target/linux/brcm2708/patches-3.10/0031-Add-cpufreq-driver.patch

   1 From 083183f7770ae4fb6f23c99a64a3c5058b9b3b40 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Sat, 2 Nov 2013 22:44:41 +0000
   4 Subject: [PATCH 031/196] 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 5468f1f..4e36ccd 100644
  16 --- a/arch/arm/Kconfig
  17 +++ b/arch/arm/Kconfig
  18 @@ -369,6 +369,7 @@ config ARCH_BCM2708
  19         select HAVE_SCHED_CLOCK
  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 6e57543..bf40783 100644
  28 --- a/drivers/cpufreq/Kconfig.arm
  29 +++ b/drivers/cpufreq/Kconfig.arm
  30 @@ -150,3 +150,11 @@ config ARM_SPEAR_CPUFREQ
  31         default y
  32         help
  33           This adds the CPUFreq driver support for SPEAr SOCs.
  34 +
  35 +config ARM_BCM2835_CPUFREQ
  36 +       bool "BCM2835 Driver"
  37 +       default y
  38 +       help
  39 +         This adds the CPUFreq driver for BCM2835
  40 +
  41 +         If in doubt, say N.
  42 diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
  43 index 3b95322..3a30bab 100644
  44 --- a/drivers/cpufreq/Makefile
  45 +++ b/drivers/cpufreq/Makefile
  46 @@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)      += sa1100-cpufreq.o
  47  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  48  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  49  obj-$(CONFIG_ARCH_TEGRA)               += tegra-cpufreq.o
  50 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  51
  52  ##################################################################################
  53  # PowerPC platform drivers
  54 diff --git a/drivers/cpufreq/bcm2835-cpufreq.c b/drivers/cpufreq/bcm2835-cpufreq.c
  55 new file mode 100755
  56 index 0000000..822139a
  57 --- /dev/null
  58 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  59 @@ -0,0 +1,239 @@
  60 +/*****************************************************************************
  61 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
  62 +*
  63 +* Unless you and Broadcom execute a separate written software license
  64 +* agreement governing use of this software, this software is licensed to you
  65 +* under the terms of the GNU General Public License version 2, available at
  66 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  67 +*
  68 +* Notwithstanding the above, under no circumstances may you combine this
  69 +* software in any way with any other Broadcom software provided under a
  70 +* license other than the GPL, without Broadcom's express prior written
  71 +* consent.
  72 +*****************************************************************************/
  73 +
  74 +/*****************************************************************************
  75 +* FILENAME: bcm2835-cpufreq.h
  76 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  77 +* processor. Messages are sent to Videocore either setting or requesting the
  78 +* frequency of the ARM in order to match an appropiate frequency to the current
  79 +* usage of the processor. The policy which selects the frequency to use is
  80 +* defined in the kernel .config file, but can be changed during runtime.
  81 +*****************************************************************************/
  82 +
  83 +/* ---------- INCLUDES ---------- */
  84 +#include <linux/kernel.h>
  85 +#include <linux/init.h>
  86 +#include <linux/module.h>
  87 +#include <linux/cpufreq.h>
  88 +#include <mach/vcio.h>
  89 +
  90 +/* ---------- DEFINES ---------- */
  91 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  92 +#define MODULE_NAME "bcm2835-cpufreq"
  93 +
  94 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  95 +
  96 +/* debug printk macros */
  97 +#ifdef CPUFREQ_DEBUG_ENABLE
  98 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  99 +#else
 100 +#define print_debug(fmt,...)
 101 +#endif
 102 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
 103 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
 104 +
 105 +/* tag part of the message */
 106 +struct vc_msg_tag {
 107 +       uint32_t tag_id;                /* the message id */
 108 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
 109 +       uint32_t data_size;             /* amount of data being sent or received */
 110 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
 111 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
 112 +};
 113 +
 114 +/* message structure to be sent to videocore */
 115 +struct vc_msg {
 116 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
 117 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
 118 +       struct vc_msg_tag tag;          /* the tag structure above to make */
 119 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
 120 +};
 121 +
 122 +/* ---------- GLOBALS ---------- */
 123 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
 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 +       policy->cpuinfo.transition_latency = 355000; /* ns */
 220 +
 221 +       /* now find out what the maximum and minimum frequencies are */
 222 +       policy->min = policy->cpuinfo.min_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 223 +       policy->max = policy->cpuinfo.max_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 224 +       policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 225 +
 226 +       print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
 227 +       return 0;
 228 +}
 229 +
 230 +/*
 231 + =================================================================================
 232 +  Target function chooses the most appropriate frequency from the table to enable
 233 + =================================================================================
 234 +*/
 235 +
 236 +static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
 237 +{
 238 +       unsigned int target = target_freq;
 239 +       unsigned int cur = policy->cur;
 240 +       print_debug("%s: min=%d max=%d cur=%d target=%d\n",policy->governor->name,policy->min,policy->max,policy->cur,target_freq);
 241 +
 242 +       /* if we are above min and using ondemand, then just use max */
 243 +       if (strcmp("ondemand", policy->governor->name)==0 && target > policy->min)
 244 +               target = policy->max;
 245 +       /* if the frequency is the same, just quit */
 246 +       if (target == policy->cur)
 247 +               return 0;
 248 +
 249 +       /* otherwise were good to set the clock frequency */
 250 +       policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
 251 +
 252 +       if (!policy->cur)
 253 +       {
 254 +               print_err("Error occurred setting a new frequency (%d)!\n", target);
 255 +               policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 256 +               return -EINVAL;
 257 +       }
 258 +       print_debug("Freq %d->%d (min=%d max=%d target=%d request=%d)\n", cur, policy->cur, policy->min, policy->max, target_freq, target);
 259 +       return 0;
 260 +}
 261 +
 262 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 263 +{
 264 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 265 +       print_debug("cpu=%d\n", actual_rate);
 266 +       return actual_rate;
 267 +}
 268 +
 269 +/*
 270 + =================================================================================
 271 +  Verify ensures that when a policy is changed, it is suitable for the CPU to use
 272 + =================================================================================
 273 +*/
 274 +
 275 +static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
 276 +{
 277 +       print_info("switching to governor %s\n", policy->governor->name);
 278 +       return 0;
 279 +}
 280 +
 281 +
 282 +/* the CPUFreq driver */
 283 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 284 +               .name   = "BCM2835 CPUFreq",
 285 +               .owner  = THIS_MODULE,
 286 +               .init   = bcm2835_cpufreq_driver_init,
 287 +               .verify = bcm2835_cpufreq_driver_verify,
 288 +               .target = bcm2835_cpufreq_driver_target,
 289 +               .get    = bcm2835_cpufreq_driver_get
 290 +};
 291 +
 292 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 293 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 294 +MODULE_LICENSE("GPL");
 295 +
 296 +module_init(bcm2835_cpufreq_module_init);
 297 +module_exit(bcm2835_cpufreq_module_exit);
 298 +
 299 --
 300 1.9.1
 301