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qemu/hw/timer/slavio_timer.c
Peter Maydell b01422622b ptimer: Rename ptimer_init() to ptimer_init_with_bh() 
Currently the ptimer design uses a QEMU bottom-half as its
mechanism for calling back into the device model using the
ptimer when the timer has expired. Unfortunately this design
is fatally flawed, because it means that there is a lag
between the ptimer updating its own state and the device
callback function updating device state, and guest accesses
to device registers between the two can return inconsistent
device state.

We want to replace the bottom-half design with one where
the guest device's callback is called either immediately
(when the ptimer triggers by timeout) or when the device
model code closes a transaction-begin/end section (when the
ptimer triggers because the device model changed the
ptimer's count value or other state). As the first step,
rename ptimer_init() to ptimer_init_with_bh(), to free up
the ptimer_init() name for the new API. We can then convert
all the ptimer users away from ptimer_init_with_bh() before
removing it entirely.

(Commit created with
 git grep -l ptimer_init | xargs sed -i -e 's/ptimer_init/ptimer_init_with_bh/'
and three overlong lines folded by hand.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191008171740.9679-2-peter.maydell@linaro.org
2019-10-15 18:09:02 +01:00

437 lines
14 KiB
C
Raw Blame History

/*
* QEMU Sparc SLAVIO timer controller emulation
*
* Copyright (c) 2003-2005 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/timer.h"
#include "hw/irq.h"
#include "hw/ptimer.h"
#include "hw/qdev-properties.h"
#include "hw/sysbus.h"
#include "migration/vmstate.h"
#include "trace.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
/*
* Registers of hardware timer in sun4m.
*
* This is the timer/counter part of chip STP2001 (Slave I/O), also
* produced as NCR89C105. See
* http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
*
* The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
* are zero. Bit 31 is 1 when count has been reached.
*
* Per-CPU timers interrupt local CPU, system timer uses normal
* interrupt routing.
*
*/
#define MAX_CPUS 16
typedef struct CPUTimerState {
qemu_irq irq;
ptimer_state *timer;
uint32_t count, counthigh, reached;
/* processor only */
uint32_t run;
uint64_t limit;
} CPUTimerState;
#define TYPE_SLAVIO_TIMER "slavio_timer"
#define SLAVIO_TIMER(obj) \
OBJECT_CHECK(SLAVIO_TIMERState, (obj), TYPE_SLAVIO_TIMER)
typedef struct SLAVIO_TIMERState {
SysBusDevice parent_obj;
uint32_t num_cpus;
uint32_t cputimer_mode;
CPUTimerState cputimer[MAX_CPUS + 1];
} SLAVIO_TIMERState;
typedef struct TimerContext {
MemoryRegion iomem;
SLAVIO_TIMERState *s;
unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
} TimerContext;
#define SYS_TIMER_SIZE 0x14
#define CPU_TIMER_SIZE 0x10
#define TIMER_LIMIT 0
#define TIMER_COUNTER 1
#define TIMER_COUNTER_NORST 2
#define TIMER_STATUS 3
#define TIMER_MODE 4
#define TIMER_COUNT_MASK32 0xfffffe00
#define TIMER_LIMIT_MASK32 0x7fffffff
#define TIMER_MAX_COUNT64 0x7ffffffffffffe00ULL
#define TIMER_MAX_COUNT32 0x7ffffe00ULL
#define TIMER_REACHED 0x80000000
#define TIMER_PERIOD 500ULL // 500ns
#define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
#define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
static int slavio_timer_is_user(TimerContext *tc)
{
SLAVIO_TIMERState *s = tc->s;
unsigned int timer_index = tc->timer_index;
return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
}
// Update count, set irq, update expire_time
// Convert from ptimer countdown units
static void slavio_timer_get_out(CPUTimerState *t)
{
uint64_t count, limit;
if (t->limit == 0) { /* free-run system or processor counter */
limit = TIMER_MAX_COUNT32;
} else {
limit = t->limit;
}
count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
t->count = count & TIMER_COUNT_MASK32;
t->counthigh = count >> 32;
}
// timer callback
static void slavio_timer_irq(void *opaque)
{
TimerContext *tc = opaque;
SLAVIO_TIMERState *s = tc->s;
CPUTimerState *t = &s->cputimer[tc->timer_index];
slavio_timer_get_out(t);
trace_slavio_timer_irq(t->counthigh, t->count);
/* if limit is 0 (free-run), there will be no match */
if (t->limit != 0) {
t->reached = TIMER_REACHED;
}
/* there is no interrupt if user timer or free-run */
if (!slavio_timer_is_user(tc) && t->limit != 0) {
qemu_irq_raise(t->irq);
}
}
static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
unsigned size)
{
TimerContext *tc = opaque;
SLAVIO_TIMERState *s = tc->s;
uint32_t saddr, ret;
unsigned int timer_index = tc->timer_index;
CPUTimerState *t = &s->cputimer[timer_index];
saddr = addr >> 2;
switch (saddr) {
case TIMER_LIMIT:
// read limit (system counter mode) or read most signifying
// part of counter (user mode)
if (slavio_timer_is_user(tc)) {
// read user timer MSW
slavio_timer_get_out(t);
ret = t->counthigh | t->reached;
} else {
// read limit
// clear irq
qemu_irq_lower(t->irq);
t->reached = 0;
ret = t->limit & TIMER_LIMIT_MASK32;
}
break;
case TIMER_COUNTER:
// read counter and reached bit (system mode) or read lsbits
// of counter (user mode)
slavio_timer_get_out(t);
if (slavio_timer_is_user(tc)) { // read user timer LSW
ret = t->count & TIMER_MAX_COUNT64;
} else { // read limit
ret = (t->count & TIMER_MAX_COUNT32) |
t->reached;
}
break;
case TIMER_STATUS:
// only available in processor counter/timer
// read start/stop status
if (timer_index > 0) {
ret = t->run;
} else {
ret = 0;
}
break;
case TIMER_MODE:
// only available in system counter
// read user/system mode
ret = s->cputimer_mode;
break;
default:
trace_slavio_timer_mem_readl_invalid(addr);
ret = 0;
break;
}
trace_slavio_timer_mem_readl(addr, ret);
return ret;
}
static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
uint64_t val, unsigned size)
{
TimerContext *tc = opaque;
SLAVIO_TIMERState *s = tc->s;
uint32_t saddr;
unsigned int timer_index = tc->timer_index;
CPUTimerState *t = &s->cputimer[timer_index];
trace_slavio_timer_mem_writel(addr, val);
saddr = addr >> 2;
switch (saddr) {
case TIMER_LIMIT:
if (slavio_timer_is_user(tc)) {
uint64_t count;
// set user counter MSW, reset counter
t->limit = TIMER_MAX_COUNT64;
t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
t->reached = 0;
count = ((uint64_t)t->counthigh << 32) | t->count;
trace_slavio_timer_mem_writel_limit(timer_index, count);
ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
} else {
// set limit, reset counter
qemu_irq_lower(t->irq);
t->limit = val & TIMER_MAX_COUNT32;
if (t->timer) {
if (t->limit == 0) { /* free-run */
ptimer_set_limit(t->timer,
LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
} else {
ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
}
}
}
break;
case TIMER_COUNTER:
if (slavio_timer_is_user(tc)) {
uint64_t count;
// set user counter LSW, reset counter
t->limit = TIMER_MAX_COUNT64;
t->count = val & TIMER_MAX_COUNT64;
t->reached = 0;
count = ((uint64_t)t->counthigh) << 32 | t->count;
trace_slavio_timer_mem_writel_limit(timer_index, count);
ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
} else {
trace_slavio_timer_mem_writel_counter_invalid();
}
break;
case TIMER_COUNTER_NORST:
// set limit without resetting counter
t->limit = val & TIMER_MAX_COUNT32;
if (t->limit == 0) { /* free-run */
ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
} else {
ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
}
break;
case TIMER_STATUS:
if (slavio_timer_is_user(tc)) {
// start/stop user counter
if (val & 1) {
trace_slavio_timer_mem_writel_status_start(timer_index);
ptimer_run(t->timer, 0);
} else {
trace_slavio_timer_mem_writel_status_stop(timer_index);
ptimer_stop(t->timer);
}
}
t->run = val & 1;
break;
case TIMER_MODE:
if (timer_index == 0) {
unsigned int i;
for (i = 0; i < s->num_cpus; i++) {
unsigned int processor = 1 << i;
CPUTimerState *curr_timer = &s->cputimer[i + 1];
// check for a change in timer mode for this processor
if ((val & processor) != (s->cputimer_mode & processor)) {
if (val & processor) { // counter -> user timer
qemu_irq_lower(curr_timer->irq);
// counters are always running
if (!curr_timer->run) {
ptimer_stop(curr_timer->timer);
}
// user timer limit is always the same
curr_timer->limit = TIMER_MAX_COUNT64;
ptimer_set_limit(curr_timer->timer,
LIMIT_TO_PERIODS(curr_timer->limit),
1);
// set this processors user timer bit in config
// register
s->cputimer_mode |= processor;
trace_slavio_timer_mem_writel_mode_user(timer_index);
} else { // user timer -> counter
// start the counter
ptimer_run(curr_timer->timer, 0);
// clear this processors user timer bit in config
// register
s->cputimer_mode &= ~processor;
trace_slavio_timer_mem_writel_mode_counter(timer_index);
}
}
}
} else {
trace_slavio_timer_mem_writel_mode_invalid();
}
break;
default:
trace_slavio_timer_mem_writel_invalid(addr);
break;
}
}
static const MemoryRegionOps slavio_timer_mem_ops = {
.read = slavio_timer_mem_readl,
.write = slavio_timer_mem_writel,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
.min_access_size = 4,
.max_access_size = 4,
},
};
static const VMStateDescription vmstate_timer = {
.name ="timer",
.version_id = 3,
.minimum_version_id = 3,
.fields = (VMStateField[]) {
VMSTATE_UINT64(limit, CPUTimerState),
VMSTATE_UINT32(count, CPUTimerState),
VMSTATE_UINT32(counthigh, CPUTimerState),
VMSTATE_UINT32(reached, CPUTimerState),
VMSTATE_UINT32(run , CPUTimerState),
VMSTATE_PTIMER(timer, CPUTimerState),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_slavio_timer = {
.name ="slavio_timer",
.version_id = 3,
.minimum_version_id = 3,
.fields = (VMStateField[]) {
VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,
vmstate_timer, CPUTimerState),
VMSTATE_END_OF_LIST()
}
};
static void slavio_timer_reset(DeviceState *d)
{
SLAVIO_TIMERState *s = SLAVIO_TIMER(d);
unsigned int i;
CPUTimerState *curr_timer;
for (i = 0; i <= MAX_CPUS; i++) {
curr_timer = &s->cputimer[i];
curr_timer->limit = 0;
curr_timer->count = 0;
curr_timer->reached = 0;
if (i <= s->num_cpus) {
ptimer_set_limit(curr_timer->timer,
LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
ptimer_run(curr_timer->timer, 0);
curr_timer->run = 1;
}
}
s->cputimer_mode = 0;
}
static void slavio_timer_init(Object *obj)
{
SLAVIO_TIMERState *s = SLAVIO_TIMER(obj);
SysBusDevice *dev = SYS_BUS_DEVICE(obj);
QEMUBH *bh;
unsigned int i;
TimerContext *tc;
for (i = 0; i <= MAX_CPUS; i++) {
uint64_t size;
char timer_name[20];
tc = g_malloc0(sizeof(TimerContext));
tc->s = s;
tc->timer_index = i;
bh = qemu_bh_new(slavio_timer_irq, tc);
s->cputimer[i].timer = ptimer_init_with_bh(bh, PTIMER_POLICY_DEFAULT);
ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);
size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
memory_region_init_io(&tc->iomem, obj, &slavio_timer_mem_ops, tc,
timer_name, size);
sysbus_init_mmio(dev, &tc->iomem);
sysbus_init_irq(dev, &s->cputimer[i].irq);
}
}
static Property slavio_timer_properties[] = {
DEFINE_PROP_UINT32("num_cpus", SLAVIO_TIMERState, num_cpus, 0),
DEFINE_PROP_END_OF_LIST(),
};
static void slavio_timer_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->reset = slavio_timer_reset;
dc->vmsd = &vmstate_slavio_timer;
dc->props = slavio_timer_properties;
}
static const TypeInfo slavio_timer_info = {
.name = TYPE_SLAVIO_TIMER,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(SLAVIO_TIMERState),
.instance_init = slavio_timer_init,
.class_init = slavio_timer_class_init,
};
static void slavio_timer_register_types(void)
{
type_register_static(&slavio_timer_info);
}
type_init(slavio_timer_register_types)
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