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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/mips-boards/generic/time.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+/*
+ * Carsten Langgaard, carstenl@mips.com
+ * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Setting up the clock on the MIPS boards.
+ */
+
+#include <linux/types.h>
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+#include <linux/mc146818rtc.h>
+
+#include <asm/mipsregs.h>
+#include <asm/ptrace.h>
+#include <asm/div64.h>
+#include <asm/cpu.h>
+#include <asm/time.h>
+#include <asm/mc146818-time.h>
+
+#include <asm/mips-boards/generic.h>
+#include <asm/mips-boards/prom.h>
+
+unsigned long cpu_khz;
+
+#if defined(CONFIG_MIPS_SEAD)
+#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ5)
+#else
+#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5)
+#endif
+
+#if defined(CONFIG_MIPS_ATLAS)
+static char display_string[] = " LINUX ON ATLAS ";
+#endif
+#if defined(CONFIG_MIPS_MALTA)
+static char display_string[] = " LINUX ON MALTA ";
+#endif
+#if defined(CONFIG_MIPS_SEAD)
+static char display_string[] = " LINUX ON SEAD ";
+#endif
+static unsigned int display_count = 0;
+#define MAX_DISPLAY_COUNT (sizeof(display_string) - 8)
+
+#define MIPS_CPU_TIMER_IRQ (NR_IRQS-1)
+
+static unsigned int timer_tick_count=0;
+
+void mips_timer_interrupt(struct pt_regs *regs)
+{
+ if ((timer_tick_count++ % HZ) == 0) {
+ mips_display_message(&display_string[display_count++]);
+ if (display_count == MAX_DISPLAY_COUNT)
+ display_count = 0;
+
+ }
+
+ ll_timer_interrupt(MIPS_CPU_TIMER_IRQ, regs);
+}
+
+/*
+ * Estimate CPU frequency. Sets mips_counter_frequency as a side-effect
+ */
+static unsigned int __init estimate_cpu_frequency(void)
+{
+ unsigned int prid = read_c0_prid() & 0xffff00;
+ unsigned int count;
+
+#ifdef CONFIG_MIPS_SEAD
+ /*
+ * The SEAD board doesn't have a real time clock, so we can't
+ * really calculate the timer frequency
+ * For now we hardwire the SEAD board frequency to 12MHz.
+ */
+
+ if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
+ (prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
+ count = 12000000;
+ else
+ count = 6000000;
+#endif
+#if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA)
+ unsigned int flags;
+
+ local_irq_save(flags);
+
+ /* Start counter exactly on falling edge of update flag */
+ while (CMOS_READ(RTC_REG_A) & RTC_UIP);
+ while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
+
+ /* Start r4k counter. */
+ write_c0_count(0);
+
+ /* Read counter exactly on falling edge of update flag */
+ while (CMOS_READ(RTC_REG_A) & RTC_UIP);
+ while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
+
+ count = read_c0_count();
+
+ /* restore interrupts */
+ local_irq_restore(flags);
+#endif
+
+ mips_hpt_frequency = count;
+ if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
+ (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
+ count *= 2;
+
+ count += 5000; /* round */
+ count -= count%10000;
+
+ return count;
+}
+
+unsigned long __init mips_rtc_get_time(void)
+{
+ return mc146818_get_cmos_time();
+}
+
+void __init mips_time_init(void)
+{
+ unsigned int est_freq, flags;
+
+ local_irq_save(flags);
+
+#if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA)
+ /* Set Data mode - binary. */
+ CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
+#endif
+
+ est_freq = estimate_cpu_frequency ();
+
+ printk("CPU frequency %d.%02d MHz\n", est_freq/1000000,
+ (est_freq%1000000)*100/1000000);
+
+ cpu_khz = est_freq / 1000;
+
+ local_irq_restore(flags);
+}
+
+void __init mips_timer_setup(struct irqaction *irq)
+{
+ /* we are using the cpu counter for timer interrupts */
+ irq->handler = no_action; /* we use our own handler */
+ setup_irq(MIPS_CPU_TIMER_IRQ, irq);
+
+ /* to generate the first timer interrupt */
+ write_c0_compare (read_c0_count() + mips_hpt_frequency/HZ);
+ set_c0_status(ALLINTS);
+}