summaryrefslogtreecommitdiff
path: root/chips/mc_clock.c
diff options
context:
space:
mode:
Diffstat (limited to 'chips/mc_clock.c')
-rw-r--r--chips/mc_clock.c516
1 files changed, 516 insertions, 0 deletions
diff --git a/chips/mc_clock.c b/chips/mc_clock.c
new file mode 100644
index 0000000..15fa049
--- /dev/null
+++ b/chips/mc_clock.c
@@ -0,0 +1,516 @@
+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ * File: mc_clock.c
+ * Author: Alessandro Forin
+ * Date: 8/90
+ *
+ * Driver for the MC146818 Clock
+ */
+
+#include <mc.h>
+#if NMC > 0
+#include <platforms.h>
+
+#include <mach/std_types.h>
+#include <machine/machspl.h> /* spl definitions */
+#include <chips/busses.h>
+
+#include <sys/time.h>
+#include <kern/time_out.h>
+#include <chips/mc_clock.h>
+
+#ifdef DECSTATION
+#include <mips/mips_cpu.h>
+#include <mips/clock.h>
+#endif /*DECSTATION*/
+
+#ifdef FLAMINGO
+#include <alpha/clock.h>
+#endif /*FLAMINGO*/
+
+#define private static
+#define public
+
+
+/* Architecture-specific defines */
+
+#ifdef DECSTATION
+
+#define MC_DEFAULT_ADDRESS (mc_clock_ram_t *)PHYS_TO_K1SEG(0x1d000000)
+#define MC_DOES_DELAYS 1
+
+/*
+ * Both the Pmax and the 3max implementations of the chip map
+ * bytes of the chip's RAM to 32 bit words (low byte).
+ * For convenience, we redefine here the chip's RAM layout
+ * making padding explicit.
+ */
+
+typedef struct {
+ volatile unsigned char mc_second;
+ char pad0[3];
+ volatile unsigned char mc_alarm_second;
+ char pad1[3];
+ volatile unsigned char mc_minute;
+ char pad2[3];
+ volatile unsigned char mc_alarm_minute;
+ char pad3[3];
+ volatile unsigned char mc_hour;
+ char pad4[3];
+ volatile unsigned char mc_alarm_hour;
+ char pad5[3];
+ volatile unsigned char mc_day_of_week;
+ char pad6[3];
+ volatile unsigned char mc_day_of_month;
+ char pad7[3];
+ volatile unsigned char mc_month;
+ char pad8[3];
+ volatile unsigned char mc_year;
+ char pad9[3];
+ volatile unsigned char mc_register_A;
+ char pad10[3];
+ volatile unsigned char mc_register_B;
+ char pad11[3];
+ volatile unsigned char mc_register_C;
+ char pad12[3];
+ volatile unsigned char mc_register_D;
+ char pad13[3];
+ unsigned char mc_non_volatile_ram[50 * 4]; /* unused */
+} mc_clock_ram_t;
+
+#define MC_CLOCK_PADDED 1
+
+#endif /*DECSTATION*/
+
+
+#ifdef FLAMINGO
+#define MC_DEFAULT_ADDRESS 0L
+
+/* padded, later */
+
+#endif /* FLAMINGO */
+
+
+
+#ifndef MC_CLOCK_PADDED
+typedef mc_clock_t mc_clock_ram_t; /* No padding needed */
+#endif
+
+/*
+ * Functions provided herein
+ */
+int mc_probe( vm_offset_t addr, struct bus_ctlr * );
+private void mc_attach();
+
+int mc_intr();
+
+void mc_open(), mc_close(), mc_write();
+private unsigned int mc_read();
+
+private void mc_wait_for_uip( mc_clock_ram_t *clock );
+
+
+/*
+ * Status
+ */
+boolean_t mc_running = FALSE;
+boolean_t mc_new_century = FALSE; /* "year" info overfloweth */
+
+private int days_per_month[12] = {
+ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+private unsigned int mc_read(); /* forward */
+private void mc_wait_for_uip();
+
+/*
+ * Where is the chip's RAM mapped
+ */
+private mc_clock_ram_t *rt_clock = MC_DEFAULT_ADDRESS;
+
+/*
+ * (Auto?)Configuration
+ */
+private vm_offset_t mc_std[NMC] = { 0 };
+private struct bus_device *mc_info[NMC];
+
+struct bus_driver mc_driver =
+ { mc_probe, 0, mc_attach, 0, mc_std, "mc", mc_info, };
+
+
+mc_probe(vm_offset_t addr, struct bus_ctlr *ui)
+{
+ rt_clock = (mc_clock_ram_t *)addr;
+ return 1;
+}
+
+private void
+mc_attach()
+{
+ printf(": MC146818 or like Time-Of-Year chip");
+}
+
+/*
+ * Interrupt routine
+ */
+#if MC_DOES_DELAYS
+
+private int config_step = 3;
+private volatile int had_intr;
+
+mc_intr(spllevel)
+ spl_t spllevel;
+{
+ /*
+ * Interrupt flags are read-to-clear.
+ */
+ if (config_step > 2)
+ return (rt_clock->mc_register_C & MC_REG_C_IRQF);
+ had_intr = (rt_clock->mc_register_C & MC_REG_C_IRQF) ? 1 : 0;
+ if (config_step++ == 0)
+ accurate_config_delay(spllevel);
+ return had_intr;
+}
+#else /* MC_DOES_DELAYS */
+
+mc_intr()
+{
+ return (rt_clock->mc_register_C); /* clear intr */
+}
+
+#endif /* MC_DOES_DELAYS */
+
+/*
+ * Start real-time clock.
+ */
+void
+mc_open()
+{
+ /*
+ * All we should need to do is to enable interrupts, but
+ * since we do not know what OS last ran on this box
+ * we'll reset it all over again. Just kidding..
+ */
+ unsigned unix_seconds_now;
+
+ /*
+ * Check for battery backup power. If we do not have it,
+ * warn the user. Time will be bogus only after power up.
+ */
+ if ((rt_clock->mc_register_D & MC_REG_D_VRT) == 0)
+ printf("WARNING: clock batteries are low\n");
+
+ /*
+ * Read the current time settings, check if the year info
+ * has been screwed up.
+ */
+ unix_seconds_now = mc_read();
+
+ if (unix_seconds_now < (SECYR * (1990 - YRREF)))
+ printf("The prom has clobbered the clock\n");
+
+ time.tv_sec = (long)unix_seconds_now;
+ mc_write();
+
+ mc_running = TRUE;
+}
+
+void
+mc_close()
+{
+ /*
+ * Disable interrupts, but keep the chip running.
+ * Note we are called at splhigh and an interrupt
+ * might be pending already.
+ */
+
+ mc_intr(0);
+ rt_clock->mc_register_B &= ~(MC_REG_B_UIE|MC_REG_B_AIE|MC_REG_B_PIE);
+ mc_running = FALSE;
+#if MC_DOES_DELAYS
+ config_step = 0;
+#endif
+}
+
+
+/*
+ * Set time-of-day. Must be called at splhigh()
+ */
+void
+mc_write()
+{
+ register mc_clock_ram_t *clock = rt_clock;
+ register unsigned years, months, days, hours, minutes, seconds;
+ register unsigned unix_seconds = time.tv_sec;
+ int frequence_selector, temp;
+ int bogus_hz = 0;
+
+ /*
+ * Convert U*x time into absolute time
+ */
+
+ years = YRREF;
+ while (1) {
+ seconds = SECYR;
+ if (LEAPYEAR(years))
+ seconds += SECDAY;
+ if (unix_seconds < seconds)
+ break;
+ unix_seconds -= seconds;
+ years++;
+ }
+
+ months = 0;
+ while (1) {
+ seconds = days_per_month[months++] * SECDAY;
+ if (months == 2 /* February */ && LEAPYEAR(years))
+ seconds += SECDAY;
+ if (unix_seconds < seconds)
+ break;
+ unix_seconds -= seconds;
+ }
+
+ days = unix_seconds / SECDAY;
+ unix_seconds -= SECDAY * days++;
+
+ hours = unix_seconds / SECHOUR;
+ unix_seconds -= SECHOUR * hours;
+
+ minutes = unix_seconds / SECMIN;
+ unix_seconds -= SECMIN * minutes;
+
+ seconds = unix_seconds;
+
+ /*
+ * Trim years into 0-99 range.
+ */
+ if ((years -= 1900) > 99) {
+ years -= 100;
+ mc_new_century = TRUE;
+ }
+
+ /*
+ * Check for "hot dates"
+ */
+ if (days >= 28 && days <= 30 &&
+ hours == 23 && minutes == 59 &&
+ seconds >= 58)
+ seconds = 57;
+
+ /*
+ * Select the interrupt frequency based on system params
+ */
+ switch (hz) {
+ case 1024:
+ frequence_selector = MC_BASE_32_KHz | MC_RATE_1024_Hz;
+ break;
+ case 512:
+ frequence_selector = MC_BASE_32_KHz | MC_RATE_512_Hz;
+ break;
+ case 256:
+ frequence_selector = MC_BASE_32_KHz | MC_RATE_256_Hz;
+ break;
+ case 128:
+ frequence_selector = MC_BASE_32_KHz | MC_RATE_128_Hz;
+ break;
+ case 64:
+default_frequence:
+ frequence_selector = MC_BASE_32_KHz | MC_RATE_64_Hz;
+ break;
+ default:
+ bogus_hz = hz;
+ hz = 64;
+ tick = 1000000 / 64;
+ goto default_frequence;
+ }
+
+ /*
+ * Stop updates while we fix it
+ */
+ mc_wait_for_uip(clock);
+ clock->mc_register_B = MC_REG_B_STOP;
+ wbflush();
+
+ /*
+ * Ack any pending interrupts
+ */
+ temp = clock->mc_register_C;
+
+ /*
+ * Reset the frequency divider, in case we are changing it.
+ */
+ clock->mc_register_A = MC_BASE_RESET;
+
+ /*
+ * Now update the time
+ */
+ clock->mc_second = seconds;
+ clock->mc_minute = minutes;
+ clock->mc_hour = hours;
+ clock->mc_day_of_month = days;
+ clock->mc_month = months;
+ clock->mc_year = years;
+
+ /*
+ * Spec says the VRT bit can be validated, but does not say how. I
+ * assume it is via reading the register.
+ */
+ temp = clock->mc_register_D;
+
+ /*
+ * Reconfigure the chip and get it started again
+ */
+ clock->mc_register_A = frequence_selector;
+ clock->mc_register_B = MC_REG_B_24HM | MC_REG_B_DM | MC_REG_B_PIE;
+
+ /*
+ * Print warnings, if we have to
+ */
+ if (bogus_hz != 0)
+ printf("Unacceptable value (%d Hz) for hz, reset to %d Hz\n",
+ bogus_hz, hz);
+}
+
+
+/*
+ * Internal functions
+ */
+
+private void
+mc_wait_for_uip(clock)
+ mc_clock_ram_t *clock;
+{
+ while (clock->mc_register_A & MC_REG_A_UIP)
+ delay(MC_UPD_MINIMUM >> 2);
+}
+
+private unsigned int
+mc_read()
+{
+ /*
+ * Note we only do this at boot time
+ */
+ register unsigned years, months, days, hours, minutes, seconds;
+ register mc_clock_ram_t *clock = rt_clock;;
+
+ /*
+ * If the chip is updating, wait
+ */
+ mc_wait_for_uip(clock);
+
+ years = clock->mc_year;
+ months = clock->mc_month;
+ days = clock->mc_day_of_month;
+ hours = clock->mc_hour;
+ minutes = clock->mc_minute;
+ seconds = clock->mc_second;
+
+ /*
+ * Convert to Unix time
+ */
+ seconds += minutes * SECMIN;
+ seconds += hours * SECHOUR;
+ seconds += (days - 1) * SECDAY;
+ if (months > 2 /* February */ && LEAPYEAR(years))
+ seconds += SECDAY;
+ while (months > 1)
+ seconds += days_per_month[--months - 1];
+
+ /*
+ * Note that in ten years from today (Aug,1990) the new century will
+ * cause the trouble that mc_new_century attempts to avoid.
+ */
+ if (mc_new_century)
+ years += 100;
+ years += 1900; /* chip base year in YRREF's century */
+
+ for (--years; years >= YRREF; years--) {
+ seconds += SECYR;
+ if (LEAPYEAR(years))
+ seconds += SECDAY;
+ }
+
+ return seconds;
+}
+
+#ifdef MC_DOES_DELAYS
+
+/*
+ * Timed delays
+ */
+extern unsigned int cpu_speed;
+
+void
+config_delay(speed)
+{
+ /*
+ * This is just an initial estimate, later on with the clock
+ * running we'll tune it more accurately.
+ */
+ cpu_speed = speed;
+}
+
+accurate_config_delay(spllevel)
+ spl_t spllevel;
+{
+ register unsigned int i;
+ register spl_t s;
+ int inner_loop_count;
+
+#ifdef mips
+ /* find "spllevel - 1" */
+ s = spllevel | ((spllevel >> 1) & SR_INT_MASK);
+ splx(s);
+#else
+#endif
+
+ /* wait till we have an interrupt pending */
+ had_intr = 0;
+ while (!had_intr)
+ continue;
+
+ had_intr = 0;
+ i = delay_timing_function(1, &had_intr, &inner_loop_count);
+
+ splx(spllevel);
+
+ i *= hz;
+ cpu_speed = i / (inner_loop_count * 1000000);
+
+ /* roundup clock speed */
+ i /= 100000;
+ if ((i % 10) >= 5)
+ i += 5;
+ printf("Estimating CPU clock at %d Mhz\n", i / 10);
+ if (isa_pmax() && cpu_speed != MC_DELAY_PMAX) {
+ printf("%s\n", "This machine looks like a DEC 2100");
+ machine_slot[cpu_number()].cpu_subtype = CPU_SUBTYPE_MIPS_R2000;
+ }
+}
+#endif /* MC_DOES_DELAYS */
+
+#endif NMC > 0
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-28 22:15:34 +0000