diff options
Diffstat (limited to 'hw/misc')
| -rw-r--r-- | hw/misc/mac_via.c | 115 | ||||
| -rw-r--r-- | hw/misc/trace-events | 1 |
2 files changed, 116 insertions, 0 deletions
diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c index e87a1b8..f2ccb12 100644 --- a/hw/misc/mac_via.c +++ b/hw/misc/mac_via.c @@ -16,6 +16,7 @@ */ #include "qemu/osdep.h" +#include "exec/address-spaces.h" #include "migration/vmstate.h" #include "hw/sysbus.h" #include "hw/irq.h" @@ -871,6 +872,112 @@ static void via1_auxmode_update(MOS6522Q800VIA1State *v1s) } } +/* + * Addresses and real values for TimeDBRA/TimeSCCB to allow timer calibration + * to succeed (NOTE: both values have been multiplied by 3 to cope with the + * speed of QEMU execution on a modern host + */ +#define MACOS_TIMEDBRA 0xd00 +#define MACOS_TIMESCCB 0xd02 + +#define MACOS_TIMEDBRA_VALUE (0x2a00 * 3) +#define MACOS_TIMESCCB_VALUE (0x079d * 3) + +static bool via1_is_toolbox_timer_calibrated(void) +{ + /* + * Indicate whether the MacOS toolbox has been calibrated by checking + * for the value of our magic constants + */ + uint16_t timedbra = lduw_be_phys(&address_space_memory, MACOS_TIMEDBRA); + uint16_t timesccdb = lduw_be_phys(&address_space_memory, MACOS_TIMESCCB); + + return (timedbra == MACOS_TIMEDBRA_VALUE && + timesccdb == MACOS_TIMESCCB_VALUE); +} + +static void via1_timer_calibration_hack(MOS6522Q800VIA1State *v1s, int addr, + uint64_t val, int size) +{ + /* + * Work around timer calibration to ensure we that we have non-zero and + * known good values for TIMEDRBA and TIMESCCDB. + * + * This works by attempting to detect the reset and calibration sequence + * of writes to VIA1 + */ + int old_timer_hack_state = v1s->timer_hack_state; + + switch (v1s->timer_hack_state) { + case 0: + if (addr == VIA_REG_PCR && val == 0x22) { + /* VIA_REG_PCR: configure VIA1 edge triggering */ + v1s->timer_hack_state = 1; + } + break; + case 1: + if (addr == VIA_REG_T2CL && val == 0xc) { + /* VIA_REG_T2CL: low byte of 1ms counter */ + if (!via1_is_toolbox_timer_calibrated()) { + v1s->timer_hack_state = 2; + } else { + v1s->timer_hack_state = 0; + } + } + break; + case 2: + if (addr == VIA_REG_T2CH && val == 0x3) { + /* + * VIA_REG_T2CH: high byte of 1ms counter (very likely at the + * start of SETUPTIMEK) + */ + if (!via1_is_toolbox_timer_calibrated()) { + v1s->timer_hack_state = 3; + } else { + v1s->timer_hack_state = 0; + } + } + break; + case 3: + if (addr == VIA_REG_IER && val == 0x20) { + /* + * VIA_REG_IER: update at end of SETUPTIMEK + * + * Timer calibration has finished: unfortunately the values in + * TIMEDBRA (0xd00) and TIMESCCDB (0xd02) are so far out they + * cause divide by zero errors. + * + * Update them with values obtained from a real Q800 but with + * a x3 scaling factor which seems to work well + */ + stw_be_phys(&address_space_memory, MACOS_TIMEDBRA, + MACOS_TIMEDBRA_VALUE); + stw_be_phys(&address_space_memory, MACOS_TIMESCCB, + MACOS_TIMESCCB_VALUE); + + v1s->timer_hack_state = 4; + } + break; + case 4: + /* + * This is the normal post-calibration timer state: we should + * generally remain here unless we detect the A/UX calibration + * loop, or a write to VIA_REG_PCR suggesting a reset + */ + if (addr == VIA_REG_PCR && val == 0x22) { + /* Looks like there has been a reset? */ + v1s->timer_hack_state = 1; + } + break; + default: + g_assert_not_reached(); + } + + if (old_timer_hack_state != v1s->timer_hack_state) { + trace_via1_timer_hack_state(v1s->timer_hack_state); + } +} + static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size) { MOS6522Q800VIA1State *s = MOS6522_Q800_VIA1(opaque); @@ -896,6 +1003,9 @@ static void mos6522_q800_via1_write(void *opaque, hwaddr addr, uint64_t val, MOS6522State *ms = MOS6522(v1s); addr = (addr >> 9) & 0xf; + + via1_timer_calibration_hack(v1s, addr, val, size); + mos6522_write(ms, addr, val, size); switch (addr) { @@ -1008,6 +1118,9 @@ static void mos6522_q800_via1_reset_hold(Object *obj) adb_set_autopoll_enabled(adb_bus, true); v1s->cmd = REG_EMPTY; v1s->alt = REG_EMPTY; + + /* Timer calibration hack */ + v1s->timer_hack_state = 0; } static void mos6522_q800_via1_realize(DeviceState *dev, Error **errp) @@ -1100,6 +1213,8 @@ static const VMStateDescription vmstate_q800_via1 = { VMSTATE_INT64(next_second, MOS6522Q800VIA1State), VMSTATE_TIMER_PTR(sixty_hz_timer, MOS6522Q800VIA1State), VMSTATE_INT64(next_sixty_hz, MOS6522Q800VIA1State), + /* Timer hack */ + VMSTATE_INT32(timer_hack_state, MOS6522Q800VIA1State), VMSTATE_END_OF_LIST() } }; diff --git a/hw/misc/trace-events b/hw/misc/trace-events index 29bc531..5a998f5 100644 --- a/hw/misc/trace-events +++ b/hw/misc/trace-events @@ -272,6 +272,7 @@ via1_adb_send(const char *state, uint8_t data, const char *vadbint) "state %s da via1_adb_receive(const char *state, uint8_t data, const char *vadbint, int status, int index, int size) "state %s data=0x%02x vADBInt=%s status=0x%x index=%d size=%d" via1_adb_poll(uint8_t data, const char *vadbint, int status, int index, int size) "data=0x%02x vADBInt=%s status=0x%x index=%d size=%d" via1_auxmode(int mode) "setting auxmode to %d" +via1_timer_hack_state(int state) "setting timer_hack_state to %d" # grlib_ahb_apb_pnp.c grlib_ahb_pnp_read(uint64_t addr, unsigned size, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" size:%u data:0x%08x" |