diff options
| -rw-r--r-- | arch/alpha/Kconfig | 36 | ||||
| -rw-r--r-- | arch/alpha/kernel/setup.c | 10 | ||||
| -rw-r--r-- | arch/alpha/kernel/time.c | 24 |
3 files changed, 59 insertions, 11 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 51cc8c35316..a67b971c830 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -627,9 +627,41 @@ config VERBOSE_MCHECK_ON Take the default (1) unless you want more control or more info. +choice + prompt "Timer interrupt frequency (HZ)?" + default HZ_128 if ALPHA_QEMU + default HZ_1200 if ALPHA_RAWHIDE + default HZ_1024 + ---help--- + The frequency at which timer interrupts occur. A high frequency + minimizes latency, whereas a low frequency minimizes overhead of + process accounting. The later effect is especially significant + when being run under QEMU. + + Note that some Alpha hardware cannot change the interrupt frequency + of the timer. If unsure, say 1024 (or 1200 for Rawhide). + + config HZ_32 + bool "32 Hz" + config HZ_64 + bool "64 Hz" + config HZ_128 + bool "128 Hz" + config HZ_256 + bool "256 Hz" + config HZ_1024 + bool "1024 Hz" + config HZ_1200 + bool "1200 Hz" +endchoice + config HZ - int - default 1200 if ALPHA_RAWHIDE + int + default 32 if HZ_32 + default 64 if HZ_64 + default 128 if HZ_128 + default 256 if HZ_256 + default 1200 if HZ_1200 default 1024 source "drivers/pci/Kconfig" diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index c38d6a1b906..b20af76f12c 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -1218,6 +1218,7 @@ show_cpuinfo(struct seq_file *f, void *slot) char *systype_name; char *sysvariation_name; int nr_processors; + unsigned long timer_freq; cpu_index = (unsigned) (cpu->type - 1); cpu_name = "Unknown"; @@ -1229,6 +1230,12 @@ show_cpuinfo(struct seq_file *f, void *slot) nr_processors = get_nr_processors(cpu, hwrpb->nr_processors); +#if CONFIG_HZ == 1024 || CONFIG_HZ == 1200 + timer_freq = (100UL * hwrpb->intr_freq) / 4096; +#else + timer_freq = 100UL * CONFIG_HZ; +#endif + seq_printf(f, "cpu\t\t\t: Alpha\n" "cpu model\t\t: %s\n" "cpu variation\t\t: %ld\n" @@ -1254,8 +1261,7 @@ show_cpuinfo(struct seq_file *f, void *slot) (char*)hwrpb->ssn, est_cycle_freq ? : hwrpb->cycle_freq, est_cycle_freq ? "est." : "", - hwrpb->intr_freq / 4096, - (100 * hwrpb->intr_freq / 4096) % 100, + timer_freq / 100, timer_freq % 100, hwrpb->pagesize, hwrpb->pa_bits, hwrpb->max_asn, diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c index ea339503655..a6bcb3113d8 100644 --- a/arch/alpha/kernel/time.c +++ b/arch/alpha/kernel/time.c @@ -201,16 +201,26 @@ irqreturn_t timer_interrupt(int irq, void *dev) void __init common_init_rtc(void) { - unsigned char x; + unsigned char x, sel = 0; /* Reset periodic interrupt frequency. */ - x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f; - /* Test includes known working values on various platforms - where 0x26 is wrong; we refuse to change those. */ - if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) { - printk("Setting RTC_FREQ to 1024 Hz (%x)\n", x); - CMOS_WRITE(0x26, RTC_FREQ_SELECT); +#if CONFIG_HZ == 1024 || CONFIG_HZ == 1200 + x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f; + /* Test includes known working values on various platforms + where 0x26 is wrong; we refuse to change those. */ + if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) { + sel = RTC_REF_CLCK_32KHZ + 6; } +#elif CONFIG_HZ == 256 || CONFIG_HZ == 128 || CONFIG_HZ == 64 || CONFIG_HZ == 32 + sel = RTC_REF_CLCK_32KHZ + __builtin_ffs(32768 / CONFIG_HZ); +#else +# error "Unknown HZ from arch/alpha/Kconfig" +#endif + if (sel) { + printk(KERN_INFO "Setting RTC_FREQ to %d Hz (%x)\n", + CONFIG_HZ, sel); + CMOS_WRITE(sel, RTC_FREQ_SELECT); + } /* Turn on periodic interrupts. */ x = CMOS_READ(RTC_CONTROL); |