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

   1 From d19db6057337b577baab7766718781d55c402fbb 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 031/174] 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 --- a/arch/arm/Kconfig
  15 +++ b/arch/arm/Kconfig
  16 @@ -369,6 +369,7 @@ config ARCH_BCM2708
  17         select HAVE_SCHED_CLOCK
  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 @@ -150,3 +150,11 @@ config ARM_SPEAR_CPUFREQ
  27         default y
  28         help
  29           This adds the CPUFreq driver support for SPEAr SOCs.
  30 +
  31 +config ARM_BCM2835_CPUFREQ
  32 +       bool "BCM2835 Driver"
  33 +       default y
  34 +       help
  35 +         This adds the CPUFreq driver for BCM2835
  36 +
  37 +         If in doubt, say N.
  38 --- a/drivers/cpufreq/Makefile
  39 +++ b/drivers/cpufreq/Makefile
  40 @@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)      += sa11
  41  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
  42  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
  43  obj-$(CONFIG_ARCH_TEGRA)               += tegra-cpufreq.o
  44 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
  45
  46  ##################################################################################
  47  # PowerPC platform drivers
  48 --- /dev/null
  49 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  50 @@ -0,0 +1,239 @@
  51 +/*****************************************************************************
  52 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
  53 +*
  54 +* Unless you and Broadcom execute a separate written software license
  55 +* agreement governing use of this software, this software is licensed to you
  56 +* under the terms of the GNU General Public License version 2, available at
  57 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  58 +*
  59 +* Notwithstanding the above, under no circumstances may you combine this
  60 +* software in any way with any other Broadcom software provided under a
  61 +* license other than the GPL, without Broadcom's express prior written
  62 +* consent.
  63 +*****************************************************************************/
  64 +
  65 +/*****************************************************************************
  66 +* FILENAME: bcm2835-cpufreq.h
  67 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  68 +* processor. Messages are sent to Videocore either setting or requesting the
  69 +* frequency of the ARM in order to match an appropiate frequency to the current
  70 +* usage of the processor. The policy which selects the frequency to use is
  71 +* defined in the kernel .config file, but can be changed during runtime.
  72 +*****************************************************************************/
  73 +
  74 +/* ---------- INCLUDES ---------- */
  75 +#include <linux/kernel.h>
  76 +#include <linux/init.h>
  77 +#include <linux/module.h>
  78 +#include <linux/cpufreq.h>
  79 +#include <mach/vcio.h>
  80 +
  81 +/* ---------- DEFINES ---------- */
  82 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  83 +#define MODULE_NAME "bcm2835-cpufreq"
  84 +
  85 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  86 +
  87 +/* debug printk macros */
  88 +#ifdef CPUFREQ_DEBUG_ENABLE
  89 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  90 +#else
  91 +#define print_debug(fmt,...)
  92 +#endif
  93 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
  94 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
  95 +
  96 +/* tag part of the message */
  97 +struct vc_msg_tag {
  98 +       uint32_t tag_id;                /* the message id */
  99 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
 100 +       uint32_t data_size;             /* amount of data being sent or received */
 101 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
 102 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
 103 +};
 104 +
 105 +/* message structure to be sent to videocore */
 106 +struct vc_msg {
 107 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
 108 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
 109 +       struct vc_msg_tag tag;          /* the tag structure above to make */
 110 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
 111 +};
 112 +
 113 +/* ---------- GLOBALS ---------- */
 114 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
 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 +       policy->cpuinfo.transition_latency = 355000; /* ns */
 211 +
 212 +       /* now find out what the maximum and minimum frequencies are */
 213 +       policy->min = policy->cpuinfo.min_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 214 +       policy->max = policy->cpuinfo.max_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 215 +       policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 216 +
 217 +       print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
 218 +       return 0;
 219 +}
 220 +
 221 +/*
 222 + =================================================================================
 223 +  Target function chooses the most appropriate frequency from the table to enable
 224 + =================================================================================
 225 +*/
 226 +
 227 +static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
 228 +{
 229 +       unsigned int target = target_freq;
 230 +       unsigned int cur = policy->cur;
 231 +       print_debug("%s: min=%d max=%d cur=%d target=%d\n",policy->governor->name,policy->min,policy->max,policy->cur,target_freq);
 232 +
 233 +       /* if we are above min and using ondemand, then just use max */
 234 +       if (strcmp("ondemand", policy->governor->name)==0 && target > policy->min)
 235 +               target = policy->max;
 236 +       /* if the frequency is the same, just quit */
 237 +       if (target == policy->cur)
 238 +               return 0;
 239 +
 240 +       /* otherwise were good to set the clock frequency */
 241 +       policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
 242 +
 243 +       if (!policy->cur)
 244 +       {
 245 +               print_err("Error occurred setting a new frequency (%d)!\n", target);
 246 +               policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 247 +               return -EINVAL;
 248 +       }
 249 +       print_debug("Freq %d->%d (min=%d max=%d target=%d request=%d)\n", cur, policy->cur, policy->min, policy->max, target_freq, target);
 250 +       return 0;
 251 +}
 252 +
 253 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 254 +{
 255 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 256 +       print_debug("cpu=%d\n", actual_rate);
 257 +       return actual_rate;
 258 +}
 259 +
 260 +/*
 261 + =================================================================================
 262 +  Verify ensures that when a policy is changed, it is suitable for the CPU to use
 263 + =================================================================================
 264 +*/
 265 +
 266 +static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
 267 +{
 268 +       print_info("switching to governor %s\n", policy->governor->name);
 269 +       return 0;
 270 +}
 271 +
 272 +
 273 +/* the CPUFreq driver */
 274 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 275 +               .name   = "BCM2835 CPUFreq",
 276 +               .owner  = THIS_MODULE,
 277 +               .init   = bcm2835_cpufreq_driver_init,
 278 +               .verify = bcm2835_cpufreq_driver_verify,
 279 +               .target = bcm2835_cpufreq_driver_target,
 280 +               .get    = bcm2835_cpufreq_driver_get
 281 +};
 282 +
 283 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 284 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 285 +MODULE_LICENSE("GPL");
 286 +
 287 +module_init(bcm2835_cpufreq_module_init);
 288 +module_exit(bcm2835_cpufreq_module_exit);
 289 +