300459d558
IPI registers of Loongson-3 include IPI_SET, IPI_CLEAR, IPI_STATUS,
IPI_EN and IPI_MAILBOX_BUF. Each bit of IPI_STATUS indicate a type of
IPI and IPI_EN indicate whether the IPI is enabled. The sender write 1
to IPI_SET bits generate IPIs in IPI_STATUS, and receiver write 1 to
bits of IPI_CLEAR to clear IPIs. IPI_MAILBOX_BUF are used to deliver
more information about IPIs.
Why we change code in arch/mips/loongson/common/setup.c?
If without this change, when SMP configured, system cannot boot since
it hang at printk() in cgroup_init_early(). The root cause is:
console_trylock()
\-->down_trylock(&console_sem)
\-->raw_spin_unlock_irqrestore(&sem->lock, flags)
\-->_raw_spin_unlock_irqrestore()(SMP/UP have different versions)
\-->__raw_spin_unlock_irqrestore() (following is the SMP case)
\-->do_raw_spin_unlock()
\-->arch_spin_unlock()
\-->nudge_writes()
\-->mb()
\-->wbflush()
\-->__wbflush()
In previous code __wbflush() is initialized in plat_mem_setup(), but
cgroup_init_early() is called before plat_mem_setup(). Therefore, In
this patch we make changes to avoid boot failure.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Signed-off-by: Hua Yan <yanh@lemote.com>
Tested-by: Alex Smith <alex.smith@imgtec.com>
Reviewed-by: Alex Smith <alex.smith@imgtec.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6638
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
/*
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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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* 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/wbflush.h>
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#include <loongson.h>
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#ifdef CONFIG_VT
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#include <linux/console.h>
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#include <linux/screen_info.h>
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#endif
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static void wbflush_loongson(void)
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{
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asm(".set\tpush\n\t"
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".set\tnoreorder\n\t"
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".set mips3\n\t"
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"sync\n\t"
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"nop\n\t"
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".set\tpop\n\t"
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".set mips0\n\t");
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}
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void (*__wbflush)(void) = wbflush_loongson;
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EXPORT_SYMBOL(__wbflush);
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void __init plat_mem_setup(void)
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{
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#ifdef CONFIG_VT
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#if defined(CONFIG_VGA_CONSOLE)
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conswitchp = &vga_con;
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screen_info = (struct screen_info) {
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.orig_x = 0,
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.orig_y = 25,
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.orig_video_cols = 80,
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.orig_video_lines = 25,
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.orig_video_isVGA = VIDEO_TYPE_VGAC,
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.orig_video_points = 16,
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};
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#elif defined(CONFIG_DUMMY_CONSOLE)
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conswitchp = &dummy_con;
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#endif
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#endif
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}
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