linux-kernel - [PATCH v2 13/13] serial: stm32: add support for "flush

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20210304162308.8984-14-erwan.leray@foss.st.com>
Date:   Thu, 4 Mar 2021 17:23:08 +0100
From:   Erwan Le Ray <erwan.leray@...s.st.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>
CC:     <linux-serial@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Erwan Le Ray <erwan.leray@...s.st.com>,
        Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
        Valentin Caron <valentin.caron@...s.st.com>
Subject: [PATCH v2 13/13] serial: stm32: add support for "flush_buffer" ops

Add the support for "flush_buffer" ops in order to flush any write buffers,
reset any DMA state and stop any ongoing DMA transfers when the
port->state->xmit circular buffer is cleared.

Signed-off-by: Erwan Le Ray <erwan.leray@...s.st.com>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 99dfa884cbef..9db6708e3d9f 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -597,6 +597,19 @@ static void stm32_usart_start_tx(struct uart_port *port)
 	stm32_usart_transmit_chars(port);
 }
 
+/* Flush the transmit buffer. */
+static void stm32_usart_flush_buffer(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	if (stm32_port->tx_ch) {
+		dmaengine_terminate_async(stm32_port->tx_ch);
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
+		stm32_port->tx_dma_busy = false;
+	}
+}
+
 /* Throttle the remote when input buffer is about to overflow. */
 static void stm32_usart_throttle(struct uart_port *port)
 {
@@ -992,6 +1005,7 @@ static const struct uart_ops stm32_uart_ops = {
 	.break_ctl	= stm32_usart_break_ctl,
 	.startup	= stm32_usart_startup,
 	.shutdown	= stm32_usart_shutdown,
+	.flush_buffer	= stm32_usart_flush_buffer,
 	.set_termios	= stm32_usart_set_termios,
 	.pm		= stm32_usart_pm,
 	.type		= stm32_usart_type,
-- 
2.17.1