On R4k DECstations the Halt button is wired to the NMI processor input rather than an ordinary interrupt input such as on R3k DECstations. This is possible with a different design of the CPU daughtercard that routes the Halt button line from the baseboard connector. Additionally the interrupt input has been reused for a different purpose on the KN04 and KN05 R4k CPU daughtercards so it is better kept masked. Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx> --- linux-dec-r4k-halt.patch Index: linux-20140404-4maxp64/arch/mips/dec/setup.c =================================================================== --- linux-20140404-4maxp64.orig/arch/mips/dec/setup.c +++ linux-20140404-4maxp64/arch/mips/dec/setup.c @@ -23,6 +23,7 @@ #include <asm/bootinfo.h> #include <asm/cpu.h> #include <asm/cpu-features.h> +#include <asm/cpu-type.h> #include <asm/irq.h> #include <asm/irq_cpu.h> #include <asm/mipsregs.h> @@ -748,6 +749,10 @@ void __init arch_init_irq(void) cpu_fpu_mask = 0; dec_interrupt[DEC_IRQ_FPU] = -1; } + /* Free the halt interrupt unused on R4k systems. */ + if (current_cpu_type() == CPU_R4000SC || + current_cpu_type() == CPU_R4400SC) + dec_interrupt[DEC_IRQ_HALT] = -1; /* Register board interrupts: FPU and cascade. */ if (dec_interrupt[DEC_IRQ_FPU] >= 0)
