mirror of https://gitee.com/openkylin/linux.git
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/***************************************************************************/
|
|
|
|
/*
|
|
* pit.c -- Motorola ColdFire PIT timer. Currently this type of
|
|
* hardware timer only exists in the Motorola ColdFire
|
|
* 5270/5271 and 5282 CPUs.
|
|
*
|
|
* Copyright (C) 1999-2004, Greg Ungerer (gerg@snapgear.com)
|
|
* Copyright (C) 2001-2004, 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 <linux/interrupt.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(irqreturn_t (*handler)(int, void *, struct pt_regs *))
|
|
{
|
|
volatile unsigned char *icrp;
|
|
volatile unsigned long *imrp;
|
|
volatile struct mcfpit *tp;
|
|
|
|
request_irq(MCFINT_VECBASE + MCFINT_PIT1, 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 << (MCFINT_PIT1 - 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 = ((pmr - pcntr) * (1000000 / HZ)) / pmr;
|
|
if ((offset < (1000000 / HZ / 2)) && (*ipr & (1 << (MCFINT_PIT1 - 32))))
|
|
offset += 1000000 / HZ;
|
|
return offset;
|
|
}
|
|
|
|
/***************************************************************************/
|