target/linux/brcm2708/patches-3.18/0016-Add-cpufreq-driver.patch

   1 From f8628f418651bcb52604f943c00c45d932ff3572 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 016/114] 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 | 224 ++++++++++++++++++++++++++++++++++++++
  11  4 files changed, 234 insertions(+)
  12  create mode 100755 drivers/cpufreq/bcm2835-cpufreq.c
  13
  14 diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
  15 index 4cedaf2..6283d7d 100644
  16 --- a/arch/arm/Kconfig
  17 +++ b/arch/arm/Kconfig
  18 @@ -390,6 +390,7 @@ 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 83a75dc..210394f 100644
  28 --- a/drivers/cpufreq/Kconfig.arm
  29 +++ b/drivers/cpufreq/Kconfig.arm
  30 @@ -241,6 +241,14 @@ 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 40c53dc..47d2922 100644
  47 --- a/drivers/cpufreq/Makefile
  48 +++ b/drivers/cpufreq/Makefile
  49 @@ -75,6 +75,7 @@ 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..447ca09
  60 --- /dev/null
  61 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
  62 @@ -0,0 +1,224 @@
  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 +static struct cpufreq_frequency_table bcm2835_freq_table[] = {
 129 +       {0, 0, 0},
 130 +       {0, 0, 0},
 131 +       {0, 0, CPUFREQ_TABLE_END},
 132 +};
 133 +
 134 +/*
 135 + ===============================================
 136 +  clk_rate either gets or sets the clock rates.
 137 + ===============================================
 138 +*/
 139 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
 140 +{
 141 +       int s, actual_rate=0;
 142 +       struct vc_msg msg;
 143 +
 144 +       /* wipe all previous message data */
 145 +       memset(&msg, 0, sizeof msg);
 146 +
 147 +       msg.msg_size = sizeof msg;
 148 +
 149 +       msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
 150 +       msg.tag.buffer_size = 8;
 151 +       msg.tag.data_size = 8;   /* we're sending the clock ID and the new rates which is a total of 2 words */
 152 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 153 +       msg.tag.val = arm_rate * 1000;
 154 +
 155 +       /* send the message */
 156 +       s = bcm_mailbox_property(&msg, sizeof msg);
 157 +
 158 +       /* check if it was all ok and return the rate in KHz */
 159 +       if (s == 0 && (msg.request_code & 0x80000000))
 160 +               actual_rate = msg.tag.val/1000;
 161 +
 162 +       print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
 163 +       return actual_rate;
 164 +}
 165 +
 166 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
 167 +{
 168 +       int s;
 169 +       int arm_rate = 0;
 170 +       struct vc_msg msg;
 171 +
 172 +       /* wipe all previous message data */
 173 +       memset(&msg, 0, sizeof msg);
 174 +
 175 +       msg.msg_size = sizeof msg;
 176 +       msg.tag.tag_id = tag;
 177 +       msg.tag.buffer_size = 8;
 178 +       msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
 179 +       msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
 180 +
 181 +       /* send the message */
 182 +       s = bcm_mailbox_property(&msg, sizeof msg);
 183 +
 184 +       /* check if it was all ok and return the rate in KHz */
 185 +       if (s == 0 && (msg.request_code & 0x80000000))
 186 +               arm_rate = msg.tag.val/1000;
 187 +
 188 +       print_debug("%s frequency = %d\n",
 189 +               tag == VCMSG_GET_CLOCK_RATE ? "Current":
 190 +               tag == VCMSG_GET_MIN_CLOCK ? "Min":
 191 +               tag == VCMSG_GET_MAX_CLOCK ? "Max":
 192 +               "Unexpected", arm_rate);
 193 +
 194 +       return arm_rate;
 195 +}
 196 +
 197 +/*
 198 + ====================================================
 199 +  Module Initialisation registers the cpufreq driver
 200 + ====================================================
 201 +*/
 202 +static int __init bcm2835_cpufreq_module_init(void)
 203 +{
 204 +       print_debug("IN\n");
 205 +       return cpufreq_register_driver(&bcm2835_cpufreq_driver);
 206 +}
 207 +
 208 +/*
 209 + =============
 210 +  Module exit
 211 + =============
 212 +*/
 213 +static void __exit bcm2835_cpufreq_module_exit(void)
 214 +{
 215 +       print_debug("IN\n");
 216 +       cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
 217 +       return;
 218 +}
 219 +
 220 +/*
 221 + ==============================================================
 222 +  Initialisation function sets up the CPU policy for first use
 223 + ==============================================================
 224 +*/
 225 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
 226 +{
 227 +       /* measured value of how long it takes to change frequency */
 228 +       const unsigned int transition_latency = 355000; /* ns */
 229 +
 230 +       /* now find out what the maximum and minimum frequencies are */
 231 +       bcm2835_freq_table[0].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
 232 +       bcm2835_freq_table[1].frequency = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
 233 +
 234 +       print_info("min=%d max=%d\n", bcm2835_freq_table[0].frequency, bcm2835_freq_table[1].frequency);
 235 +       return cpufreq_generic_init(policy, bcm2835_freq_table, transition_latency);
 236 +}
 237 +
 238 +/*
 239 + =====================================================================
 240 +  Target index function chooses the requested frequency from the table
 241 + =====================================================================
 242 +*/
 243 +
 244 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
 245 +{
 246 +       unsigned int target_freq = bcm2835_freq_table[state].frequency;
 247 +       unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
 248 +
 249 +       if (!cur)
 250 +       {
 251 +               print_err("Error occurred setting a new frequency (%d)\n", target_freq);
 252 +               return -EINVAL;
 253 +       }
 254 +       print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
 255 +       return 0;
 256 +}
 257 +
 258 +/*
 259 + ======================================================
 260 +  Get function returns the current frequency from table
 261 + ======================================================
 262 +*/
 263 +
 264 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
 265 +{
 266 +       unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
 267 +       print_debug("%d: freq=%d\n", cpu, actual_rate);
 268 +       return actual_rate <= bcm2835_freq_table[0].frequency ? bcm2835_freq_table[0].frequency : bcm2835_freq_table[1].frequency;
 269 +}
 270 +
 271 +/* the CPUFreq driver */
 272 +static struct cpufreq_driver bcm2835_cpufreq_driver = {
 273 +       .name         = "BCM2835 CPUFreq",
 274 +       .init         = bcm2835_cpufreq_driver_init,
 275 +       .verify       = cpufreq_generic_frequency_table_verify,
 276 +       .target_index = bcm2835_cpufreq_driver_target_index,
 277 +       .get          = bcm2835_cpufreq_driver_get,
 278 +       .attr         = cpufreq_generic_attr,
 279 +};
 280 +
 281 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
 282 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
 283 +MODULE_LICENSE("GPL");
 284 +
 285 +module_init(bcm2835_cpufreq_module_init);
 286 +module_exit(bcm2835_cpufreq_module_exit);
 287 --
 288 1.8.3.2
 289