enum {
R_RXTX = 0,
R_DIV,
+ R_STAT,
+ R_CTRL,
+ R_DBG,
R_MAX
};
+enum {
+ STAT_THRE = (1<<0),
+ STAT_RX_EVT = (1<<1),
+ STAT_TX_EVT = (1<<2),
+};
+
+enum {
+ CTRL_RX_IRQ_EN = (1<<0),
+ CTRL_TX_IRQ_EN = (1<<1),
+ CTRL_THRU_EN = (1<<2),
+};
+
+enum {
+ DBG_BREAK_EN = (1<<0),
+};
+
struct MilkymistUartState {
SysBusDevice busdev;
+ MemoryRegion regs_region;
CharDriverState *chr;
- qemu_irq rx_irq;
- qemu_irq tx_irq;
+ qemu_irq irq;
uint32_t regs[R_MAX];
};
typedef struct MilkymistUartState MilkymistUartState;
-static uint32_t uart_read(void *opaque, target_phys_addr_t addr)
+static void uart_update_irq(MilkymistUartState *s)
+{
+ int rx_event = s->regs[R_STAT] & STAT_RX_EVT;
+ int tx_event = s->regs[R_STAT] & STAT_TX_EVT;
+ int rx_irq_en = s->regs[R_CTRL] & CTRL_RX_IRQ_EN;
+ int tx_irq_en = s->regs[R_CTRL] & CTRL_TX_IRQ_EN;
+
+ if ((rx_irq_en && rx_event) || (tx_irq_en && tx_event)) {
+ trace_milkymist_uart_raise_irq();
+ qemu_irq_raise(s->irq);
+ } else {
+ trace_milkymist_uart_lower_irq();
+ qemu_irq_lower(s->irq);
+ }
+}
+
+static uint64_t uart_read(void *opaque, hwaddr addr,
+ unsigned size)
{
MilkymistUartState *s = opaque;
uint32_t r = 0;
addr >>= 2;
switch (addr) {
case R_RXTX:
+ r = s->regs[addr];
+ break;
case R_DIV:
+ case R_STAT:
+ case R_CTRL:
+ case R_DBG:
r = s->regs[addr];
break;
return r;
}
-static void uart_write(void *opaque, target_phys_addr_t addr, uint32_t value)
+static void uart_write(void *opaque, hwaddr addr, uint64_t value,
+ unsigned size)
{
MilkymistUartState *s = opaque;
unsigned char ch = value;
if (s->chr) {
qemu_chr_fe_write(s->chr, &ch, 1);
}
- trace_milkymist_uart_pulse_irq_tx();
- qemu_irq_pulse(s->tx_irq);
+ s->regs[R_STAT] |= STAT_TX_EVT;
break;
case R_DIV:
+ case R_CTRL:
+ case R_DBG:
s->regs[addr] = value;
break;
+ case R_STAT:
+ /* write one to clear bits */
+ s->regs[addr] &= ~(value & (STAT_RX_EVT | STAT_TX_EVT));
+ break;
+
default:
error_report("milkymist_uart: write access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
break;
}
-}
-static CPUReadMemoryFunc * const uart_read_fn[] = {
- NULL,
- NULL,
- &uart_read,
-};
+ uart_update_irq(s);
+}
-static CPUWriteMemoryFunc * const uart_write_fn[] = {
- NULL,
- NULL,
- &uart_write,
+static const MemoryRegionOps uart_mmio_ops = {
+ .read = uart_read,
+ .write = uart_write,
+ .valid = {
+ .min_access_size = 4,
+ .max_access_size = 4,
+ },
+ .endianness = DEVICE_NATIVE_ENDIAN,
};
static void uart_rx(void *opaque, const uint8_t *buf, int size)
{
MilkymistUartState *s = opaque;
+ assert(!(s->regs[R_STAT] & STAT_RX_EVT));
+
+ s->regs[R_STAT] |= STAT_RX_EVT;
s->regs[R_RXTX] = *buf;
- trace_milkymist_uart_pulse_irq_rx();
- qemu_irq_pulse(s->rx_irq);
+
+ uart_update_irq(s);
}
static int uart_can_rx(void *opaque)
{
- return 1;
+ MilkymistUartState *s = opaque;
+
+ return !(s->regs[R_STAT] & STAT_RX_EVT);
}
static void uart_event(void *opaque, int event)
for (i = 0; i < R_MAX; i++) {
s->regs[i] = 0;
}
+
+ /* THRE is always set */
+ s->regs[R_STAT] = STAT_THRE;
}
static int milkymist_uart_init(SysBusDevice *dev)
{
MilkymistUartState *s = FROM_SYSBUS(typeof(*s), dev);
- int uart_regs;
- sysbus_init_irq(dev, &s->rx_irq);
- sysbus_init_irq(dev, &s->tx_irq);
+ sysbus_init_irq(dev, &s->irq);
- uart_regs = cpu_register_io_memory(uart_read_fn, uart_write_fn, s,
- DEVICE_NATIVE_ENDIAN);
- sysbus_init_mmio(dev, R_MAX * 4, uart_regs);
+ memory_region_init_io(&s->regs_region, &uart_mmio_ops, s,
+ "milkymist-uart", R_MAX * 4);
+ sysbus_init_mmio(dev, &s->regs_region);
- s->chr = qdev_init_chardev(&dev->qdev);
+ s->chr = qemu_char_get_next_serial();
if (s->chr) {
qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s);
}
}
};
-static SysBusDeviceInfo milkymist_uart_info = {
- .init = milkymist_uart_init,
- .qdev.name = "milkymist-uart",
- .qdev.size = sizeof(MilkymistUartState),
- .qdev.vmsd = &vmstate_milkymist_uart,
- .qdev.reset = milkymist_uart_reset,
+static void milkymist_uart_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+ k->init = milkymist_uart_init;
+ dc->reset = milkymist_uart_reset;
+ dc->vmsd = &vmstate_milkymist_uart;
+}
+
+static TypeInfo milkymist_uart_info = {
+ .name = "milkymist-uart",
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(MilkymistUartState),
+ .class_init = milkymist_uart_class_init,
};
-static void milkymist_uart_register(void)
+static void milkymist_uart_register_types(void)
{
- sysbus_register_withprop(&milkymist_uart_info);
+ type_register_static(&milkymist_uart_info);
}
-device_init(milkymist_uart_register)
+type_init(milkymist_uart_register_types)