mirror of https://github.com/hak5/openwrt.git
267 lines
9.2 KiB
Diff
267 lines
9.2 KiB
Diff
--- /dev/null
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+++ b/drivers/cpufreq/bcm2835-cpufreq.c
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@@ -0,0 +1,239 @@
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+/*****************************************************************************
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+* Copyright 2011 Broadcom Corporation. All rights reserved.
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+*
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+* Unless you and Broadcom execute a separate written software license
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+* agreement governing use of this software, this software is licensed to you
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+* under the terms of the GNU General Public License version 2, available at
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+* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
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+*
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+* Notwithstanding the above, under no circumstances may you combine this
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+* software in any way with any other Broadcom software provided under a
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+* license other than the GPL, without Broadcom's express prior written
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+* consent.
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+*****************************************************************************/
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+
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+/*****************************************************************************
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+* FILENAME: bcm2835-cpufreq.h
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+* DESCRIPTION: This driver dynamically manages the CPU Frequency of the ARM
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+* processor. Messages are sent to Videocore either setting or requesting the
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+* frequency of the ARM in order to match an appropiate frequency to the current
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+* usage of the processor. The policy which selects the frequency to use is
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+* defined in the kernel .config file, but can be changed during runtime.
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+*****************************************************************************/
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+
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+/* ---------- INCLUDES ---------- */
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+#include <linux/kernel.h>
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+#include <linux/init.h>
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+#include <linux/module.h>
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+#include <linux/cpufreq.h>
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+#include <mach/vcio.h>
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+
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+/* ---------- DEFINES ---------- */
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+/*#define CPUFREQ_DEBUG_ENABLE*/ /* enable debugging */
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+#define MODULE_NAME "bcm2835-cpufreq"
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+
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+#define VCMSG_ID_ARM_CLOCK 0x000000003 /* Clock/Voltage ID's */
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+
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+/* debug printk macros */
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+#ifdef CPUFREQ_DEBUG_ENABLE
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+#define print_debug(fmt,...) pr_debug("%s:%s:%d: "fmt, MODULE_NAME, __func__, __LINE__, ##__VA_ARGS__)
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+#else
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+#define print_debug(fmt,...)
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+#endif
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+#define print_err(fmt,...) pr_err("%s:%s:%d: "fmt, MODULE_NAME, __func__,__LINE__, ##__VA_ARGS__)
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+#define print_info(fmt,...) pr_info("%s: "fmt, MODULE_NAME, ##__VA_ARGS__)
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+
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+/* tag part of the message */
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+struct vc_msg_tag {
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+ uint32_t tag_id; /* the message id */
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+ uint32_t buffer_size; /* size of the buffer (which in this case is always 8 bytes) */
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+ uint32_t data_size; /* amount of data being sent or received */
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+ uint32_t dev_id; /* the ID of the clock/voltage to get or set */
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+ uint32_t val; /* the value (e.g. rate (in Hz)) to set */
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+};
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+
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+/* message structure to be sent to videocore */
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+struct vc_msg {
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+ uint32_t msg_size; /* simply, sizeof(struct vc_msg) */
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+ uint32_t request_code; /* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
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+ struct vc_msg_tag tag; /* the tag structure above to make */
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+ uint32_t end_tag; /* an end identifier, should be set to NULL */
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+};
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+
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+/* ---------- GLOBALS ---------- */
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+static struct cpufreq_driver bcm2835_cpufreq_driver; /* the cpufreq driver global */
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+
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+/*
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+ ===============================================
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+ clk_rate either gets or sets the clock rates.
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+ ===============================================
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+*/
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+static uint32_t bcm2835_cpufreq_set_clock(int cur_rate, int arm_rate)
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+{
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+ int s, actual_rate=0;
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+ struct vc_msg msg;
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+
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+ /* wipe all previous message data */
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+ memset(&msg, 0, sizeof msg);
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+
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+ msg.msg_size = sizeof msg;
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+
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+ msg.tag.tag_id = VCMSG_SET_CLOCK_RATE;
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+ msg.tag.buffer_size = 8;
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+ msg.tag.data_size = 8; /* we're sending the clock ID and the new rates which is a total of 2 words */
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+ msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
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+ msg.tag.val = arm_rate * 1000;
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+
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+ /* send the message */
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+ s = bcm_mailbox_property(&msg, sizeof msg);
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+
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+ /* check if it was all ok and return the rate in KHz */
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+ if (s == 0 && (msg.request_code & 0x80000000))
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+ actual_rate = msg.tag.val/1000;
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+
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+ print_debug("Setting new frequency = %d -> %d (actual %d)\n", cur_rate, arm_rate, actual_rate);
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+ return actual_rate;
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+}
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+
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+static uint32_t bcm2835_cpufreq_get_clock(int tag)
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+{
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+ int s;
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+ int arm_rate = 0;
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+ struct vc_msg msg;
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+
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+ /* wipe all previous message data */
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+ memset(&msg, 0, sizeof msg);
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+
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+ msg.msg_size = sizeof msg;
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+ msg.tag.tag_id = tag;
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+ msg.tag.buffer_size = 8;
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+ msg.tag.data_size = 4; /* we're just sending the clock ID which is one word long */
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+ msg.tag.dev_id = VCMSG_ID_ARM_CLOCK;
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+
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+ /* send the message */
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+ s = bcm_mailbox_property(&msg, sizeof msg);
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+
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+ /* check if it was all ok and return the rate in KHz */
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+ if (s == 0 && (msg.request_code & 0x80000000))
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+ arm_rate = msg.tag.val/1000;
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+
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+ print_debug("%s frequency = %d\n",
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+ tag == VCMSG_GET_CLOCK_RATE ? "Current":
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+ tag == VCMSG_GET_MIN_CLOCK ? "Min":
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+ tag == VCMSG_GET_MAX_CLOCK ? "Max":
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+ "Unexpected", arm_rate);
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+
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+ return arm_rate;
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+}
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+
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+/*
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+ ====================================================
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+ Module Initialisation registers the cpufreq driver
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+ ====================================================
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+*/
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+static int __init bcm2835_cpufreq_module_init(void)
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+{
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+ print_debug("IN\n");
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+ return cpufreq_register_driver(&bcm2835_cpufreq_driver);
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+}
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+
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+/*
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+ =============
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+ Module exit
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+ =============
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+*/
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+static void __exit bcm2835_cpufreq_module_exit(void)
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+{
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+ print_debug("IN\n");
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+ cpufreq_unregister_driver(&bcm2835_cpufreq_driver);
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+ return;
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+}
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+
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+/*
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+ ==============================================================
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+ Initialisation function sets up the CPU policy for first use
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+ ==============================================================
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+*/
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+static int bcm2835_cpufreq_driver_init(struct cpufreq_policy *policy)
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+{
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+ /* measured value of how long it takes to change frequency */
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+ policy->cpuinfo.transition_latency = 355000; /* ns */
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+
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+ /* now find out what the maximum and minimum frequencies are */
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+ policy->min = policy->cpuinfo.min_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MIN_CLOCK);
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+ policy->max = policy->cpuinfo.max_freq = bcm2835_cpufreq_get_clock(VCMSG_GET_MAX_CLOCK);
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+ policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
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+
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+ print_info("min=%d max=%d cur=%d\n", policy->min, policy->max, policy->cur);
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+ return 0;
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+}
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+
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+/*
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+ =================================================================================
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+ Target function chooses the most appropriate frequency from the table to enable
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+ =================================================================================
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+*/
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+
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+static int bcm2835_cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation)
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+{
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+ unsigned int target = target_freq;
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+ unsigned int cur = policy->cur;
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+ print_debug("%s: min=%d max=%d cur=%d target=%d\n",policy->governor->name,policy->min,policy->max,policy->cur,target_freq);
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+
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+ /* if we are above min and using ondemand, then just use max */
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+ if (strcmp("ondemand", policy->governor->name)==0 && target > policy->min)
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+ target = policy->max;
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+ /* if the frequency is the same, just quit */
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+ if (target == policy->cur)
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+ return 0;
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+
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+ /* otherwise were good to set the clock frequency */
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+ policy->cur = bcm2835_cpufreq_set_clock(policy->cur, target);
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+
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+ if (!policy->cur)
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+ {
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+ print_err("Error occurred setting a new frequency (%d)!\n", target);
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+ policy->cur = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
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+ return -EINVAL;
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+ }
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+ print_debug("Freq %d->%d (min=%d max=%d target=%d request=%d)\n", cur, policy->cur, policy->min, policy->max, target_freq, target);
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+ return 0;
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+}
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+
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+static unsigned int bcm2835_cpufreq_driver_get(unsigned int cpu)
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+{
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+ unsigned int actual_rate = bcm2835_cpufreq_get_clock(VCMSG_GET_CLOCK_RATE);
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+ print_debug("cpu=%d\n", actual_rate);
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+ return actual_rate;
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+}
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+
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+/*
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+ =================================================================================
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+ Verify ensures that when a policy is changed, it is suitable for the CPU to use
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+ =================================================================================
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+*/
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+
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+static int bcm2835_cpufreq_driver_verify(struct cpufreq_policy *policy)
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+{
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+ print_info("switching to governor %s\n", policy->governor->name);
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+ return 0;
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+}
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+
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+
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+/* the CPUFreq driver */
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+static struct cpufreq_driver bcm2835_cpufreq_driver = {
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+ .name = "BCM2835 CPUFreq",
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+ .owner = THIS_MODULE,
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+ .init = bcm2835_cpufreq_driver_init,
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+ .verify = bcm2835_cpufreq_driver_verify,
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+ .target = bcm2835_cpufreq_driver_target,
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+ .get = bcm2835_cpufreq_driver_get
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+};
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+
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+MODULE_AUTHOR("Dorian Peake and Dom Cobley");
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+MODULE_DESCRIPTION("CPU frequency driver for BCM2835 chip");
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+MODULE_LICENSE("GPL");
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+
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+module_init(bcm2835_cpufreq_module_init);
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+module_exit(bcm2835_cpufreq_module_exit);
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+
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--- a/drivers/cpufreq/Kconfig.arm
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+++ b/drivers/cpufreq/Kconfig.arm
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@@ -150,3 +150,11 @@ config ARM_SPEAR_CPUFREQ
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default y
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help
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This adds the CPUFreq driver support for SPEAr SOCs.
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+
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+config ARM_BCM2835_CPUFREQ
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+ bool "BCM2835 Driver"
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+ default y
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+ help
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+ This adds the CPUFreq driver for BCM2835
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+
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+ If in doubt, say N.
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--- a/drivers/cpufreq/Makefile
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+++ b/drivers/cpufreq/Makefile
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@@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa11
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obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
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obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
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obj-$(CONFIG_ARCH_TEGRA) += tegra-cpufreq.o
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+obj-$(CONFIG_ARM_BCM2835_CPUFREQ) += bcm2835-cpufreq.o
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##################################################################################
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# PowerPC platform drivers
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