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Commit 64c32eab authored by Erwan Le Ray's avatar Erwan Le Ray Committed by Greg Kroah-Hartman
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serial: stm32: Add support of TC bit status check 



Adds a check on the Transmission Complete bit status before closing the
com port. Prevents the port closure before the end of the transmission.
TC poll loop is moved from stm32_tx_dma_complete to stm32_shutdown
routine, in order to check TC before shutdown in both dma and
PIO tx modes.
TC clear is added in stm32_transmit_char routine, in order to be cleared
before transmitting in both dma and PIO tx modes.

Fixes: 34891872 ("serial: stm32: adding dma support")
Signed-off-by: default avatarErwan Le Ray <erwan.leray@st.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b83b957c

drivers/tty/serial/stm32-usart.c

+15 −17
Original line number Diff line number Diff line
@@ -290,21 +290,6 @@ static void stm32_tx_dma_complete(void *arg) 
	struct uart_port *port = arg;

	struct stm32_port *stm32port = to_stm32_port(port);

	struct stm32_usart_offsets *ofs = &stm32port->info->ofs;

	unsigned int isr;

	int ret;



	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,

						isr,

						(isr & USART_SR_TC),

						10, 100000);



	if (ret)

		dev_err(port->dev, "terminal count not set\n");



	if (ofs->icr == UNDEF_REG)

		stm32_clr_bits(port, ofs->isr, USART_SR_TC);

	else

		stm32_set_bits(port, ofs->icr, USART_CR_TC);



	stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);

	stm32port->tx_dma_busy = false;
@@ -396,7 +381,6 @@ static void stm32_transmit_chars_dma(struct uart_port *port) 
	/* Issue pending DMA TX requests */

	dma_async_issue_pending(stm32port->tx_ch);



	stm32_clr_bits(port, ofs->isr, USART_SR_TC);

	stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);



	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
@@ -425,6 +409,11 @@ static void stm32_transmit_chars(struct uart_port *port) 
		return;

	}



	if (ofs->icr == UNDEF_REG)

		stm32_clr_bits(port, ofs->isr, USART_SR_TC);

	else

		stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);



	if (stm32_port->tx_ch)

		stm32_transmit_chars_dma(port);

	else
@@ -601,12 +590,21 @@ static void stm32_shutdown(struct uart_port *port) 
	struct stm32_port *stm32_port = to_stm32_port(port);

	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;

	struct stm32_usart_config *cfg = &stm32_port->info->cfg;

	u32 val;

	u32 val, isr;

	int ret;



	val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;

	val |= BIT(cfg->uart_enable_bit);

	if (stm32_port->fifoen)

		val |= USART_CR1_FIFOEN;



	ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,

					 isr, (isr & USART_SR_TC),

					 10, 100000);



	if (ret)

		dev_err(port->dev, "transmission complete not set\n");



	stm32_clr_bits(port, ofs->cr1, val);



	dev_pm_clear_wake_irq(port->dev);