--- /dev/null
+/*
+ * ColdFire UART emulation.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ * This code is licenced under the GPL
+ */
+#include "vl.h"
+
+typedef struct {
+ uint8_t mr[2];
+ uint8_t sr;
+ uint8_t isr;
+ uint8_t imr;
+ uint8_t bg1;
+ uint8_t bg2;
+ uint8_t fifo[4];
+ uint8_t tb;
+ int current_mr;
+ int fifo_len;
+ int tx_enabled;
+ int rx_enabled;
+ qemu_irq irq;
+ CharDriverState *chr;
+} mcf_uart_state;
+
+/* UART Status Register bits. */
+#define MCF_UART_RxRDY 0x01
+#define MCF_UART_FFULL 0x02
+#define MCF_UART_TxRDY 0x04
+#define MCF_UART_TxEMP 0x08
+#define MCF_UART_OE 0x10
+#define MCF_UART_PE 0x20
+#define MCF_UART_FE 0x40
+#define MCF_UART_RB 0x80
+
+/* Interrupt flags. */
+#define MCF_UART_TxINT 0x01
+#define MCF_UART_RxINT 0x02
+#define MCF_UART_DBINT 0x04
+#define MCF_UART_COSINT 0x80
+
+/* UMR1 flags. */
+#define MCF_UART_BC0 0x01
+#define MCF_UART_BC1 0x02
+#define MCF_UART_PT 0x04
+#define MCF_UART_PM0 0x08
+#define MCF_UART_PM1 0x10
+#define MCF_UART_ERR 0x20
+#define MCF_UART_RxIRQ 0x40
+#define MCF_UART_RxRTS 0x80
+
+static void mcf_uart_update(mcf_uart_state *s)
+{
+ s->isr &= ~(MCF_UART_TxINT | MCF_UART_RxINT);
+ if (s->sr & MCF_UART_TxRDY)
+ s->isr |= MCF_UART_TxINT;
+ if ((s->sr & ((s->mr[0] & MCF_UART_RxIRQ)
+ ? MCF_UART_FFULL : MCF_UART_RxRDY)) != 0)
+ s->isr |= MCF_UART_RxINT;
+
+ qemu_set_irq(s->irq, (s->isr & s->imr) != 0);
+}
+
+uint32_t mcf_uart_read(void *opaque, target_phys_addr_t addr)
+{
+ mcf_uart_state *s = (mcf_uart_state *)opaque;
+ switch (addr & 0x3f) {
+ case 0x00:
+ return s->mr[s->current_mr];
+ case 0x04:
+ return s->sr;
+ case 0x0c:
+ {
+ uint8_t val;
+ int i;
+
+ if (s->fifo_len == 0)
+ return 0;
+
+ val = s->fifo[0];
+ s->fifo_len--;
+ for (i = 0; i < s->fifo_len; i++)
+ s->fifo[i] = s->fifo[i + 1];
+ s->sr &= ~MCF_UART_FFULL;
+ if (s->fifo_len == 0)
+ s->sr &= ~MCF_UART_RxRDY;
+ mcf_uart_update(s);
+ return val;
+ }
+ case 0x10:
+ /* TODO: Implement IPCR. */
+ return 0;
+ case 0x14:
+ return s->isr;
+ case 0x18:
+ return s->bg1;
+ case 0x1c:
+ return s->bg2;
+ default:
+ return 0;
+ }
+}
+
+/* Update TxRDY flag and set data if present and enabled. */
+static void mcf_uart_do_tx(mcf_uart_state *s)
+{
+ if (s->tx_enabled && (s->sr & MCF_UART_TxEMP) == 0) {
+ if (s->chr)
+ qemu_chr_write(s->chr, (unsigned char *)&s->tb, 1);
+ s->sr |= MCF_UART_TxEMP;
+ }
+ if (s->tx_enabled) {
+ s->sr |= MCF_UART_TxRDY;
+ } else {
+ s->sr &= ~MCF_UART_TxRDY;
+ }
+}
+
+static void mcf_do_command(mcf_uart_state *s, uint8_t cmd)
+{
+ /* Misc command. */
+ switch ((cmd >> 4) & 3) {
+ case 0: /* No-op. */
+ break;
+ case 1: /* Reset mode register pointer. */
+ s->current_mr = 0;
+ break;
+ case 2: /* Reset receiver. */
+ s->rx_enabled = 0;
+ s->fifo_len = 0;
+ s->sr &= ~(MCF_UART_RxRDY | MCF_UART_FFULL);
+ break;
+ case 3: /* Reset transmitter. */
+ s->tx_enabled = 0;
+ s->sr |= MCF_UART_TxEMP;
+ s->sr &= ~MCF_UART_TxRDY;
+ break;
+ case 4: /* Reset error status. */
+ break;
+ case 5: /* Reset break-change interrupt. */
+ s->isr &= ~MCF_UART_DBINT;
+ break;
+ case 6: /* Start break. */
+ case 7: /* Stop break. */
+ break;
+ }
+
+ /* Transmitter command. */
+ switch ((cmd >> 2) & 3) {
+ case 0: /* No-op. */
+ break;
+ case 1: /* Enable. */
+ s->tx_enabled = 1;
+ mcf_uart_do_tx(s);
+ break;
+ case 2: /* Disable. */
+ s->tx_enabled = 0;
+ mcf_uart_do_tx(s);
+ break;
+ case 3: /* Reserved. */
+ fprintf(stderr, "mcf_uart: Bad TX command\n");
+ break;
+ }
+
+ /* Receiver command. */
+ switch (cmd & 3) {
+ case 0: /* No-op. */
+ break;
+ case 1: /* Enable. */
+ s->rx_enabled = 1;
+ break;
+ case 2:
+ s->rx_enabled = 0;
+ break;
+ case 3: /* Reserved. */
+ fprintf(stderr, "mcf_uart: Bad RX command\n");
+ break;
+ }
+}
+
+void mcf_uart_write(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+ mcf_uart_state *s = (mcf_uart_state *)opaque;
+ switch (addr & 0x3f) {
+ case 0x00:
+ s->mr[s->current_mr] = val;
+ s->current_mr = 1;
+ break;
+ case 0x04:
+ /* CSR is ignored. */
+ break;
+ case 0x08: /* Command Register. */
+ mcf_do_command(s, val);
+ break;
+ case 0x0c: /* Transmit Buffer. */
+ s->sr &= ~MCF_UART_TxEMP;
+ s->tb = val;
+ mcf_uart_do_tx(s);
+ break;
+ case 0x10:
+ /* ACR is ignored. */
+ break;
+ case 0x14:
+ s->imr = val;
+ break;
+ default:
+ break;
+ }
+ mcf_uart_update(s);
+}
+
+static void mcf_uart_reset(mcf_uart_state *s)
+{
+ s->fifo_len = 0;
+ s->mr[0] = 0;
+ s->mr[1] = 0;
+ s->sr = MCF_UART_TxEMP;
+ s->tx_enabled = 0;
+ s->rx_enabled = 0;
+ s->isr = 0;
+ s->imr = 0;
+}
+
+static void mcf_uart_push_byte(mcf_uart_state *s, uint8_t data)
+{
+ /* Break events overwrite the last byte if the fifo is full. */
+ if (s->fifo_len == 4)
+ s->fifo_len--;
+
+ s->fifo[s->fifo_len] = data;
+ s->fifo_len++;
+ s->sr |= MCF_UART_RxRDY;
+ if (s->fifo_len == 4)
+ s->sr |= MCF_UART_FFULL;
+
+ mcf_uart_update(s);
+}
+
+static void mcf_uart_event(void *opaque, int event)
+{
+ mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+ switch (event) {
+ case CHR_EVENT_BREAK:
+ s->isr |= MCF_UART_DBINT;
+ mcf_uart_push_byte(s, 0);
+ break;
+ default:
+ break;
+ }
+}
+
+static int mcf_uart_can_receive(void *opaque)
+{
+ mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+ return s->rx_enabled && (s->sr & MCF_UART_FFULL) == 0;
+}
+
+static void mcf_uart_receive(void *opaque, const uint8_t *buf, int size)
+{
+ mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+ mcf_uart_push_byte(s, buf[0]);
+}
+
+void *mcf_uart_init(qemu_irq irq, CharDriverState *chr)
+{
+ mcf_uart_state *s;
+
+ s = qemu_mallocz(sizeof(mcf_uart_state));
+ s->chr = chr;
+ s->irq = irq;
+ if (chr) {
+ qemu_chr_add_handlers(chr, mcf_uart_can_receive, mcf_uart_receive,
+ mcf_uart_event, s);
+ }
+ mcf_uart_reset(s);
+ return s;
+}
+
+
+static CPUReadMemoryFunc *mcf_uart_readfn[] = {
+ mcf_uart_read,
+ mcf_uart_read,
+ mcf_uart_read
+};
+
+static CPUWriteMemoryFunc *mcf_uart_writefn[] = {
+ mcf_uart_write,
+ mcf_uart_write,
+ mcf_uart_write
+};
+
+void mcf_uart_mm_init(target_phys_addr_t base, qemu_irq irq,
+ CharDriverState *chr)
+{
+ mcf_uart_state *s;
+ int iomemtype;
+
+ s = mcf_uart_init(irq, chr);
+ iomemtype = cpu_register_io_memory(0, mcf_uart_readfn,
+ mcf_uart_writefn, s);
+ cpu_register_physical_memory(base, 0x40, iomemtype);
+}
projects / mirror_qemu.git / blobdiff