[PATCH AUTOSEL 4.19 010/191] serial: uartps: Fix suspend functionality

[PATCH AUTOSEL 4.19 010/191] serial: uartps: Fix suspend functionality

[Sasha Levin]

From: Nava kishore Manne <nava.manne@xilinx.com>

[ Upstream commit 4b9d33c6a30688344a3e95179654ea31b07f59b7 ]

The driver's suspend/resume functions were buggy.
If UART node contains any child node in the DT and
the child is established a communication path with
the parent UART. The relevant /dev/ttyPS* node will
be not available for other operations.
If the driver is trying to do any operations like
suspend/resume without checking the tty->dev status
it leads to the kernel crash/hang.

This patch fix this issue by call the device_may_wake()
with the generic parameter of type struct device.
in the uart suspend and resume paths.

It also fixes a race condition in the uart suspend
path(i.e uart_suspend_port() should be called at the
end of cdns_uart_suspend API this path updates the same)

Signed-off-by: Nava kishore Manne <navam@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/xilinx_uartps.c | 41 +++++++++---------------------
 1 file changed, 12 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 77efa0a43fe76..66d49d5118853 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1279,24 +1279,11 @@ static struct uart_driver cdns_uart_uart_driver = {
 static int cdns_uart_suspend(struct device *device)
 {
 	struct uart_port *port = dev_get_drvdata(device);
-	struct tty_struct *tty;
-	struct device *tty_dev;
-	int may_wake = 0;
-
-	/* Get the tty which could be NULL so don't assume it's valid */
-	tty = tty_port_tty_get(&port->state->port);
-	if (tty) {
-		tty_dev = tty->dev;
-		may_wake = device_may_wakeup(tty_dev);
-		tty_kref_put(tty);
-	}
+	int may_wake;
 
-	/*
-	 * Call the API provided in serial_core.c file which handles
-	 * the suspend.
-	 */
-	uart_suspend_port(&cdns_uart_uart_driver, port);
-	if (!(console_suspend_enabled && !may_wake)) {
+	may_wake = device_may_wakeup(device);
+
+	if (console_suspend_enabled && may_wake) {
 		unsigned long flags = 0;
 
 		spin_lock_irqsave(&port->lock, flags);
@@ -1311,7 +1298,11 @@ static int cdns_uart_suspend(struct device *device)
 		spin_unlock_irqrestore(&port->lock, flags);
 	}
 
-	return 0;
+	/*
+	 * Call the API provided in serial_core.c file which handles
+	 * the suspend.
+	 */
+	return uart_suspend_port(&cdns_uart_uart_driver, port);
 }
 
 /**
@@ -1325,17 +1316,9 @@ static int cdns_uart_resume(struct device *device)
 	struct uart_port *port = dev_get_drvdata(device);
 	unsigned long flags = 0;
 	u32 ctrl_reg;
-	struct tty_struct *tty;
-	struct device *tty_dev;
-	int may_wake = 0;
-
-	/* Get the tty which could be NULL so don't assume it's valid */
-	tty = tty_port_tty_get(&port->state->port);
-	if (tty) {
-		tty_dev = tty->dev;
-		may_wake = device_may_wakeup(tty_dev);
-		tty_kref_put(tty);
-	}
+	int may_wake;
+
+	may_wake = device_may_wakeup(device);
 
 	if (console_suspend_enabled && !may_wake) {
 		struct cdns_uart *cdns_uart = port->private_data;
-- 
2.20.1

[PATCH AUTOSEL 4.19 011/191] serial: samsung: Enable baud clock for UART reset procedure in resume

[Sasha Levin]

From: Marek Szyprowski <m.szyprowski@samsung.com>

[ Upstream commit 1ff3652bc7111df26b5807037f624be294cf69d5 ]

Ensure that the baud clock is also enabled for UART register writes in
driver resume. On Exynos5433 SoC this is needed to avoid external abort
issue.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/samsung.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index c6058b52d5d59..2a49b6d876b87 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1944,7 +1944,11 @@ static int s3c24xx_serial_resume(struct device *dev)
 
 	if (port) {
 		clk_prepare_enable(ourport->clk);
+		if (!IS_ERR(ourport->baudclk))
+			clk_prepare_enable(ourport->baudclk);
 		s3c24xx_serial_resetport(port, s3c24xx_port_to_cfg(port));
+		if (!IS_ERR(ourport->baudclk))
+			clk_disable_unprepare(ourport->baudclk);
 		clk_disable_unprepare(ourport->clk);
 
 		uart_resume_port(&s3c24xx_uart_drv, port);
@@ -1967,7 +1971,11 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
 			if (rx_enabled(port))
 				uintm &= ~S3C64XX_UINTM_RXD_MSK;
 			clk_prepare_enable(ourport->clk);
+			if (!IS_ERR(ourport->baudclk))
+				clk_prepare_enable(ourport->baudclk);
 			wr_regl(port, S3C64XX_UINTM, uintm);
+			if (!IS_ERR(ourport->baudclk))
+				clk_disable_unprepare(ourport->baudclk);
 			clk_disable_unprepare(ourport->clk);
 		}
 	}
-- 
2.20.1

[PATCH AUTOSEL 4.19 012/191] serial: mxs-auart: Fix potential infinite loop

[Sasha Levin]

From: Anton Vasilyev <vasilyev@ispras.ru>

[ Upstream commit 5963e8a3122471cadfe0eba41c4ceaeaa5c8bb4d ]

On the error path of mxs_auart_request_gpio_irq() is performed
backward iterating with index i of enum type. Underline enum type
may be unsigned char. In this case check (--i >= 0) will be always
true and error handling goes into infinite loop.

The patch changes the check so that it is valid for signed and unsigned
types.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/mxs-auart.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 34acdf29713d7..4c188f4079b3e 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1634,8 +1634,9 @@ static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s)
 
 	/*
 	 * If something went wrong, rollback.
+	 * Be careful: i may be unsigned.
 	 */
-	while (err && (--i >= 0))
+	while (err && (i-- > 0))
 		if (irq[i] >= 0)
 			free_irq(irq[i], s);
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 013/191] tty: serial: qcom_geni_serial: Fix serial when not used as console

[Sasha Levin]

From: Douglas Anderson <dianders@chromium.org>

[ Upstream commit c362272bdea32bf048d6916b0a2dc485eb9cf787 ]

If you've got the "console" serial port setup to use just as a UART
(AKA there is no "console=ttyMSMX" on the kernel command line) then
certain initialization is skipped.  When userspace later tries to do
something with the port then things go boom (specifically, on my
system, some sort of exception hit that caused the system to reboot
itself w/ no error messages).

Let's cleanup / refactor the init so that we always run the same init
code regardless of whether we're using the console.

To make this work, we make rely on qcom_geni_serial_pm doing its job
to turn resources on.

For the record, here is a trace of the order of things (after this
patch) when console= is specified on the command line and we have an
agetty on the port:
  qcom_geni_serial_pm: 4 (undefined) => 0 (on)
  qcom_geni_console_setup
  qcom_geni_serial_port_setup
  qcom_geni_serial_console_write
  qcom_geni_serial_startup
  qcom_geni_serial_start_tx

...and here is the order of things (after this patch) when console= is
_NOT_ specified on the command line and we have an agetty port:
  qcom_geni_serial_pm: 4 => 0
  qcom_geni_serial_pm: 0 => 3
  qcom_geni_serial_pm: 3 => 0
  qcom_geni_serial_startup
  qcom_geni_serial_port_setup
  qcom_geni_serial_pm: 0 => 3
  qcom_geni_serial_pm: 3 => 0
  qcom_geni_serial_startup
  qcom_geni_serial_start_tx

Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 55 +++++++++++++--------------
 1 file changed, 26 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 5b96df4ad5b30..69b980bb8ac29 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -851,6 +851,23 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 	unsigned int rxstale = DEFAULT_BITS_PER_CHAR * STALE_TIMEOUT;
+	u32 proto;
+
+	if (uart_console(uport))
+		port->tx_bytes_pw = 1;
+	else
+		port->tx_bytes_pw = 4;
+	port->rx_bytes_pw = RX_BYTES_PW;
+
+	proto = geni_se_read_proto(&port->se);
+	if (proto != GENI_SE_UART) {
+		dev_err(uport->dev, "Invalid FW loaded, proto: %d\n", proto);
+		return -ENXIO;
+	}
+
+	qcom_geni_serial_stop_rx(uport);
+
+	get_tx_fifo_size(port);
 
 	set_rfr_wm(port);
 	writel_relaxed(rxstale, uport->membase + SE_UART_RX_STALE_CNT);
@@ -874,30 +891,19 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
 			return -ENOMEM;
 	}
 	port->setup = true;
+
 	return 0;
 }
 
 static int qcom_geni_serial_startup(struct uart_port *uport)
 {
 	int ret;
-	u32 proto;
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 
 	scnprintf(port->name, sizeof(port->name),
 		  "qcom_serial_%s%d",
 		(uart_console(uport) ? "console" : "uart"), uport->line);
 
-	if (!uart_console(uport)) {
-		port->tx_bytes_pw = 4;
-		port->rx_bytes_pw = RX_BYTES_PW;
-	}
-	proto = geni_se_read_proto(&port->se);
-	if (proto != GENI_SE_UART) {
-		dev_err(uport->dev, "Invalid FW loaded, proto: %d\n", proto);
-		return -ENXIO;
-	}
-
-	get_tx_fifo_size(port);
 	if (!port->setup) {
 		ret = qcom_geni_serial_port_setup(uport);
 		if (ret)
@@ -1056,6 +1062,7 @@ static int __init qcom_geni_console_setup(struct console *co, char *options)
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
+	int ret;
 
 	if (co->index >= GENI_UART_CONS_PORTS  || co->index < 0)
 		return -ENXIO;
@@ -1071,21 +1078,10 @@ static int __init qcom_geni_console_setup(struct console *co, char *options)
 	if (unlikely(!uport->membase))
 		return -ENXIO;
 
-	if (geni_se_resources_on(&port->se)) {
-		dev_err(port->se.dev, "Error turning on resources\n");
-		return -ENXIO;
-	}
-
-	if (unlikely(geni_se_read_proto(&port->se) != GENI_SE_UART)) {
-		geni_se_resources_off(&port->se);
-		return -ENXIO;
-	}
-
 	if (!port->setup) {
-		port->tx_bytes_pw = 1;
-		port->rx_bytes_pw = RX_BYTES_PW;
-		qcom_geni_serial_stop_rx(uport);
-		qcom_geni_serial_port_setup(uport);
+		ret = qcom_geni_serial_port_setup(uport);
+		if (ret)
+			return ret;
 	}
 
 	if (options)
@@ -1203,11 +1199,12 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 
+	/* If we've never been called, treat it as off */
+	if (old_state == UART_PM_STATE_UNDEFINED)
+		old_state = UART_PM_STATE_OFF;
+
 	if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF)
 		geni_se_resources_on(&port->se);
-	else if (!uart_console(uport) && (new_state == UART_PM_STATE_ON &&
-				old_state == UART_PM_STATE_UNDEFINED))
-		geni_se_resources_on(&port->se);
 	else if (new_state == UART_PM_STATE_OFF &&
 			old_state == UART_PM_STATE_ON)
 		geni_se_resources_off(&port->se);
-- 
2.20.1