Initial source

1 files changed, 236 insertions, 0 deletions

diff --git a/i386/i386/pit.c b/i386/i386/pit.c
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+/* 
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989 Carnegie Mellon University
+ * Copyright (c) 1991 IBM Corporation 
+ * 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,
+ * and that the name IBM not be used in advertising or publicity 
+ * pertaining to distribution of the software without specific, written
+ * prior permission.
+ * 
+ * CARNEGIE MELLON AND IBM ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON AND IBM DISCLAIM 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.
+ */
+/*
+  Copyright 1988, 1989 by Intel Corporation, Santa Clara, California.
+
+		All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby
+granted, provided that the above copyright notice appears in all
+copies and that both the copyright notice and this permission notice
+appear in supporting documentation, and that the name of Intel
+not be used in advertising or publicity pertaining to distribution
+of the software without specific, written prior permission.
+
+INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
+IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
+NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
+WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <platforms.h>
+#include <kern/time_out.h>
+#include <i386/ipl.h>
+#include <i386/pit.h>
+
+int pitctl_port  = PITCTL_PORT;		/* For 386/20 Board */
+int pitctr0_port = PITCTR0_PORT;	/* For 386/20 Board */
+int pitctr1_port = PITCTR1_PORT;	/* For 386/20 Board */
+int pitctr2_port = PITCTR2_PORT;	/* For 386/20 Board */
+/* We want PIT 0 in square wave mode */
+
+int pit0_mode = PIT_C0|PIT_SQUAREMODE|PIT_READMODE ;
+
+
+unsigned int delaycount;		/* loop count in trying to delay for
+					 * 1 millisecond
+					 */
+unsigned long microdata=50;		/* loop count for 10 microsecond wait.
+					   MUST be initialized for those who
+					   insist on calling "tenmicrosec"
+					   it before the clock has been
+					   initialized.
+					 */
+unsigned int clknumb = CLKNUM;		/* interrupt interval for timer 0 */
+
+#ifdef PS2
+extern int clock_int_handler();
+
+#include <sys/types.h>
+#include <i386ps2/abios.h>
+static struct generic_request *clock_request_block;
+static int     clock_flags;
+char cqbuf[200];        /*XXX temporary.. should use kmem_alloc or whatever..*/
+#endif  /* PS2 */
+
+clkstart()
+{
+	unsigned int	flags;
+	unsigned char	byte;
+	int s;
+
+	intpri[0] = SPLHI;
+	form_pic_mask();
+
+	findspeed();
+	microfind();
+	s = sploff();         /* disable interrupts */
+
+#ifdef	PS2
+        abios_clock_start();
+#endif /* PS2 */
+
+	/* Since we use only timer 0, we program that.
+	 * 8254 Manual specifically says you do not need to program
+	 * timers you do not use
+	 */
+	outb(pitctl_port, pit0_mode);
+	clknumb = CLKNUM/hz;
+	byte = clknumb;
+	outb(pitctr0_port, byte);
+	byte = clknumb>>8;
+	outb(pitctr0_port, byte); 
+	splon(s);         /* restore interrupt state */
+}
+
+#define COUNT   10000   /* should be a multiple of 1000! */
+
+findspeed()
+{
+	unsigned int flags;
+	unsigned char byte;
+	unsigned int leftover;
+	int i;
+	int j;
+	int s;
+
+	s = sploff();                 /* disable interrupts */
+	/* Put counter in count down mode */
+#define PIT_COUNTDOWN PIT_READMODE|PIT_NDIVMODE
+	outb(pitctl_port, PIT_COUNTDOWN);
+	/* output a count of -1 to counter 0 */
+	outb(pitctr0_port, 0xff);
+	outb(pitctr0_port, 0xff);
+	delaycount = COUNT;
+	spinwait(1);
+	/* Read the value left in the counter */
+	byte = inb(pitctr0_port);	/* least siginifcant */
+	leftover = inb(pitctr0_port);	/* most significant */
+	leftover = (leftover<<8) + byte ;
+	/* Formula for delaycount is :
+	 *  (loopcount * timer clock speed)/ (counter ticks * 1000)
+	 * 1000 is for figuring out milliseconds 
+	 */
+        /* we arrange calculation so that it doesn't overflow */
+        delaycount = ((COUNT/1000) * CLKNUM) / (0xffff-leftover);
+        printf("findspeed: delaycount=%d (tics=%d)\n",
+	       delaycount, (0xffff-leftover));
+	splon(s);         /* restore interrupt state */
+}
+
+#ifdef PS2
+
+abios_clock_start()
+{
+        struct generic_request  temp_request_block;
+        int rc;
+
+        nmi_enable();   /* has to happen somewhere! */
+        temp_request_block.r_current_req_blck_len = ABIOS_MIN_REQ_SIZE;
+        temp_request_block.r_logical_id = abios_next_LID(SYSTIME_ID,
+                                                        ABIOS_FIRST_LID);
+        temp_request_block.r_unit = 0;
+        temp_request_block.r_function = ABIOS_LOGICAL_PARAMETER;
+        temp_request_block.r_return_code = ABIOS_UNDEFINED;
+
+        abios_common_start(&temp_request_block,0);
+        if (temp_request_block.r_return_code != ABIOS_DONE) {
+                panic("couldn init abios time code!\n");
+	      }
+
+        /*
+         * now build the clock request for the hardware system clock
+         */
+        clock_request_block = (struct generic_request *)cqbuf;
+        clock_request_block->r_current_req_blck_len =
+                                temp_request_block.r_request_block_length;
+        clock_request_block->r_logical_id = temp_request_block.r_logical_id;
+        clock_request_block->r_unit = 0;
+        clock_request_block->r_function = ABIOS_DEFAULT_INTERRUPT;
+        clock_request_block->r_return_code = ABIOS_UNDEFINED;
+        clock_flags = temp_request_block.r_logical_id_flags;
+}
+
+ackrtclock()
+{
+        if (clock_request_block) {
+	  clock_request_block->r_return_code = ABIOS_UNDEFINED;
+	  abios_common_interrupt(clock_request_block,clock_flags);
+	}
+      }
+#endif /* PS2 */
+
+
+spinwait(millis)
+	int millis;		/* number of milliseconds to delay */
+{
+	int i, j;
+
+	for (i=0;i<millis;i++)
+		for (j=0;j<delaycount;j++)
+			;
+}
+
+#define MICROCOUNT      1000    /* keep small to prevent overflow */
+microfind()
+{
+	unsigned int flags;
+	unsigned char byte;
+	unsigned short leftover;
+	int s;
+
+
+	s = sploff();                 /* disable interrupts */
+
+	/* Put counter in count down mode */
+	outb(pitctl_port, PIT_COUNTDOWN);
+	/* output a count of -1 to counter 0 */
+	outb(pitctr0_port, 0xff);
+	outb(pitctr0_port, 0xff);
+	microdata=MICROCOUNT;
+	tenmicrosec();
+	/* Read the value left in the counter */
+	byte = inb(pitctr0_port);	/* least siginifcant */
+	leftover = inb(pitctr0_port);	/* most significant */
+	leftover = (leftover<<8) + byte ;
+	/* Formula for delaycount is :
+	 *  (loopcount * timer clock speed)/ (counter ticks * 1000)
+	 *  Note also that 1000 is for figuring out milliseconds
+	 */
+        microdata = (MICROCOUNT * CLKNUM) / ((0xffff-leftover)*100000);
+	if (!microdata)
+		microdata++;
+
+	splon(s);         /* restore interrupt state */
+}