[PATCH v2 1/3] serial: 8250_mxpcie: set the driver data before registering ports

[Linmao Li]

mxpcie8250_rs485_config() looks the board up with dev_get_drvdata() on
the PCI device, but pci_set_drvdata() only runs after the registration
loop.  Where mxpcie8250_setup_port() presets rs485.flags to
SER_RS485_ENABLED and the flag survives uart_get_rs485_mode() - the
device has no firmware node, or its node sets
linux,rs485-enabled-at-boot-time - uart_configure_port() calls
->rs485_config() from inside serial8250_register_8250_port(), and the
callback dereferences a NULL board pointer.

Publish the driver data before the first port is registered.

Fixes: d21a1509c623 ("serial: 8250_mxpcie: support serial interface mode switching")
Signed-off-by: Linmao Li <lilinmao@xxxxxxxxxx>
---
v2: no code change; the commit message now says the crash needs
    SER_RS485_ENABLED to survive uart_get_rs485_mode() (Crescent
    Hsieh).

 drivers/tty/serial/8250/8250_mxpcie.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_mxpcie.c b/drivers/tty/serial/8250/8250_mxpcie.c
index ce873fbd62e9..c0e3517d4e4e 100644
--- a/drivers/tty/serial/8250/8250_mxpcie.c
+++ b/drivers/tty/serial/8250/8250_mxpcie.c
@@ -542,6 +542,8 @@ static int mxpcie8250_probe(struct pci_dev *pdev, const struct pci_device_id *id
 
 	mxpcie8250_init_board(pdev, priv);
 
+	pci_set_drvdata(pdev, priv);
+
 	up.port.dev = dev;
 	up.port.irq = pdev->irq;
 	up.port.uartclk = MOXA_PUART_BASE_BAUD * 16;
@@ -578,7 +580,6 @@ static int mxpcie8250_probe(struct pci_dev *pdev, const struct pci_device_id *id
 		}
 		priv->port[i].rx_trig_level = MOXA_PUART_RX_TRIG_DEFAULT;
 	}
-	pci_set_drvdata(pdev, priv);
 
 	return 0;
 }
-- 
2.25.1