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
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
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
22 + select ARCH_HAS_CPUFREQ
23 select GENERIC_CLOCKEVENTS
24 select ARM_ERRATA_411920
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
32 This adds the CPUFreq driver support for SPEAr SOCs.
34 +config ARM_BCM2835_CPUFREQ
35 + bool "BCM2835 Driver"
38 + This adds the CPUFreq driver for BCM2835
42 config ARM_TEGRA_CPUFREQ
43 bool "TEGRA CPUFreq support"
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
57 diff --git a/drivers/cpufreq/bcm2835-cpufreq.c b/drivers/cpufreq/bcm2835-cpufreq.c
59 index 0000000..447ca09
61 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
63 +/*****************************************************************************
64 +* Copyright 2011 Broadcom Corporation. All rights reserved.
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").
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
75 +*****************************************************************************/
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 +*****************************************************************************/
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>
93 +/* ---------- DEFINES ---------- */
94 +/*#define CPUFREQ_DEBUG_ENABLE*/ /* enable debugging */
95 +#define MODULE_NAME "bcm2835-cpufreq"
97 +#define VCMSG_ID_ARM_CLOCK 0x000000003 /* Clock/Voltage ID's */
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__)
103 +#define print_debug(fmt,...)
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__)
108 +/* tag part of the message */
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 */
117 +/* message structure to be sent to videocore */
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 */
125 +/* ---------- GLOBALS ---------- */
126 +static struct cpufreq_driver bcm2835_cpufreq_driver; /* the cpufreq driver global */
128 +static struct cpufreq_frequency_table bcm2835_freq_table[] = {
131 + {0, 0, CPUFREQ_TABLE_END},
135 + ===============================================
136 + clk_rate either gets or sets the clock rates.
137 + ===============================================
139 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
141 + int s, actual_rate=0;
144 + /* wipe all previous message data */
145 + memset(&msg, 0, sizeof msg);
147 + msg.msg_size = sizeof msg;
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;
155 + /* send the message */
156 + s = bcm_mailbox_property(&msg, sizeof msg);
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;
162 + print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
163 + return actual_rate;
166 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
172 + /* wipe all previous message data */
173 + memset(&msg, 0, sizeof msg);
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;
181 + /* send the message */
182 + s = bcm_mailbox_property(&msg, sizeof msg);
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;
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);
198 + ====================================================
199 + Module Initialisation registers the cpufreq driver
200 + ====================================================
202 +static int __init bcm2835_cpufreq_module_init(void)
204 + print_debug("IN\n");
205 + return cpufreq_register_driver(&bcm2835_cpufreq_driver);
213 +static void __exit bcm2835_cpufreq_module_exit(void)
215 + print_debug("IN\n");
216 + cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
221 + ==============================================================
222 + Initialisation function sets up the CPU policy for first use
223 + ==============================================================
225 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
227 + /* measured value of how long it takes to change frequency */
228 + const unsigned int transition_latency = 355000; /* ns */
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);
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);
239 + =====================================================================
240 + Target index function chooses the requested frequency from the table
241 + =====================================================================
244 +static int bcm2835_cpufreq_driver_target_index(struct cpufreq_policy *policy, unsigned int state)
246 + unsigned int target_freq = bcm2835_freq_table[state].frequency;
247 + unsigned int cur = bcm2835_cpufreq_set_clock(policy->cur, target_freq);
251 + print_err("Error occurred setting a new frequency (%d)\n", target_freq);
254 + print_debug("%s: %i: freq %d->%d\n", policy->governor->name, state, policy->cur, cur);
259 + ======================================================
260 + Get function returns the current frequency from table
261 + ======================================================
264 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
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;
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,
281 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
282 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
283 +MODULE_LICENSE("GPL");
285 +module_init(bcm2835_cpufreq_module_init);
286 +module_exit(bcm2835_cpufreq_module_exit);