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;