target/linux/brcm2708/patches-3.10/011-bcm2835-cpufreq-driver.patch

   1 --- /dev/null
   2 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
   3 @@ -0,0 +1,239 @@
   4 +/*****************************************************************************
   5 +* Copyright 2011 Broadcom Corporation.  All rights reserved.
   6 +*
   7 +* Unless you and Broadcom execute a separate written software license
   8 +* agreement governing use of this software, this software is licensed to you
   9 +* under the terms of the GNU General Public License version 2, available at
  10 +* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
  11 +*
  12 +* Notwithstanding the above, under no circumstances may you combine this
  13 +* software in any way with any other Broadcom software provided under a
  14 +* license other than the GPL, without Broadcom's express prior written
  15 +* consent.
  16 +*****************************************************************************/
  17 +
  18 +/*****************************************************************************
  19 +* FILENAME: bcm2835-cpufreq.h
  20 +* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
  21 +* processor. Messages are sent to Videocore either setting or requesting the
  22 +* frequency of the ARM in order to match an appropiate frequency to the current
  23 +* usage of the processor. The policy which selects the frequency to use is
  24 +* defined in the kernel .config file, but can be changed during runtime.
  25 +*****************************************************************************/
  26 +
  27 +/* ---------- INCLUDES ---------- */
  28 +#include <linux/kernel.h>
  29 +#include <linux/init.h>
  30 +#include <linux/module.h>
  31 +#include <linux/cpufreq.h>
  32 +#include <mach/vcio.h>
  33 +
  34 +/* ---------- DEFINES ---------- */
  35 +/*#define CPUFREQ_DEBUG_ENABLE*/               /* enable debugging */
  36 +#define MODULE_NAME "bcm2835-cpufreq"
  37 +
  38 +#define VCMSG_ID_ARM_CLOCK 0x000000003         /* Clock/Voltage ID's */
  39 +
  40 +/* debug printk macros */
  41 +#ifdef CPUFREQ_DEBUG_ENABLE
  42 +#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
  43 +#else
  44 +#define print_debug(fmt,...)
  45 +#endif
  46 +#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
  47 +#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
  48 +
  49 +/* tag part of the message */
  50 +struct vc_msg_tag {
  51 +       uint32_t tag_id;                /* the message id */
  52 +       uint32_t buffer_size;           /* size of the buffer (which in this case is always 8 bytes) */
  53 +       uint32_t data_size;             /* amount of data being sent or received */
  54 +       uint32_t dev_id;                /* the ID of the clock/voltage to get or set */
  55 +       uint32_t val;                   /* the value (e.g. rate (in Hz)) to set */
  56 +};
  57 +
  58 +/* message structure to be sent to videocore */
  59 +struct vc_msg {
  60 +       uint32_t msg_size;              /* simply, sizeof(struct vc_msg) */
  61 +       uint32_t request_code;          /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
  62 +       struct vc_msg_tag tag;          /* the tag structure above to make */
  63 +       uint32_t end_tag;               /* an end identifier, should be set to NULL */
  64 +};
  65 +
  66 +/* ---------- GLOBALS ---------- */
  67 +static struct cpufreq_driver bcm2835_cpufreq_driver;   /* the cpufreq driver global */
  68 +
  69 +/*
  70 + ===============================================
  71 +  clk_rate either gets or sets the clock rates.
  72 + ===============================================
  73 +*/
  74 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
  75 +{
  76 +       int s, actual_rate=0;
  77 +       struct vc_msg msg;
  78 +
  79 +       /* wipe all previous message data */
  80 +       memset(&msg, 0, sizeof msg);
  81 +
  82 +       msg.msg_size = sizeof msg;
  83 +
  84 +       msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
  85 +       msg.tag.buffer_size = 8;
  86 +       msg.tag.data_size = 8;   /* we're sending the clock ID and the new rates which is a total of 2 words */
  87 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
  88 +       msg.tag.val = arm_rate * 1000;
  89 +
  90 +       /* send the message */
  91 +       s = bcm_mailbox_property(&msg, sizeof msg);
  92 +
  93 +       /* check if it was all ok and return the rate in KHz */
  94 +       if (s == 0 && (msg.request_code & 0x80000000))
  95 +               actual_rate = msg.tag.val/1000;
  96 +
  97 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
  98 +       return actual_rate;
  99 +}
 100 +
 101 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 102 +{
 103 +       int s;
 104 +       int arm_rate = 0;
 105 +       struct vc_msg msg;
 106 +
 107 +       /* wipe all previous message data */
 108 +       memset(&msg, 0, sizeof msg);
 109 +
 110 +       msg.msg_size = sizeof msg;
 111 +       msg.tag.tag_id = tag;
 112 +       msg.tag.buffer_size = 8;
 113 +       msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
 114 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 115 +
 116 +       /* send the message */
 117 +       s = bcm_mailbox_property(&msg, sizeof msg);
 118 +
 119 +       /* check if it was all ok and return the rate in KHz */
 120 +       if (s == 0 && (msg.request_code & 0x80000000))
 121 +               arm_rate = msg.tag.val/1000;
 122 +
 123 +       print_debug("%s frequency = %d\n",
 124 +               tag == VCMSG_GET_CLOCK_RATE ? "Current":
 125 +               tag == VCMSG_GET_MIN_CLOCK ? "Min":
 126 +               tag == VCMSG_GET_MAX_CLOCK ? "Max":
 127 +               "Unexpected", arm_rate);
 128 +
 129 +       return arm_rate;
 130 +}
 131 +
 132 +/*
 133 + ====================================================
 134 +  Module Initialisation registers the cpufreq driver
 135 + ====================================================
 136 +*/
 137 +static int __init bcm2835_cpufreq_module_init(void)
 138 +{
 139 +       print_debug("IN\n");
 140 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 141 +}
 142 +
 143 +/*
 144 + =============
 145 +  Module exit
 146 + =============
 147 +*/
 148 +static void __exit bcm2835_cpufreq_module_exit(void)
 149 +{
 150 +       print_debug("IN\n");
 151 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 152 +       return;
 153 +}
 154 +
 155 +/*
 156 + ==============================================================
 157 +  Initialisation function sets up the CPU policy for first use
 158 + ==============================================================
 159 +*/
 160 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 161 +{
 162 +       /* measured value of how long it takes to change frequency */
 163 +       policy->cpuinfo.transition_latency = 355000; /* ns */
 164 +
 165 +       /* now find out what the maximum and minimum frequencies are */
 166 +       policy->min = policy->cpuinfo.min_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 167 +       policy->max = policy->cpuinfo.max_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 168 +       policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 169 +
 170 +       print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
 171 +       return 0;
 172 +}
 173 +
 174 +/*
 175 + =================================================================================
 176 +  Target function chooses the most appropriate frequency from the table to enable
 177 + =================================================================================
 178 +*/
 179 +
 180 +static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
 181 +{
 182 +       unsigned int target = target_freq;
 183 +       unsigned int cur = policy->cur;
 184 +       print_debug("%s: min=%d max=%d cur=%d target=%d\n",policy->governor->name,policy->min,policy->max,policy->cur,target_freq);
 185 +
 186 +       /* if we are above min and using ondemand, then just use max */
 187 +       if (strcmp("ondemand", policy->governor->name)==0 && target > policy->min)
 188 +               target = policy->max;
 189 +       /* if the frequency is the same, just quit */
 190 +       if (target == policy->cur)
 191 +               return 0;
 192 +
 193 +       /* otherwise were good to set the clock frequency */
 194 +       policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
 195 +
 196 +       if (!policy->cur)
 197 +       {
 198 +               print_err("Error occurred setting a new frequency (%d)!\n", target);
 199 +               policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 200 +               return -EINVAL;
 201 +       }
 202 +       print_debug("Freq %d->%d (min=%d max=%d target=%d request=%d)\n", cur, policy->cur, policy->min, policy->max, target_freq, target);
 203 +       return 0;
 204 +}
 205 +
 206 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 207 +{
 208 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 209 +       print_debug("cpu=%d\n", actual_rate);
 210 +       return actual_rate;
 211 +}
 212 +
 213 +/*
 214 + =================================================================================
 215 +  Verify ensures that when a policy is changed, it is suitable for the CPU to use
 216 + =================================================================================
 217 +*/
 218 +
 219 +static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
 220 +{
 221 +       print_info("switching to governor %s\n", policy->governor->name);
 222 +       return 0;
 223 +}
 224 +
 225 +
 226 +/* the CPUFreq driver */
 227 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 228 +               .name   = "BCM2835 CPUFreq",
 229 +               .owner  = THIS_MODULE,
 230 +               .init   = bcm2835_cpufreq_driver_init,
 231 +               .verify = bcm2835_cpufreq_driver_verify,
 232 +               .target = bcm2835_cpufreq_driver_target,
 233 +               .get    = bcm2835_cpufreq_driver_get
 234 +};
 235 +
 236 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 237 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 238 +MODULE_LICENSE("GPL");
 239 +
 240 +module_init(bcm2835_cpufreq_module_init);
 241 +module_exit(bcm2835_cpufreq_module_exit);
 242 +
 243 --- a/drivers/cpufreq/Kconfig.arm
 244 +++ b/drivers/cpufreq/Kconfig.arm
 245 @@ -150,3 +150,11 @@ config ARM_SPEAR_CPUFREQ
 246         default y
 247         help
 248           This adds the CPUFreq driver support for SPEAr SOCs.
 249 +
 250 +config ARM_BCM2835_CPUFREQ
 251 +       bool "BCM2835 Driver"
 252 +       default y
 253 +       help
 254 +         This adds the CPUFreq driver for BCM2835
 255 +
 256 +         If in doubt, say N.
 257 --- a/drivers/cpufreq/Makefile
 258 +++ b/drivers/cpufreq/Makefile
 259 @@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)      += sa11
 260  obj-$(CONFIG_ARM_SA1110_CPUFREQ)       += sa1110-cpufreq.o
 261  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
 262  obj-$(CONFIG_ARCH_TEGRA)               += tegra-cpufreq.o
 263 +obj-$(CONFIG_ARM_BCM2835_CPUFREQ)      += bcm2835-cpufreq.o
 264
 265  ##################################################################################
 266  # PowerPC platform drivers