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qemu/hw/timer/imx_gpt.c
Kurban Mallachiev c98c9eba88 ARM i.MX timers: fix reset handling 
The i.MX timer device can be reset by writing to the SWR bit
of the CR register. This has to behave differently from hard
(power-on) reset because it does not reset all of the bits
in the CR register.

We were incorrectly implementing soft reset and hard reset
the same way, and in addition had a logic error which meant
that we were clearing the bits that soft-reset is supposed
to preserve and not touching the bits that soft-reset clears.
This was not correct behaviour for either kind of reset.

Separate out the soft reset and hard reset code paths, and
correct the handling of reset of the CR register so that it
is correct in both cases.

Signed-off-by: Kurban Mallachiev <mallachiev@ispras.ru>
[PMM: rephrased commit message, spacing on operators;
 use bool rather than int for is_soft_reset]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-02-28 12:08:16 +00:00

543 lines
14 KiB
C
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/*
* IMX GPT Timer
*
* Copyright (c) 2008 OK Labs
* Copyright (c) 2011 NICTA Pty Ltd
* Originally written by Hans Jiang
* Updated by Peter Chubb
* Updated by Jean-Christophe Dubois <jcd@tribudubois.net>
*
* This code is licensed under GPL version 2 or later. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "hw/timer/imx_gpt.h"
#include "qemu/main-loop.h"
#include "qemu/log.h"
#ifndef DEBUG_IMX_GPT
#define DEBUG_IMX_GPT 0
#endif
#define DPRINTF(fmt, args...) \
do { \
if (DEBUG_IMX_GPT) { \
fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_GPT, \
__func__, ##args); \
} \
} while (0)
static const char *imx_gpt_reg_name(uint32_t reg)
{
switch (reg) {
case 0:
return "CR";
case 1:
return "PR";
case 2:
return "SR";
case 3:
return "IR";
case 4:
return "OCR1";
case 5:
return "OCR2";
case 6:
return "OCR3";
case 7:
return "ICR1";
case 8:
return "ICR2";
case 9:
return "CNT";
default:
return "[?]";
}
}
static const VMStateDescription vmstate_imx_timer_gpt = {
.name = TYPE_IMX_GPT,
.version_id = 3,
.minimum_version_id = 3,
.fields = (VMStateField[]) {
VMSTATE_UINT32(cr, IMXGPTState),
VMSTATE_UINT32(pr, IMXGPTState),
VMSTATE_UINT32(sr, IMXGPTState),
VMSTATE_UINT32(ir, IMXGPTState),
VMSTATE_UINT32(ocr1, IMXGPTState),
VMSTATE_UINT32(ocr2, IMXGPTState),
VMSTATE_UINT32(ocr3, IMXGPTState),
VMSTATE_UINT32(icr1, IMXGPTState),
VMSTATE_UINT32(icr2, IMXGPTState),
VMSTATE_UINT32(cnt, IMXGPTState),
VMSTATE_UINT32(next_timeout, IMXGPTState),
VMSTATE_UINT32(next_int, IMXGPTState),
VMSTATE_UINT32(freq, IMXGPTState),
VMSTATE_PTIMER(timer, IMXGPTState),
VMSTATE_END_OF_LIST()
}
};
static const IMXClk imx25_gpt_clocks[] = {
CLK_NONE, /* 000 No clock source */
CLK_IPG, /* 001 ipg_clk, 532MHz*/
CLK_IPG_HIGH, /* 010 ipg_clk_highfreq */
CLK_NONE, /* 011 not defined */
CLK_32k, /* 100 ipg_clk_32k */
CLK_32k, /* 101 ipg_clk_32k */
CLK_32k, /* 110 ipg_clk_32k */
CLK_32k, /* 111 ipg_clk_32k */
};
static const IMXClk imx31_gpt_clocks[] = {
CLK_NONE, /* 000 No clock source */
CLK_IPG, /* 001 ipg_clk, 532MHz*/
CLK_IPG_HIGH, /* 010 ipg_clk_highfreq */
CLK_NONE, /* 011 not defined */
CLK_32k, /* 100 ipg_clk_32k */
CLK_NONE, /* 101 not defined */
CLK_NONE, /* 110 not defined */
CLK_NONE, /* 111 not defined */
};
static const IMXClk imx6_gpt_clocks[] = {
CLK_NONE, /* 000 No clock source */
CLK_IPG, /* 001 ipg_clk, 532MHz*/
CLK_IPG_HIGH, /* 010 ipg_clk_highfreq */
CLK_EXT, /* 011 External clock */
CLK_32k, /* 100 ipg_clk_32k */
CLK_HIGH_DIV, /* 101 reference clock / 8 */
CLK_NONE, /* 110 not defined */
CLK_HIGH, /* 111 reference clock */
};
static void imx_gpt_set_freq(IMXGPTState *s)
{
uint32_t clksrc = extract32(s->cr, GPT_CR_CLKSRC_SHIFT, 3);
s->freq = imx_ccm_get_clock_frequency(s->ccm,
s->clocks[clksrc]) / (1 + s->pr);
DPRINTF("Setting clksrc %d to frequency %d\n", clksrc, s->freq);
if (s->freq) {
ptimer_set_freq(s->timer, s->freq);
}
}
static void imx_gpt_update_int(IMXGPTState *s)
{
if ((s->sr & s->ir) && (s->cr & GPT_CR_EN)) {
qemu_irq_raise(s->irq);
} else {
qemu_irq_lower(s->irq);
}
}
static uint32_t imx_gpt_update_count(IMXGPTState *s)
{
s->cnt = s->next_timeout - (uint32_t)ptimer_get_count(s->timer);
return s->cnt;
}
static inline uint32_t imx_gpt_find_limit(uint32_t count, uint32_t reg,
uint32_t timeout)
{
if ((count < reg) && (timeout > reg)) {
timeout = reg;
}
return timeout;
}
static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event)
{
uint32_t timeout = GPT_TIMER_MAX;
uint32_t count;
long long limit;
if (!(s->cr & GPT_CR_EN)) {
/* if not enabled just return */
return;
}
/* update the count */
count = imx_gpt_update_count(s);
if (event) {
/*
* This is an event (the ptimer reached 0 and stopped), and the
* timer counter is now equal to s->next_timeout.
*/
if (!(s->cr & GPT_CR_FRR) && (count == s->ocr1)) {
/* We are in restart mode and we crossed the compare channel 1
* value. We need to reset the counter to 0.
*/
count = s->cnt = s->next_timeout = 0;
} else if (count == GPT_TIMER_MAX) {
/* We reached GPT_TIMER_MAX so we need to rollover */
count = s->cnt = s->next_timeout = 0;
}
}
/* now, find the next timeout related to count */
if (s->ir & GPT_IR_OF1IE) {
timeout = imx_gpt_find_limit(count, s->ocr1, timeout);
}
if (s->ir & GPT_IR_OF2IE) {
timeout = imx_gpt_find_limit(count, s->ocr2, timeout);
}
if (s->ir & GPT_IR_OF3IE) {
timeout = imx_gpt_find_limit(count, s->ocr3, timeout);
}
/* find the next set of interrupts to raise for next timer event */
s->next_int = 0;
if ((s->ir & GPT_IR_OF1IE) && (timeout == s->ocr1)) {
s->next_int |= GPT_SR_OF1;
}
if ((s->ir & GPT_IR_OF2IE) && (timeout == s->ocr2)) {
s->next_int |= GPT_SR_OF2;
}
if ((s->ir & GPT_IR_OF3IE) && (timeout == s->ocr3)) {
s->next_int |= GPT_SR_OF3;
}
if ((s->ir & GPT_IR_ROVIE) && (timeout == GPT_TIMER_MAX)) {
s->next_int |= GPT_SR_ROV;
}
/* the new range to count down from */
limit = timeout - imx_gpt_update_count(s);
if (limit < 0) {
/*
* if we reach here, then QEMU is running too slow and we pass the
* timeout limit while computing it. Let's deliver the interrupt
* and compute a new limit.
*/
s->sr |= s->next_int;
imx_gpt_compute_next_timeout(s, event);
imx_gpt_update_int(s);
} else {
/* New timeout value */
s->next_timeout = timeout;
/* reset the limit to the computed range */
ptimer_set_limit(s->timer, limit, 1);
}
}
static uint64_t imx_gpt_read(void *opaque, hwaddr offset, unsigned size)
{
IMXGPTState *s = IMX_GPT(opaque);
uint32_t reg_value = 0;
switch (offset >> 2) {
case 0: /* Control Register */
reg_value = s->cr;
break;
case 1: /* prescaler */
reg_value = s->pr;
break;
case 2: /* Status Register */
reg_value = s->sr;
break;
case 3: /* Interrupt Register */
reg_value = s->ir;
break;
case 4: /* Output Compare Register 1 */
reg_value = s->ocr1;
break;
case 5: /* Output Compare Register 2 */
reg_value = s->ocr2;
break;
case 6: /* Output Compare Register 3 */
reg_value = s->ocr3;
break;
case 7: /* input Capture Register 1 */
qemu_log_mask(LOG_UNIMP, "[%s]%s: icr1 feature is not implemented\n",
TYPE_IMX_GPT, __func__);
reg_value = s->icr1;
break;
case 8: /* input Capture Register 2 */
qemu_log_mask(LOG_UNIMP, "[%s]%s: icr2 feature is not implemented\n",
TYPE_IMX_GPT, __func__);
reg_value = s->icr2;
break;
case 9: /* cnt */
imx_gpt_update_count(s);
reg_value = s->cnt;
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_GPT, __func__, offset);
break;
}
DPRINTF("(%s) = 0x%08x\n", imx_gpt_reg_name(offset >> 2), reg_value);
return reg_value;
}
static void imx_gpt_reset_common(IMXGPTState *s, bool is_soft_reset)
{
/* stop timer */
ptimer_stop(s->timer);
/* Soft reset and hard reset differ only in their handling of the CR
* register -- soft reset preserves the values of some bits there.
*/
if (is_soft_reset) {
/* Clear all CR bits except those that are preserved by soft reset. */
s->cr &= GPT_CR_EN | GPT_CR_ENMOD | GPT_CR_STOPEN | GPT_CR_DOZEN |
GPT_CR_WAITEN | GPT_CR_DBGEN |
(GPT_CR_CLKSRC_MASK << GPT_CR_CLKSRC_SHIFT);
} else {
s->cr = 0;
}
s->sr = 0;
s->pr = 0;
s->ir = 0;
s->cnt = 0;
s->ocr1 = GPT_TIMER_MAX;
s->ocr2 = GPT_TIMER_MAX;
s->ocr3 = GPT_TIMER_MAX;
s->icr1 = 0;
s->icr2 = 0;
s->next_timeout = GPT_TIMER_MAX;
s->next_int = 0;
/* compute new freq */
imx_gpt_set_freq(s);
/* reset the limit to GPT_TIMER_MAX */
ptimer_set_limit(s->timer, GPT_TIMER_MAX, 1);
/* if the timer is still enabled, restart it */
if (s->freq && (s->cr & GPT_CR_EN)) {
ptimer_run(s->timer, 1);
}
}
static void imx_gpt_soft_reset(DeviceState *dev)
{
IMXGPTState *s = IMX_GPT(dev);
imx_gpt_reset_common(s, true);
}
static void imx_gpt_reset(DeviceState *dev)
{
IMXGPTState *s = IMX_GPT(dev);
imx_gpt_reset_common(s, false);
}
static void imx_gpt_write(void *opaque, hwaddr offset, uint64_t value,
unsigned size)
{
IMXGPTState *s = IMX_GPT(opaque);
uint32_t oldreg;
DPRINTF("(%s, value = 0x%08x)\n", imx_gpt_reg_name(offset >> 2),
(uint32_t)value);
switch (offset >> 2) {
case 0:
oldreg = s->cr;
s->cr = value & ~0x7c14;
if (s->cr & GPT_CR_SWR) { /* force reset */
/* handle the reset */
imx_gpt_soft_reset(DEVICE(s));
} else {
/* set our freq, as the source might have changed */
imx_gpt_set_freq(s);
if ((oldreg ^ s->cr) & GPT_CR_EN) {
if (s->cr & GPT_CR_EN) {
if (s->cr & GPT_CR_ENMOD) {
s->next_timeout = GPT_TIMER_MAX;
ptimer_set_count(s->timer, GPT_TIMER_MAX);
imx_gpt_compute_next_timeout(s, false);
}
ptimer_run(s->timer, 1);
} else {
/* stop timer */
ptimer_stop(s->timer);
}
}
}
break;
case 1: /* Prescaler */
s->pr = value & 0xfff;
imx_gpt_set_freq(s);
break;
case 2: /* SR */
s->sr &= ~(value & 0x3f);
imx_gpt_update_int(s);
break;
case 3: /* IR -- interrupt register */
s->ir = value & 0x3f;
imx_gpt_update_int(s);
imx_gpt_compute_next_timeout(s, false);
break;
case 4: /* OCR1 -- output compare register */
s->ocr1 = value;
/* In non-freerun mode, reset count when this register is written */
if (!(s->cr & GPT_CR_FRR)) {
s->next_timeout = GPT_TIMER_MAX;
ptimer_set_limit(s->timer, GPT_TIMER_MAX, 1);
}
/* compute the new timeout */
imx_gpt_compute_next_timeout(s, false);
break;
case 5: /* OCR2 -- output compare register */
s->ocr2 = value;
/* compute the new timeout */
imx_gpt_compute_next_timeout(s, false);
break;
case 6: /* OCR3 -- output compare register */
s->ocr3 = value;
/* compute the new timeout */
imx_gpt_compute_next_timeout(s, false);
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_GPT, __func__, offset);
break;
}
}
static void imx_gpt_timeout(void *opaque)
{
IMXGPTState *s = IMX_GPT(opaque);
DPRINTF("\n");
s->sr |= s->next_int;
s->next_int = 0;
imx_gpt_compute_next_timeout(s, true);
imx_gpt_update_int(s);
if (s->freq && (s->cr & GPT_CR_EN)) {
ptimer_run(s->timer, 1);
}
}
static const MemoryRegionOps imx_gpt_ops = {
.read = imx_gpt_read,
.write = imx_gpt_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void imx_gpt_realize(DeviceState *dev, Error **errp)
{
IMXGPTState *s = IMX_GPT(dev);
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
QEMUBH *bh;
sysbus_init_irq(sbd, &s->irq);
memory_region_init_io(&s->iomem, OBJECT(s), &imx_gpt_ops, s, TYPE_IMX_GPT,
0x00001000);
sysbus_init_mmio(sbd, &s->iomem);
bh = qemu_bh_new(imx_gpt_timeout, s);
s->timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
}
static void imx_gpt_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = imx_gpt_realize;
dc->reset = imx_gpt_reset;
dc->vmsd = &vmstate_imx_timer_gpt;
dc->desc = "i.MX general timer";
}
static void imx25_gpt_init(Object *obj)
{
IMXGPTState *s = IMX_GPT(obj);
s->clocks = imx25_gpt_clocks;
}
static void imx31_gpt_init(Object *obj)
{
IMXGPTState *s = IMX_GPT(obj);
s->clocks = imx31_gpt_clocks;
}
static void imx6_gpt_init(Object *obj)
{
IMXGPTState *s = IMX_GPT(obj);
s->clocks = imx6_gpt_clocks;
}
static const TypeInfo imx25_gpt_info = {
.name = TYPE_IMX25_GPT,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMXGPTState),
.instance_init = imx25_gpt_init,
.class_init = imx_gpt_class_init,
};
static const TypeInfo imx31_gpt_info = {
.name = TYPE_IMX31_GPT,
.parent = TYPE_IMX25_GPT,
.instance_init = imx31_gpt_init,
};
static const TypeInfo imx6_gpt_info = {
.name = TYPE_IMX6_GPT,
.parent = TYPE_IMX25_GPT,
.instance_init = imx6_gpt_init,
};
static void imx_gpt_register_types(void)
{
type_register_static(&imx25_gpt_info);
type_register_static(&imx31_gpt_info);
type_register_static(&imx6_gpt_info);
}
type_init(imx_gpt_register_types)
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