--- /dev/null
+/*
+ * QEMU model of the Milkymist UART block.
+ *
+ * Copyright (c) 2010 Michael Walle <michael@walle.cc>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Specification available at:
+ * http://www.milkymist.org/socdoc/uart.pdf
+ */
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "trace.h"
+#include "sysemu/char.h"
+#include "qemu/error-report.h"
+
+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),
+};
+
+#define TYPE_MILKYMIST_UART "milkymist-uart"
+#define MILKYMIST_UART(obj) \
+ OBJECT_CHECK(MilkymistUartState, (obj), TYPE_MILKYMIST_UART)
+
+struct MilkymistUartState {
+ SysBusDevice parent_obj;
+
+ MemoryRegion regs_region;
+ CharDriverState *chr;
+ qemu_irq irq;
+
+ uint32_t regs[R_MAX];
+};
+typedef struct MilkymistUartState MilkymistUartState;
+
+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;
+
+ default:
+ error_report("milkymist_uart: read access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+
+ trace_milkymist_uart_memory_read(addr << 2, r);
+
+ return r;
+}
+
+static void uart_write(void *opaque, hwaddr addr, uint64_t value,
+ unsigned size)
+{
+ MilkymistUartState *s = opaque;
+ unsigned char ch = value;
+
+ trace_milkymist_uart_memory_write(addr, value);
+
+ addr >>= 2;
+ switch (addr) {
+ case R_RXTX:
+ if (s->chr) {
+ qemu_chr_fe_write_all(s->chr, &ch, 1);
+ }
+ 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));
+ qemu_chr_accept_input(s->chr);
+ break;
+
+ default:
+ error_report("milkymist_uart: write access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+
+ uart_update_irq(s);
+}
+
+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;
+
+ uart_update_irq(s);
+}
+
+static int uart_can_rx(void *opaque)
+{
+ MilkymistUartState *s = opaque;
+
+ return !(s->regs[R_STAT] & STAT_RX_EVT);
+}
+
+static void uart_event(void *opaque, int event)
+{
+}
+
+static void milkymist_uart_reset(DeviceState *d)
+{
+ MilkymistUartState *s = MILKYMIST_UART(d);
+ int i;
+
+ for (i = 0; i < R_MAX; i++) {
+ s->regs[i] = 0;
+ }
+
+ /* THRE is always set */
+ s->regs[R_STAT] = STAT_THRE;
+}
+
+static void milkymist_uart_realize(DeviceState *dev, Error **errp)
+{
+ MilkymistUartState *s = MILKYMIST_UART(dev);
+
+ /* FIXME use a qdev chardev prop instead of qemu_char_get_next_serial() */
+ 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 void milkymist_uart_init(Object *obj)
+{
+ SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+ MilkymistUartState *s = MILKYMIST_UART(obj);
+
+ sysbus_init_irq(sbd, &s->irq);
+
+ memory_region_init_io(&s->regs_region, OBJECT(s), &uart_mmio_ops, s,
+ "milkymist-uart", R_MAX * 4);
+ sysbus_init_mmio(sbd, &s->regs_region);
+}
+
+static const VMStateDescription vmstate_milkymist_uart = {
+ .name = "milkymist-uart",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT32_ARRAY(regs, MilkymistUartState, R_MAX),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void milkymist_uart_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->realize = milkymist_uart_realize;
+ dc->reset = milkymist_uart_reset;
+ dc->vmsd = &vmstate_milkymist_uart;
+ /* Reason: realize() method uses qemu_char_get_next_serial() */
+ dc->cannot_instantiate_with_device_add_yet = true;
+}
+
+static const TypeInfo milkymist_uart_info = {
+ .name = TYPE_MILKYMIST_UART,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(MilkymistUartState),
+ .instance_init = milkymist_uart_init,
+ .class_init = milkymist_uart_class_init,
+};
+
+static void milkymist_uart_register_types(void)
+{
+ type_register_static(&milkymist_uart_info);
+}
+
+type_init(milkymist_uart_register_types)
Code Review / kvmfornfv.git / blobdiff