hw/char/stm32f2xx_usart.c - qemu - Git at Google

 /*
  * STM32F2XX USART
  *
  * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
  *
  * 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 "hw/char/stm32f2xx_usart.h"
 #include "hw/irq.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "qemu/log.h"
 #include "qemu/module.h"

 #ifndef STM_USART_ERR_DEBUG
 #define STM_USART_ERR_DEBUG 0
 #endif

 #define DB_PRINT_L(lvl, fmt, args...) do { \
     if (STM_USART_ERR_DEBUG >= lvl) { \
         qemu_log("%s: " fmt, __func__, ## args); \
     } \
 } while (0)

 #define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)

 static int stm32f2xx_usart_can_receive(void *opaque)
 {
     STM32F2XXUsartState *s = opaque;

     if (!(s->usart_sr & USART_SR_RXNE)) {
         return 1;
     }

     return 0;
 }

 static void stm32f2xx_update_irq(STM32F2XXUsartState *s)
 {
     uint32_t mask = s->usart_sr & s->usart_cr1;

     if (mask & (USART_SR_TXE | USART_SR_TC | USART_SR_RXNE)) {
         qemu_set_irq(s->irq, 1);
     } else {
         qemu_set_irq(s->irq, 0);
     }
 }

 static void stm32f2xx_usart_receive(void *opaque, const uint8_t *buf, int size)
 {
     STM32F2XXUsartState *s = opaque;

     if (!(s->usart_cr1 & USART_CR1_UE && s->usart_cr1 & USART_CR1_RE)) {
         /* USART not enabled - drop the chars */
         DB_PRINT("Dropping the chars\n");
         return;
     }

     s->usart_dr = *buf;
     s->usart_sr |= USART_SR_RXNE;

     stm32f2xx_update_irq(s);

     DB_PRINT("Receiving: %c\n", s->usart_dr);
 }

 static void stm32f2xx_usart_reset(DeviceState *dev)
 {
     STM32F2XXUsartState *s = STM32F2XX_USART(dev);

     s->usart_sr = USART_SR_RESET;
     s->usart_dr = 0x00000000;
     s->usart_brr = 0x00000000;
     s->usart_cr1 = 0x00000000;
     s->usart_cr2 = 0x00000000;
     s->usart_cr3 = 0x00000000;
     s->usart_gtpr = 0x00000000;

     stm32f2xx_update_irq(s);
 }

 static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
                                        unsigned int size)
 {
     STM32F2XXUsartState *s = opaque;
     uint64_t retvalue;

     DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);

     switch (addr) {
     case USART_SR:
         retvalue = s->usart_sr;
         qemu_chr_fe_accept_input(&s->chr);
         return retvalue;
     case USART_DR:
         DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
         retvalue = s->usart_dr & 0x3FF;
         s->usart_sr &= ~USART_SR_RXNE;
         qemu_chr_fe_accept_input(&s->chr);
         stm32f2xx_update_irq(s);
         return retvalue;
     case USART_BRR:
         return s->usart_brr;
     case USART_CR1:
         return s->usart_cr1;
     case USART_CR2:
         return s->usart_cr2;
     case USART_CR3:
         return s->usart_cr3;
     case USART_GTPR:
         return s->usart_gtpr;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
         return 0;
     }

     return 0;
 }

 static void stm32f2xx_usart_write(void *opaque, hwaddr addr,
                                   uint64_t val64, unsigned int size)
 {
     STM32F2XXUsartState *s = opaque;
     uint32_t value = val64;
     unsigned char ch;

     DB_PRINT("Write 0x%" PRIx32 ", 0x%"HWADDR_PRIx"\n", value, addr);

     switch (addr) {
     case USART_SR:
         if (value <= 0x3FF) {
             /* I/O being synchronous, TXE is always set. In addition, it may
                only be set by hardware, so keep it set here. */
             s->usart_sr = value | USART_SR_TXE;
         } else {
             s->usart_sr &= value;
         }
         stm32f2xx_update_irq(s);
         return;
     case USART_DR:
         if (value < 0xF000) {
             ch = value;
             /* 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);
             /* XXX I/O are currently synchronous, making it impossible for
                software to observe transient states where TXE or TC aren't
                set. Unlike TXE however, which is read-only, software may
                clear TC by writing 0 to the SR register, so set it again
                on each write. */
             s->usart_sr |= USART_SR_TC;
             stm32f2xx_update_irq(s);
         }
         return;
     case USART_BRR:
         s->usart_brr = value;
         return;
     case USART_CR1:
         s->usart_cr1 = value;
         stm32f2xx_update_irq(s);
         return;
     case USART_CR2:
         s->usart_cr2 = value;
         return;
     case USART_CR3:
         s->usart_cr3 = value;
         return;
     case USART_GTPR:
         s->usart_gtpr = value;
         return;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
     }
 }

 static const MemoryRegionOps stm32f2xx_usart_ops = {
     .read = stm32f2xx_usart_read,
     .write = stm32f2xx_usart_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
 };

 static Property stm32f2xx_usart_properties[] = {
     DEFINE_PROP_CHR("chardev", STM32F2XXUsartState, chr),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void stm32f2xx_usart_init(Object *obj)
 {
     STM32F2XXUsartState *s = STM32F2XX_USART(obj);

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

     memory_region_init_io(&s->mmio, obj, &stm32f2xx_usart_ops, s,
                           TYPE_STM32F2XX_USART, 0x400);
     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
 }

 static void stm32f2xx_usart_realize(DeviceState *dev, Error **errp)
 {
     STM32F2XXUsartState *s = STM32F2XX_USART(dev);

     qemu_chr_fe_set_handlers(&s->chr, stm32f2xx_usart_can_receive,
                              stm32f2xx_usart_receive, NULL, NULL,
                              s, NULL, true);
 }

 static void stm32f2xx_usart_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->reset = stm32f2xx_usart_reset;
     device_class_set_props(dc, stm32f2xx_usart_properties);
     dc->realize = stm32f2xx_usart_realize;
 }

 static const TypeInfo stm32f2xx_usart_info = {
     .name          = TYPE_STM32F2XX_USART,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(STM32F2XXUsartState),
     .instance_init = stm32f2xx_usart_init,
     .class_init    = stm32f2xx_usart_class_init,
 };

 static void stm32f2xx_usart_register_types(void)
 {
     type_register_static(&stm32f2xx_usart_info);
 }

 type_init(stm32f2xx_usart_register_types)
	/*
	* STM32F2XX USART
	*
	* Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
	*
	* 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 "hw/char/stm32f2xx_usart.h"
	#include "hw/irq.h"
	#include "hw/qdev-properties.h"
	#include "hw/qdev-properties-system.h"
	#include "qemu/log.h"
	#include "qemu/module.h"

	#ifndef STM_USART_ERR_DEBUG
	#define STM_USART_ERR_DEBUG 0
	#endif

	#define DB_PRINT_L(lvl, fmt, args...) do { \
	if (STM_USART_ERR_DEBUG >= lvl) { \
	qemu_log("%s: " fmt, __func__, ## args); \
	} \
	} while (0)

	#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)

	static int stm32f2xx_usart_can_receive(void *opaque)
	{
	STM32F2XXUsartState *s = opaque;

	if (!(s->usart_sr & USART_SR_RXNE)) {
	return 1;
	}

	return 0;
	}

	static void stm32f2xx_update_irq(STM32F2XXUsartState *s)
	{
	uint32_t mask = s->usart_sr & s->usart_cr1;

	if (mask & (USART_SR_TXE \| USART_SR_TC \| USART_SR_RXNE)) {
	qemu_set_irq(s->irq, 1);
	} else {
	qemu_set_irq(s->irq, 0);
	}
	}

	static void stm32f2xx_usart_receive(void opaque, const uint8_t buf, int size)
	{
	STM32F2XXUsartState *s = opaque;

	if (!(s->usart_cr1 & USART_CR1_UE && s->usart_cr1 & USART_CR1_RE)) {
	/* USART not enabled - drop the chars */
	DB_PRINT("Dropping the chars\n");
	return;
	}

	s->usart_dr = *buf;
	s->usart_sr \|= USART_SR_RXNE;

	stm32f2xx_update_irq(s);

	DB_PRINT("Receiving: %c\n", s->usart_dr);
	}

	static void stm32f2xx_usart_reset(DeviceState *dev)
	{
	STM32F2XXUsartState *s = STM32F2XX_USART(dev);

	s->usart_sr = USART_SR_RESET;
	s->usart_dr = 0x00000000;
	s->usart_brr = 0x00000000;
	s->usart_cr1 = 0x00000000;
	s->usart_cr2 = 0x00000000;
	s->usart_cr3 = 0x00000000;
	s->usart_gtpr = 0x00000000;

	stm32f2xx_update_irq(s);
	}

	static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
	unsigned int size)
	{
	STM32F2XXUsartState *s = opaque;
	uint64_t retvalue;

	DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);

	switch (addr) {
	case USART_SR:
	retvalue = s->usart_sr;
	qemu_chr_fe_accept_input(&s->chr);
	return retvalue;
	case USART_DR:
	DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
	retvalue = s->usart_dr & 0x3FF;
	s->usart_sr &= ~USART_SR_RXNE;
	qemu_chr_fe_accept_input(&s->chr);
	stm32f2xx_update_irq(s);
	return retvalue;
	case USART_BRR:
	return s->usart_brr;
	case USART_CR1:
	return s->usart_cr1;
	case USART_CR2:
	return s->usart_cr2;
	case USART_CR3:
	return s->usart_cr3;
	case USART_GTPR:
	return s->usart_gtpr;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
	return 0;
	}

	return 0;
	}

	static void stm32f2xx_usart_write(void *opaque, hwaddr addr,
	uint64_t val64, unsigned int size)
	{
	STM32F2XXUsartState *s = opaque;
	uint32_t value = val64;
	unsigned char ch;

	DB_PRINT("Write 0x%" PRIx32 ", 0x%"HWADDR_PRIx"\n", value, addr);

	switch (addr) {
	case USART_SR:
	if (value <= 0x3FF) {
	/* I/O being synchronous, TXE is always set. In addition, it may
	only be set by hardware, so keep it set here. */
	s->usart_sr = value \| USART_SR_TXE;
	} else {
	s->usart_sr &= value;
	}
	stm32f2xx_update_irq(s);
	return;
	case USART_DR:
	if (value < 0xF000) {
	ch = value;
	/* 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);
	/* XXX I/O are currently synchronous, making it impossible for
	software to observe transient states where TXE or TC aren't
	set. Unlike TXE however, which is read-only, software may
	clear TC by writing 0 to the SR register, so set it again
	on each write. */
	s->usart_sr \|= USART_SR_TC;
	stm32f2xx_update_irq(s);
	}
	return;
	case USART_BRR:
	s->usart_brr = value;
	return;
	case USART_CR1:
	s->usart_cr1 = value;
	stm32f2xx_update_irq(s);
	return;
	case USART_CR2:
	s->usart_cr2 = value;
	return;
	case USART_CR3:
	s->usart_cr3 = value;
	return;
	case USART_GTPR:
	s->usart_gtpr = value;
	return;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
	}
	}

	static const MemoryRegionOps stm32f2xx_usart_ops = {
	.read = stm32f2xx_usart_read,
	.write = stm32f2xx_usart_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	};

	static Property stm32f2xx_usart_properties[] = {
	DEFINE_PROP_CHR("chardev", STM32F2XXUsartState, chr),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void stm32f2xx_usart_init(Object *obj)
	{
	STM32F2XXUsartState *s = STM32F2XX_USART(obj);

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

	memory_region_init_io(&s->mmio, obj, &stm32f2xx_usart_ops, s,
	TYPE_STM32F2XX_USART, 0x400);
	sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
	}

	static void stm32f2xx_usart_realize(DeviceState dev, Error *errp)
	{
	STM32F2XXUsartState *s = STM32F2XX_USART(dev);

	qemu_chr_fe_set_handlers(&s->chr, stm32f2xx_usart_can_receive,
	stm32f2xx_usart_receive, NULL, NULL,
	s, NULL, true);
	}

	static void stm32f2xx_usart_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->reset = stm32f2xx_usart_reset;
	device_class_set_props(dc, stm32f2xx_usart_properties);
	dc->realize = stm32f2xx_usart_realize;
	}

	static const TypeInfo stm32f2xx_usart_info = {
	.name = TYPE_STM32F2XX_USART,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(STM32F2XXUsartState),
	.instance_init = stm32f2xx_usart_init,
	.class_init = stm32f2xx_usart_class_init,
	};

	static void stm32f2xx_usart_register_types(void)
	{
	type_register_static(&stm32f2xx_usart_info);
	}

	type_init(stm32f2xx_usart_register_types)