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hw/m68k: implement ADB bus support for via
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VIA needs to be able to poll the ADB interface and to read/write data
from/to the bus.

This patch adds functions allowing that.

Co-developed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Message-Id: <20191026164546.30020-7-laurent@vivier.eu>
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vivier committed Oct 28, 2019
1 parent 6dca62a commit 87a34e2
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1 change: 1 addition & 0 deletions hw/misc/Kconfig
View file
Expand Up @@ -123,5 +123,6 @@ config UNIMP
config MAC_VIA
bool
select MOS6522
select ADB

source macio/Kconfig
197 changes: 197 additions & 0 deletions hw/misc/mac_via.c
View file
Expand Up @@ -264,10 +264,16 @@
* Table 19-10 ADB transaction states
*/

#define ADB_STATE_NEW 0
#define ADB_STATE_EVEN 1
#define ADB_STATE_ODD 2
#define ADB_STATE_IDLE 3

#define VIA1B_vADB_StateMask (VIA1B_vADBS1 | VIA1B_vADBS2)
#define VIA1B_vADB_StateShift 4

#define VIA_TIMER_FREQ (783360)
#define VIA_ADB_POLL_FREQ 50 /* XXX: not real */

/* VIA returns time offset from Jan 1, 1904, not 1970 */
#define RTC_OFFSET 2082844800
Expand Down Expand Up @@ -472,6 +478,181 @@ static void via1_rtc_update(MacVIAState *m)
}
}

static int adb_via_poll(MacVIAState *s, int state, uint8_t *data)
{
if (state != ADB_STATE_IDLE) {
return 0;
}

if (s->adb_data_in_size < s->adb_data_in_index) {
return 0;
}

if (s->adb_data_out_index != 0) {
return 0;
}

s->adb_data_in_index = 0;
s->adb_data_out_index = 0;
s->adb_data_in_size = adb_poll(&s->adb_bus, s->adb_data_in, 0xffff);

if (s->adb_data_in_size) {
*data = s->adb_data_in[s->adb_data_in_index++];
qemu_irq_raise(s->adb_data_ready);
}

return s->adb_data_in_size;
}

static int adb_via_send(MacVIAState *s, int state, uint8_t data)
{
switch (state) {
case ADB_STATE_NEW:
s->adb_data_out_index = 0;
break;
case ADB_STATE_EVEN:
if ((s->adb_data_out_index & 1) == 0) {
return 0;
}
break;
case ADB_STATE_ODD:
if (s->adb_data_out_index & 1) {
return 0;
}
break;
case ADB_STATE_IDLE:
return 0;
}

assert(s->adb_data_out_index < sizeof(s->adb_data_out) - 1);

s->adb_data_out[s->adb_data_out_index++] = data;
qemu_irq_raise(s->adb_data_ready);
return 1;
}

static int adb_via_receive(MacVIAState *s, int state, uint8_t *data)
{
switch (state) {
case ADB_STATE_NEW:
return 0;

case ADB_STATE_EVEN:
if (s->adb_data_in_size <= 0) {
qemu_irq_raise(s->adb_data_ready);
return 0;
}

if (s->adb_data_in_index >= s->adb_data_in_size) {
*data = 0;
qemu_irq_raise(s->adb_data_ready);
return 1;
}

if ((s->adb_data_in_index & 1) == 0) {
return 0;
}

break;

case ADB_STATE_ODD:
if (s->adb_data_in_size <= 0) {
qemu_irq_raise(s->adb_data_ready);
return 0;
}

if (s->adb_data_in_index >= s->adb_data_in_size) {
*data = 0;
qemu_irq_raise(s->adb_data_ready);
return 1;
}

if (s->adb_data_in_index & 1) {
return 0;
}

break;

case ADB_STATE_IDLE:
if (s->adb_data_out_index == 0) {
return 0;
}

s->adb_data_in_size = adb_request(&s->adb_bus, s->adb_data_in,
s->adb_data_out,
s->adb_data_out_index);
s->adb_data_out_index = 0;
s->adb_data_in_index = 0;
if (s->adb_data_in_size < 0) {
*data = 0xff;
qemu_irq_raise(s->adb_data_ready);
return -1;
}

if (s->adb_data_in_size == 0) {
return 0;
}

break;
}

assert(s->adb_data_in_index < sizeof(s->adb_data_in) - 1);

*data = s->adb_data_in[s->adb_data_in_index++];
qemu_irq_raise(s->adb_data_ready);
if (*data == 0xff || *data == 0) {
return 0;
}
return 1;
}

static void via1_adb_update(MacVIAState *m)
{
MOS6522Q800VIA1State *v1s = MOS6522_Q800_VIA1(&m->mos6522_via1);
MOS6522State *s = MOS6522(v1s);
int state;
int ret;

state = (s->b & VIA1B_vADB_StateMask) >> VIA1B_vADB_StateShift;

if (s->acr & VIA1ACR_vShiftOut) {
/* output mode */
ret = adb_via_send(m, state, s->sr);
if (ret > 0) {
s->b &= ~VIA1B_vADBInt;
} else {
s->b |= VIA1B_vADBInt;
}
} else {
/* input mode */
ret = adb_via_receive(m, state, &s->sr);
if (ret > 0 && s->sr != 0xff) {
s->b &= ~VIA1B_vADBInt;
} else {
s->b |= VIA1B_vADBInt;
}
}
}

static void via_adb_poll(void *opaque)
{
MacVIAState *m = opaque;
MOS6522Q800VIA1State *v1s = MOS6522_Q800_VIA1(&m->mos6522_via1);
MOS6522State *s = MOS6522(v1s);
int state;

if (s->b & VIA1B_vADBInt) {
state = (s->b & VIA1B_vADB_StateMask) >> VIA1B_vADB_StateShift;
if (adb_via_poll(m, state, &s->sr)) {
s->b &= ~VIA1B_vADBInt;
}
}

timer_mod(m->adb_poll_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
(NANOSECONDS_PER_SECOND / VIA_ADB_POLL_FREQ));
}

static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size)
{
MOS6522Q800VIA1State *s = MOS6522_Q800_VIA1(opaque);
Expand Down Expand Up @@ -553,6 +734,10 @@ static void mac_via_reset(DeviceState *dev)
MacVIAState *m = MAC_VIA(dev);
MOS6522Q800VIA1State *v1s = &m->mos6522_via1;

timer_mod(m->adb_poll_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
(NANOSECONDS_PER_SECOND / VIA_ADB_POLL_FREQ));

timer_del(v1s->VBL_timer);
v1s->next_VBL = 0;
timer_del(v1s->one_second_timer);
Expand Down Expand Up @@ -593,6 +778,10 @@ static void mac_via_realize(DeviceState *dev, Error **errp)

qemu_get_timedate(&tm, 0);
m->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;

m->adb_poll_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, via_adb_poll, m);
m->adb_data_ready = qdev_get_gpio_in_named(dev, "via1-irq",
VIA1_IRQ_ADB_READY_BIT);
}

static void mac_via_init(Object *obj)
Expand Down Expand Up @@ -642,6 +831,13 @@ static const VMStateDescription vmstate_mac_via = {
VMSTATE_UINT8(cmd, MacVIAState),
VMSTATE_INT32(wprotect, MacVIAState),
VMSTATE_INT32(alt, MacVIAState),
/* ADB */
VMSTATE_TIMER_PTR(adb_poll_timer, MacVIAState),
VMSTATE_INT32(adb_data_in_size, MacVIAState),
VMSTATE_INT32(adb_data_in_index, MacVIAState),
VMSTATE_INT32(adb_data_out_index, MacVIAState),
VMSTATE_BUFFER(adb_data_in, MacVIAState),
VMSTATE_BUFFER(adb_data_out, MacVIAState),
VMSTATE_END_OF_LIST()
}
};
Expand Down Expand Up @@ -671,6 +867,7 @@ static void mos6522_q800_via1_portB_write(MOS6522State *s)
MacVIAState *m = container_of(v1s, MacVIAState, mos6522_via1);

via1_rtc_update(m);
via1_adb_update(m);

v1s->last_b = s->b;
}
Expand Down
7 changes: 7 additions & 0 deletions include/hw/misc/mac_via.h
View file
Expand Up @@ -103,6 +103,13 @@ typedef struct MacVIAState {

/* ADB */
ADBBusState adb_bus;
QEMUTimer *adb_poll_timer;
qemu_irq adb_data_ready;
int adb_data_in_size;
int adb_data_in_index;
int adb_data_out_index;
uint8_t adb_data_in[128];
uint8_t adb_data_out[16];
} MacVIAState;

#endif

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