8250.c: support specifying DW APB UARTs in device platform_data

Allow the private_data field to be specified in platform_data for the
standard 8250/16550 UART.  This field is used by DW APB type UARTs and
without this patch it's only possible to set this field when registering
the port by hand.  If private_data is not set then the driver will
potentially oops with a NULL pointer dereference.

Signed-off-by: Will Newton <will.newton@gmail.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/8250.c

@@ -2662,16 +2662,17 @@ static int __devinit serial8250_probe(struct platform_device *dev)
 	memset(&port, 0, sizeof(struct uart_port));
 
 	for (i = 0; p && p->flags != 0; p++, i++) {
-		port.iobase	= p->iobase;
-		port.membase	= p->membase;
-		port.irq	= p->irq;
-		port.uartclk	= p->uartclk;
-		port.regshift	= p->regshift;
-		port.iotype	= p->iotype;
-		port.flags	= p->flags;
-		port.mapbase	= p->mapbase;
-		port.hub6	= p->hub6;
-		port.dev	= &dev->dev;
+		port.iobase		= p->iobase;
+		port.membase		= p->membase;
+		port.irq		= p->irq;
+		port.uartclk		= p->uartclk;
+		port.regshift		= p->regshift;
+		port.iotype		= p->iotype;
+		port.flags		= p->flags;
+		port.mapbase		= p->mapbase;
+		port.hub6		= p->hub6;
+		port.private_data	= p->private_data;
+		port.dev		= &dev->dev;
 		if (share_irqs)
 			port.flags |= UPF_SHARE_IRQ;
 		ret = serial8250_register_port(&port);
@@ -2812,15 +2813,16 @@ int serial8250_register_port(struct uart_port *port)
 	if (uart) {
 		uart_remove_one_port(&serial8250_reg, &uart->port);
 
-		uart->port.iobase   = port->iobase;
-		uart->port.membase  = port->membase;
-		uart->port.irq      = port->irq;
-		uart->port.uartclk  = port->uartclk;
-		uart->port.fifosize = port->fifosize;
-		uart->port.regshift = port->regshift;
-		uart->port.iotype   = port->iotype;
-		uart->port.flags    = port->flags | UPF_BOOT_AUTOCONF;
-		uart->port.mapbase  = port->mapbase;
+		uart->port.iobase       = port->iobase;
+		uart->port.membase      = port->membase;
+		uart->port.irq          = port->irq;
+		uart->port.uartclk      = port->uartclk;
+		uart->port.fifosize     = port->fifosize;
+		uart->port.regshift     = port->regshift;
+		uart->port.iotype       = port->iotype;
+		uart->port.flags        = port->flags | UPF_BOOT_AUTOCONF;
+		uart->port.mapbase      = port->mapbase;
+		uart->port.private_data = port->private_data;
 		if (port->dev)
 			uart->port.dev = port->dev;
 

include/linux/serial_8250.h

@@ -23,6 +23,7 @@ struct plat_serial8250_port {
 	resource_size_t	mapbase;	/* resource base */
 	unsigned int	irq;		/* interrupt number */
 	unsigned int	uartclk;	/* UART clock rate */
+	void            *private_data;
 	unsigned char	regshift;	/* register shift */
 	unsigned char	iotype;		/* UPIO_* */
 	unsigned char	hub6;