hw/char/xilinx_uartlite.c - qemu - Git at Google

 /*
  * QEMU model of Xilinx uartlite.
  *
  * Copyright (c) 2009 Edgar E. Iglesias.
  *
  * 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 "qemu/osdep.h"
 #include "qemu/log.h"
 #include "hw/irq.h"
 #include "hw/qdev-properties.h"
 #include "hw/sysbus.h"
 #include "qemu/module.h"
 #include "chardev/char-fe.h"

 #define DUART(x)

 #define R_RX            0
 #define R_TX            1
 #define R_STATUS        2
 #define R_CTRL          3
 #define R_MAX           4

 #define STATUS_RXVALID    0x01
 #define STATUS_RXFULL     0x02
 #define STATUS_TXEMPTY    0x04
 #define STATUS_TXFULL     0x08
 #define STATUS_IE         0x10
 #define STATUS_OVERRUN    0x20
 #define STATUS_FRAME      0x40
 #define STATUS_PARITY     0x80

 #define CONTROL_RST_TX    0x01
 #define CONTROL_RST_RX    0x02
 #define CONTROL_IE        0x10

 #define TYPE_XILINX_UARTLITE "xlnx.xps-uartlite"
 #define XILINX_UARTLITE(obj) \
     OBJECT_CHECK(XilinxUARTLite, (obj), TYPE_XILINX_UARTLITE)

 typedef struct XilinxUARTLite {
     SysBusDevice parent_obj;

     MemoryRegion mmio;
     CharBackend chr;
     qemu_irq irq;

     uint8_t rx_fifo[8];
     unsigned int rx_fifo_pos;
     unsigned int rx_fifo_len;

     uint32_t regs[R_MAX];
 } XilinxUARTLite;

 static void uart_update_irq(XilinxUARTLite *s)
 {
     unsigned int irq;

     if (s->rx_fifo_len)
         s->regs[R_STATUS] |= STATUS_IE;

     irq = (s->regs[R_STATUS] & STATUS_IE) && (s->regs[R_CTRL] & CONTROL_IE);
     qemu_set_irq(s->irq, irq);
 }

 static void uart_update_status(XilinxUARTLite *s)
 {
     uint32_t r;

     r = s->regs[R_STATUS];
     r &= ~7;
     r |= 1 << 2; /* Tx fifo is always empty. We are fast :) */
     r |= (s->rx_fifo_len == sizeof (s->rx_fifo)) << 1;
     r |= (!!s->rx_fifo_len);
     s->regs[R_STATUS] = r;
 }

 static void xilinx_uartlite_reset(DeviceState *dev)
 {
     uart_update_status(XILINX_UARTLITE(dev));
 }

 static uint64_t
 uart_read(void *opaque, hwaddr addr, unsigned int size)
 {
     XilinxUARTLite *s = opaque;
     uint32_t r = 0;
     addr >>= 2;
     switch (addr)
     {
         case R_RX:
             r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 7];
             if (s->rx_fifo_len)
                 s->rx_fifo_len--;
             uart_update_status(s);
             uart_update_irq(s);
             qemu_chr_fe_accept_input(&s->chr);
             break;

         default:
             if (addr < ARRAY_SIZE(s->regs))
                 r = s->regs[addr];
             DUART(qemu_log("%s addr=%x v=%x\n", __func__, addr, r));
             break;
     }
     return r;
 }

 static void
 uart_write(void *opaque, hwaddr addr,
            uint64_t val64, unsigned int size)
 {
     XilinxUARTLite *s = opaque;
     uint32_t value = val64;
     unsigned char ch = value;

     addr >>= 2;
     switch (addr)
     {
         case R_STATUS:
             qemu_log_mask(LOG_GUEST_ERROR, "%s: write to UART STATUS\n",
                           __func__);
             break;

         case R_CTRL:
             if (value & CONTROL_RST_RX) {
                 s->rx_fifo_pos = 0;
                 s->rx_fifo_len = 0;
             }
             s->regs[addr] = value;
             break;

         case R_TX:
             /* XXX this blocks entire thread. Rewrite to use
              * qemu_chr_fe_write and background I/O callbacks */
             qemu_chr_fe_write_all(&s->chr, &ch, 1);
             s->regs[addr] = value;

             /* hax.  */
             s->regs[R_STATUS] |= STATUS_IE;
             break;

         default:
             DUART(printf("%s addr=%x v=%x\n", __func__, addr, value));
             if (addr < ARRAY_SIZE(s->regs))
                 s->regs[addr] = value;
             break;
     }
     uart_update_status(s);
     uart_update_irq(s);
 }

 static const MemoryRegionOps uart_ops = {
     .read = uart_read,
     .write = uart_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .valid = {
         .min_access_size = 1,
         .max_access_size = 4
     }
 };

 static Property xilinx_uartlite_properties[] = {
     DEFINE_PROP_CHR("chardev", XilinxUARTLite, chr),
     DEFINE_PROP_END_OF_LIST(),
 };

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

     /* Got a byte.  */
     if (s->rx_fifo_len >= 8) {
         printf("WARNING: UART dropped char.\n");
         return;
     }
     s->rx_fifo[s->rx_fifo_pos] = *buf;
     s->rx_fifo_pos++;
     s->rx_fifo_pos &= 0x7;
     s->rx_fifo_len++;

     uart_update_status(s);
     uart_update_irq(s);
 }

 static int uart_can_rx(void *opaque)
 {
     XilinxUARTLite *s = opaque;

     return s->rx_fifo_len < sizeof(s->rx_fifo);
 }

 static void uart_event(void *opaque, QEMUChrEvent event)
 {

 }

 static void xilinx_uartlite_realize(DeviceState *dev, Error **errp)
 {
     XilinxUARTLite *s = XILINX_UARTLITE(dev);

     qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
                              uart_event, NULL, s, NULL, true);
 }

 static void xilinx_uartlite_init(Object *obj)
 {
     XilinxUARTLite *s = XILINX_UARTLITE(obj);

     sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);

     memory_region_init_io(&s->mmio, obj, &uart_ops, s,
                           "xlnx.xps-uartlite", R_MAX * 4);
     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
 }

 static void xilinx_uartlite_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->reset = xilinx_uartlite_reset;
     dc->realize = xilinx_uartlite_realize;
     device_class_set_props(dc, xilinx_uartlite_properties);
 }

 static const TypeInfo xilinx_uartlite_info = {
     .name          = TYPE_XILINX_UARTLITE,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(XilinxUARTLite),
     .instance_init = xilinx_uartlite_init,
     .class_init    = xilinx_uartlite_class_init,
 };

 static void xilinx_uart_register_types(void)
 {
     type_register_static(&xilinx_uartlite_info);
 }

 type_init(xilinx_uart_register_types)
	/*
	* QEMU model of Xilinx uartlite.
	*
	* Copyright (c) 2009 Edgar E. Iglesias.
	*
	* 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 "qemu/osdep.h"
	#include "qemu/log.h"
	#include "hw/irq.h"
	#include "hw/qdev-properties.h"
	#include "hw/sysbus.h"
	#include "qemu/module.h"
	#include "chardev/char-fe.h"

	#define DUART(x)

	#define R_RX 0
	#define R_TX 1
	#define R_STATUS 2
	#define R_CTRL 3
	#define R_MAX 4

	#define STATUS_RXVALID 0x01
	#define STATUS_RXFULL 0x02
	#define STATUS_TXEMPTY 0x04
	#define STATUS_TXFULL 0x08
	#define STATUS_IE 0x10
	#define STATUS_OVERRUN 0x20
	#define STATUS_FRAME 0x40
	#define STATUS_PARITY 0x80

	#define CONTROL_RST_TX 0x01
	#define CONTROL_RST_RX 0x02
	#define CONTROL_IE 0x10

	#define TYPE_XILINX_UARTLITE "xlnx.xps-uartlite"
	#define XILINX_UARTLITE(obj) \
	OBJECT_CHECK(XilinxUARTLite, (obj), TYPE_XILINX_UARTLITE)

	typedef struct XilinxUARTLite {
	SysBusDevice parent_obj;

	MemoryRegion mmio;
	CharBackend chr;
	qemu_irq irq;

	uint8_t rx_fifo[8];
	unsigned int rx_fifo_pos;
	unsigned int rx_fifo_len;

	uint32_t regs[R_MAX];
	} XilinxUARTLite;

	static void uart_update_irq(XilinxUARTLite *s)
	{
	unsigned int irq;

	if (s->rx_fifo_len)
	s->regs[R_STATUS] \|= STATUS_IE;

	irq = (s->regs[R_STATUS] & STATUS_IE) && (s->regs[R_CTRL] & CONTROL_IE);
	qemu_set_irq(s->irq, irq);
	}

	static void uart_update_status(XilinxUARTLite *s)
	{
	uint32_t r;

	r = s->regs[R_STATUS];
	r &= ~7;
	r \|= 1 << 2; /* Tx fifo is always empty. We are fast :) */
	r \|= (s->rx_fifo_len == sizeof (s->rx_fifo)) << 1;
	r \|= (!!s->rx_fifo_len);
	s->regs[R_STATUS] = r;
	}

	static void xilinx_uartlite_reset(DeviceState *dev)
	{
	uart_update_status(XILINX_UARTLITE(dev));
	}

	static uint64_t
	uart_read(void *opaque, hwaddr addr, unsigned int size)
	{
	XilinxUARTLite *s = opaque;
	uint32_t r = 0;
	addr >>= 2;
	switch (addr)
	{
	case R_RX:
	r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 7];
	if (s->rx_fifo_len)
	s->rx_fifo_len--;
	uart_update_status(s);
	uart_update_irq(s);
	qemu_chr_fe_accept_input(&s->chr);
	break;

	default:
	if (addr < ARRAY_SIZE(s->regs))
	r = s->regs[addr];
	DUART(qemu_log("%s addr=%x v=%x\n", __func__, addr, r));
	break;
	}
	return r;
	}

	static void
	uart_write(void *opaque, hwaddr addr,
	uint64_t val64, unsigned int size)
	{
	XilinxUARTLite *s = opaque;
	uint32_t value = val64;
	unsigned char ch = value;

	addr >>= 2;
	switch (addr)
	{
	case R_STATUS:
	qemu_log_mask(LOG_GUEST_ERROR, "%s: write to UART STATUS\n",
	__func__);
	break;

	case R_CTRL:
	if (value & CONTROL_RST_RX) {
	s->rx_fifo_pos = 0;
	s->rx_fifo_len = 0;
	}
	s->regs[addr] = value;
	break;

	case R_TX:
	/* XXX this blocks entire thread. Rewrite to use
	* qemu_chr_fe_write and background I/O callbacks */
	qemu_chr_fe_write_all(&s->chr, &ch, 1);
	s->regs[addr] = value;

	/* hax. */
	s->regs[R_STATUS] \|= STATUS_IE;
	break;

	default:
	DUART(printf("%s addr=%x v=%x\n", __func__, addr, value));
	if (addr < ARRAY_SIZE(s->regs))
	s->regs[addr] = value;
	break;
	}
	uart_update_status(s);
	uart_update_irq(s);
	}

	static const MemoryRegionOps uart_ops = {
	.read = uart_read,
	.write = uart_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
	.min_access_size = 1,
	.max_access_size = 4
	}
	};

	static Property xilinx_uartlite_properties[] = {
	DEFINE_PROP_CHR("chardev", XilinxUARTLite, chr),
	DEFINE_PROP_END_OF_LIST(),
	};

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

	/* Got a byte. */
	if (s->rx_fifo_len >= 8) {
	printf("WARNING: UART dropped char.\n");
	return;
	}
	s->rx_fifo[s->rx_fifo_pos] = *buf;
	s->rx_fifo_pos++;
	s->rx_fifo_pos &= 0x7;
	s->rx_fifo_len++;

	uart_update_status(s);
	uart_update_irq(s);
	}

	static int uart_can_rx(void *opaque)
	{
	XilinxUARTLite *s = opaque;

	return s->rx_fifo_len < sizeof(s->rx_fifo);
	}

	static void uart_event(void *opaque, QEMUChrEvent event)
	{

	}

	static void xilinx_uartlite_realize(DeviceState dev, Error *errp)
	{
	XilinxUARTLite *s = XILINX_UARTLITE(dev);

	qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
	uart_event, NULL, s, NULL, true);
	}

	static void xilinx_uartlite_init(Object *obj)
	{
	XilinxUARTLite *s = XILINX_UARTLITE(obj);

	sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);

	memory_region_init_io(&s->mmio, obj, &uart_ops, s,
	"xlnx.xps-uartlite", R_MAX * 4);
	sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
	}

	static void xilinx_uartlite_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->reset = xilinx_uartlite_reset;
	dc->realize = xilinx_uartlite_realize;
	device_class_set_props(dc, xilinx_uartlite_properties);
	}

	static const TypeInfo xilinx_uartlite_info = {
	.name = TYPE_XILINX_UARTLITE,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(XilinxUARTLite),
	.instance_init = xilinx_uartlite_init,
	.class_init = xilinx_uartlite_class_init,
	};

	static void xilinx_uart_register_types(void)
	{
	type_register_static(&xilinx_uartlite_info);
	}

	type_init(xilinx_uart_register_types)