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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>
62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
/*
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* Based on Ocelot Linux port, which is
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* Copyright 2001 MontaVista Software Inc.
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* Author: jsun@mvista.com or jsun@junsun.net
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*
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* Copyright 2003 ICT CAS
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* Author: Michael Guo <guoyi@ict.ac.cn>
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*
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* Copyright (C) 2007 Lemote Inc. & Insititute of Computing Technology
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* Author: Fuxin Zhang, zhangfx@lemote.com
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*
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* Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
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* Author: Wu Zhangjin, wuzj@lemote.com
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/module.h>
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#include <asm/bootinfo.h>
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#include <loongson.h>
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unsigned long bus_clock, cpu_clock_freq;
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EXPORT_SYMBOL(cpu_clock_freq);
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unsigned long memsize, highmemsize;
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/* pmon passes arguments in 32bit pointers */
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int *_prom_envp;
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#define parse_even_earlier(res, option, p) \
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do { \
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if (strncmp(option, (char *)p, strlen(option)) == 0) \
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strict_strtol((char *)p + strlen(option"="), \
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10, &res); \
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} while (0)
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void __init prom_init_env(void)
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{
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long l;
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/* firmware arguments are initialized in head.S */
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_prom_envp = (int *)fw_arg2;
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l = (long)*_prom_envp;
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while (l != 0) {
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parse_even_earlier(bus_clock, "busclock", l);
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parse_even_earlier(cpu_clock_freq, "cpuclock", l);
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parse_even_earlier(memsize, "memsize", l);
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parse_even_earlier(highmemsize, "highmemsize", l);
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_prom_envp++;
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l = (long)*_prom_envp;
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}
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if (memsize == 0)
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memsize = 256;
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pr_info("busclock=%ld, cpuclock=%ld, memsize=%ld, highmemsize=%ld\n",
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bus_clock, cpu_clock_freq, memsize, highmemsize);
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}
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