[PATCH 4/4] serial: stm32: correct loop for dma error handling

From: Valentin Caron <valentin.caron@foss.st.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Gerald Baeza <gerald.baeza@st.com>,
	Erwan Le Ray <erwan.leray@foss.st.com>,
	Valentin Caron <valentin.caron@foss.st.com>,
	<linux-serial@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH 4/4] serial: stm32: correct loop for dma error handling
Date: Tue, 4 Jan 2022 19:24:45 +0100	[thread overview]
Message-ID: <20220104182445.4195-5-valentin.caron@foss.st.com> (raw)
In-Reply-To: <20220104182445.4195-1-valentin.caron@foss.st.com>

In this error handling, "transmit_chars_dma" function will call
"transmit_chars_pio" once per characters. But "transmit_chars_pio" will
continue to send characters while xmit buffer is not empty.

Remove this useless loop, one call is sufficient.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 drivers/tty/serial/stm32-usart.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 788e002688f2..1f89ab0e49ac 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -477,7 +477,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 	struct circ_buf *xmit = &port->state->xmit;
 	struct dma_async_tx_descriptor *desc = NULL;
-	unsigned int count, i;
+	unsigned int count;
 
 	if (stm32_usart_tx_dma_started(stm32port)) {
 		if (!stm32_usart_tx_dma_enabled(stm32port))
@@ -542,8 +542,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 	return;
 
 fallback_err:
-	for (i = count; i > 0; i--)
-		stm32_usart_transmit_chars_pio(port);
+	stm32_usart_transmit_chars_pio(port);
 }
 
 static void stm32_usart_transmit_chars(struct uart_port *port)
-- 
2.17.1

