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Commit a61c2d78 authored by Dave Jones's avatar Dave Jones Committed by Russell King
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[SERIAL] Make the number of UARTs registered configurable. 



Also add a nr_uarts module option to the 8250 code to override
this, up to a maximum of CONFIG_SERIAL_8250_NR_UARTS

This should appease people who complain about a proliferation
of /dev/ttyS & /sysfs nodes whilst at the same time allowing
a single kernel image to support the rarer occasions of
lots of devices.

Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent f61051cd

Documentation/kernel-parameters.txt

+2 −0
Original line number Diff line number Diff line
@@ -998,6 +998,8 @@ running once the system is up. 


	nowb		[ARM]



	nr_uarts=	[SERIAL] maximum number of UARTs to be registered.



	opl3=		[HW,OSS]

			Format: <io>

drivers/serial/8250.c

+18 −10
Original line number Diff line number Diff line
@@ -54,6 +54,8 @@ 
 */

static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;



static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;



/*

 * Debugging.

 */
@@ -2118,7 +2120,7 @@ static void __init serial8250_isa_init_ports(void) 
		return;

	first = 0;



	for (i = 0; i < UART_NR; i++) {

	for (i = 0; i < nr_uarts; i++) {

		struct uart_8250_port *up = &serial8250_ports[i];



		up->port.line = i;
@@ -2137,7 +2139,7 @@ static void __init serial8250_isa_init_ports(void) 
	}



	for (i = 0, up = serial8250_ports;

	     i < ARRAY_SIZE(old_serial_port) && i < UART_NR;

	     i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;

	     i++, up++) {

		up->port.iobase   = old_serial_port[i].port;

		up->port.irq      = irq_canonicalize(old_serial_port[i].irq);
@@ -2159,7 +2161,7 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev) 


	serial8250_isa_init_ports();



	for (i = 0; i < UART_NR; i++) {

	for (i = 0; i < nr_uarts; i++) {

		struct uart_8250_port *up = &serial8250_ports[i];



		up->port.dev = dev;
@@ -2262,7 +2264,7 @@ static int serial8250_console_setup(struct console *co, char *options) 
	 * if so, search for the first available port that does have

	 * console support.

	 */

	if (co->index >= UART_NR)

	if (co->index >= nr_uarts)

		co->index = 0;

	port = &serial8250_ports[co->index].port;

	if (!port->iobase && !port->membase)
@@ -2298,7 +2300,7 @@ static int __init find_port(struct uart_port *p) 
	int line;

	struct uart_port *port;



	for (line = 0; line < UART_NR; line++) {

	for (line = 0; line < nr_uarts; line++) {

		port = &serial8250_ports[line].port;

		if (uart_match_port(p, port))

			return line;
@@ -2420,7 +2422,7 @@ static int __devexit serial8250_remove(struct platform_device *dev) 
{

	int i;



	for (i = 0; i < UART_NR; i++) {

	for (i = 0; i < nr_uarts; i++) {

		struct uart_8250_port *up = &serial8250_ports[i];



		if (up->port.dev == &dev->dev)
@@ -2487,7 +2489,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * 
	/*

	 * First, find a port entry which matches.

	 */

	for (i = 0; i < UART_NR; i++)

	for (i = 0; i < nr_uarts; i++)

		if (uart_match_port(&serial8250_ports[i].port, port))

			return &serial8250_ports[i];
@@ -2496,7 +2498,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * 
	 * free entry.  We look for one which hasn't been previously

	 * used (indicated by zero iobase).

	 */

	for (i = 0; i < UART_NR; i++)

	for (i = 0; i < nr_uarts; i++)

		if (serial8250_ports[i].port.type == PORT_UNKNOWN &&

		    serial8250_ports[i].port.iobase == 0)

			return &serial8250_ports[i];
@@ -2505,7 +2507,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * 
	 * That also failed.  Last resort is to find any entry which

	 * doesn't have a real port associated with it.

	 */

	for (i = 0; i < UART_NR; i++)

	for (i = 0; i < nr_uarts; i++)

		if (serial8250_ports[i].port.type == PORT_UNKNOWN)

			return &serial8250_ports[i];
@@ -2590,8 +2592,11 @@ static int __init serial8250_init(void) 
{

	int ret, i;



	if (nr_uarts > UART_NR)

		nr_uarts = UART_NR;



	printk(KERN_INFO "Serial: 8250/16550 driver $Revision: 1.90 $ "

		"%d ports, IRQ sharing %sabled\n", (int) UART_NR,

		"%d ports, IRQ sharing %sabled\n", nr_uarts,

		share_irqs ? "en" : "dis");



	for (i = 0; i < NR_IRQS; i++)
@@ -2651,6 +2656,9 @@ module_param(share_irqs, uint, 0644); 
MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices"

	" (unsafe)");



module_param(nr_uarts, uint, 0644);

MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");



#ifdef CONFIG_SERIAL_8250_RSA

module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);

MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");

drivers/serial/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -95,6 +95,16 @@ config SERIAL_8250_NR_UARTS 
	  PCI enumeration and any ports that may be added at run-time

	  via hot-plug, or any ISA multi-port serial cards.



config SERIAL_8250_RUNTIME_UARTS

	int "Number of 8250/16550 serial ports to register at runtime"

	depends on SERIAL_8250

	default "4"

	help

	  Set this to the maximum number of serial ports you want

	  the kernel to register at boot time.  This can be overriden

	  with the module parameter "nr_uarts", or boot-time parameter

	  8250.nr_uarts



config SERIAL_8250_EXTENDED

	bool "Extended 8250/16550 serial driver options"

	depends on SERIAL_8250