[PATCH AUTOSEL 5.10 029/176] tty: serial: jsm: hold port lock when reporting modem line changes

[PATCH AUTOSEL 5.10 029/176] tty: serial: jsm: hold port lock when reporting modem line changes

[Sasha Levin]

From: Zheyu Ma <zheyuma97@gmail.com>

[ Upstream commit 240e126c28df084222f0b661321e8e3ecb0d232e ]

uart_handle_dcd_change() requires a port lock to be held and will emit a
warning when lockdep is enabled.

Held corresponding lock to fix the following warnings.

[  132.528648] WARNING: CPU: 5 PID: 11600 at drivers/tty/serial/serial_core.c:3046 uart_handle_dcd_change+0xf4/0x120
[  132.530482] Modules linked in:
[  132.531050] CPU: 5 PID: 11600 Comm: jsm Not tainted 5.14.0-rc1-00003-g7fef2edf7cc7-dirty #31
[  132.535268] RIP: 0010:uart_handle_dcd_change+0xf4/0x120
[  132.557100] Call Trace:
[  132.557562]  ? __free_pages+0x83/0xb0
[  132.558213]  neo_parse_modem+0x156/0x220
[  132.558897]  neo_param+0x399/0x840
[  132.559495]  jsm_tty_open+0x12f/0x2d0
[  132.560131]  uart_startup.part.18+0x153/0x340
[  132.560888]  ? lock_is_held_type+0xe9/0x140
[  132.561660]  uart_port_activate+0x7f/0xe0
[  132.562351]  ? uart_startup.part.18+0x340/0x340
[  132.563003]  tty_port_open+0x8d/0xf0
[  132.563523]  ? uart_set_options+0x1e0/0x1e0
[  132.564125]  uart_open+0x24/0x40
[  132.564604]  tty_open+0x15c/0x630

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1626242003-3809-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/jsm/jsm_neo.c | 2 ++
 drivers/tty/serial/jsm/jsm_tty.c | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/tty/serial/jsm/jsm_neo.c b/drivers/tty/serial/jsm/jsm_neo.c
index bf0e2a4cb0ce..c6f927a76c3b 100644
--- a/drivers/tty/serial/jsm/jsm_neo.c
+++ b/drivers/tty/serial/jsm/jsm_neo.c
@@ -815,7 +815,9 @@ static void neo_parse_isr(struct jsm_board *brd, u32 port)
 		/* Parse any modem signal changes */
 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 			"MOD_STAT: sending to parse_modem_sigs\n");
+		spin_lock_irqsave(&ch->uart_port.lock, lock_flags);
 		neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
+		spin_unlock_irqrestore(&ch->uart_port.lock, lock_flags);
 	}
 }
 
diff --git a/drivers/tty/serial/jsm/jsm_tty.c b/drivers/tty/serial/jsm/jsm_tty.c
index 689774c073ca..8438454ca653 100644
--- a/drivers/tty/serial/jsm/jsm_tty.c
+++ b/drivers/tty/serial/jsm/jsm_tty.c
@@ -187,6 +187,7 @@ static void jsm_tty_break(struct uart_port *port, int break_state)
 
 static int jsm_tty_open(struct uart_port *port)
 {
+	unsigned long lock_flags;
 	struct jsm_board *brd;
 	struct jsm_channel *channel =
 		container_of(port, struct jsm_channel, uart_port);
@@ -240,6 +241,7 @@ static int jsm_tty_open(struct uart_port *port)
 	channel->ch_cached_lsr = 0;
 	channel->ch_stops_sent = 0;
 
+	spin_lock_irqsave(&port->lock, lock_flags);
 	termios = &port->state->port.tty->termios;
 	channel->ch_c_cflag	= termios->c_cflag;
 	channel->ch_c_iflag	= termios->c_iflag;
@@ -259,6 +261,7 @@ static int jsm_tty_open(struct uart_port *port)
 	jsm_carrier(channel);
 
 	channel->ch_open_count++;
+	spin_unlock_irqrestore(&port->lock, lock_flags);
 
 	jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
 	return 0;
-- 
2.30.2

[PATCH AUTOSEL 5.10 053/176] serial: 8250: Define RX trigger levels for OxSemi 950 devices

[Sasha Levin]

From: "Maciej W. Rozycki" <macro@orcam.me.uk>

[ Upstream commit d7aff291d069c4418285f3c8ee27b0ff67ce5998 ]

Oxford Semiconductor 950 serial port devices have a 128-byte FIFO and in
the enhanced (650) mode, which we select in `autoconfig_has_efr' with
the ECB bit set in the EFR register, they support the receive interrupt
trigger level selectable with FCR bits 7:6 from the set of 16, 32, 112,
120.  This applies to the original OX16C950 discrete UART[1] as well as
950 cores embedded into more complex devices.

For these devices we set the default to 112, which sets an excessively
high level of 112 or 7/8 of the FIFO capacity, unlike with other port
types where we choose at most 1/2 of their respective FIFO capacities.
Additionally we don't make the trigger level configurable.  Consequently
frequent input overruns happen with high bit rates where hardware flow
control cannot be used (e.g. terminal applications) even with otherwise
highly-performant systems.

Lower the default receive interrupt trigger level to 32 then, and make
it configurable.  Document the trigger levels along with other port
types, including the set of 16, 32, 64, 112 for the transmit interrupt
as well[2].

References:

[1] "OX16C950 rev B High Performance UART with 128 byte FIFOs", Oxford
    Semiconductor, Inc., DS-0031, Sep 05, Table 10: "Receiver Trigger
    Levels", p. 22

[2] same, Table 9: "Transmit Interrupt Trigger Levels", p. 22

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260608480.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_port.c | 3 ++-
 include/uapi/linux/serial_reg.h     | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3de0a16e055a..5d40f1010fbf 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -122,7 +122,8 @@ static const struct serial8250_config uart_config[] = {
 		.name		= "16C950/954",
 		.fifo_size	= 128,
 		.tx_loadsz	= 128,
-		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
+		.rxtrig_bytes	= {16, 32, 112, 120},
 		/* UART_CAP_EFR breaks billionon CF bluetooth card. */
 		.flags		= UART_CAP_FIFO | UART_CAP_SLEEP,
 	},
diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
index be07b5470f4b..f51bc8f36813 100644
--- a/include/uapi/linux/serial_reg.h
+++ b/include/uapi/linux/serial_reg.h
@@ -62,6 +62,7 @@
  * ST16C654:	 8  16  56  60		 8  16  32  56	PORT_16654
  * TI16C750:	 1  16  32  56		xx  xx  xx  xx	PORT_16750
  * TI16C752:	 8  16  56  60		 8  16  32  56
+ * OX16C950:	16  32 112 120		16  32  64 112	PORT_16C950
  * Tegra:	 1   4   8  14		16   8   4   1	PORT_TEGRA
  */
 #define UART_FCR_R_TRIG_00	0x00
-- 
2.30.2

[PATCH AUTOSEL 5.10 056/176] serial: 8250_pci: make setup_port() parameters explicitly unsigned

[Sasha Levin]

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 3a96e97ab4e835078e6f27b7e1c0947814df3841 ]

The bar and offset parameters to setup_port() are used in pointer math,
and while it would be very difficult to get them to wrap as a negative
number, just be "safe" and make them unsigned so that static checkers do
not trip over them unintentionally.

Cc: Jiri Slaby <jirislaby@kernel.org>
Reported-by: Jordy Zomer <jordy@pwning.systems>
Link: https://lore.kernel.org/r/20210726130717.2052096-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 39f9ea24e316..58f718ed1bb9 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -87,7 +87,7 @@ static void moan_device(const char *str, struct pci_dev *dev)
 
 static int
 setup_port(struct serial_private *priv, struct uart_8250_port *port,
-	   int bar, int offset, int regshift)
+	   u8 bar, unsigned int offset, int regshift)
 {
 	struct pci_dev *dev = priv->dev;
 
-- 
2.30.2

[PATCH AUTOSEL 5.10 081/176] serial: 8250_omap: Handle optional overrun-throttle-ms property

[Sasha Levin]

From: Tony Lindgren <tony@atomide.com>

[ Upstream commit 1fe0e1fa3209ad8e9124147775bd27b1d9f04bd4 ]

Handle optional overrun-throttle-ms property as done for 8250_fsl in commit
6d7f677a2afa ("serial: 8250: Rate limit serial port rx interrupts during
input overruns"). This can be used to rate limit the UART interrupts on
noisy lines that end up producing messages like the following:

ttyS ttyS2: 4 input overrun(s)

At least on droid4, the multiplexed USB and UART port is left to UART mode
by the bootloader for a debug console, and if a USB charger is connected
on boot, we get noise on the UART until the PMIC related drivers for PHY
and charger are loaded.

With this patch and overrun-throttle-ms = <500> we avoid the extra rx
interrupts.

Cc: Carl Philipp Klemm <philipp@uvos.xyz>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20210727103533.51547-2-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_omap.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 95e2d6de4f21..cd85491a52f9 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -604,7 +604,7 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 	struct uart_port *port = dev_id;
 	struct omap8250_priv *priv = port->private_data;
 	struct uart_8250_port *up = up_to_u8250p(port);
-	unsigned int iir;
+	unsigned int iir, lsr;
 	int ret;
 
 #ifdef CONFIG_SERIAL_8250_DMA
@@ -615,6 +615,7 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 #endif
 
 	serial8250_rpm_get(up);
+	lsr = serial_port_in(port, UART_LSR);
 	iir = serial_port_in(port, UART_IIR);
 	ret = serial8250_handle_irq(port, iir);
 
@@ -629,6 +630,24 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
 		serial_port_in(port, UART_RX);
 	}
 
+	/* Stop processing interrupts on input overrun */
+	if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) {
+		unsigned long delay;
+
+		up->ier = port->serial_in(port, UART_IER);
+		if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
+			port->ops->stop_rx(port);
+		} else {
+			/* Keep restarting the timer until
+			 * the input overrun subsides.
+			 */
+			cancel_delayed_work(&up->overrun_backoff);
+		}
+
+		delay = msecs_to_jiffies(up->overrun_backoff_time_ms);
+		schedule_delayed_work(&up->overrun_backoff, delay);
+	}
+
 	serial8250_rpm_put(up);
 
 	return IRQ_RETVAL(ret);
@@ -1345,6 +1364,10 @@ static int omap8250_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (of_property_read_u32(np, "overrun-throttle-ms",
+				 &up.overrun_backoff_time_ms) != 0)
+		up.overrun_backoff_time_ms = 0;
+
 	priv->wakeirq = irq_of_parse_and_map(np, 1);
 
 	pdata = of_device_get_match_data(&pdev->dev);
-- 
2.30.2

[PATCH AUTOSEL 5.10 117/176] serial: sh-sci: fix break handling for sysrq

[Sasha Levin]

From: Ulrich Hecht <uli+renesas@fpond.eu>

[ Upstream commit 87b8061bad9bd4b549b2daf36ffbaa57be2789a2 ]

This fixes two issues that cause the sysrq sequence to be inadvertently
aborted on SCIF serial consoles:

- a NUL character remains in the RX queue after a break has been detected,
  which is then passed on to uart_handle_sysrq_char()
- the break interrupt is handled twice on controllers with multiplexed ERI
  and BRI interrupts

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20210816162201.28801-1-uli+renesas@fpond.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/sh-sci.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 70898a999a49..f700bfaef129 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1760,6 +1760,10 @@ static irqreturn_t sci_br_interrupt(int irq, void *ptr)
 
 	/* Handle BREAKs */
 	sci_handle_breaks(port);
+
+	/* drop invalid character received before break was detected */
+	serial_port_in(port, SCxRDR);
+
 	sci_clear_SCxSR(port, SCxSR_BREAK_CLEAR(port));
 
 	return IRQ_HANDLED;
@@ -1839,7 +1843,8 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
 		ret = sci_er_interrupt(irq, ptr);
 
 	/* Break Interrupt */
-	if ((ssr_status & SCxSR_BRK(port)) && err_enabled)
+	if (s->irqs[SCIx_ERI_IRQ] != s->irqs[SCIx_BRI_IRQ] &&
+	    (ssr_status & SCxSR_BRK(port)) && err_enabled)
 		ret = sci_br_interrupt(irq, ptr);
 
 	/* Overrun Interrupt */
-- 
2.30.2