qemu/include/hw/char/stm32f2xx_usart.h
Richard Braun f6bfe45af2 hw/char/stm32f2xx_usart: fix TXE/TC bit handling
I/O currently being synchronous, there is no reason to ever clear the
SR_TXE bit. However the SR_TC bit may be cleared by software writing
to the SR register, so set it on each write.

In addition, fix the reset value of the USART status register.

Signed-off-by: Richard Braun <rbraun@sceen.net>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
[PMM: removed XXX tag from comment, since it isn't something
 we need to come back and fix in QEMU]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-22 15:12:51 +00:00

79 lines
2.4 KiB
C

/*
* 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.
*/
#ifndef HW_STM32F2XX_USART_H
#define HW_STM32F2XX_USART_H
#include "hw/sysbus.h"
#include "chardev/char-fe.h"
#include "hw/hw.h"
#define USART_SR 0x00
#define USART_DR 0x04
#define USART_BRR 0x08
#define USART_CR1 0x0C
#define USART_CR2 0x10
#define USART_CR3 0x14
#define USART_GTPR 0x18
/*
* NB: The reset value mentioned in "24.6.1 Status register" seems bogus.
* Looking at "Table 98 USART register map and reset values", it seems it
* should be 0xc0, and that's how real hardware behaves.
*/
#define USART_SR_RESET (USART_SR_TXE | USART_SR_TC)
#define USART_SR_TXE (1 << 7)
#define USART_SR_TC (1 << 6)
#define USART_SR_RXNE (1 << 5)
#define USART_CR1_UE (1 << 13)
#define USART_CR1_RXNEIE (1 << 5)
#define USART_CR1_TE (1 << 3)
#define USART_CR1_RE (1 << 2)
#define TYPE_STM32F2XX_USART "stm32f2xx-usart"
#define STM32F2XX_USART(obj) \
OBJECT_CHECK(STM32F2XXUsartState, (obj), TYPE_STM32F2XX_USART)
typedef struct {
/* <private> */
SysBusDevice parent_obj;
/* <public> */
MemoryRegion mmio;
uint32_t usart_sr;
uint32_t usart_dr;
uint32_t usart_brr;
uint32_t usart_cr1;
uint32_t usart_cr2;
uint32_t usart_cr3;
uint32_t usart_gtpr;
CharBackend chr;
qemu_irq irq;
} STM32F2XXUsartState;
#endif /* HW_STM32F2XX_USART_H */