8a96669d77
On my Yeeloong 8089, I noticed the machine fails to shutdown
properly, and often, the function mach_prepare_reboot() is
unexpectedly executed, thus the machine reboots instead. A
wait loop is needed to ensure the system is in a well-defined
state before going down.
In commit 997e93d4df ("MIPS: Hang more efficiently on
halt/powerdown/restart"), a general superset of the wait loop for all
platforms is already provided, so we don't need to implement our own.
This commit simply removes the unreachable() compiler marco after
mach_prepare_reboot(), thus allowing the execution of machine_hang().
My test shows that the machine is now able to shutdown successfully.
Please note that there are two different bugs preventing the machine
from shutting down, another work-in-progress commit is needed to
fix a lockup in cpufreq / i8259 driver, please read Reference, this
commit does not fix that bug.
Reference: https://lkml.org/lkml/2019/2/5/908
Signed-off-by: Yifeng Li <tomli@tomli.me>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: stable@vger.kernel.org # v4.17+
98 lines
2.0 KiB
C
98 lines
2.0 KiB
C
/*
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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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* Copyright (C) 2007 Lemote, Inc. & Institute of Computing Technology
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* Author: Fuxin Zhang, zhangfx@lemote.com
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* Copyright (C) 2009 Lemote, Inc.
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* Author: Zhangjin Wu, wuzhangjin@gmail.com
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*/
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#include <linux/init.h>
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#include <linux/pm.h>
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#include <asm/idle.h>
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#include <asm/reboot.h>
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#include <loongson.h>
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#include <boot_param.h>
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static inline void loongson_reboot(void)
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{
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#ifndef CONFIG_CPU_JUMP_WORKAROUNDS
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((void (*)(void))ioremap_nocache(LOONGSON_BOOT_BASE, 4)) ();
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#else
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void (*func)(void);
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func = (void *)ioremap_nocache(LOONGSON_BOOT_BASE, 4);
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__asm__ __volatile__(
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" .set noat \n"
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" jr %[func] \n"
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" .set at \n"
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: /* No outputs */
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: [func] "r" (func));
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#endif
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}
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static void loongson_restart(char *command)
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{
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#ifndef CONFIG_LEFI_FIRMWARE_INTERFACE
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/* do preparation for reboot */
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mach_prepare_reboot();
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/* reboot via jumping to boot base address */
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loongson_reboot();
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#else
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void (*fw_restart)(void) = (void *)loongson_sysconf.restart_addr;
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fw_restart();
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while (1) {
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if (cpu_wait)
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cpu_wait();
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}
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#endif
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}
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static void loongson_poweroff(void)
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{
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#ifndef CONFIG_LEFI_FIRMWARE_INTERFACE
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mach_prepare_shutdown();
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/*
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* It needs a wait loop here, but mips/kernel/reset.c already calls
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* a generic delay loop, machine_hang(), so simply return.
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*/
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return;
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#else
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void (*fw_poweroff)(void) = (void *)loongson_sysconf.poweroff_addr;
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fw_poweroff();
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while (1) {
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if (cpu_wait)
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cpu_wait();
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}
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#endif
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}
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static void loongson_halt(void)
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{
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pr_notice("\n\n** You can safely turn off the power now **\n\n");
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while (1) {
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if (cpu_wait)
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cpu_wait();
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}
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}
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static int __init mips_reboot_setup(void)
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{
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_machine_restart = loongson_restart;
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_machine_halt = loongson_halt;
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pm_power_off = loongson_poweroff;
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return 0;
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}
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arch_initcall(mips_reboot_setup);
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