diff options
| -rw-r--r-- | arch/alpha/Kconfig | 24 | ||||
| -rw-r--r-- | arch/alpha/include/asm/pal.h | 1 | ||||
| -rw-r--r-- | arch/alpha/include/uapi/asm/pal.h | 1 | ||||
| -rw-r--r-- | arch/alpha/kernel/process.c | 17 | ||||
| -rw-r--r-- | arch/alpha/kernel/traps.c | 15 |
5 files changed, 58 insertions, 0 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index a67b971c830a..f9e84da49716 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -586,6 +586,30 @@ config NUMA Access). This option is for configuring high-end multiprocessor server machines. If in doubt, say N. +config ALPHA_WTINT + bool "Use WTINT" if ALPHA_SRM || ALPHA_GENERIC + default y if ALPHA_QEMU + default n if ALPHA_EV5 || ALPHA_EV56 || (ALPHA_EV4 && !ALPHA_LCA) + default n if !ALPHA_SRM && !ALPHA_GENERIC + default y if SMP + ---help--- + The Wait for Interrupt (WTINT) PALcall attempts to place the CPU + to sleep until the next interrupt. This may reduce the power + consumed, and the heat produced by the computer. However, it has + the side effect of making the cycle counter unreliable as a timing + device across the sleep. + + For emulation under QEMU, definitely say Y here, as we have other + mechanisms for measuring time than the cycle counter. + + For EV4 (but not LCA), EV5 and EV56 systems, or for systems running + MILO, sleep mode is not supported so you might as well say N here. + + For SMP systems we cannot use the cycle counter for timing anyway, + so you might as well say Y here. + + If unsure, say N. + config NODES_SHIFT int default "7" diff --git a/arch/alpha/include/asm/pal.h b/arch/alpha/include/asm/pal.h index 6fcd2b5b08f0..e78ec9bcc768 100644 --- a/arch/alpha/include/asm/pal.h +++ b/arch/alpha/include/asm/pal.h @@ -89,6 +89,7 @@ __CALL_PAL_W1(wrmces, unsigned long); __CALL_PAL_RW2(wrperfmon, unsigned long, unsigned long, unsigned long); __CALL_PAL_W1(wrusp, unsigned long); __CALL_PAL_W1(wrvptptr, unsigned long); +__CALL_PAL_RW1(wtint, unsigned long, unsigned long); /* * TB routines.. diff --git a/arch/alpha/include/uapi/asm/pal.h b/arch/alpha/include/uapi/asm/pal.h index 3c0ce08e5f59..dfc8140b9088 100644 --- a/arch/alpha/include/uapi/asm/pal.h +++ b/arch/alpha/include/uapi/asm/pal.h @@ -46,6 +46,7 @@ #define PAL_rdusp 58 #define PAL_whami 60 #define PAL_retsys 61 +#define PAL_wtint 62 #define PAL_rti 63 diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c index f2360a74e5d5..1941a07b5811 100644 --- a/arch/alpha/kernel/process.c +++ b/arch/alpha/kernel/process.c @@ -46,6 +46,23 @@ void (*pm_power_off)(void) = machine_power_off; EXPORT_SYMBOL(pm_power_off); +#ifdef CONFIG_ALPHA_WTINT +/* + * Sleep the CPU. + * EV6, LCA45 and QEMU know how to power down, skipping N timer interrupts. + */ +void arch_cpu_idle(void) +{ + wtint(0); + local_irq_enable(); +} + +void arch_cpu_idle_dead(void) +{ + wtint(INT_MAX); +} +#endif /* ALPHA_WTINT */ + struct halt_info { int mode; char *restart_cmd; diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c index bd0665cdc840..9c4c189eb22f 100644 --- a/arch/alpha/kernel/traps.c +++ b/arch/alpha/kernel/traps.c @@ -241,6 +241,21 @@ do_entIF(unsigned long type, struct pt_regs *regs) (const char *)(data[1] | (long)data[2] << 32), data[0]); } +#ifdef CONFIG_ALPHA_WTINT + if (type == 4) { + /* If CALL_PAL WTINT is totally unsupported by the + PALcode, e.g. MILO, "emulate" it by overwriting + the insn. */ + unsigned int *pinsn + = (unsigned int *) regs->pc - 1; + if (*pinsn == PAL_wtint) { + *pinsn = 0x47e01400; /* mov 0,$0 */ + imb(); + regs->r0 = 0; + return; + } + } +#endif /* ALPHA_WTINT */ die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"), regs, type, NULL); } |