diff options
Diffstat (limited to 'arch/powerpc/platforms/maple/time.c')
| -rw-r--r-- | arch/powerpc/platforms/maple/time.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/maple/time.c b/arch/powerpc/platforms/maple/time.c new file mode 100644 index 000000000..91606411d --- /dev/null +++ b/arch/powerpc/platforms/maple/time.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org), + * IBM Corp. + */ + +#undef DEBUG + +#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/pmu.h> +#include <linux/interrupt.h> +#include <linux/mc146818rtc.h> +#include <linux/bcd.h> +#include <linux/of_address.h> + +#include <asm/sections.h> +#include <asm/io.h> +#include <asm/machdep.h> +#include <asm/time.h> + +#include "maple.h" + +#ifdef DEBUG +#define DBG(x...) printk(x) +#else +#define DBG(x...) +#endif + +static int maple_rtc_addr; + +static int maple_clock_read(int addr) +{ + outb_p(addr, maple_rtc_addr); + return inb_p(maple_rtc_addr+1); +} + +static void maple_clock_write(unsigned long val, int addr) +{ + outb_p(addr, maple_rtc_addr); + outb_p(val, maple_rtc_addr+1); +} + +void maple_get_rtc_time(struct rtc_time *tm) +{ + do { + tm->tm_sec = maple_clock_read(RTC_SECONDS); + tm->tm_min = maple_clock_read(RTC_MINUTES); + tm->tm_hour = maple_clock_read(RTC_HOURS); + tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH); + tm->tm_mon = maple_clock_read(RTC_MONTH); + tm->tm_year = maple_clock_read(RTC_YEAR); + } while (tm->tm_sec != maple_clock_read(RTC_SECONDS)); + + if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY) + || RTC_ALWAYS_BCD) { + tm->tm_sec = bcd2bin(tm->tm_sec); + tm->tm_min = bcd2bin(tm->tm_min); + tm->tm_hour = bcd2bin(tm->tm_hour); + tm->tm_mday = bcd2bin(tm->tm_mday); + tm->tm_mon = bcd2bin(tm->tm_mon); + tm->tm_year = bcd2bin(tm->tm_year); + } + if ((tm->tm_year + 1900) < 1970) + tm->tm_year += 100; + + tm->tm_wday = -1; +} + +int maple_set_rtc_time(struct rtc_time *tm) +{ + unsigned char save_control, save_freq_select; + int sec, min, hour, mon, mday, year; + + spin_lock(&rtc_lock); + + save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */ + + maple_clock_write((save_control|RTC_SET), RTC_CONTROL); + + save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */ + + maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); + + sec = tm->tm_sec; + min = tm->tm_min; + hour = tm->tm_hour; + mon = tm->tm_mon; + mday = tm->tm_mday; + year = tm->tm_year; + + if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { + sec = bin2bcd(sec); + min = bin2bcd(min); + hour = bin2bcd(hour); + mon = bin2bcd(mon); + mday = bin2bcd(mday); + year = bin2bcd(year); + } + maple_clock_write(sec, RTC_SECONDS); + maple_clock_write(min, RTC_MINUTES); + maple_clock_write(hour, RTC_HOURS); + maple_clock_write(mon, RTC_MONTH); + maple_clock_write(mday, RTC_DAY_OF_MONTH); + maple_clock_write(year, RTC_YEAR); + + /* The following flags have to be released exactly in this order, + * otherwise the DS12887 (popular MC146818A clone with integrated + * battery and quartz) will not reset the oscillator and will not + * update precisely 500 ms later. You won't find this mentioned in + * the Dallas Semiconductor data sheets, but who believes data + * sheets anyway ... -- Markus Kuhn + */ + maple_clock_write(save_control, RTC_CONTROL); + maple_clock_write(save_freq_select, RTC_FREQ_SELECT); + + spin_unlock(&rtc_lock); + + return 0; +} + +static struct resource rtc_iores = { + .name = "rtc", + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +time64_t __init maple_get_boot_time(void) +{ + struct rtc_time tm; + struct device_node *rtcs; + + rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00"); + if (rtcs) { + struct resource r; + if (of_address_to_resource(rtcs, 0, &r)) { + printk(KERN_EMERG "Maple: Unable to translate RTC" + " address\n"); + goto bail; + } + if (!(r.flags & IORESOURCE_IO)) { + printk(KERN_EMERG "Maple: RTC address isn't PIO!\n"); + goto bail; + } + maple_rtc_addr = r.start; + printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n", + maple_rtc_addr); + } + bail: + of_node_put(rtcs); + if (maple_rtc_addr == 0) { + maple_rtc_addr = RTC_PORT(0); /* legacy address */ + printk(KERN_INFO "Maple: No device node for RTC, assuming " + "legacy address (0x%x)\n", maple_rtc_addr); + } + + rtc_iores.start = maple_rtc_addr; + rtc_iores.end = maple_rtc_addr + 7; + request_resource(&ioport_resource, &rtc_iores); + + maple_get_rtc_time(&tm); + return rtc_tm_to_time64(&tm); +} + |