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
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
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
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 6e57543..bf40783 100644
28 --- a/drivers/cpufreq/Kconfig.arm
29 +++ b/drivers/cpufreq/Kconfig.arm
30 @@ -150,3 +150,11 @@ config ARM_SPEAR_CPUFREQ
33 This adds the CPUFreq driver support for SPEAr SOCs.
35 +config ARM_BCM2835_CPUFREQ
36 + bool "BCM2835 Driver"
39 + This adds the CPUFreq driver for BCM2835
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
52 ##################################################################################
53 # PowerPC platform drivers
54 diff --git a/drivers/cpufreq/bcm2835-cpufreq.c b/drivers/cpufreq/bcm2835-cpufreq.c
56 index 0000000..822139a
58 +++ b/drivers/cpufreq/bcm2835-cpufreq.c
60 +/*****************************************************************************
61 +* Copyright 2011 Broadcom Corporation. All rights reserved.
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").
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
72 +*****************************************************************************/
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 +*****************************************************************************/
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>
90 +/* ---------- DEFINES ---------- */
91 +/*#define CPUFREQ_DEBUG_ENABLE*/ /* enable debugging */
92 +#define MODULE_NAME "bcm2835-cpufreq"
94 +#define VCMSG_ID_ARM_CLOCK 0x000000003 /* Clock/Voltage ID's */
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__)
100 +#define print_debug(fmt,...)
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__)
105 +/* tag part of the message */
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 */
114 +/* message structure to be sent to videocore */
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 */
122 +/* ---------- GLOBALS ---------- */
123 +static struct cpufreq_driver bcm2835_cpufreq_driver; /* the cpufreq driver global */
126 + ===============================================
127 + clk_rate either gets or sets the clock rates.
128 + ===============================================
130 +static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
132 + int s, actual_rate=0;
135 + /* wipe all previous message data */
136 + memset(&msg, 0, sizeof msg);
138 + msg.msg_size = sizeof msg;
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;
146 + /* send the message */
147 + s = bcm_mailbox_property(&msg, sizeof msg);
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;
153 + print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
154 + return actual_rate;
157 +static uint32_t bcm2835_cpufreq_get_clock(int tag)
163 + /* wipe all previous message data */
164 + memset(&msg, 0, sizeof msg);
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;
172 + /* send the message */
173 + s = bcm_mailbox_property(&msg, sizeof msg);
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;
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);
189 + ====================================================
190 + Module Initialisation registers the cpufreq driver
191 + ====================================================
193 +static int __init bcm2835_cpufreq_module_init(void)
195 + print_debug("IN\n");
196 + return cpufreq_register_driver(&bcm2835_cpufreq_driver);
204 +static void __exit bcm2835_cpufreq_module_exit(void)
206 + print_debug("IN\n");
207 + cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
212 + ==============================================================
213 + Initialisation function sets up the CPU policy for first use
214 + ==============================================================
216 +static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
218 + /* measured value of how long it takes to change frequency */
219 + policy->cpuinfo.transition_latency = 355000; /* ns */
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);
226 + print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
231 + =================================================================================
232 + Target function chooses the most appropriate frequency from the table to enable
233 + =================================================================================
236 +static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
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);
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)
249 + /* otherwise were good to set the clock frequency */
250 + policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
254 + print_err("Error occurred setting a new frequency (%d)!\n", target);
255 + policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
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);
262 +static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
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;
270 + =================================================================================
271 + Verify ensures that when a policy is changed, it is suitable for the CPU to use
272 + =================================================================================
275 +static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
277 + print_info("switching to governor %s\n", policy->governor->name);
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
292 +MODULE_AUTHOR("Dorian Peake and Dom Cobley");
293 +MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
294 +MODULE_LICENSE("GPL");
296 +module_init(bcm2835_cpufreq_module_init);
297 +module_exit(bcm2835_cpufreq_module_exit);