lm32: uart model

This patch add support for the LatticeMico32 UART.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

1 files changed, 288 insertions, 0 deletions

diff --git a/hw/lm32_uart.c b/hw/lm32_uart.c
new file mode 100644
index 0000000..e225087
--- /dev/null
+++ b/hw/lm32_uart.c
@@ -0,0 +1,288 @@
+/*
+ *  QEMU model of the LatticeMico32 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.latticesemi.com/documents/mico32uart.pdf
+ */
+
+
+#include "hw.h"
+#include "sysbus.h"
+#include "trace.h"
+#include "qemu-char.h"
+#include "qemu-error.h"
+
+enum {
+    R_RXTX = 0,
+    R_IER,
+    R_IIR,
+    R_LCR,
+    R_MCR,
+    R_LSR,
+    R_MSR,
+    R_DIV,
+    R_MAX
+};
+
+enum {
+    IER_RBRI = (1<<0),
+    IER_THRI = (1<<1),
+    IER_RLSI = (1<<2),
+    IER_MSI  = (1<<3),
+};
+
+enum {
+    IIR_STAT = (1<<0),
+    IIR_ID0  = (1<<1),
+    IIR_ID1  = (1<<2),
+};
+
+enum {
+    LCR_WLS0 = (1<<0),
+    LCR_WLS1 = (1<<1),
+    LCR_STB  = (1<<2),
+    LCR_PEN  = (1<<3),
+    LCR_EPS  = (1<<4),
+    LCR_SP   = (1<<5),
+    LCR_SB   = (1<<6),
+};
+
+enum {
+    MCR_DTR  = (1<<0),
+    MCR_RTS  = (1<<1),
+};
+
+enum {
+    LSR_DR   = (1<<0),
+    LSR_OE   = (1<<1),
+    LSR_PE   = (1<<2),
+    LSR_FE   = (1<<3),
+    LSR_BI   = (1<<4),
+    LSR_THRE = (1<<5),
+    LSR_TEMT = (1<<6),
+};
+
+enum {
+    MSR_DCTS = (1<<0),
+    MSR_DDSR = (1<<1),
+    MSR_TERI = (1<<2),
+    MSR_DDCD = (1<<3),
+    MSR_CTS  = (1<<4),
+    MSR_DSR  = (1<<5),
+    MSR_RI   = (1<<6),
+    MSR_DCD  = (1<<7),
+};
+
+struct LM32UartState {
+    SysBusDevice busdev;
+    CharDriverState *chr;
+    qemu_irq irq;
+
+    uint32_t regs[R_MAX];
+};
+typedef struct LM32UartState LM32UartState;
+
+static void uart_update_irq(LM32UartState *s)
+{
+    unsigned int irq;
+
+    if ((s->regs[R_LSR] & (LSR_OE | LSR_PE | LSR_FE | LSR_BI))
+            && (s->regs[R_IER] & IER_RLSI)) {
+        irq = 1;
+        s->regs[R_IIR] = IIR_ID1 | IIR_ID0;
+    } else if ((s->regs[R_LSR] & LSR_DR) && (s->regs[R_IER] & IER_RBRI)) {
+        irq = 1;
+        s->regs[R_IIR] = IIR_ID1;
+    } else if ((s->regs[R_LSR] & LSR_THRE) && (s->regs[R_IER] & IER_THRI)) {
+        irq = 1;
+        s->regs[R_IIR] = IIR_ID0;
+    } else if ((s->regs[R_MSR] & 0x0f) && (s->regs[R_IER] & IER_MSI)) {
+        irq = 1;
+        s->regs[R_IIR] = 0;
+    } else {
+        irq = 0;
+        s->regs[R_IIR] = IIR_STAT;
+    }
+
+    trace_lm32_uart_irq_state(irq);
+    qemu_set_irq(s->irq, irq);
+}
+
+static uint32_t uart_read(void *opaque, target_phys_addr_t addr)
+{
+    LM32UartState *s = opaque;
+    uint32_t r = 0;
+
+    addr >>= 2;
+    switch (addr) {
+    case R_RXTX:
+        r = s->regs[R_RXTX];
+        s->regs[R_LSR] &= ~LSR_DR;
+        uart_update_irq(s);
+        break;
+    case R_IIR:
+    case R_LSR:
+    case R_MSR:
+        r = s->regs[addr];
+        break;
+    case R_IER:
+    case R_LCR:
+    case R_MCR:
+    case R_DIV:
+        error_report("lm32_uart: read access to write only register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    default:
+        error_report("lm32_uart: read access to unkown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+
+    trace_lm32_uart_memory_read(addr << 2, r);
+    return r;
+}
+
+static void uart_write(void *opaque, target_phys_addr_t addr, uint32_t value)
+{
+    LM32UartState *s = opaque;
+    unsigned char ch = value;
+
+    trace_lm32_uart_memory_write(addr, value);
+
+    addr >>= 2;
+    switch (addr) {
+    case R_RXTX:
+        if (s->chr) {
+            qemu_chr_write(s->chr, &ch, 1);
+        }
+        break;
+    case R_IER:
+    case R_LCR:
+    case R_MCR:
+    case R_DIV:
+        s->regs[addr] = value;
+        break;
+    case R_IIR:
+    case R_LSR:
+    case R_MSR:
+        error_report("lm32_uart: write access to read only register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    default:
+        error_report("lm32_uart: write access to unkown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+    uart_update_irq(s);
+}
+
+static CPUReadMemoryFunc * const uart_read_fn[] = {
+    NULL,
+    NULL,
+    &uart_read,
+};
+
+static CPUWriteMemoryFunc * const uart_write_fn[] = {
+    NULL,
+    NULL,
+    &uart_write,
+};
+
+static void uart_rx(void *opaque, const uint8_t *buf, int size)
+{
+    LM32UartState *s = opaque;
+
+    if (s->regs[R_LSR] & LSR_DR) {
+        s->regs[R_LSR] |= LSR_OE;
+    }
+
+    s->regs[R_LSR] |= LSR_DR;
+    s->regs[R_RXTX] = *buf;
+
+    uart_update_irq(s);
+}
+
+static int uart_can_rx(void *opaque)
+{
+    LM32UartState *s = opaque;
+
+    return !(s->regs[R_LSR] & LSR_DR);
+}
+
+static void uart_event(void *opaque, int event)
+{
+}
+
+static void uart_reset(DeviceState *d)
+{
+    LM32UartState *s = container_of(d, LM32UartState, busdev.qdev);
+    int i;
+
+    for (i = 0; i < R_MAX; i++) {
+        s->regs[i] = 0;
+    }
+
+    /* defaults */
+    s->regs[R_LSR] = LSR_THRE | LSR_TEMT;
+}
+
+static int lm32_uart_init(SysBusDevice *dev)
+{
+    LM32UartState *s = FROM_SYSBUS(typeof(*s), dev);
+    int uart_regs;
+
+    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);
+
+    s->chr = qdev_init_chardev(&dev->qdev);
+    if (s->chr) {
+        qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s);
+    }
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_lm32_uart = {
+    .name = "lm32-uart",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, LM32UartState, R_MAX),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static SysBusDeviceInfo lm32_uart_info = {
+    .init = lm32_uart_init,
+    .qdev.name  = "lm32-uart",
+    .qdev.size  = sizeof(LM32UartState),
+    .qdev.vmsd  = &vmstate_lm32_uart,
+    .qdev.reset = uart_reset,
+};
+
+static void lm32_uart_register(void)
+{
+    sysbus_register_withprop(&lm32_uart_info);
+}
+
+device_init(lm32_uart_register)