From: Michael Walle <michael@walle.cc>
To: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Angelo Dureghello <angelo.dureghello@timesys.com>,
Johan Hovold <johan@kernel.org>,
Philippe Schenker <philippe.schenker@toradex.com>,
Michael Walle <michael@walle.cc>
Subject: [PATCH v2 5/9] serial: fsl_lpuart: handle break and make sysrq work
Date: Wed, 12 May 2021 16:12:51 +0200 [thread overview]
Message-ID: <20210512141255.18277-6-michael@walle.cc> (raw)
In-Reply-To: <20210512141255.18277-1-michael@walle.cc>
Although there is already sysrq characters handling, a break condition
was never detected. Add support for it.
The LPUART can't distinguish between a framing error and a break
condition. We assume it is a break if the received data is all zero.
Signed-off-by: Michael Walle <michael@walle.cc>
---
drivers/tty/serial/fsl_lpuart.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 63a1dac7c3aa..c76bdb855ba9 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -910,6 +910,7 @@ static void lpuart32_rxint(struct lpuart_port *sport)
unsigned int flg, ignored = 0;
struct tty_port *port = &sport->port.state->port;
unsigned long rx, sr;
+ bool is_break;
spin_lock(&sport->port.lock);
@@ -924,14 +925,27 @@ static void lpuart32_rxint(struct lpuart_port *sport)
rx = lpuart32_read(&sport->port, UARTDATA);
rx &= UARTDATA_MASK;
+ /*
+ * The LPUART can't distinguish between a break and a framing error,
+ * thus we assume it is a break if the received data is zero.
+ */
+ is_break = (sr & UARTSTAT_FE) && !rx;
+
+ if (is_break && uart_handle_break(&sport->port))
+ continue;
+
if (uart_prepare_sysrq_char(&sport->port, rx))
continue;
if (sr & (UARTSTAT_PE | UARTSTAT_OR | UARTSTAT_FE)) {
- if (sr & UARTSTAT_PE)
- sport->port.icount.parity++;
- else if (sr & UARTSTAT_FE)
+ if (sr & UARTSTAT_PE) {
+ if (is_break)
+ sport->port.icount.brk++;
+ else
+ sport->port.icount.parity++;
+ } else if (sr & UARTSTAT_FE) {
sport->port.icount.frame++;
+ }
if (sr & UARTSTAT_OR)
sport->port.icount.overrun++;
@@ -944,15 +958,17 @@ static void lpuart32_rxint(struct lpuart_port *sport)
sr &= sport->port.read_status_mask;
- if (sr & UARTSTAT_PE)
- flg = TTY_PARITY;
- else if (sr & UARTSTAT_FE)
+ if (sr & UARTSTAT_PE) {
+ if (is_break)
+ flg = TTY_BREAK;
+ else
+ flg = TTY_PARITY;
+ } else if (sr & UARTSTAT_FE) {
flg = TTY_FRAME;
+ }
if (sr & UARTSTAT_OR)
flg = TTY_OVERRUN;
-
- sport->port.sysrq = 0;
}
tty_insert_flip_char(port, rx, flg);
--
2.20.1
next prev parent reply other threads:[~2021-05-12 14:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 14:12 [PATCH v2 0/9] serial: fsl_lpuart: sysrq, loopback support and fixes Michael Walle
2021-05-12 14:12 ` [PATCH v2 1/9] serial: fsl_lpuart: don't modify arbitrary data on lpuart32 Michael Walle
2021-05-12 14:12 ` [PATCH v2 2/9] serial: fsl_lpuart: use UARTDATA_MASK macro Michael Walle
2021-05-12 14:12 ` [PATCH v2 3/9] serial: fsl_lpuart: don't restore interrupt state in ISR Michael Walle
2021-05-12 14:12 ` [PATCH v2 4/9] serial: fsl_lpuart: split sysrq handling Michael Walle
2021-05-12 14:12 ` Michael Walle [this message]
2021-05-12 14:12 ` [PATCH v2 6/9] serial: fsl_lpuart: remove RTSCTS handling from get_mctrl() Michael Walle
2021-05-12 14:12 ` [PATCH v2 7/9] serial: fsl_lpuart: remove manual RTSCTS control from 8-bit LPUART Michael Walle
2021-05-12 14:12 ` [PATCH v2 8/9] serial: fsl_lpuart: add loopback support Michael Walle
2021-05-12 14:12 ` [PATCH v2 9/9] serial: fsl_lpuart: disable DMA for console and fix sysrq Michael Walle
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