[PATCH] add pit timer for m68knommu/5282 CPU support

This code supports the PIT timer of the 5282 ColdFire.

This new timer device is completely different to the previous ColdFire
timer device.

arch/m68knommu/platform/5282/pit.c

+/***************************************************************************/
+
+/*
+ *	pit.c -- Motorola ColdFire PIT timer. Currently this type of
+ *	         hardware timer only exists in the Motorola ColdFire
+ *		 5282 CPU.
+ *
+ *	Copyright (C) 1999-2003, Greg Ungerer (gerg@snapgear.com)
+ *	Copyright (C) 2001-2003, SnapGear Inc. (www.snapgear.com)
+ *
+ */
+
+/***************************************************************************/
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/param.h>
+#include <linux/init.h>
+#include <asm/irq.h>
+#include <asm/coldfire.h>
+#include <asm/mcfpit.h>
+#include <asm/mcfsim.h>
+
+/***************************************************************************/
+
+void coldfire_pit_tick(void)
+{
+	volatile struct mcfpit *tp;
+
+	/* Reset the ColdFire timer */
+	tp = (volatile struct mcfpit *) (MCF_IPSBAR + MCFPIT_BASE1);
+	tp->pcsr |= MCFPIT_PCSR_PIF;
+}
+
+/***************************************************************************/
+
+void coldfire_pit_init(void (*handler)(int, void *, struct pt_regs *))
+{
+	volatile unsigned char *icrp;
+	volatile unsigned long *imrp;
+	volatile struct mcfpit *tp;
+
+	request_irq(64+55, handler, SA_INTERRUPT, "ColdFire Timer", NULL);
+
+	icrp = (volatile unsigned char *) (MCF_IPSBAR + MCFICM_INTC0 +
+		MCFINTC_ICR0 + MCFINT_PIT1);
+	*icrp = 0x2b; /* PIT1 with level 5, priority 3 */
+
+	imrp = (volatile unsigned long *) (MCF_IPSBAR + MCFICM_INTC0 + MCFINTC_IMRH);
+	*imrp &= ~(1 << (55 - 32));
+
+	/* Set up PIT timer 1 as poll clock */
+	tp = (volatile struct mcfpit *) (MCF_IPSBAR + MCFPIT_BASE1);
+	tp->pcsr = MCFPIT_PCSR_DISABLE;
+
+	tp->pmr = ((MCF_CLK / 2) / 64) / HZ;
+	tp->pcsr = MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | MCFPIT_PCSR_OVW |
+		MCFPIT_PCSR_RLD | MCFPIT_PCSR_CLK64;
+}
+
+/***************************************************************************/
+
+unsigned long coldfire_pit_offset(void)
+{
+	volatile struct mcfpit *tp;
+	volatile unsigned long *ipr;
+	unsigned long pmr, pcntr, offset;
+
+	tp = (volatile struct mcfpit *) (MCF_IPSBAR + MCFPIT_BASE1);
+	ipr = (volatile unsigned long *) (MCF_IPSBAR + MCFICM_INTC0 + MCFINTC_IPRH);
+
+	pmr = tp->pmr;
+	pcntr = tp->pcntr;
+
+	/*
+	 * If we are still in the first half of the upcount and a
+	 * timer interupt is pending, then add on a ticks worth of time.
+	 */
+	offset = ((pcntr * (1000000 / HZ)) / pmr);
+	if ((offset < (1000000 / HZ / 2)) && (*ipr & (1 << (55 - 32))))
+		offset += 1000000 / HZ;
+	return offset;	
+}
+
+/***************************************************************************/