hw/arm_timer.c - qemu - Git at Google

 /*
  * ARM PrimeCell Timer modules.
  *
  * Copyright (c) 2005-2006 CodeSourcery.
  * Written by Paul Brook
  *
  * This code is licenced under the GPL.
  */

 #include "vl.h"
 #include "arm_pic.h"

 /* Common timer implementation.  */

 #define TIMER_CTRL_ONESHOT      (1 << 0)
 #define TIMER_CTRL_32BIT        (1 << 1)
 #define TIMER_CTRL_DIV1         (0 << 2)
 #define TIMER_CTRL_DIV16        (1 << 2)
 #define TIMER_CTRL_DIV256       (2 << 2)
 #define TIMER_CTRL_IE           (1 << 5)
 #define TIMER_CTRL_PERIODIC     (1 << 6)
 #define TIMER_CTRL_ENABLE       (1 << 7)

 typedef struct {
     int64_t next_time;
     int64_t expires;
     int64_t loaded;
     QEMUTimer *timer;
     uint32_t control;
     uint32_t count;
     uint32_t limit;
     int raw_freq;
     int freq;
     int int_level;
     void *pic;
     int irq;
 } arm_timer_state;

 /* Calculate the new expiry time of the given timer.  */

 static void arm_timer_reload(arm_timer_state *s)
 {
     int64_t delay;

     s->loaded = s->expires;
     delay = muldiv64(s->count, ticks_per_sec, s->freq);
     if (delay == 0)
         delay = 1;
     s->expires += delay;
 }

 /* Check all active timers, and schedule the next timer interrupt.  */

 static void arm_timer_update(arm_timer_state *s, int64_t now)
 {
     int64_t next;

     /* Ignore disabled timers.  */
     if ((s->control & TIMER_CTRL_ENABLE) == 0)
         return;
     /* Ignore expired one-shot timers.  */
     if (s->count == 0 && (s->control & TIMER_CTRL_ONESHOT))
         return;
     if (s->expires - now <= 0) {
         /* Timer has expired.  */
         s->int_level = 1;
         if (s->control & TIMER_CTRL_ONESHOT) {
             /* One-shot.  */
             s->count = 0;
         } else {
             if ((s->control & TIMER_CTRL_PERIODIC) == 0) {
                 /* Free running.  */
                 if (s->control & TIMER_CTRL_32BIT)
                     s->count = 0xffffffff;
                 else
                     s->count = 0xffff;
             } else {
                   /* Periodic.  */
                   s->count = s->limit;
             }
         }
     }
     while (s->expires - now <= 0) {
         arm_timer_reload(s);
     }
     /* Update interrupts.  */
     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
         pic_set_irq_new(s->pic, s->irq, 1);
     } else {
         pic_set_irq_new(s->pic, s->irq, 0);
     }

     next = now;
     if (next - s->expires < 0)
         next = s->expires;

     /* Schedule the next timer interrupt.  */
     if (next == now) {
         qemu_del_timer(s->timer);
         s->next_time = 0;
     } else if (next != s->next_time) {
         qemu_mod_timer(s->timer, next);
         s->next_time = next;
     }
 }

 /* Return the current value of the timer.  */
 static uint32_t arm_timer_getcount(arm_timer_state *s, int64_t now)
 {
     int64_t elapsed;
     int64_t period;

     if (s->count == 0)
         return 0;
     if ((s->control & TIMER_CTRL_ENABLE) == 0)
         return s->count;
     elapsed = now - s->loaded;
     period = s->expires - s->loaded;
     /* If the timer should have expired then return 0.  This can happen
        when the host timer signal doesnt occur immediately.  It's better to
        have a timer appear to sit at zero for a while than have it wrap
        around before the guest interrupt is raised.  */
     /* ??? Could we trigger the interrupt here?  */
     if (elapsed > period)
         return 0;
     /* We need to calculate count * elapsed / period without overfowing.
        Scale both elapsed and period so they fit in a 32-bit int.  */
     while (period != (int32_t)period) {
         period >>= 1;
         elapsed >>= 1;
     }
     return ((uint64_t)s->count * (uint64_t)(int32_t)elapsed)
             / (int32_t)period;
 }

 uint32_t arm_timer_read(void *opaque, target_phys_addr_t offset)
 {
     arm_timer_state *s = (arm_timer_state *)opaque;

     switch (offset >> 2) {
     case 0: /* TimerLoad */
     case 6: /* TimerBGLoad */
         return s->limit;
     case 1: /* TimerValue */
         return arm_timer_getcount(s, qemu_get_clock(vm_clock));
     case 2: /* TimerControl */
         return s->control;
     case 4: /* TimerRIS */
         return s->int_level;
     case 5: /* TimerMIS */
         if ((s->control & TIMER_CTRL_IE) == 0)
             return 0;
         return s->int_level;
     default:
         cpu_abort (cpu_single_env, "arm_timer_read: Bad offset %x\n", offset);
         return 0;
     }
 }

 static void arm_timer_write(void *opaque, target_phys_addr_t offset,
                             uint32_t value)
 {
     arm_timer_state *s = (arm_timer_state *)opaque;
     int64_t now;

     now = qemu_get_clock(vm_clock);
     switch (offset >> 2) {
     case 0: /* TimerLoad */
         s->limit = value;
         s->count = value;
         s->expires = now;
         arm_timer_reload(s);
         break;
     case 1: /* TimerValue */
         /* ??? Linux seems to want to write to this readonly register.
            Ignore it.  */
         break;
     case 2: /* TimerControl */
         if (s->control & TIMER_CTRL_ENABLE) {
             /* Pause the timer if it is running.  This may cause some
                inaccuracy dure to rounding, but avoids a whole lot of other
                messyness.  */
             s->count = arm_timer_getcount(s, now);
         }
         s->control = value;
         s->freq = s->raw_freq;
         /* ??? Need to recalculate expiry time after changing divisor.  */
         switch ((value >> 2) & 3) {
         case 1: s->freq >>= 4; break;
         case 2: s->freq >>= 8; break;
         }
         if (s->control & TIMER_CTRL_ENABLE) {
             /* Restart the timer if still enabled.  */
             s->expires = now;
             arm_timer_reload(s);
         }
         break;
     case 3: /* TimerIntClr */
         s->int_level = 0;
         break;
     case 6: /* TimerBGLoad */
         s->limit = value;
         break;
     default:
         cpu_abort (cpu_single_env, "arm_timer_write: Bad offset %x\n", offset);
     }
     arm_timer_update(s, now);
 }

 static void arm_timer_tick(void *opaque)
 {
     int64_t now;

     now = qemu_get_clock(vm_clock);
     arm_timer_update((arm_timer_state *)opaque, now);
 }

 static void *arm_timer_init(uint32_t freq, void *pic, int irq)
 {
     arm_timer_state *s;

     s = (arm_timer_state *)qemu_mallocz(sizeof(arm_timer_state));
     s->pic = pic;
     s->irq = irq;
     s->raw_freq = s->freq = 1000000;
     s->control = TIMER_CTRL_IE;
     s->count = 0xffffffff;

     s->timer = qemu_new_timer(vm_clock, arm_timer_tick, s);
     /* ??? Save/restore.  */
     return s;
 }

 /* ARM PrimeCell SP804 dual timer module.
    Docs for this device don't seem to be publicly available.  This
    implementation is based on gueswork, the linux kernel sources and the
    Integrator/CP timer modules.  */

 typedef struct {
     /* Include a pseudo-PIC device to merge the two interrupt sources.  */
     arm_pic_handler handler;
     void *timer[2];
     int level[2];
     uint32_t base;
     /* The output PIC device.  */
     void *pic;
     int irq;
 } sp804_state;

 static void sp804_set_irq(void *opaque, int irq, int level)
 {
     sp804_state *s = (sp804_state *)opaque;

     s->level[irq] = level;
     pic_set_irq_new(s->pic, s->irq, s->level[0] || s->level[1]);
 }

 static uint32_t sp804_read(void *opaque, target_phys_addr_t offset)
 {
     sp804_state *s = (sp804_state *)opaque;

     /* ??? Don't know the PrimeCell ID for this device.  */
     offset -= s->base;
     if (offset < 0x20) {
         return arm_timer_read(s->timer[0], offset);
     } else {
         return arm_timer_read(s->timer[1], offset - 0x20);
     }
 }

 static void sp804_write(void *opaque, target_phys_addr_t offset,
                         uint32_t value)
 {
     sp804_state *s = (sp804_state *)opaque;

     offset -= s->base;
     if (offset < 0x20) {
         arm_timer_write(s->timer[0], offset, value);
     } else {
         arm_timer_write(s->timer[1], offset - 0x20, value);
     }
 }

 static CPUReadMemoryFunc *sp804_readfn[] = {
    sp804_read,
    sp804_read,
    sp804_read
 };

 static CPUWriteMemoryFunc *sp804_writefn[] = {
    sp804_write,
    sp804_write,
    sp804_write
 };

 void sp804_init(uint32_t base, void *pic, int irq)
 {
     int iomemtype;
     sp804_state *s;

     s = (sp804_state *)qemu_mallocz(sizeof(sp804_state));
     s->handler = sp804_set_irq;
     s->base = base;
     s->pic = pic;
     s->irq = irq;
     /* ??? The timers are actually configurable between 32kHz and 1MHz, but
        we don't implement that.  */
     s->timer[0] = arm_timer_init(1000000, s, 0);
     s->timer[1] = arm_timer_init(1000000, s, 1);
     iomemtype = cpu_register_io_memory(0, sp804_readfn,
                                        sp804_writefn, s);
     cpu_register_physical_memory(base, 0x00000fff, iomemtype);
     /* ??? Save/restore.  */
 }


 /* Integrator/CP timer module.  */

 typedef struct {
     void *timer[3];
     uint32_t base;
 } icp_pit_state;

 static uint32_t icp_pit_read(void *opaque, target_phys_addr_t offset)
 {
     icp_pit_state *s = (icp_pit_state *)opaque;
     int n;

     /* ??? Don't know the PrimeCell ID for this device.  */
     offset -= s->base;
     n = offset >> 8;
     if (n > 3)
         cpu_abort(cpu_single_env, "sp804_read: Bad timer %d\n", n);

     return arm_timer_read(s->timer[n], offset & 0xff);
 }

 static void icp_pit_write(void *opaque, target_phys_addr_t offset,
                           uint32_t value)
 {
     icp_pit_state *s = (icp_pit_state *)opaque;
     int n;

     offset -= s->base;
     n = offset >> 8;
     if (n > 3)
         cpu_abort(cpu_single_env, "sp804_write: Bad timer %d\n", n);

     arm_timer_write(s->timer[n], offset & 0xff, value);
 }


 static CPUReadMemoryFunc *icp_pit_readfn[] = {
    icp_pit_read,
    icp_pit_read,
    icp_pit_read
 };

 static CPUWriteMemoryFunc *icp_pit_writefn[] = {
    icp_pit_write,
    icp_pit_write,
    icp_pit_write
 };

 void icp_pit_init(uint32_t base, void *pic, int irq)
 {
     int iomemtype;
     icp_pit_state *s;

     s = (icp_pit_state *)qemu_mallocz(sizeof(icp_pit_state));
     s->base = base;
     /* Timer 0 runs at the system clock speed (40MHz).  */
     s->timer[0] = arm_timer_init(40000000, pic, irq);
     /* The other two timers run at 1MHz.  */
     s->timer[1] = arm_timer_init(1000000, pic, irq + 1);
     s->timer[2] = arm_timer_init(1000000, pic, irq + 2);

     iomemtype = cpu_register_io_memory(0, icp_pit_readfn,
                                        icp_pit_writefn, s);
     cpu_register_physical_memory(base, 0x00000fff, iomemtype);
     /* ??? Save/restore.  */
 }
	/*
	* ARM PrimeCell Timer modules.
	*
	* Copyright (c) 2005-2006 CodeSourcery.
	* Written by Paul Brook
	*
	* This code is licenced under the GPL.
	*/

	#include "vl.h"
	#include "arm_pic.h"

	/* Common timer implementation. */

	#define TIMER_CTRL_ONESHOT (1 << 0)
	#define TIMER_CTRL_32BIT (1 << 1)
	#define TIMER_CTRL_DIV1 (0 << 2)
	#define TIMER_CTRL_DIV16 (1 << 2)
	#define TIMER_CTRL_DIV256 (2 << 2)
	#define TIMER_CTRL_IE (1 << 5)
	#define TIMER_CTRL_PERIODIC (1 << 6)
	#define TIMER_CTRL_ENABLE (1 << 7)

	typedef struct {
	int64_t next_time;
	int64_t expires;
	int64_t loaded;
	QEMUTimer *timer;
	uint32_t control;
	uint32_t count;
	uint32_t limit;
	int raw_freq;
	int freq;
	int int_level;
	void *pic;
	int irq;
	} arm_timer_state;

	/* Calculate the new expiry time of the given timer. */

	static void arm_timer_reload(arm_timer_state *s)
	{
	int64_t delay;

	s->loaded = s->expires;
	delay = muldiv64(s->count, ticks_per_sec, s->freq);
	if (delay == 0)
	delay = 1;
	s->expires += delay;
	}

	/* Check all active timers, and schedule the next timer interrupt. */

	static void arm_timer_update(arm_timer_state *s, int64_t now)
	{
	int64_t next;

	/* Ignore disabled timers. */
	if ((s->control & TIMER_CTRL_ENABLE) == 0)
	return;
	/* Ignore expired one-shot timers. */
	if (s->count == 0 && (s->control & TIMER_CTRL_ONESHOT))
	return;
	if (s->expires - now <= 0) {
	/* Timer has expired. */
	s->int_level = 1;
	if (s->control & TIMER_CTRL_ONESHOT) {
	/* One-shot. */
	s->count = 0;
	} else {
	if ((s->control & TIMER_CTRL_PERIODIC) == 0) {
	/* Free running. */
	if (s->control & TIMER_CTRL_32BIT)
	s->count = 0xffffffff;
	else
	s->count = 0xffff;
	} else {
	/* Periodic. */
	s->count = s->limit;
	}
	}
	}
	while (s->expires - now <= 0) {
	arm_timer_reload(s);
	}
	/* Update interrupts. */
	if (s->int_level && (s->control & TIMER_CTRL_IE)) {
	pic_set_irq_new(s->pic, s->irq, 1);
	} else {
	pic_set_irq_new(s->pic, s->irq, 0);
	}

	next = now;
	if (next - s->expires < 0)
	next = s->expires;

	/* Schedule the next timer interrupt. */
	if (next == now) {
	qemu_del_timer(s->timer);
	s->next_time = 0;
	} else if (next != s->next_time) {
	qemu_mod_timer(s->timer, next);
	s->next_time = next;
	}
	}

	/* Return the current value of the timer. */
	static uint32_t arm_timer_getcount(arm_timer_state *s, int64_t now)
	{
	int64_t elapsed;
	int64_t period;

	if (s->count == 0)
	return 0;
	if ((s->control & TIMER_CTRL_ENABLE) == 0)
	return s->count;
	elapsed = now - s->loaded;
	period = s->expires - s->loaded;
	/* If the timer should have expired then return 0. This can happen
	when the host timer signal doesnt occur immediately. It's better to
	have a timer appear to sit at zero for a while than have it wrap
	around before the guest interrupt is raised. */
	/* ??? Could we trigger the interrupt here? */
	if (elapsed > period)
	return 0;
	/* We need to calculate count * elapsed / period without overfowing.
	Scale both elapsed and period so they fit in a 32-bit int. */
	while (period != (int32_t)period) {
	period >>= 1;
	elapsed >>= 1;
	}
	return ((uint64_t)s->count * (uint64_t)(int32_t)elapsed)
	/ (int32_t)period;
	}

	uint32_t arm_timer_read(void *opaque, target_phys_addr_t offset)
	{
	arm_timer_state s = (arm_timer_state )opaque;

	switch (offset >> 2) {
	case 0: /* TimerLoad */
	case 6: /* TimerBGLoad */
	return s->limit;
	case 1: /* TimerValue */
	return arm_timer_getcount(s, qemu_get_clock(vm_clock));
	case 2: /* TimerControl */
	return s->control;
	case 4: /* TimerRIS */
	return s->int_level;
	case 5: /* TimerMIS */
	if ((s->control & TIMER_CTRL_IE) == 0)
	return 0;
	return s->int_level;
	default:
	cpu_abort (cpu_single_env, "arm_timer_read: Bad offset %x\n", offset);
	return 0;
	}
	}

	static void arm_timer_write(void *opaque, target_phys_addr_t offset,
	uint32_t value)
	{
	arm_timer_state s = (arm_timer_state )opaque;
	int64_t now;

	now = qemu_get_clock(vm_clock);
	switch (offset >> 2) {
	case 0: /* TimerLoad */
	s->limit = value;
	s->count = value;
	s->expires = now;
	arm_timer_reload(s);
	break;
	case 1: /* TimerValue */
	/* ??? Linux seems to want to write to this readonly register.
	Ignore it. */
	break;
	case 2: /* TimerControl */
	if (s->control & TIMER_CTRL_ENABLE) {
	/* Pause the timer if it is running. This may cause some
	inaccuracy dure to rounding, but avoids a whole lot of other
	messyness. */
	s->count = arm_timer_getcount(s, now);
	}
	s->control = value;
	s->freq = s->raw_freq;
	/* ??? Need to recalculate expiry time after changing divisor. */
	switch ((value >> 2) & 3) {
	case 1: s->freq >>= 4; break;
	case 2: s->freq >>= 8; break;
	}
	if (s->control & TIMER_CTRL_ENABLE) {
	/* Restart the timer if still enabled. */
	s->expires = now;
	arm_timer_reload(s);
	}
	break;
	case 3: /* TimerIntClr */
	s->int_level = 0;
	break;
	case 6: /* TimerBGLoad */
	s->limit = value;
	break;
	default:
	cpu_abort (cpu_single_env, "arm_timer_write: Bad offset %x\n", offset);
	}
	arm_timer_update(s, now);
	}

	static void arm_timer_tick(void *opaque)
	{
	int64_t now;

	now = qemu_get_clock(vm_clock);
	arm_timer_update((arm_timer_state *)opaque, now);
	}

	static void arm_timer_init(uint32_t freq, void pic, int irq)
	{
	arm_timer_state *s;

	s = (arm_timer_state *)qemu_mallocz(sizeof(arm_timer_state));
	s->pic = pic;
	s->irq = irq;
	s->raw_freq = s->freq = 1000000;
	s->control = TIMER_CTRL_IE;
	s->count = 0xffffffff;

	s->timer = qemu_new_timer(vm_clock, arm_timer_tick, s);
	/* ??? Save/restore. */
	return s;
	}

	/* ARM PrimeCell SP804 dual timer module.
	Docs for this device don't seem to be publicly available. This
	implementation is based on gueswork, the linux kernel sources and the
	Integrator/CP timer modules. */

	typedef struct {
	/* Include a pseudo-PIC device to merge the two interrupt sources. */
	arm_pic_handler handler;
	void *timer[2];
	int level[2];
	uint32_t base;
	/* The output PIC device. */
	void *pic;
	int irq;
	} sp804_state;

	static void sp804_set_irq(void *opaque, int irq, int level)
	{
	sp804_state s = (sp804_state )opaque;

	s->level[irq] = level;
	pic_set_irq_new(s->pic, s->irq, s->level[0] \|\| s->level[1]);
	}

	static uint32_t sp804_read(void *opaque, target_phys_addr_t offset)
	{
	sp804_state s = (sp804_state )opaque;

	/* ??? Don't know the PrimeCell ID for this device. */
	offset -= s->base;
	if (offset < 0x20) {
	return arm_timer_read(s->timer[0], offset);
	} else {
	return arm_timer_read(s->timer[1], offset - 0x20);
	}
	}

	static void sp804_write(void *opaque, target_phys_addr_t offset,
	uint32_t value)
	{
	sp804_state s = (sp804_state )opaque;

	offset -= s->base;
	if (offset < 0x20) {
	arm_timer_write(s->timer[0], offset, value);
	} else {
	arm_timer_write(s->timer[1], offset - 0x20, value);
	}
	}

	static CPUReadMemoryFunc *sp804_readfn[] = {
	sp804_read,
	sp804_read,
	sp804_read
	};

	static CPUWriteMemoryFunc *sp804_writefn[] = {
	sp804_write,
	sp804_write,
	sp804_write
	};

	void sp804_init(uint32_t base, void *pic, int irq)
	{
	int iomemtype;
	sp804_state *s;

	s = (sp804_state *)qemu_mallocz(sizeof(sp804_state));
	s->handler = sp804_set_irq;
	s->base = base;
	s->pic = pic;
	s->irq = irq;
	/* ??? The timers are actually configurable between 32kHz and 1MHz, but
	we don't implement that. */
	s->timer[0] = arm_timer_init(1000000, s, 0);
	s->timer[1] = arm_timer_init(1000000, s, 1);
	iomemtype = cpu_register_io_memory(0, sp804_readfn,
	sp804_writefn, s);
	cpu_register_physical_memory(base, 0x00000fff, iomemtype);
	/* ??? Save/restore. */
	}


	/* Integrator/CP timer module. */

	typedef struct {
	void *timer[3];
	uint32_t base;
	} icp_pit_state;

	static uint32_t icp_pit_read(void *opaque, target_phys_addr_t offset)
	{
	icp_pit_state s = (icp_pit_state )opaque;
	int n;

	/* ??? Don't know the PrimeCell ID for this device. */
	offset -= s->base;
	n = offset >> 8;
	if (n > 3)
	cpu_abort(cpu_single_env, "sp804_read: Bad timer %d\n", n);

	return arm_timer_read(s->timer[n], offset & 0xff);
	}

	static void icp_pit_write(void *opaque, target_phys_addr_t offset,
	uint32_t value)
	{
	icp_pit_state s = (icp_pit_state )opaque;
	int n;

	offset -= s->base;
	n = offset >> 8;
	if (n > 3)
	cpu_abort(cpu_single_env, "sp804_write: Bad timer %d\n", n);

	arm_timer_write(s->timer[n], offset & 0xff, value);
	}


	static CPUReadMemoryFunc *icp_pit_readfn[] = {
	icp_pit_read,
	icp_pit_read,
	icp_pit_read
	};

	static CPUWriteMemoryFunc *icp_pit_writefn[] = {
	icp_pit_write,
	icp_pit_write,
	icp_pit_write
	};

	void icp_pit_init(uint32_t base, void *pic, int irq)
	{
	int iomemtype;
	icp_pit_state *s;

	s = (icp_pit_state *)qemu_mallocz(sizeof(icp_pit_state));
	s->base = base;
	/* Timer 0 runs at the system clock speed (40MHz). */
	s->timer[0] = arm_timer_init(40000000, pic, irq);
	/* The other two timers run at 1MHz. */
	s->timer[1] = arm_timer_init(1000000, pic, irq + 1);
	s->timer[2] = arm_timer_init(1000000, pic, irq + 2);

	iomemtype = cpu_register_io_memory(0, icp_pit_readfn,
	icp_pit_writefn, s);
	cpu_register_physical_memory(base, 0x00000fff, iomemtype);
	/* ??? Save/restore. */
	}