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[MIPS] IP27: Convert to clock_event_device.
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This separates the tick timer stuff from the generic MIPS time.c.

Signed-off-by: Ralf Baechle <[email protected]>
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@ralfbaechle
ralfbaechle committed Oct 18, 2007
1 parent 832348f commit e887b24
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Showing 2 changed files with 94 additions and 66 deletions.
5 changes: 2 additions & 3 deletions arch/mips/sgi-ip27/ip27-irq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down
155 changes: 92 additions & 63 deletions arch/mips/sgi-ip27/ip27-timer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -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)
{
Expand Down Expand Up @@ -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>
Expand Down Expand Up @@ -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)
{
}
Expand All @@ -171,33 +168,64 @@ 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,
.mask = CPU_MASK_NONE,
.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)
Expand All @@ -206,19 +234,25 @@ 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),
.shift = 32,
.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;
Expand Down Expand Up @@ -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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