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-rw-r--r--hw/i8254.c227
1 files changed, 163 insertions, 64 deletions
diff --git a/hw/i8254.c b/hw/i8254.c
index ad61a14af2..1eb4a1860f 100644
--- a/hw/i8254.c
+++ b/hw/i8254.c
@@ -25,14 +25,36 @@
//#define DEBUG_PIT
-#define RW_STATE_LSB 0
-#define RW_STATE_MSB 1
-#define RW_STATE_WORD0 2
-#define RW_STATE_WORD1 3
-#define RW_STATE_LATCHED_WORD0 4
-#define RW_STATE_LATCHED_WORD1 5
+#define RW_STATE_LSB 1
+#define RW_STATE_MSB 2
+#define RW_STATE_WORD0 3
+#define RW_STATE_WORD1 4
-PITChannelState pit_channels[3];
+typedef struct PITChannelState {
+ int count; /* can be 65536 */
+ uint16_t latched_count;
+ uint8_t count_latched;
+ uint8_t status_latched;
+ uint8_t status;
+ uint8_t read_state;
+ uint8_t write_state;
+ uint8_t write_latch;
+ uint8_t rw_mode;
+ uint8_t mode;
+ uint8_t bcd; /* not supported */
+ uint8_t gate; /* timer start */
+ int64_t count_load_time;
+ /* irq handling */
+ int64_t next_transition_time;
+ QEMUTimer *irq_timer;
+ int irq;
+} PITChannelState;
+
+struct PITState {
+ PITChannelState channels[3];
+};
+
+static PITState pit_state;
static void pit_irq_timer_update(PITChannelState *s, int64_t current_time);
@@ -61,7 +83,7 @@ static int pit_get_count(PITChannelState *s)
}
/* get pit output bit */
-int pit_get_out(PITChannelState *s, int64_t current_time)
+static int pit_get_out1(PITChannelState *s, int64_t current_time)
{
uint64_t d;
int out;
@@ -92,6 +114,12 @@ int pit_get_out(PITChannelState *s, int64_t current_time)
return out;
}
+int pit_get_out(PITState *pit, int channel, int64_t current_time)
+{
+ PITChannelState *s = &pit->channels[channel];
+ return pit_get_out1(s, current_time);
+}
+
/* return -1 if no transition will occur. */
static int64_t pit_get_next_transition_time(PITChannelState *s,
int64_t current_time)
@@ -144,8 +172,10 @@ static int64_t pit_get_next_transition_time(PITChannelState *s,
}
/* val must be 0 or 1 */
-void pit_set_gate(PITChannelState *s, int val)
+void pit_set_gate(PITState *pit, int channel, int val)
{
+ PITChannelState *s = &pit->channels[channel];
+
switch(s->mode) {
default:
case 0:
@@ -173,6 +203,12 @@ void pit_set_gate(PITChannelState *s, int val)
s->gate = val;
}
+int pit_get_gate(PITState *pit, int channel)
+{
+ PITChannelState *s = &pit->channels[channel];
+ return s->gate;
+}
+
static inline void pit_load_count(PITChannelState *s, int val)
{
if (val == 0)
@@ -182,33 +218,62 @@ static inline void pit_load_count(PITChannelState *s, int val)
pit_irq_timer_update(s, s->count_load_time);
}
+/* if already latched, do not latch again */
+static void pit_latch_count(PITChannelState *s)
+{
+ if (!s->count_latched) {
+ s->latched_count = pit_get_count(s);
+ s->count_latched = s->rw_mode;
+ }
+}
+
static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
+ PITState *pit = opaque;
int channel, access;
PITChannelState *s;
addr &= 3;
if (addr == 3) {
channel = val >> 6;
- if (channel == 3)
- return;
- s = &pit_channels[channel];
- access = (val >> 4) & 3;
- switch(access) {
- case 0:
- s->latched_count = pit_get_count(s);
- s->rw_state = RW_STATE_LATCHED_WORD0;
- break;
- default:
- s->mode = (val >> 1) & 7;
- s->bcd = val & 1;
- s->rw_state = access - 1 + RW_STATE_LSB;
- /* XXX: update irq timer ? */
- break;
+ if (channel == 3) {
+ /* read back command */
+ for(channel = 0; channel < 3; channel++) {
+ s = &pit->channels[channel];
+ if (val & (2 << channel)) {
+ if (!(val & 0x20)) {
+ pit_latch_count(s);
+ }
+ if (!(val & 0x10) && !s->status_latched) {
+ /* status latch */
+ /* XXX: add BCD and null count */
+ s->status = (pit_get_out1(s, qemu_get_clock(vm_clock)) << 7) |
+ (s->rw_mode << 4) |
+ (s->mode << 1) |
+ s->bcd;
+ s->status_latched = 1;
+ }
+ }
+ }
+ } else {
+ s = &pit->channels[channel];
+ access = (val >> 4) & 3;
+ if (access == 0) {
+ pit_latch_count(s);
+ } else {
+ s->rw_mode = access;
+ s->read_state = access;
+ s->write_state = access;
+
+ s->mode = (val >> 1) & 7;
+ s->bcd = val & 1;
+ /* XXX: update irq timer ? */
+ }
}
} else {
- s = &pit_channels[addr];
- switch(s->rw_state) {
+ s = &pit->channels[addr];
+ switch(s->write_state) {
+ default:
case RW_STATE_LSB:
pit_load_count(s, val);
break;
@@ -216,13 +281,12 @@ static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
pit_load_count(s, val << 8);
break;
case RW_STATE_WORD0:
+ s->write_latch = val;
+ s->write_state = RW_STATE_WORD1;
+ break;
case RW_STATE_WORD1:
- if (s->rw_state & 1) {
- pit_load_count(s, (s->latched_count & 0xff) | (val << 8));
- } else {
- s->latched_count = val;
- }
- s->rw_state ^= 1;
+ pit_load_count(s, s->write_latch | (val << 8));
+ s->write_state = RW_STATE_WORD0;
break;
}
}
@@ -230,33 +294,53 @@ static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
static uint32_t pit_ioport_read(void *opaque, uint32_t addr)
{
+ PITState *pit = opaque;
int ret, count;
PITChannelState *s;
addr &= 3;
- s = &pit_channels[addr];
- switch(s->rw_state) {
- case RW_STATE_LSB:
- case RW_STATE_MSB:
- case RW_STATE_WORD0:
- case RW_STATE_WORD1:
- count = pit_get_count(s);
- if (s->rw_state & 1)
- ret = (count >> 8) & 0xff;
- else
- ret = count & 0xff;
- if (s->rw_state & 2)
- s->rw_state ^= 1;
- break;
- default:
- case RW_STATE_LATCHED_WORD0:
- case RW_STATE_LATCHED_WORD1:
- if (s->rw_state & 1)
+ s = &pit->channels[addr];
+ if (s->status_latched) {
+ s->status_latched = 0;
+ ret = s->status;
+ } else if (s->count_latched) {
+ switch(s->count_latched) {
+ default:
+ case RW_STATE_LSB:
+ ret = s->latched_count & 0xff;
+ s->count_latched = 0;
+ break;
+ case RW_STATE_MSB:
ret = s->latched_count >> 8;
- else
+ s->count_latched = 0;
+ break;
+ case RW_STATE_WORD0:
ret = s->latched_count & 0xff;
- s->rw_state ^= 1;
- break;
+ s->count_latched = RW_STATE_MSB;
+ break;
+ }
+ } else {
+ switch(s->read_state) {
+ default:
+ case RW_STATE_LSB:
+ count = pit_get_count(s);
+ ret = count & 0xff;
+ break;
+ case RW_STATE_MSB:
+ count = pit_get_count(s);
+ ret = (count >> 8) & 0xff;
+ break;
+ case RW_STATE_WORD0:
+ count = pit_get_count(s);
+ ret = count & 0xff;
+ s->read_state = RW_STATE_WORD1;
+ break;
+ case RW_STATE_WORD1:
+ count = pit_get_count(s);
+ ret = (count >> 8) & 0xff;
+ s->read_state = RW_STATE_WORD0;
+ break;
+ }
}
return ret;
}
@@ -269,7 +353,7 @@ static void pit_irq_timer_update(PITChannelState *s, int64_t current_time)
if (!s->irq_timer)
return;
expire_time = pit_get_next_transition_time(s, current_time);
- irq_level = pit_get_out(s, current_time);
+ irq_level = pit_get_out1(s, current_time);
pic_set_irq(s->irq, irq_level);
#ifdef DEBUG_PIT
printf("irq_level=%d next_delay=%f\n",
@@ -292,14 +376,21 @@ static void pit_irq_timer(void *opaque)
static void pit_save(QEMUFile *f, void *opaque)
{
+ PITState *pit = opaque;
PITChannelState *s;
int i;
for(i = 0; i < 3; i++) {
- s = &pit_channels[i];
+ s = &pit->channels[i];
qemu_put_be32s(f, &s->count);
qemu_put_be16s(f, &s->latched_count);
- qemu_put_8s(f, &s->rw_state);
+ qemu_put_8s(f, &s->count_latched);
+ qemu_put_8s(f, &s->status_latched);
+ qemu_put_8s(f, &s->status);
+ qemu_put_8s(f, &s->read_state);
+ qemu_put_8s(f, &s->write_state);
+ qemu_put_8s(f, &s->write_latch);
+ qemu_put_8s(f, &s->rw_mode);
qemu_put_8s(f, &s->mode);
qemu_put_8s(f, &s->bcd);
qemu_put_8s(f, &s->gate);
@@ -313,6 +404,7 @@ static void pit_save(QEMUFile *f, void *opaque)
static int pit_load(QEMUFile *f, void *opaque, int version_id)
{
+ PITState *pit = opaque;
PITChannelState *s;
int i;
@@ -320,10 +412,16 @@ static int pit_load(QEMUFile *f, void *opaque, int version_id)
return -EINVAL;
for(i = 0; i < 3; i++) {
- s = &pit_channels[i];
+ s = &pit->channels[i];
qemu_get_be32s(f, &s->count);
qemu_get_be16s(f, &s->latched_count);
- qemu_get_8s(f, &s->rw_state);
+ qemu_get_8s(f, &s->count_latched);
+ qemu_get_8s(f, &s->status_latched);
+ qemu_get_8s(f, &s->status);
+ qemu_get_8s(f, &s->read_state);
+ qemu_get_8s(f, &s->write_state);
+ qemu_get_8s(f, &s->write_latch);
+ qemu_get_8s(f, &s->rw_mode);
qemu_get_8s(f, &s->mode);
qemu_get_8s(f, &s->bcd);
qemu_get_8s(f, &s->gate);
@@ -336,13 +434,14 @@ static int pit_load(QEMUFile *f, void *opaque, int version_id)
return 0;
}
-void pit_init(int base, int irq)
+PITState *pit_init(int base, int irq)
{
+ PITState *pit = &pit_state;
PITChannelState *s;
int i;
for(i = 0;i < 3; i++) {
- s = &pit_channels[i];
+ s = &pit->channels[i];
if (i == 0) {
/* the timer 0 is connected to an IRQ */
s->irq_timer = qemu_new_timer(vm_clock, pit_irq_timer, s);
@@ -353,9 +452,9 @@ void pit_init(int base, int irq)
pit_load_count(s, 0);
}
- register_savevm("i8254", base, 1, pit_save, pit_load, NULL);
+ register_savevm("i8254", base, 1, pit_save, pit_load, pit);
- register_ioport_write(base, 4, 1, pit_ioport_write, NULL);
- register_ioport_read(base, 3, 1, pit_ioport_read, NULL);
+ register_ioport_write(base, 4, 1, pit_ioport_write, pit);
+ register_ioport_read(base, 3, 1, pit_ioport_read, pit);
+ return pit;
}
-
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-15 15:01:24 +0000