================
 216 +  Initialisation function sets up the CPU policy for first use
 217 + ==============================================================
 218 +*/
 219 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 220 +{
 221 +       /* measured value of how long it takes to change frequency */
 222 +       policy->cpuinfo.transition_latency = 355000; /* ns */
 223 +
 224 +       /* now find out what the maximum and minimum frequencies are */
 225 +       policy->min = policy->cpuinfo.min_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 226 +       policy->max = policy->cpuinfo.max_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 227 +       policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 228 +
 229 +       print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
 230 +       return 0;
 231 +}
 232 +
 233 +/*
 234 + =================================================================================
 235 +  Target function chooses the most appropriate frequency from the table to enable
 236 + =================================================================================
 237 +*/
 238 +
 239 +static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
 240 +{
 241 +       unsigned int target = target_freq;
 242 +#ifdef CPUFREQ_DEBUG_ENABLE
 243 +       unsigned int cur = policy->cur;
 244 +#endif
 245 +       print_debug("%s: min=%d max=%d cur=%d target=%d\n",policy->governor->name,policy->min,policy->max,policy->cur,target_freq);
 246 +
 247 +       /* if we are above min and using ondemand, then just use max */
 248 +       if (strcmp("ondemand", policy->governor->name)==0 && target > policy->min)
 249 +               target = policy->max;
 250 +       /* if the frequency is the same, just quit */
 251 +       if (target == policy->cur)
 252 +               return 0;
 253 +
 254 +       /* otherwise were good to set the clock frequency */
 255 +       policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
 256 +
 257 +       if (!policy->cur)
 258 +       {
 259 +               print_err("Error occurred setting a new frequency (%d)!\n", target);
 260 +               policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 261 +               return -EINVAL;
 262 +       }
 263 +       print_debug("Freq %d->%d (min=%d max=%d target=%d request=%d)\n", cur, policy->cur, policy->min, policy->max, target_freq, target);
 264 +       return 0;
 265 +}
 266 +
 267 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 268 +{
 269 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 270 +       print_debug("cpu=%d\n", actual_rate);
 271 +       return actual_rate;
 272 +}
 273 +
 274 +/*
 275 + =================================================================================
 276 +  Verify ensures that when a policy is changed, it is suitable for the CPU to use
 277 + =================================================================================
 278 +*/
 279 +
 280 +static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
 281 +{
 282 +       print_info("switching to governor %s\n", policy->governor->name);
 283 +       return 0;
 284 +}
 285 +
 286 +
 287 +/* the CPUFreq driver */
 288 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 289 +               .name   = "BCM2835 CPUFreq",
 290 +               .init   = bcm2835_cpufreq_driver_init,
 291 +               .verify = bcm2835_cpufreq_driver_verify,
 292 +               .target = bcm2835_cpufreq_driver_target,
 293 +               .get    = bcm2835_cpufreq_driver_get
 294 +};
 295 +
 296 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 297 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 298 +MODULE_LICENSE("GPL");
 299 +
 300 +module_init(bcm2835_cpufreq_module_init);
 301 +module_exit(bcm2835_cpufreq_module_exit);
 302 --
 303 1.9.1
 304