hw/syborg_serial.c - qemu - Git at Google

 /*
  * Syborg serial port
  *
  * Copyright (c) 2008 CodeSourcery
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "sysbus.h"
 #include "qemu-char.h"
 #include "syborg.h"

 //#define DEBUG_SYBORG_SERIAL

 #ifdef DEBUG_SYBORG_SERIAL
 #define DPRINTF(fmt, ...) \
 do { printf("syborg_serial: " fmt , ##args); } while (0)
 #define BADF(fmt, ...) \
 do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__); \
     exit(1);} while (0)
 #else
 #define DPRINTF(fmt, ...) do {} while(0)
 #define BADF(fmt, ...) \
 do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__);} while (0)
 #endif

 enum {
     SERIAL_ID           = 0,
     SERIAL_DATA         = 1,
     SERIAL_FIFO_COUNT   = 2,
     SERIAL_INT_ENABLE   = 3,
     SERIAL_DMA_TX_ADDR  = 4,
     SERIAL_DMA_TX_COUNT = 5, /* triggers dma */
     SERIAL_DMA_RX_ADDR  = 6,
     SERIAL_DMA_RX_COUNT = 7, /* triggers dma */
     SERIAL_FIFO_SIZE    = 8
 };

 #define SERIAL_INT_FIFO   (1u << 0)
 #define SERIAL_INT_DMA_TX (1u << 1)
 #define SERIAL_INT_DMA_RX (1u << 2)

 typedef struct {
     SysBusDevice busdev;
     uint32_t int_enable;
     uint32_t fifo_size;
     uint32_t *read_fifo;
     int read_pos;
     int read_count;
     CharDriverState *chr;
     qemu_irq irq;
     uint32_t dma_tx_ptr;
     uint32_t dma_rx_ptr;
     uint32_t dma_rx_size;
 } SyborgSerialState;

 static void syborg_serial_update(SyborgSerialState *s)
 {
     int level;
     level = 0;
     if ((s->int_enable & SERIAL_INT_FIFO) && s->read_count)
         level = 1;
     if (s->int_enable & SERIAL_INT_DMA_TX)
         level = 1;
     if ((s->int_enable & SERIAL_INT_DMA_RX) && s->dma_rx_size == 0)
         level = 1;

     qemu_set_irq(s->irq, level);
 }

 static uint32_t fifo_pop(SyborgSerialState *s)
 {
     const uint32_t c = s->read_fifo[s->read_pos];
     s->read_count--;
     s->read_pos++;
     if (s->read_pos == s->fifo_size)
         s->read_pos = 0;

     DPRINTF("FIFO pop %x (%d)\n", c, s->read_count);
     return c;
 }

 static void fifo_push(SyborgSerialState *s, uint32_t new_value)
 {
     int slot;

     DPRINTF("FIFO push %x (%d)\n", new_value, s->read_count);
     slot = s->read_pos + s->read_count;
     if (slot >= s->fifo_size)
           slot -= s->fifo_size;
     s->read_fifo[slot] = new_value;
     s->read_count++;
 }

 static void do_dma_tx(SyborgSerialState *s, uint32_t count)
 {
     unsigned char ch;

     if (count == 0)
         return;

     if (s->chr != NULL) {
         /* optimize later. Now, 1 byte per iteration */
         while (count--) {
             cpu_physical_memory_read(s->dma_tx_ptr, &ch, 1);
             qemu_chr_write(s->chr, &ch, 1);
             s->dma_tx_ptr++;
         }
     } else {
         s->dma_tx_ptr += count;
     }
     /* QEMU char backends do not have a nonblocking mode, so we transmit all
        the data imediately and the interrupt status will be unchanged.  */
 }

 /* Initiate RX DMA, and transfer data from the FIFO.  */
 static void dma_rx_start(SyborgSerialState *s, uint32_t len)
 {
     uint32_t dest;
     unsigned char ch;

     dest = s->dma_rx_ptr;
     if (s->read_count < len) {
         s->dma_rx_size = len - s->read_count;
         len = s->read_count;
     } else {
         s->dma_rx_size = 0;
     }

     while (len--) {
         ch = fifo_pop(s);
         cpu_physical_memory_write(dest, &ch, 1);
         dest++;
     }
     s->dma_rx_ptr = dest;
     syborg_serial_update(s);
 }

 static uint32_t syborg_serial_read(void *opaque, target_phys_addr_t offset)
 {
     SyborgSerialState *s = (SyborgSerialState *)opaque;
     uint32_t c;

     offset &= 0xfff;
     DPRINTF("read 0x%x\n", (int)offset);
     switch(offset >> 2) {
     case SERIAL_ID:
         return SYBORG_ID_SERIAL;
     case SERIAL_DATA:
         if (s->read_count > 0)
             c = fifo_pop(s);
         else
             c = -1;
         syborg_serial_update(s);
         return c;
     case SERIAL_FIFO_COUNT:
         return s->read_count;
     case SERIAL_INT_ENABLE:
         return s->int_enable;
     case SERIAL_DMA_TX_ADDR:
         return s->dma_tx_ptr;
     case SERIAL_DMA_TX_COUNT:
         return 0;
     case SERIAL_DMA_RX_ADDR:
         return s->dma_rx_ptr;
     case SERIAL_DMA_RX_COUNT:
         return s->dma_rx_size;
     case SERIAL_FIFO_SIZE:
         return s->fifo_size;

     default:
         cpu_abort(cpu_single_env, "syborg_serial_read: Bad offset %x\n",
                   (int)offset);
         return 0;
     }
 }

 static void syborg_serial_write(void *opaque, target_phys_addr_t offset,
                                 uint32_t value)
 {
     SyborgSerialState *s = (SyborgSerialState *)opaque;
     unsigned char ch;

     offset &= 0xfff;
     DPRINTF("Write 0x%x=0x%x\n", (int)offset, value);
     switch (offset >> 2) {
     case SERIAL_DATA:
         ch = value;
         if (s->chr)
             qemu_chr_write(s->chr, &ch, 1);
         break;
     case SERIAL_INT_ENABLE:
         s->int_enable = value;
         syborg_serial_update(s);
         break;
     case SERIAL_DMA_TX_ADDR:
         s->dma_tx_ptr = value;
         break;
     case SERIAL_DMA_TX_COUNT:
         do_dma_tx(s, value);
         break;
     case SERIAL_DMA_RX_ADDR:
         /* For safety, writes to this register cancel any pending DMA.  */
         s->dma_rx_size = 0;
         s->dma_rx_ptr = value;
         break;
     case SERIAL_DMA_RX_COUNT:
         dma_rx_start(s, value);
         break;
     default:
         cpu_abort(cpu_single_env, "syborg_serial_write: Bad offset %x\n",
                   (int)offset);
         break;
     }
 }

 static int syborg_serial_can_receive(void *opaque)
 {
     SyborgSerialState *s = (SyborgSerialState *)opaque;

     if (s->dma_rx_size)
         return s->dma_rx_size;
     return s->fifo_size - s->read_count;
 }

 static void syborg_serial_receive(void *opaque, const uint8_t *buf, int size)
 {
     SyborgSerialState *s = (SyborgSerialState *)opaque;

     if (s->dma_rx_size) {
         /* Place it in the DMA buffer.  */
         cpu_physical_memory_write(s->dma_rx_ptr, buf, size);
         s->dma_rx_size -= size;
         s->dma_rx_ptr += size;
     } else {
         while (size--)
             fifo_push(s, *buf);
     }

     syborg_serial_update(s);
 }

 static void syborg_serial_event(void *opaque, int event)
 {
     /* TODO: Report BREAK events?  */
 }

 static CPUReadMemoryFunc * const syborg_serial_readfn[] = {
      syborg_serial_read,
      syborg_serial_read,
      syborg_serial_read
 };

 static CPUWriteMemoryFunc * const syborg_serial_writefn[] = {
      syborg_serial_write,
      syborg_serial_write,
      syborg_serial_write
 };

 static void syborg_serial_save(QEMUFile *f, void *opaque)
 {
     SyborgSerialState *s = opaque;
     int i;

     qemu_put_be32(f, s->fifo_size);
     qemu_put_be32(f, s->int_enable);
     qemu_put_be32(f, s->read_pos);
     qemu_put_be32(f, s->read_count);
     qemu_put_be32(f, s->dma_tx_ptr);
     qemu_put_be32(f, s->dma_rx_ptr);
     qemu_put_be32(f, s->dma_rx_size);
     for (i = 0; i < s->fifo_size; i++) {
         qemu_put_be32(f, s->read_fifo[i]);
     }
 }

 static int syborg_serial_load(QEMUFile *f, void *opaque, int version_id)
 {
     SyborgSerialState *s = opaque;
     int i;

     if (version_id != 1)
         return -EINVAL;

     i = qemu_get_be32(f);
     if (s->fifo_size != i)
         return -EINVAL;

     s->int_enable = qemu_get_be32(f);
     s->read_pos = qemu_get_be32(f);
     s->read_count = qemu_get_be32(f);
     s->dma_tx_ptr = qemu_get_be32(f);
     s->dma_rx_ptr = qemu_get_be32(f);
     s->dma_rx_size = qemu_get_be32(f);
     for (i = 0; i < s->fifo_size; i++) {
         s->read_fifo[i] = qemu_get_be32(f);
     }

     return 0;
 }

 static int syborg_serial_init(SysBusDevice *dev)
 {
     SyborgSerialState *s = FROM_SYSBUS(SyborgSerialState, dev);
     int iomemtype;

     sysbus_init_irq(dev, &s->irq);
     iomemtype = cpu_register_io_memory(syborg_serial_readfn,
                                        syborg_serial_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     s->chr = qdev_init_chardev(&dev->qdev);
     if (s->chr) {
         qemu_chr_add_handlers(s->chr, syborg_serial_can_receive,
                               syborg_serial_receive, syborg_serial_event, s);
     }
     if (s->fifo_size <= 0) {
         fprintf(stderr, "syborg_serial: fifo too small\n");
         s->fifo_size = 16;
     }
     s->read_fifo = qemu_mallocz(s->fifo_size * sizeof(s->read_fifo[0]));

     register_savevm("syborg_serial", -1, 1,
                     syborg_serial_save, syborg_serial_load, s);
     return 0;
 }

 static SysBusDeviceInfo syborg_serial_info = {
     .init = syborg_serial_init,
     .qdev.name  = "syborg,serial",
     .qdev.size  = sizeof(SyborgSerialState),
     .qdev.props = (Property[]) {
         DEFINE_PROP_UINT32("fifo-size", SyborgSerialState, fifo_size, 16),
         DEFINE_PROP_END_OF_LIST(),
     }
 };

 static void syborg_serial_register_devices(void)
 {
     sysbus_register_withprop(&syborg_serial_info);
 }

 device_init(syborg_serial_register_devices)
	/*
	* Syborg serial port
	*
	* Copyright (c) 2008 CodeSourcery
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "sysbus.h"
	#include "qemu-char.h"
	#include "syborg.h"

	//#define DEBUG_SYBORG_SERIAL

	#ifdef DEBUG_SYBORG_SERIAL
	#define DPRINTF(fmt, ...) \
	do { printf("syborg_serial: " fmt , ##args); } while (0)
	#define BADF(fmt, ...) \
	do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__); \
	exit(1);} while (0)
	#else
	#define DPRINTF(fmt, ...) do {} while(0)
	#define BADF(fmt, ...) \
	do { fprintf(stderr, "syborg_serial: error: " fmt , ## __VA_ARGS__);} while (0)
	#endif

	enum {
	SERIAL_ID = 0,
	SERIAL_DATA = 1,
	SERIAL_FIFO_COUNT = 2,
	SERIAL_INT_ENABLE = 3,
	SERIAL_DMA_TX_ADDR = 4,
	SERIAL_DMA_TX_COUNT = 5, /* triggers dma */
	SERIAL_DMA_RX_ADDR = 6,
	SERIAL_DMA_RX_COUNT = 7, /* triggers dma */
	SERIAL_FIFO_SIZE = 8
	};

	#define SERIAL_INT_FIFO (1u << 0)
	#define SERIAL_INT_DMA_TX (1u << 1)
	#define SERIAL_INT_DMA_RX (1u << 2)

	typedef struct {
	SysBusDevice busdev;
	uint32_t int_enable;
	uint32_t fifo_size;
	uint32_t *read_fifo;
	int read_pos;
	int read_count;
	CharDriverState *chr;
	qemu_irq irq;
	uint32_t dma_tx_ptr;
	uint32_t dma_rx_ptr;
	uint32_t dma_rx_size;
	} SyborgSerialState;

	static void syborg_serial_update(SyborgSerialState *s)
	{
	int level;
	level = 0;
	if ((s->int_enable & SERIAL_INT_FIFO) && s->read_count)
	level = 1;
	if (s->int_enable & SERIAL_INT_DMA_TX)
	level = 1;
	if ((s->int_enable & SERIAL_INT_DMA_RX) && s->dma_rx_size == 0)
	level = 1;

	qemu_set_irq(s->irq, level);
	}

	static uint32_t fifo_pop(SyborgSerialState *s)
	{
	const uint32_t c = s->read_fifo[s->read_pos];
	s->read_count--;
	s->read_pos++;
	if (s->read_pos == s->fifo_size)
	s->read_pos = 0;

	DPRINTF("FIFO pop %x (%d)\n", c, s->read_count);
	return c;
	}

	static void fifo_push(SyborgSerialState *s, uint32_t new_value)
	{
	int slot;

	DPRINTF("FIFO push %x (%d)\n", new_value, s->read_count);
	slot = s->read_pos + s->read_count;
	if (slot >= s->fifo_size)
	slot -= s->fifo_size;
	s->read_fifo[slot] = new_value;
	s->read_count++;
	}

	static void do_dma_tx(SyborgSerialState *s, uint32_t count)
	{
	unsigned char ch;

	if (count == 0)
	return;

	if (s->chr != NULL) {
	/* optimize later. Now, 1 byte per iteration */
	while (count--) {
	cpu_physical_memory_read(s->dma_tx_ptr, &ch, 1);
	qemu_chr_write(s->chr, &ch, 1);
	s->dma_tx_ptr++;
	}
	} else {
	s->dma_tx_ptr += count;
	}
	/* QEMU char backends do not have a nonblocking mode, so we transmit all
	the data imediately and the interrupt status will be unchanged. */
	}

	/* Initiate RX DMA, and transfer data from the FIFO. */
	static void dma_rx_start(SyborgSerialState *s, uint32_t len)
	{
	uint32_t dest;
	unsigned char ch;

	dest = s->dma_rx_ptr;
	if (s->read_count < len) {
	s->dma_rx_size = len - s->read_count;
	len = s->read_count;
	} else {
	s->dma_rx_size = 0;
	}

	while (len--) {
	ch = fifo_pop(s);
	cpu_physical_memory_write(dest, &ch, 1);
	dest++;
	}
	s->dma_rx_ptr = dest;
	syborg_serial_update(s);
	}

	static uint32_t syborg_serial_read(void *opaque, target_phys_addr_t offset)
	{
	SyborgSerialState s = (SyborgSerialState )opaque;
	uint32_t c;

	offset &= 0xfff;
	DPRINTF("read 0x%x\n", (int)offset);
	switch(offset >> 2) {
	case SERIAL_ID:
	return SYBORG_ID_SERIAL;
	case SERIAL_DATA:
	if (s->read_count > 0)
	c = fifo_pop(s);
	else
	c = -1;
	syborg_serial_update(s);
	return c;
	case SERIAL_FIFO_COUNT:
	return s->read_count;
	case SERIAL_INT_ENABLE:
	return s->int_enable;
	case SERIAL_DMA_TX_ADDR:
	return s->dma_tx_ptr;
	case SERIAL_DMA_TX_COUNT:
	return 0;
	case SERIAL_DMA_RX_ADDR:
	return s->dma_rx_ptr;
	case SERIAL_DMA_RX_COUNT:
	return s->dma_rx_size;
	case SERIAL_FIFO_SIZE:
	return s->fifo_size;

	default:
	cpu_abort(cpu_single_env, "syborg_serial_read: Bad offset %x\n",
	(int)offset);
	return 0;
	}
	}

	static void syborg_serial_write(void *opaque, target_phys_addr_t offset,
	uint32_t value)
	{
	SyborgSerialState s = (SyborgSerialState )opaque;
	unsigned char ch;

	offset &= 0xfff;
	DPRINTF("Write 0x%x=0x%x\n", (int)offset, value);
	switch (offset >> 2) {
	case SERIAL_DATA:
	ch = value;
	if (s->chr)
	qemu_chr_write(s->chr, &ch, 1);
	break;
	case SERIAL_INT_ENABLE:
	s->int_enable = value;
	syborg_serial_update(s);
	break;
	case SERIAL_DMA_TX_ADDR:
	s->dma_tx_ptr = value;
	break;
	case SERIAL_DMA_TX_COUNT:
	do_dma_tx(s, value);
	break;
	case SERIAL_DMA_RX_ADDR:
	/* For safety, writes to this register cancel any pending DMA. */
	s->dma_rx_size = 0;
	s->dma_rx_ptr = value;
	break;
	case SERIAL_DMA_RX_COUNT:
	dma_rx_start(s, value);
	break;
	default:
	cpu_abort(cpu_single_env, "syborg_serial_write: Bad offset %x\n",
	(int)offset);
	break;
	}
	}

	static int syborg_serial_can_receive(void *opaque)
	{
	SyborgSerialState s = (SyborgSerialState )opaque;

	if (s->dma_rx_size)
	return s->dma_rx_size;
	return s->fifo_size - s->read_count;
	}

	static void syborg_serial_receive(void opaque, const uint8_t buf, int size)
	{
	SyborgSerialState s = (SyborgSerialState )opaque;

	if (s->dma_rx_size) {
	/* Place it in the DMA buffer. */
	cpu_physical_memory_write(s->dma_rx_ptr, buf, size);
	s->dma_rx_size -= size;
	s->dma_rx_ptr += size;
	} else {
	while (size--)
	fifo_push(s, *buf);
	}

	syborg_serial_update(s);
	}

	static void syborg_serial_event(void *opaque, int event)
	{
	/* TODO: Report BREAK events? */
	}

	static CPUReadMemoryFunc * const syborg_serial_readfn[] = {
	syborg_serial_read,
	syborg_serial_read,
	syborg_serial_read
	};

	static CPUWriteMemoryFunc * const syborg_serial_writefn[] = {
	syborg_serial_write,
	syborg_serial_write,
	syborg_serial_write
	};

	static void syborg_serial_save(QEMUFile f, void opaque)
	{
	SyborgSerialState *s = opaque;
	int i;

	qemu_put_be32(f, s->fifo_size);
	qemu_put_be32(f, s->int_enable);
	qemu_put_be32(f, s->read_pos);
	qemu_put_be32(f, s->read_count);
	qemu_put_be32(f, s->dma_tx_ptr);
	qemu_put_be32(f, s->dma_rx_ptr);
	qemu_put_be32(f, s->dma_rx_size);
	for (i = 0; i < s->fifo_size; i++) {
	qemu_put_be32(f, s->read_fifo[i]);
	}
	}

	static int syborg_serial_load(QEMUFile f, void opaque, int version_id)
	{
	SyborgSerialState *s = opaque;
	int i;

	if (version_id != 1)
	return -EINVAL;

	i = qemu_get_be32(f);
	if (s->fifo_size != i)
	return -EINVAL;

	s->int_enable = qemu_get_be32(f);
	s->read_pos = qemu_get_be32(f);
	s->read_count = qemu_get_be32(f);
	s->dma_tx_ptr = qemu_get_be32(f);
	s->dma_rx_ptr = qemu_get_be32(f);
	s->dma_rx_size = qemu_get_be32(f);
	for (i = 0; i < s->fifo_size; i++) {
	s->read_fifo[i] = qemu_get_be32(f);
	}

	return 0;
	}

	static int syborg_serial_init(SysBusDevice *dev)
	{
	SyborgSerialState *s = FROM_SYSBUS(SyborgSerialState, dev);
	int iomemtype;

	sysbus_init_irq(dev, &s->irq);
	iomemtype = cpu_register_io_memory(syborg_serial_readfn,
	syborg_serial_writefn, s);
	sysbus_init_mmio(dev, 0x1000, iomemtype);
	s->chr = qdev_init_chardev(&dev->qdev);
	if (s->chr) {
	qemu_chr_add_handlers(s->chr, syborg_serial_can_receive,
	syborg_serial_receive, syborg_serial_event, s);
	}
	if (s->fifo_size <= 0) {
	fprintf(stderr, "syborg_serial: fifo too small\n");
	s->fifo_size = 16;
	}
	s->read_fifo = qemu_mallocz(s->fifo_size * sizeof(s->read_fifo[0]));

	register_savevm("syborg_serial", -1, 1,
	syborg_serial_save, syborg_serial_load, s);
	return 0;
	}

	static SysBusDeviceInfo syborg_serial_info = {
	.init = syborg_serial_init,
	.qdev.name = "syborg,serial",
	.qdev.size = sizeof(SyborgSerialState),
	.qdev.props = (Property[]) {
	DEFINE_PROP_UINT32("fifo-size", SyborgSerialState, fifo_size, 16),
	DEFINE_PROP_END_OF_LIST(),
	}
	};

	static void syborg_serial_register_devices(void)
	{
	sysbus_register_withprop(&syborg_serial_info);
	}

	device_init(syborg_serial_register_devices)