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hw/timer/imx_epit: Simplify and fix imx_epit implementation

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When imx_epit.c was last refactored, a common usecase (comparison
register zero) broke.  This patch fixes that, and simplifies the code
yet more.  It also fixes a major thinko in the reset path --- the
wrong bits in the control register were being cleared.

Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Reviewed-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Chubb 2013-08-20 14:54:32 +01:00 committed by Peter Maydell
parent 66aae5e1ec
commit 230058106a
1 changed files with 36 additions and 58 deletions
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94
hw/timer/imx_epit.c
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@ -43,7 +43,7 @@ static char const *imx_epit_reg_name(uint32_t reg)
}
# define DPRINTF(fmt, args...) \
do { printf("%s: " fmt , __func__, ##args); } while (0)
do { fprintf(stderr, "%s: " fmt , __func__, ##args); } while (0)
#else
# define DPRINTF(fmt, args...) do {} while (0)
#endif
@ -152,7 +152,7 @@ static void imx_epit_reset(DeviceState *dev)
/*
* Soft reset doesn't touch some bits; hard reset clears them
*/
s->cr &= ~(CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN);
s->cr &= (CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN);
s->sr = 0;
s->lr = TIMER_MAX;
s->cmp = 0;
@ -167,7 +167,7 @@ static void imx_epit_reset(DeviceState *dev)
ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
if (s->freq && (s->cr & CR_EN)) {
/* if the timer is still enabled, restart it */
ptimer_run(s->timer_reload, 1);
ptimer_run(s->timer_reload, 0);
}
}
@ -218,17 +218,17 @@ static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size)
static void imx_epit_reload_compare_timer(IMXEPITState *s)
{
if ((s->cr & CR_OCIEN) && s->cmp) {
/* if the compare feature is on */
if ((s->cr & (CR_EN | CR_OCIEN)) == (CR_EN | CR_OCIEN)) {
/* if the compare feature is on and timers are running */
uint32_t tmp = imx_epit_update_count(s);
uint64_t next;
if (tmp > s->cmp) {
/* reinit the cmp timer if required */
ptimer_set_count(s->timer_cmp, tmp - s->cmp);
if ((s->cr & CR_EN)) {
/* Restart the cmp timer if required */
ptimer_run(s->timer_cmp, 0);
}
/* It'll fire in this round of the timer */
next = tmp - s->cmp;
} else { /* catch it next time around */
next = tmp - s->cmp + ((s->cr & CR_RLD) ? TIMER_MAX : s->lr);
}
ptimer_set_count(s->timer_cmp, next);
}
}
@ -237,11 +237,14 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
{
IMXEPITState *s = IMX_EPIT(opaque);
uint32_t reg = offset >> 2;
uint64_t oldcr;
DPRINTF("(%s, value = 0x%08x)\n", imx_epit_reg_name(reg), (uint32_t)value);
switch (reg) {
case 0: /* CR */
oldcr = s->cr;
s->cr = value & 0x03ffffff;
if (s->cr & CR_SWR) {
/* handle the reset */
@ -250,22 +253,35 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
imx_epit_set_freq(s);
}
if (s->freq && (s->cr & CR_EN)) {
if (s->freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) {
if (s->cr & CR_ENMOD) {
if (s->cr & CR_RLD) {
ptimer_set_limit(s->timer_reload, s->lr, 1);
ptimer_set_limit(s->timer_cmp, s->lr, 1);
} else {
ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
ptimer_set_limit(s->timer_cmp, TIMER_MAX, 1);
}
}
imx_epit_reload_compare_timer(s);
ptimer_run(s->timer_reload, 1);
} else {
ptimer_run(s->timer_reload, 0);
if (s->cr & CR_OCIEN) {
ptimer_run(s->timer_cmp, 0);
} else {
ptimer_stop(s->timer_cmp);
}
} else if (!(s->cr & CR_EN)) {
/* stop both timers */
ptimer_stop(s->timer_reload);
ptimer_stop(s->timer_cmp);
} else if (s->cr & CR_OCIEN) {
if (!(oldcr & CR_OCIEN)) {
imx_epit_reload_compare_timer(s);
ptimer_run(s->timer_cmp, 0);
}
} else {
ptimer_stop(s->timer_cmp);
}
break;
@ -284,13 +300,13 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
/* Also set the limit if the LRD bit is set */
/* If IOVW bit is set then set the timer value */
ptimer_set_limit(s->timer_reload, s->lr, s->cr & CR_IOVW);
ptimer_set_limit(s->timer_cmp, s->lr, 0);
} else if (s->cr & CR_IOVW) {
/* If IOVW bit is set then set the timer value */
ptimer_set_count(s->timer_reload, s->lr);
}
imx_epit_reload_compare_timer(s);
break;
case 3: /* CMP */
@ -306,51 +322,14 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
break;
}
}
static void imx_epit_timeout(void *opaque)
{
IMXEPITState *s = IMX_EPIT(opaque);
DPRINTF("\n");
if (!(s->cr & CR_EN)) {
return;
}
if (s->cr & CR_RLD) {
ptimer_set_limit(s->timer_reload, s->lr, 1);
} else {
ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
}
if (s->cr & CR_OCIEN) {
/* if compare register is 0 then we handle the interrupt here */
if (s->cmp == 0) {
s->sr = 1;
imx_epit_update_int(s);
} else if (s->cmp <= s->lr) {
/* We should launch the compare register */
ptimer_set_count(s->timer_cmp, s->lr - s->cmp);
ptimer_run(s->timer_cmp, 0);
} else {
IPRINTF("s->lr < s->cmp\n");
}
}
}
static void imx_epit_cmp(void *opaque)
{
IMXEPITState *s = IMX_EPIT(opaque);
DPRINTF("\n");
DPRINTF("sr was %d\n", s->sr);
ptimer_stop(s->timer_cmp);
/* compare register is not 0 */
if (s->cmp) {
s->sr = 1;
imx_epit_update_int(s);
}
s->sr = 1;
imx_epit_update_int(s);
}
void imx_timerp_create(const hwaddr addr, qemu_irq irq, DeviceState *ccm)
@ -400,8 +379,7 @@ static void imx_epit_realize(DeviceState *dev, Error **errp)
0x00001000);
sysbus_init_mmio(sbd, &s->iomem);
bh = qemu_bh_new(imx_epit_timeout, s);
s->timer_reload = ptimer_init(bh);
s->timer_reload = ptimer_init(NULL);
bh = qemu_bh_new(imx_epit_cmp, s);
s->timer_cmp = ptimer_init(bh);