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STM32 Serial: PX4 HW workarround for flaky STM32 RTS. From David Sidrane

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This commit is contained in:
Gregory Nutt 2014-12-27 18:58:18 -06:00
parent d597e94332
commit 59c6f42be4
2 changed files with 46 additions and 3 deletions
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10
arch/arm/src/stm32/Kconfig
View File

@ -3109,6 +3109,16 @@ config SERIAL_DISABLE_REORDERING
want the side effect of having all serial port names change when just
the console is moved from serial to USB.
config STM32_FLOWCONTROL_BROKEN
bool "Use Software UART RTS flow control"
depends on STM32_USART
default n
---help---
Enable UART RTS flow control using Software. Because STM
Current STM32 have broken HW based RTS behavior (they assert
nRTS after every byte received) Enable this setting workaround
this issue by useing software based management of RTS
endmenu
config STM32_USART_SINGLEWIRE

39
arch/arm/src/stm32/stm32_serial.c
View File

@ -410,6 +410,9 @@ static const struct uart_ops_s g_uart_dma_ops =
.receive = up_dma_receive,
.rxint = up_dma_rxint,
.rxavailable = up_dma_rxavailable,
#ifdef CONFIG_SERIAL_IFLOWCONTROL
.rxflowcontrol = up_rxflowcontrol,
#endif
.send = up_send,
.txint = up_txint,
.txready = up_txready,
@ -1294,7 +1297,7 @@ static void up_set_format(struct uart_dev_s *dev)
regval = up_serialin(priv, STM32_USART_CR3_OFFSET);
regval &= ~(USART_CR3_CTSE|USART_CR3_RTSE);
#ifdef CONFIG_SERIAL_IFLOWCONTROL
#if defined(CONFIG_SERIAL_IFLOWCONTROL) && !defined(CONFIG_STM32_FLOWCONTROL_BROKEN)
if (priv->iflow && (priv->rts_gpio != 0))
{
regval |= USART_CR3_RTSE;
@ -1437,8 +1440,15 @@ static int up_setup(struct uart_dev_s *dev)
#ifdef CONFIG_SERIAL_IFLOWCONTROL
if (priv->rts_gpio != 0)
{
stm32_configgpio(priv->rts_gpio);
}
uint32_t config = priv->rts_gpio;
#ifdef CONFIG_STM32_FLOWCONTROL_BROKEN
/* Instead of letting hw manage this pin, we will bitbang */
config = (config & ~GPIO_MODE_MASK) | GPIO_OUTPUT;
#endif
stm32_configgpio(config);
}
#endif
#if HAVE_RS485
@ -2140,6 +2150,18 @@ static bool up_rxavailable(struct uart_dev_s *dev)
* Return true if UART activated RX flow control to block more incoming
* data
*
* Input parameters:
* dev - UART device instance
* nbuffered - the number of characters currently buffered
* (if CONFIG_SERIAL_IFLOWCONTROL_WATERMARKS is
* not defined the value will be 0 for an empty buffer or the
* defined buffer size for a full buffer)
* upper - true indicates the upper watermark was crossed where
* false indicates the lower watermark has been crossed
*
* Returned Value:
* true if RX flow control activated.
*
****************************************************************************/
#ifdef CONFIG_SERIAL_IFLOWCONTROL
@ -2149,6 +2171,16 @@ static bool up_rxflowcontrol(struct uart_dev_s *dev,
struct up_dev_s *priv = (struct up_dev_s*)dev->priv;
uint16_t ie;
#if defined(CONFIG_SERIAL_IFLOWCONTROL_WATERMARKS) && defined(CONFIG_STM32_FLOWCONTROL_BROKEN)
if (priv->iflow && (priv->rts_gpio != 0))
{
/* Assert/de-assert nRTS set it high resume/stop sending */
stm32_gpiowrite(priv->rts_gpio, upper);
return upper;
}
#else
if (priv->iflow)
{
/* Is the RX buffer full? */
@ -2185,6 +2217,7 @@ static bool up_rxflowcontrol(struct uart_dev_s *dev,
up_rxint(dev, true);
}
}
#endif
return false;
}