Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e887b24592c5ddf46d37e592b2ee6bd2188257e1
Commit:     e887b24592c5ddf46d37e592b2ee6bd2188257e1
Parent:     832348ff0bf1538e026ff862f91ab6db06e73499
Author:     Ralf Baechle <[EMAIL PROTECTED]>
AuthorDate: Thu Oct 18 13:34:12 2007 +0100
Committer:  Ralf Baechle <[EMAIL PROTECTED]>
CommitDate: Thu Oct 18 18:11:47 2007 +0100

    [MIPS] IP27: Convert to clock_event_device.
    
    This separates the tick timer stuff from the generic MIPS time.c.
    
    Signed-off-by: Ralf Baechle <[EMAIL PROTECTED]>
---
 arch/mips/sgi-ip27/ip27-irq.c   |    5 +-
 arch/mips/sgi-ip27/ip27-timer.c |  155 +++++++++++++++++++++++----------------
 2 files changed, 94 insertions(+), 66 deletions(-)

diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
index 856649c..1bb692a 100644
--- a/arch/mips/sgi-ip27/ip27-irq.c
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -374,14 +374,13 @@ int __devinit request_bridge_irq(struct bridge_controller 
*bc)
        return irq;
 }
 
-extern void ip27_rt_timer_interrupt(void);
-
 asmlinkage void plat_irq_dispatch(void)
 {
        unsigned long pending = read_c0_cause() & read_c0_status();
+       extern unsigned int rt_timer_irq;
 
        if (pending & CAUSEF_IP4)
-               ip27_rt_timer_interrupt();
+               do_IRQ(rt_timer_irq);
        else if (pending & CAUSEF_IP2)  /* PI_INT_PEND_0 or CC_PEND_{A|B} */
                ip27_do_irq_mask0();
        else if (pending & CAUSEF_IP3)  /* PI_INT_PEND_1 */
diff --git a/arch/mips/sgi-ip27/ip27-timer.c b/arch/mips/sgi-ip27/ip27-timer.c
index b7b3479..d467bf4 100644
--- a/arch/mips/sgi-ip27/ip27-timer.c
+++ b/arch/mips/sgi-ip27/ip27-timer.c
@@ -3,6 +3,7 @@
  * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
  */
 #include <linux/bcd.h>
+#include <linux/clockchips.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -25,22 +26,8 @@
 #include <asm/sn/sn0/ip27.h>
 #include <asm/sn/sn0/hub.h>
 
-/*
- * This is a hack; we really need to figure these values out dynamically
- *
- * Since 800 ns works very well with various HUB frequencies, such as
- * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
- *
- * Ralf: which clock rate is used to feed the counter?
- */
-#define NSEC_PER_CYCLE         800
-#define CYCLES_PER_SEC         (NSEC_PER_SEC/NSEC_PER_CYCLE)
-#define CYCLES_PER_JIFFY       (CYCLES_PER_SEC/HZ)
-
 #define TICK_SIZE (tick_nsec / 1000)
 
-static unsigned long ct_cur[NR_CPUS];  /* What counter should be at next timer 
irq */
-
 #if 0
 static int set_rtc_mmss(unsigned long nowtime)
 {
@@ -86,36 +73,6 @@ static int set_rtc_mmss(unsigned long nowtime)
 }
 #endif
 
-static unsigned int rt_timer_irq;
-
-void ip27_rt_timer_interrupt(void)
-{
-       int cpu = smp_processor_id();
-       int cpuA = cputoslice(cpu) == 0;
-       unsigned int irq = rt_timer_irq;
-
-       irq_enter();
-       write_seqlock(&xtime_lock);
-
-again:
-       LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);     /* Ack  */
-       ct_cur[cpu] += CYCLES_PER_JIFFY;
-       LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
-
-       if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
-               goto again;
-
-       kstat_this_cpu.irqs[irq]++;             /* kstat only for bootcpu? */
-
-       if (cpu == 0)
-               do_timer(1);
-
-       update_process_times(user_mode(get_irq_regs()));
-
-       write_sequnlock(&xtime_lock);
-       irq_exit();
-}
-
 /* Includes for ioc3_init().  */
 #include <asm/sn/types.h>
 #include <asm/sn/sn0/addrs.h>
@@ -154,6 +111,46 @@ unsigned long read_persistent_clock(void)
         return mktime(year, month, date, hour, min, sec);
 }
 
+static int rt_set_next_event(unsigned long delta,
+               struct clock_event_device *evt)
+{
+       unsigned int cpu = smp_processor_id();
+       int slice = cputoslice(cpu) == 0;
+       unsigned long cnt;
+
+       cnt = LOCAL_HUB_L(PI_RT_COUNT);
+       cnt += delta;
+       LOCAL_HUB_S(slice ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, cnt);
+
+       return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
+}
+
+static void rt_set_mode(enum clock_event_mode mode,
+               struct clock_event_device *evt)
+{
+       switch (mode) {
+       case CLOCK_EVT_MODE_PERIODIC:
+               /* The only mode supported */
+               break;
+
+       case CLOCK_EVT_MODE_UNUSED:
+       case CLOCK_EVT_MODE_SHUTDOWN:
+       case CLOCK_EVT_MODE_ONESHOT:
+       case CLOCK_EVT_MODE_RESUME:
+               /* Nothing to do  */
+               break;
+       }
+}
+
+struct clock_event_device rt_clock_event_device = {
+       .name           = "HUB-RT",
+       .features       = CLOCK_EVT_FEAT_ONESHOT,
+
+       .rating         = 300,
+       .set_next_event = rt_set_next_event,
+       .set_mode       = rt_set_mode,
+};
+
 static void enable_rt_irq(unsigned int irq)
 {
 }
@@ -171,6 +168,20 @@ static struct irq_chip rt_irq_type = {
        .eoi            = enable_rt_irq,
 };
 
+unsigned int rt_timer_irq;
+
+static irqreturn_t ip27_rt_timer_interrupt(int irq, void *dev_id)
+{
+       struct clock_event_device *cd = &rt_clock_event_device;
+       unsigned int cpu = smp_processor_id();
+       int slice = cputoslice(cpu) == 0;
+
+       LOCAL_HUB_S(slice ? PI_RT_PEND_A : PI_RT_PEND_B, 0);    /* Ack  */
+       cd->event_handler(cd);
+
+       return IRQ_HANDLED;
+}
+
 static struct irqaction rt_irqaction = {
        .handler        = (irq_handler_t) ip27_rt_timer_interrupt,
        .flags          = IRQF_DISABLED,
@@ -178,26 +189,43 @@ static struct irqaction rt_irqaction = {
        .name           = "timer"
 };
 
-void __init plat_timer_setup(struct irqaction *irq)
+/*
+ * This is a hack; we really need to figure these values out dynamically
+ *
+ * Since 800 ns works very well with various HUB frequencies, such as
+ * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
+ *
+ * Ralf: which clock rate is used to feed the counter?
+ */
+#define NSEC_PER_CYCLE         800
+#define CYCLES_PER_SEC         (NSEC_PER_SEC / NSEC_PER_CYCLE)
+
+static void __init ip27_rt_clock_event_init(void)
 {
-       int irqno  = allocate_irqno();
+       struct clock_event_device *cd = &rt_clock_event_device;
+       unsigned int cpu = smp_processor_id();
+       int irq = allocate_irqno();
 
-       if (irqno < 0)
+       if (irq < 0)
                panic("Can't allocate interrupt number for timer interrupt");
 
-       set_irq_chip_and_handler(irqno, &rt_irq_type, handle_percpu_irq);
+       rt_timer_irq = irq;
 
-       /* over-write the handler, we use our own way */
-       irq->handler = no_action;
+       cd->irq                 = irq,
+       cd->cpumask             = cpumask_of_cpu(cpu),
 
-       /* setup irqaction */
-       irq_desc[irqno].status |= IRQ_PER_CPU;
-
-       rt_timer_irq = irqno;
        /*
-        * Only needed to get /proc/interrupt to display timer irq stats
+        * Calculate the min / max delta
         */
-       setup_irq(irqno, &rt_irqaction);
+       cd->mult                =
+               div_sc((unsigned long) CYCLES_PER_SEC, NSEC_PER_SEC, 32);
+       cd->shift               = 32;
+       cd->max_delta_ns        = clockevent_delta2ns(0x7fffffff, cd);
+       cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
+       clockevents_register_device(cd);
+
+       set_irq_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
+       setup_irq(irq, &rt_irqaction);
 }
 
 static cycle_t hub_rt_read(void)
@@ -206,7 +234,7 @@ static cycle_t hub_rt_read(void)
 }
 
 struct clocksource ht_rt_clocksource = {
-       .name   = "HUB",
+       .name   = "HUB-RT",
        .rating = 200,
        .read   = hub_rt_read,
        .mask   = CLOCKSOURCE_MASK(52),
@@ -214,11 +242,17 @@ struct clocksource ht_rt_clocksource = {
        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-void __init plat_time_init(void)
+static void __init ip27_rt_clocksource_init(void)
 {
        clocksource_register(&ht_rt_clocksource);
 }
 
+void __init plat_time_init(void)
+{
+       ip27_rt_clock_event_init();
+       ip27_rt_clocksource_init();
+}
+
 void __init cpu_time_init(void)
 {
        lboard_t *board;
@@ -248,17 +282,12 @@ void __init hub_rtc_init(cnodeid_t cnode)
         * node and timeouts will not happen there.
         */
        if (get_compact_nodeid() == cnode) {
-               int cpu = smp_processor_id();
                LOCAL_HUB_S(PI_RT_EN_A, 1);
                LOCAL_HUB_S(PI_RT_EN_B, 1);
                LOCAL_HUB_S(PI_PROF_EN_A, 0);
                LOCAL_HUB_S(PI_PROF_EN_B, 0);
-               ct_cur[cpu] = CYCLES_PER_JIFFY;
-               LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
                LOCAL_HUB_S(PI_RT_COUNT, 0);
                LOCAL_HUB_S(PI_RT_PEND_A, 0);
-               LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
-               LOCAL_HUB_S(PI_RT_COUNT, 0);
                LOCAL_HUB_S(PI_RT_PEND_B, 0);
        }
 }
-
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