diff options
Diffstat (limited to 'arch/powerpc/platforms/powermac/pmac_time.c')
| -rw-r--r-- | arch/powerpc/platforms/powermac/pmac_time.c | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powermac/pmac_time.c b/arch/powerpc/platforms/powermac/pmac_time.c new file mode 100644 index 000000000000..ff6adff36cb8 --- /dev/null +++ b/arch/powerpc/platforms/powermac/pmac_time.c @@ -0,0 +1,291 @@ +/* + * Support for periodic interrupts (100 per second) and for getting + * the current time from the RTC on Power Macintoshes. + * + * We use the decrementer register for our periodic interrupts. + * + * Paul Mackerras August 1996. + * Copyright (C) 1996 Paul Mackerras. + */ +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/adb.h> +#include <linux/cuda.h> +#include <linux/pmu.h> +#include <linux/hardirq.h> + +#include <asm/sections.h> +#include <asm/prom.h> +#include <asm/system.h> +#include <asm/io.h> +#include <asm/pgtable.h> +#include <asm/machdep.h> +#include <asm/time.h> +#include <asm/nvram.h> + +/* Apparently the RTC stores seconds since 1 Jan 1904 */ +#define RTC_OFFSET 2082844800 + +/* + * Calibrate the decrementer frequency with the VIA timer 1. + */ +#define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ + +/* VIA registers */ +#define RS 0x200 /* skip between registers */ +#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ +#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ +#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ +#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ +#define ACR (11*RS) /* Auxiliary control register */ +#define IFR (13*RS) /* Interrupt flag register */ + +/* Bits in ACR */ +#define T1MODE 0xc0 /* Timer 1 mode */ +#define T1MODE_CONT 0x40 /* continuous interrupts */ + +/* Bits in IFR and IER */ +#define T1_INT 0x40 /* Timer 1 interrupt */ + +extern struct timezone sys_tz; + +long __init +pmac_time_init(void) +{ +#ifdef CONFIG_NVRAM + s32 delta = 0; + int dst; + + delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; + delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; + delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); + if (delta & 0x00800000UL) + delta |= 0xFF000000UL; + dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); + printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, + dst ? "on" : "off"); + return delta; +#else + return 0; +#endif +} + +unsigned long +pmac_get_rtc_time(void) +{ +#if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) + struct adb_request req; + unsigned long now; +#endif + + /* Get the time from the RTC */ + switch (sys_ctrler) { +#ifdef CONFIG_ADB_CUDA + case SYS_CTRLER_CUDA: + if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0) + return 0; + while (!req.complete) + cuda_poll(); + if (req.reply_len != 7) + printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", + req.reply_len); + now = (req.reply[3] << 24) + (req.reply[4] << 16) + + (req.reply[5] << 8) + req.reply[6]; + return now - RTC_OFFSET; +#endif /* CONFIG_ADB_CUDA */ +#ifdef CONFIG_ADB_PMU + case SYS_CTRLER_PMU: + if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0) + return 0; + while (!req.complete) + pmu_poll(); + if (req.reply_len != 4) + printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", + req.reply_len); + now = (req.reply[0] << 24) + (req.reply[1] << 16) + + (req.reply[2] << 8) + req.reply[3]; + return now - RTC_OFFSET; +#endif /* CONFIG_ADB_PMU */ + default: ; + } + return 0; +} + +int +pmac_set_rtc_time(unsigned long nowtime) +{ +#if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) + struct adb_request req; +#endif + + nowtime += RTC_OFFSET; + + switch (sys_ctrler) { +#ifdef CONFIG_ADB_CUDA + case SYS_CTRLER_CUDA: + if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME, + nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0) + return 0; + while (!req.complete) + cuda_poll(); + if ((req.reply_len != 3) && (req.reply_len != 7)) + printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n", + req.reply_len); + return 1; +#endif /* CONFIG_ADB_CUDA */ +#ifdef CONFIG_ADB_PMU + case SYS_CTRLER_PMU: + if (pmu_request(&req, NULL, 5, PMU_SET_RTC, + nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0) + return 0; + while (!req.complete) + pmu_poll(); + if (req.reply_len != 0) + printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n", + req.reply_len); + return 1; +#endif /* CONFIG_ADB_PMU */ + default: + return 0; + } +} + +/* + * Calibrate the decrementer register using VIA timer 1. + * This is used both on powermacs and CHRP machines. + */ +int __init +via_calibrate_decr(void) +{ + struct device_node *vias; + volatile unsigned char __iomem *via; + int count = VIA_TIMER_FREQ_6 / 100; + unsigned int dstart, dend; + + vias = find_devices("via-cuda"); + if (vias == 0) + vias = find_devices("via-pmu"); + if (vias == 0) + vias = find_devices("via"); + if (vias == 0 || vias->n_addrs == 0) + return 0; + via = ioremap(vias->addrs[0].address, vias->addrs[0].size); + + /* set timer 1 for continuous interrupts */ + out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); + /* set the counter to a small value */ + out_8(&via[T1CH], 2); + /* set the latch to `count' */ + out_8(&via[T1LL], count); + out_8(&via[T1LH], count >> 8); + /* wait until it hits 0 */ + while ((in_8(&via[IFR]) & T1_INT) == 0) + ; + dstart = get_dec(); + /* clear the interrupt & wait until it hits 0 again */ + in_8(&via[T1CL]); + while ((in_8(&via[IFR]) & T1_INT) == 0) + ; + dend = get_dec(); + + tb_ticks_per_jiffy = (dstart - dend) / (6 * (HZ/100)); + tb_to_us = mulhwu_scale_factor(dstart - dend, 60000); + + printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n", + tb_ticks_per_jiffy, dstart - dend); + + iounmap(via); + + return 1; +} + +#ifdef CONFIG_PM +/* + * Reset the time after a sleep. + */ +static int +time_sleep_notify(struct pmu_sleep_notifier *self, int when) +{ + static unsigned long time_diff; + unsigned long flags; + unsigned long seq; + + switch (when) { + case PBOOK_SLEEP_NOW: + do { + seq = read_seqbegin_irqsave(&xtime_lock, flags); + time_diff = xtime.tv_sec - pmac_get_rtc_time(); + } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); + break; + case PBOOK_WAKE: + write_seqlock_irqsave(&xtime_lock, flags); + xtime.tv_sec = pmac_get_rtc_time() + time_diff; + xtime.tv_nsec = 0; + last_rtc_update = xtime.tv_sec; + write_sequnlock_irqrestore(&xtime_lock, flags); + break; + } + return PBOOK_SLEEP_OK; +} + +static struct pmu_sleep_notifier time_sleep_notifier = { + time_sleep_notify, SLEEP_LEVEL_MISC, +}; +#endif /* CONFIG_PM */ + +/* + * Query the OF and get the decr frequency. + * This was taken from the pmac time_init() when merging the prep/pmac + * time functions. + */ +void __init +pmac_calibrate_decr(void) +{ + struct device_node *cpu; + unsigned int freq, *fp; + +#ifdef CONFIG_PM + pmu_register_sleep_notifier(&time_sleep_notifier); +#endif /* CONFIG_PM */ + + /* We assume MacRISC2 machines have correct device-tree + * calibration. That's better since the VIA itself seems + * to be slightly off. --BenH + */ + if (!machine_is_compatible("MacRISC2") && + !machine_is_compatible("MacRISC3") && + !machine_is_compatible("MacRISC4")) + if (via_calibrate_decr()) + return; + + /* Special case: QuickSilver G4s seem to have a badly calibrated + * timebase-frequency in OF, VIA is much better on these. We should + * probably implement calibration based on the KL timer on these + * machines anyway... -BenH + */ + if (machine_is_compatible("PowerMac3,5")) + if (via_calibrate_decr()) + return; + /* + * The cpu node should have a timebase-frequency property + * to tell us the rate at which the decrementer counts. + */ + cpu = find_type_devices("cpu"); + if (cpu == 0) + panic("can't find cpu node in time_init"); + fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL); + if (fp == 0) + panic("can't get cpu timebase frequency"); + freq = *fp; + printk("time_init: decrementer frequency = %u.%.6u MHz\n", + freq/1000000, freq%1000000); + tb_ticks_per_jiffy = freq / HZ; + tb_to_us = mulhwu_scale_factor(freq, 1000000); +} |