diff options
Diffstat (limited to 'arch/mips/kernel/reset.c')
| -rw-r--r-- | arch/mips/kernel/reset.c | 68 |
1 files changed, 62 insertions, 6 deletions
diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c index 7c746d3458e7..6288780b779e 100644 --- a/arch/mips/kernel/reset.c +++ b/arch/mips/kernel/reset.c @@ -13,6 +13,9 @@ #include <linux/reboot.h> #include <linux/delay.h> +#include <asm/compiler.h> +#include <asm/idle.h> +#include <asm/mipsregs.h> #include <asm/reboot.h> /* @@ -26,6 +29,62 @@ void (*pm_power_off)(void); EXPORT_SYMBOL(pm_power_off); +static void machine_hang(void) +{ + /* + * We're hanging the system so we don't want to be interrupted anymore. + * Any interrupt handlers that ran would at best be useless & at worst + * go awry because the system isn't in a functional state. + */ + local_irq_disable(); + + /* + * Mask all interrupts, giving us a better chance of remaining in the + * low power wait state. + */ + clear_c0_status(ST0_IM); + + while (true) { + if (cpu_has_mips_r) { + /* + * We know that the wait instruction is supported so + * make use of it directly, leaving interrupts + * disabled. + */ + asm volatile( + ".set push\n\t" + ".set " MIPS_ISA_ARCH_LEVEL "\n\t" + "wait\n\t" + ".set pop"); + } else if (cpu_wait) { + /* + * Try the cpu_wait() callback. This isn't ideal since + * it'll re-enable interrupts, but that ought to be + * harmless given that they're all masked. + */ + cpu_wait(); + local_irq_disable(); + } else { + /* + * We're going to burn some power running round the + * loop, but we don't really have a choice. This isn't + * a path we should expect to run for long during + * typical use anyway. + */ + } + + /* + * In most modern MIPS CPUs interrupts will cause the wait + * instruction to graduate even when disabled, and in some + * cases even when masked. In order to prevent a timer + * interrupt from continuously taking us out of the low power + * wait state, we clear any pending timer interrupt here. + */ + if (cpu_has_counter) + write_c0_compare(0); + } +} + void machine_restart(char *command) { if (_machine_restart) @@ -38,8 +97,7 @@ void machine_restart(char *command) do_kernel_restart(command); mdelay(1000); pr_emerg("Reboot failed -- System halted\n"); - local_irq_disable(); - while (1); + machine_hang(); } void machine_halt(void) @@ -51,8 +109,7 @@ void machine_halt(void) preempt_disable(); smp_send_stop(); #endif - local_irq_disable(); - while (1); + machine_hang(); } void machine_power_off(void) @@ -64,6 +121,5 @@ void machine_power_off(void) preempt_disable(); smp_send_stop(); #endif - local_irq_disable(); - while (1); + machine_hang(); } |