/*
* 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. */
}
