mirror of
https://github.com/xemu-project/xemu.git
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336 lines
9.4 KiB
C
336 lines
9.4 KiB
C
/*
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* Syborg serial port
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*
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* Copyright (c) 2008 CodeSourcery
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "sysbus.h"
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#include "qemu-char.h"
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#include "syborg.h"
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//#define DEBUG_SYBORG_SERIAL
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#ifdef DEBUG_SYBORG_SERIAL
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#define DPRINTF(fmt, ...) \
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do { printf("syborg_serial: " fmt , ##args); } while (0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__); \
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exit(1);} while (0)
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#else
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#define DPRINTF(fmt, ...) do {} while(0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__);} while (0)
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#endif
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enum {
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SERIAL_ID = 0,
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SERIAL_DATA = 1,
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SERIAL_FIFO_COUNT = 2,
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SERIAL_INT_ENABLE = 3,
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SERIAL_DMA_TX_ADDR = 4,
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SERIAL_DMA_TX_COUNT = 5, /* triggers dma */
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SERIAL_DMA_RX_ADDR = 6,
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SERIAL_DMA_RX_COUNT = 7, /* triggers dma */
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SERIAL_FIFO_SIZE = 8
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};
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#define SERIAL_INT_FIFO (1u << 0)
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#define SERIAL_INT_DMA_TX (1u << 1)
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#define SERIAL_INT_DMA_RX (1u << 2)
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typedef struct {
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SysBusDevice busdev;
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uint32_t int_enable;
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uint32_t fifo_size;
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uint32_t *read_fifo;
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int read_pos;
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int read_count;
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CharDriverState *chr;
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qemu_irq irq;
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uint32_t dma_tx_ptr;
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uint32_t dma_rx_ptr;
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uint32_t dma_rx_size;
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} SyborgSerialState;
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static void syborg_serial_update(SyborgSerialState *s)
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{
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int level;
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level = 0;
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if ((s->int_enable & SERIAL_INT_FIFO) && s->read_count)
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level = 1;
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if (s->int_enable & SERIAL_INT_DMA_TX)
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level = 1;
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if ((s->int_enable & SERIAL_INT_DMA_RX) && s->dma_rx_size == 0)
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level = 1;
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qemu_set_irq(s->irq, level);
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}
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static uint32_t fifo_pop(SyborgSerialState *s)
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{
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const uint32_t c = s->read_fifo[s->read_pos];
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s->read_count--;
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s->read_pos++;
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if (s->read_pos == s->fifo_size)
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s->read_pos = 0;
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DPRINTF("FIFO pop %x (%d)\n", c, s->read_count);
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return c;
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}
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static void fifo_push(SyborgSerialState *s, uint32_t new_value)
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{
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int slot;
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DPRINTF("FIFO push %x (%d)\n", new_value, s->read_count);
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slot = s->read_pos + s->read_count;
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if (slot >= s->fifo_size)
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slot -= s->fifo_size;
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s->read_fifo[slot] = new_value;
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s->read_count++;
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}
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static void do_dma_tx(SyborgSerialState *s, uint32_t count)
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{
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unsigned char ch;
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if (count == 0)
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return;
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if (s->chr != NULL) {
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/* optimize later. Now, 1 byte per iteration */
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while (count--) {
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cpu_physical_memory_read(s->dma_tx_ptr, &ch, 1);
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qemu_chr_write(s->chr, &ch, 1);
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s->dma_tx_ptr++;
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}
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} else {
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s->dma_tx_ptr += count;
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}
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/* QEMU char backends do not have a nonblocking mode, so we transmit all
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the data imediately and the interrupt status will be unchanged. */
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}
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/* Initiate RX DMA, and transfer data from the FIFO. */
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static void dma_rx_start(SyborgSerialState *s, uint32_t len)
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{
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uint32_t dest;
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unsigned char ch;
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dest = s->dma_rx_ptr;
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if (s->read_count < len) {
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s->dma_rx_size = len - s->read_count;
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len = s->read_count;
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} else {
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s->dma_rx_size = 0;
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}
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while (len--) {
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ch = fifo_pop(s);
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cpu_physical_memory_write(dest, &ch, 1);
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dest++;
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}
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s->dma_rx_ptr = dest;
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syborg_serial_update(s);
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}
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static uint32_t syborg_serial_read(void *opaque, target_phys_addr_t offset)
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{
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SyborgSerialState *s = (SyborgSerialState *)opaque;
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uint32_t c;
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offset &= 0xfff;
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DPRINTF("read 0x%x\n", (int)offset);
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switch(offset >> 2) {
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case SERIAL_ID:
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return SYBORG_ID_SERIAL;
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case SERIAL_DATA:
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if (s->read_count > 0)
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c = fifo_pop(s);
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else
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c = -1;
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syborg_serial_update(s);
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return c;
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case SERIAL_FIFO_COUNT:
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return s->read_count;
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case SERIAL_INT_ENABLE:
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return s->int_enable;
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case SERIAL_DMA_TX_ADDR:
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return s->dma_tx_ptr;
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case SERIAL_DMA_TX_COUNT:
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return 0;
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case SERIAL_DMA_RX_ADDR:
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return s->dma_rx_ptr;
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case SERIAL_DMA_RX_COUNT:
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return s->dma_rx_size;
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case SERIAL_FIFO_SIZE:
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return s->fifo_size;
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default:
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cpu_abort(cpu_single_env, "syborg_serial_read: Bad offset %x\n",
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(int)offset);
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return 0;
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}
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}
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static void syborg_serial_write(void *opaque, target_phys_addr_t offset,
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uint32_t value)
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{
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SyborgSerialState *s = (SyborgSerialState *)opaque;
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unsigned char ch;
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offset &= 0xfff;
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DPRINTF("Write 0x%x=0x%x\n", (int)offset, value);
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switch (offset >> 2) {
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case SERIAL_DATA:
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ch = value;
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if (s->chr)
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qemu_chr_write(s->chr, &ch, 1);
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break;
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case SERIAL_INT_ENABLE:
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s->int_enable = value;
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syborg_serial_update(s);
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break;
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case SERIAL_DMA_TX_ADDR:
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s->dma_tx_ptr = value;
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break;
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case SERIAL_DMA_TX_COUNT:
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do_dma_tx(s, value);
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break;
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case SERIAL_DMA_RX_ADDR:
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/* For safety, writes to this register cancel any pending DMA. */
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s->dma_rx_size = 0;
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s->dma_rx_ptr = value;
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break;
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case SERIAL_DMA_RX_COUNT:
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dma_rx_start(s, value);
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break;
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default:
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cpu_abort(cpu_single_env, "syborg_serial_write: Bad offset %x\n",
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(int)offset);
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break;
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}
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}
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static int syborg_serial_can_receive(void *opaque)
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{
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SyborgSerialState *s = (SyborgSerialState *)opaque;
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if (s->dma_rx_size)
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return s->dma_rx_size;
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return s->fifo_size - s->read_count;
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}
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static void syborg_serial_receive(void *opaque, const uint8_t *buf, int size)
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{
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SyborgSerialState *s = (SyborgSerialState *)opaque;
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if (s->dma_rx_size) {
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/* Place it in the DMA buffer. */
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cpu_physical_memory_write(s->dma_rx_ptr, buf, size);
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s->dma_rx_size -= size;
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s->dma_rx_ptr += size;
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} else {
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while (size--)
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fifo_push(s, *buf);
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}
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syborg_serial_update(s);
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}
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static void syborg_serial_event(void *opaque, int event)
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{
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/* TODO: Report BREAK events? */
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}
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static CPUReadMemoryFunc * const syborg_serial_readfn[] = {
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syborg_serial_read,
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syborg_serial_read,
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syborg_serial_read
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};
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static CPUWriteMemoryFunc * const syborg_serial_writefn[] = {
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syborg_serial_write,
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syborg_serial_write,
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syborg_serial_write
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};
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static const VMStateDescription vmstate_syborg_serial = {
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.name = "syborg_serial",
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.version_id = 1,
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.minimum_version_id = 1,
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.minimum_version_id_old = 1,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32_EQUAL(fifo_size, SyborgSerialState),
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VMSTATE_UINT32(int_enable, SyborgSerialState),
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VMSTATE_INT32(read_pos, SyborgSerialState),
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VMSTATE_INT32(read_count, SyborgSerialState),
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VMSTATE_UINT32(dma_tx_ptr, SyborgSerialState),
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VMSTATE_UINT32(dma_rx_ptr, SyborgSerialState),
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VMSTATE_UINT32(dma_rx_size, SyborgSerialState),
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VMSTATE_VARRAY_UINT32(read_fifo, SyborgSerialState, fifo_size, 1,
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vmstate_info_uint32, uint32),
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VMSTATE_END_OF_LIST()
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}
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};
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static int syborg_serial_init(SysBusDevice *dev)
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{
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SyborgSerialState *s = FROM_SYSBUS(SyborgSerialState, dev);
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int iomemtype;
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sysbus_init_irq(dev, &s->irq);
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iomemtype = cpu_register_io_memory(syborg_serial_readfn,
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syborg_serial_writefn, s,
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DEVICE_NATIVE_ENDIAN);
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sysbus_init_mmio(dev, 0x1000, iomemtype);
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s->chr = qdev_init_chardev(&dev->qdev);
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if (s->chr) {
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qemu_chr_add_handlers(s->chr, syborg_serial_can_receive,
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syborg_serial_receive, syborg_serial_event, s);
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}
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if (s->fifo_size <= 0) {
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fprintf(stderr, "syborg_serial: fifo too small\n");
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s->fifo_size = 16;
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}
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s->read_fifo = qemu_mallocz(s->fifo_size * sizeof(s->read_fifo[0]));
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return 0;
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}
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static SysBusDeviceInfo syborg_serial_info = {
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.init = syborg_serial_init,
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.qdev.name = "syborg,serial",
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.qdev.size = sizeof(SyborgSerialState),
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.qdev.vmsd = &vmstate_syborg_serial,
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.qdev.props = (Property[]) {
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DEFINE_PROP_UINT32("fifo-size", SyborgSerialState, fifo_size, 16),
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DEFINE_PROP_END_OF_LIST(),
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}
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};
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static void syborg_serial_register_devices(void)
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{
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sysbus_register_withprop(&syborg_serial_info);
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}
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device_init(syborg_serial_register_devices)
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