From: Erwan Le Ray <erwan.leray@foss.st.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: <linux-serial@vger.kernel.org>,
<linux-stm32@st-md-mailman.stormreply.com>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
Erwan Le Ray <erwan.leray@foss.st.com>,
Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
Valentin Caron <valentin.caron@foss.st.com>
Subject: [PATCH v2 04/13] serial: stm32: fix TX and RX FIFO thresholds
Date: Thu, 4 Mar 2021 17:22:59 +0100 [thread overview]
Message-ID: <20210304162308.8984-5-erwan.leray@foss.st.com> (raw)
In-Reply-To: <20210304162308.8984-1-erwan.leray@foss.st.com>
TX and RX FIFO thresholds may be cleared after suspend/resume, depending
on the low power mode.
Those configurations (done in startup) are not effective for UART console,
as:
- the reference manual indicates that FIFOEN bit can only be written when
the USART is disabled (UE=0)
- a set_termios (where UE is set) is requested firstly for console
enabling, before the startup.
Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index eae54b8cf5e2..223cec70c57c 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -649,19 +649,8 @@ static int stm32_usart_startup(struct uart_port *port)
if (ofs->rqr != UNDEF_REG)
stm32_usart_set_bits(port, ofs->rqr, USART_RQR_RXFRQ);
- /* Tx and RX FIFO configuration */
- if (stm32_port->fifoen) {
- val = readl_relaxed(port->membase + ofs->cr3);
- val &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
- val |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
- val |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
- writel_relaxed(val, port->membase + ofs->cr3);
- }
-
- /* RX FIFO enabling */
+ /* RX enabling */
val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
- if (stm32_port->fifoen)
- val |= USART_CR1_FIFOEN;
stm32_usart_set_bits(port, ofs->cr1, val);
return 0;
@@ -770,9 +759,15 @@ static void stm32_usart_set_termios(struct uart_port *port,
if (stm32_port->fifoen)
cr1 |= USART_CR1_FIFOEN;
cr2 = 0;
+
+ /* Tx and RX FIFO configuration */
cr3 = readl_relaxed(port->membase + ofs->cr3);
- cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
- | USART_CR3_TXFTCFG_MASK;
+ cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
+ if (stm32_port->fifoen) {
+ cr3 &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
+ cr3 |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
+ cr3 |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
+ }
if (cflag & CSTOPB)
cr2 |= USART_CR2_STOP_2B;
--
2.17.1
next prev parent reply other threads:[~2021-03-04 16:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 16:22 [PATCH v2 00/13] stm32 usart various fixes Erwan Le Ray
2021-03-04 16:22 ` [PATCH v2 01/13] serial: stm32: fix probe and remove order for dma Erwan Le Ray
2021-03-04 16:22 ` [PATCH v2 02/13] serial: stm32: fix startup by enabling usart for reception Erwan Le Ray
2021-03-04 16:22 ` [PATCH v2 03/13] serial: stm32: fix incorrect characters on console Erwan Le Ray
2021-03-04 16:22 ` Erwan Le Ray [this message]
2021-03-04 16:23 ` [PATCH v2 05/13] serial: stm32: fix a deadlock condition with wakeup event Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 06/13] serial: stm32: fix wake-up flag handling Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 07/13] serial: stm32: fix a deadlock in set_termios Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 08/13] serial: stm32: fix tx dma completion, release channel Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 09/13] serial: stm32: call stm32_transmit_chars locked Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 10/13] serial: stm32: fix FIFO flush in startup and set_termios Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 11/13] serial: stm32: add FIFO flush when port is closed Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 12/13] serial: stm32: fix tx_empty condition Erwan Le Ray
2021-03-04 16:23 ` [PATCH v2 13/13] serial: stm32: add support for "flush_buffer" ops Erwan Le Ray
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