m68knommu: switch ColdFire PIT timer to use GENERIC_TIME

Switch the ColdFire PIT timer to using GENERIC_TIME.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/m68knommu/platform/coldfire/pit.c b/arch/m68knommu/platform/coldfire/pit.c
index 173b754..4290638 100644 (file)
--- a/arch/m68knommu/platform/coldfire/pit.c
+++ b/arch/m68knommu/platform/coldfire/pit.c
@@ -3,9 +3,10 @@
 /*
  *     pit.c -- Freescale ColdFire PIT timer. Currently this type of
  *              hardware timer only exists in the Freescale ColdFire
- *              5270/5271, 5282 and other CPUs.
+ *              5270/5271, 5282 and 5208 CPUs. No doubt newer ColdFire
+ *              family members will probably use it too.
  *
- *     Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
+ *     Copyright (C) 1999-2008, Greg Ungerer (gerg@snapgear.com)
  *     Copyright (C) 2001-2004, SnapGear Inc. (www.snapgear.com)
  */
 
@@ -17,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/clocksource.h>
 #include <asm/machdep.h>
 #include <asm/io.h>
 #include <asm/coldfire.h>
@@ -28,70 +30,84 @@
 /*
  *     By default use timer1 as the system clock timer.
  */
+#define        FREQ    ((MCF_CLK / 2) / 64)
 #define        TA(a)   (MCF_IPSBAR + MCFPIT_BASE1 + (a))
+#define        INTC0   (MCF_IPSBAR + MCFICM_INTC0)
+
+static u32 pit_cycles_per_jiffy;
+static u32 pit_cnt;
 
 /***************************************************************************/
 
-static irqreturn_t hw_tick(int irq, void *dummy)
+static irqreturn_t pit_tick(int irq, void *dummy)
 {
-       unsigned short pcsr;
+       u16 pcsr;
 
        /* Reset the ColdFire timer */
        pcsr = __raw_readw(TA(MCFPIT_PCSR));
        __raw_writew(pcsr | MCFPIT_PCSR_PIF, TA(MCFPIT_PCSR));
 
+       pit_cnt += pit_cycles_per_jiffy;
        return arch_timer_interrupt(irq, dummy);
 }
 
 /***************************************************************************/
 
-static struct irqaction coldfire_pit_irq = {
+static struct irqaction pit_irq = {
        .name    = "timer",
        .flags   = IRQF_DISABLED | IRQF_TIMER,
-       .handler = hw_tick,
+       .handler = pit_tick,
 };
 
-void hw_timer_init(void)
+/***************************************************************************/
+
+static cycle_t pit_read_clk(void)
 {
-       volatile unsigned char *icrp;
-       volatile unsigned long *imrp;
+       unsigned long flags;
+       u32 cycles;
+       u16 pcntr;
 
-       setup_irq(MCFINT_VECBASE + MCFINT_PIT1, &coldfire_pit_irq);
+       local_irq_save(flags);
+       pcntr = __raw_readw(TA(MCFPIT_PCNTR));
+       cycles = pit_cnt;
+       local_irq_restore(flags);
 
-       icrp = (volatile unsigned char *) (MCF_IPSBAR + MCFICM_INTC0 +
-               MCFINTC_ICR0 + MCFINT_PIT1);
-       *icrp = ICR_INTRCONF;
+       return cycles + pit_cycles_per_jiffy - pcntr;
+}
 
-       imrp = (volatile unsigned long *) (MCF_IPSBAR + MCFICM_INTC0 + MCFPIT_IMR);
-       *imrp &= ~MCFPIT_IMR_IBIT;
+/***************************************************************************/
 
-       /* Set up PIT timer 1 as poll clock */
-       __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
-       __raw_writew(((MCF_CLK / 2) / 64) / HZ, TA(MCFPIT_PMR));
-       __raw_writew(MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | MCFPIT_PCSR_OVW |
-               MCFPIT_PCSR_RLD | MCFPIT_PCSR_CLK64, TA(MCFPIT_PCSR));
-}
+static struct clocksource pit_clk = {
+       .name   = "pit",
+       .rating = 250,
+       .read   = pit_read_clk,
+       .shift  = 20,
+       .mask   = CLOCKSOURCE_MASK(32),
+       .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
 
 /***************************************************************************/
 
-unsigned long hw_timer_offset(void)
+void hw_timer_init(void)
 {
-       volatile unsigned long *ipr;
-       unsigned long pmr, pcntr, offset;
+       u32 imr;
 
-       ipr = (volatile unsigned long *) (MCF_IPSBAR + MCFICM_INTC0 + MCFPIT_IMR);
+       setup_irq(MCFINT_VECBASE + MCFINT_PIT1, &pit_irq);
 
-       pmr = __raw_readw(TA(MCFPIT_PMR));
-       pcntr = __raw_readw(TA(MCFPIT_PCNTR));
+       __raw_writeb(ICR_INTRCONF, INTC0 + MCFINTC_ICR0 + MCFINT_PIT1);
+       imr = __raw_readl(INTC0 + MCFPIT_IMR);
+       imr &= ~MCFPIT_IMR_IBIT;
+       __raw_writel(imr, INTC0 + MCFPIT_IMR);
+
+       /* Set up PIT timer 1 as poll clock */
+       pit_cycles_per_jiffy = FREQ / HZ;
+       __raw_writew(MCFPIT_PCSR_DISABLE, TA(MCFPIT_PCSR));
+       __raw_writew(pit_cycles_per_jiffy, TA(MCFPIT_PMR));
+       __raw_writew(MCFPIT_PCSR_EN | MCFPIT_PCSR_PIE | MCFPIT_PCSR_OVW |
+               MCFPIT_PCSR_RLD | MCFPIT_PCSR_CLK64, TA(MCFPIT_PCSR));
 
-       /*
-        * If we are still in the first half of the upcount and a
-        * timer interrupt is pending, then add on a ticks worth of time.
-        */
-       offset = ((pmr - pcntr) * (1000000 / HZ)) / pmr;
-       if ((offset < (1000000 / HZ / 2)) && (*ipr & MCFPIT_IMR_IBIT))
-               offset += 1000000 / HZ;
-       return offset;  
+       pit_clk.mult = clocksource_hz2mult(FREQ, pit_clk.shift);
+       clocksource_register(&pit_clk);
 }
 
 /***************************************************************************/