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authorWu Zhangjin <wuzhangjin@gmail.com>2009-11-17 01:32:59 +0800
committerRalf Baechle <ralf@linux-mips.org>2009-12-17 01:57:20 +0000
commitf8ede0f700f5478851f242f291d203cde54ca6cf (patch)
tree37fba17288bcd12468c454eb6c585d72fb6f9770 /arch/mips/loongson/common
parent9726b43a4d7aaa5b30f559e78768aeb3d17bc224 (diff)
MIPS: Loongson 2F: Add CPU frequency scaling support
Loongson 2F supports CPU clock scaling. When put it into wait mode by setting the frequency as ZERO it will stay in this mode until an external interrupt wakes the CPU again. To enable clock scaling support, an external timer of a known stable rate is required. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Cc: cpufreq@vger.kernel.org, Cc: Dave Jones <davej@redhat.com>, Cc: Dominik Brodowski <linux@dominikbrodowski.net>, Cc: yanh@lemote.com Cc: huhb@lemote.com, Patchwork: http://patchwork.linux-mips.org/patch/660/ Patchwork: http://patchwork.linux-mips.org/patch/751/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/loongson/common')
-rw-r--r--arch/mips/loongson/common/Makefile2
-rw-r--r--arch/mips/loongson/common/env.c3
-rw-r--r--arch/mips/loongson/common/platform.c30
3 files changed, 34 insertions, 1 deletions
diff --git a/arch/mips/loongson/common/Makefile b/arch/mips/loongson/common/Makefile
index a21724d50e2..8d71892413d 100644
--- a/arch/mips/loongson/common/Makefile
+++ b/arch/mips/loongson/common/Makefile
@@ -3,7 +3,7 @@
#
obj-y += setup.o init.o cmdline.o env.o time.o reset.o irq.o \
- pci.o bonito-irq.o mem.o machtype.o uart_base.o
+ pci.o bonito-irq.o mem.o machtype.o platform.o uart_base.o
#
# Early printk support
diff --git a/arch/mips/loongson/common/env.c b/arch/mips/loongson/common/env.c
index b9ef5038554..196d947d929 100644
--- a/arch/mips/loongson/common/env.c
+++ b/arch/mips/loongson/common/env.c
@@ -17,11 +17,14 @@
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
+#include <linux/module.h>
+
#include <asm/bootinfo.h>
#include <loongson.h>
unsigned long bus_clock, cpu_clock_freq;
+EXPORT_SYMBOL(cpu_clock_freq);
unsigned long memsize, highmemsize;
/* pmon passes arguments in 32bit pointers */
diff --git a/arch/mips/loongson/common/platform.c b/arch/mips/loongson/common/platform.c
new file mode 100644
index 00000000000..be81777eb94
--- /dev/null
+++ b/arch/mips/loongson/common/platform.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2009 Lemote Inc.
+ * Author: Wu Zhangjin, wuzj@lemote.com
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/platform_device.h>
+
+static struct platform_device loongson2_cpufreq_device = {
+ .name = "loongson2_cpufreq",
+ .id = -1,
+};
+
+static int __init loongson2_cpufreq_init(void)
+{
+ struct cpuinfo_mips *c = &current_cpu_data;
+
+ /* Only 2F revision and it's successors support CPUFreq */
+ if ((c->processor_id & PRID_REV_MASK) >= PRID_REV_LOONGSON2F)
+ return platform_device_register(&loongson2_cpufreq_device);
+
+ return -ENODEV;
+}
+
+arch_initcall(loongson2_cpufreq_init);