[SERIAL] Add new port registration/unregistration functions.

serial8250_register_port()/serial8250_unregister_port() has the
capability of registering ports with their struct device nodes,
which allows sysfs to indicate which tty devices belong to which
hardware devices.

We also add a serial8250 platform device driver in an initial
attempt at PM for ISA ports.  However, I'm leaving out the
platform device for the time being since adding that would cause
potential oops issues.

drivers/serial/8250.c

@@ -1980,7 +1980,8 @@ static void __init serial8250_isa_init_ports(void)
 	}
 }
 
-static void __init serial8250_register_ports(struct uart_driver *drv)
+static void __init
+serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 {
 	int i;
 
@@ -1991,6 +1992,7 @@ static void __init serial8250_register_ports(struct uart_driver *drv)
 
 		up->port.line = i;
 		up->port.ops = &serial8250_pops;
+		up->port.dev = dev;
 		init_timer(&up->timer);
 		up->timer.function = serial8250_timeout;
 
@@ -2157,60 +2159,6 @@ static struct uart_driver serial8250_reg = {
 	.cons			= SERIAL8250_CONSOLE,
 };
 
-/*
- * register_serial and unregister_serial allows for 16x50 serial ports to be
- * configured at run-time, to support PCMCIA modems.
- */
-
-static int __register_serial(struct serial_struct *req, int line)
-{
-	struct uart_port port;
-
-	port.iobase   = req->port;
-	port.membase  = req->iomem_base;
-	port.irq      = req->irq;
-	port.uartclk  = req->baud_base * 16;
-	port.fifosize = req->xmit_fifo_size;
-	port.regshift = req->iomem_reg_shift;
-	port.iotype   = req->io_type;
-	port.flags    = req->flags | UPF_BOOT_AUTOCONF;
-	port.mapbase  = req->iomap_base;
-	port.line     = line;
-
-	if (share_irqs)
-		port.flags |= UPF_SHARE_IRQ;
-
-	if (HIGH_BITS_OFFSET)
-		port.iobase |= (long) req->port_high << HIGH_BITS_OFFSET;
-
-	/*
-	 * If a clock rate wasn't specified by the low level
-	 * driver, then default to the standard clock rate.
-	 */
-	if (port.uartclk == 0)
-		port.uartclk = BASE_BAUD * 16;
-
-	return uart_register_port(&serial8250_reg, &port);
-}
-
-/**
- *	register_serial - configure a 16x50 serial port at runtime
- *	@req: request structure
- *
- *	Configure the serial port specified by the request. If the
- *	port exists and is in use an error is returned. If the port
- *	is not currently in the table it is added.
- *
- *	The port is then probed and if necessary the IRQ is autodetected
- *	If this fails an error is returned.
- *
- *	On success the port is ready to use and the line number is returned.
- */
-int register_serial(struct serial_struct *req)
-{
-	return __register_serial(req, -1);
-}
-
 int __init early_serial_setup(struct uart_port *port)
 {
 	if (port->line >= ARRAY_SIZE(serial8250_ports))
@@ -2222,18 +2170,6 @@ int __init early_serial_setup(struct uart_port *port)
 	return 0;
 }
 
-/**
- *	unregister_serial - remove a 16x50 serial port at runtime
- *	@line: serial line number
- *
- *	Remove one serial port.  This may be called from interrupt
- *	context.
- */
-void unregister_serial(int line)
-{
-	uart_unregister_port(&serial8250_reg, line);
-}
-
 /*
  * This is for ISAPNP only.
  */
@@ -2272,6 +2208,174 @@ void serial8250_resume_port(int line)
 	uart_resume_port(&serial8250_reg, &serial8250_ports[line].port);
 }
 
+static int serial8250_suspend(struct device *dev, u32 state, u32 level)
+{
+	int i;
+
+	if (level != SUSPEND_DISABLE)
+		return 0;
+
+	for (i = 0; i < UART_NR; i++) {
+		struct uart_8250_port *up = &serial8250_ports[i];
+
+		if (up->port.type != PORT_UNKNOWN && up->port.dev == dev)
+			uart_suspend_port(&serial8250_reg, &up->port);
+	}
+
+	return 0;
+}
+
+static int serial8250_resume(struct device *dev, u32 level)
+{
+	int i;
+
+	if (level != RESUME_ENABLE)
+		return 0;
+
+	for (i = 0; i < UART_NR; i++) {
+		struct uart_8250_port *up = &serial8250_ports[i];
+
+		if (up->port.type != PORT_UNKNOWN && up->port.dev == dev)
+			uart_resume_port(&serial8250_reg, &up->port);
+	}
+
+	return 0;
+}
+
+static struct device_driver serial8250_isa_driver = {
+	.name		= "serial8250",
+	.bus		= &platform_bus_type,
+
+	.suspend	= serial8250_suspend,
+	.resume		= serial8250_resume,
+};
+
+/*
+ * serial8250_register_port and serial8250_unregister_port allows for
+ * 16x50 serial ports to be configured at run-time, to support PCMCIA
+ * modems and PCI multiport cards.
+ */
+static DECLARE_MUTEX(serial_sem);
+
+/*
+ *	Are the two ports equivalent?
+ */
+static int uart_match_port(struct uart_port *port1, struct uart_port *port2)
+{
+	if (port1->iotype != port2->iotype)
+		return 0;
+
+	switch (port1->iotype) {
+	case UPIO_PORT:
+		return (port1->iobase == port2->iobase);
+	case UPIO_HUB6:
+		return (port1->iobase == port2->iobase) &&
+		       (port1->hub6   == port2->hub6);
+	case UPIO_MEM:
+		return (port1->membase == port2->membase);
+	}
+	return 0;
+}
+
+static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *port)
+{
+	int i;
+
+	/*
+	 * First, find a port entry which matches.
+	 */
+	for (i = 0; i < UART_NR; i++)
+		if (uart_match_port(&serial8250_ports[i].port, port))
+			return &serial8250_ports[i];
+
+	/*
+	 * We didn't find a matching entry, so look for the first
+	 * free entry.  We look for one which hasn't been previously
+	 * used (indicated by zero iobase).
+	 */
+	for (i = 0; i < UART_NR; i++)
+		if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
+		    serial8250_ports[i].port.iobase == 0)
+			return &serial8250_ports[i];
+
+	/*
+	 * 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++)
+		if (serial8250_ports[i].port.type == PORT_UNKNOWN)
+			return &serial8250_ports[i];
+
+	return NULL;
+}
+
+/**
+ *	serial8250_register_port - register a serial port
+ *	@port: serial port template
+ *
+ *	Configure the serial port specified by the request. If the
+ *	port exists and is in use, it is hung up and unregistered
+ *	first.
+ *
+ *	The port is then probed and if necessary the IRQ is autodetected
+ *	If this fails an error is returned.
+ *
+ *	On success the port is ready to use and the line number is returned.
+ */
+int serial8250_register_port(struct uart_port *port)
+{
+	struct uart_8250_port *uart;
+	int ret = -ENOSPC;
+
+	down(&serial_sem);
+
+	uart = serial8250_find_match_or_unused(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;
+		if (port->dev)
+			uart->port.dev = port->dev;
+
+		ret = uart_add_one_port(&serial8250_reg, &uart->port);
+		if (ret == 0)
+			ret = uart->port.line;
+	}
+	up(&serial_sem);
+
+	return ret;
+}
+EXPORT_SYMBOL(serial8250_register_port);
+
+/**
+ *	serial8250_unregister_port - remove a 16x50 serial port at runtime
+ *	@line: serial line number
+ *
+ *	Remove one serial port.  This may not be called from interrupt
+ *	context.  We hand the port back to the our control.
+ */
+void serial8250_unregister_port(int line)
+{
+	struct uart_8250_port *uart = &serial8250_ports[line];
+
+	down(&serial_sem);
+	uart_remove_one_port(&serial8250_reg, &uart->port);
+	uart->port.flags &= ~UPF_BOOT_AUTOCONF;
+	uart->port.type = PORT_UNKNOWN;
+	uart->port.dev = NULL;
+	uart_add_one_port(&serial8250_reg, &uart->port);
+	up(&serial_sem);
+}
+EXPORT_SYMBOL(serial8250_unregister_port);
+
 static int __init serial8250_init(void)
 {
 	int ret, i;
@@ -2280,13 +2384,23 @@ static int __init serial8250_init(void)
 		"%d ports, IRQ sharing %sabled\n", (int) UART_NR,
 		share_irqs ? "en" : "dis");
 
+	ret = driver_register(&serial8250_isa_driver);
+	if (ret)
+		goto out;
+
 	for (i = 0; i < NR_IRQS; i++)
 		spin_lock_init(&irq_lists[i].lock);
 
 	ret = uart_register_driver(&serial8250_reg);
-	if (ret >= 0)
-		serial8250_register_ports(&serial8250_reg);
+	if (ret)
+		goto unreg;
+
+	serial8250_register_ports(&serial8250_reg, NULL);
+	goto out;
 
+ unreg:
+	driver_unregister(&serial8250_isa_driver);
+ out:
 	return ret;
 }
 
@@ -2298,13 +2412,12 @@ static void __exit serial8250_exit(void)
 		uart_remove_one_port(&serial8250_reg, &serial8250_ports[i].port);
 
 	uart_unregister_driver(&serial8250_reg);
+	driver_unregister(&serial8250_isa_driver);
 }
 
 module_init(serial8250_init);
 module_exit(serial8250_exit);
 
-EXPORT_SYMBOL(register_serial);
-EXPORT_SYMBOL(unregister_serial);
 EXPORT_SYMBOL(serial8250_get_irq_map);
 EXPORT_SYMBOL(serial8250_suspend_port);
 EXPORT_SYMBOL(serial8250_resume_port);
@@ -2321,3 +2434,61 @@ module_param_array(probe_rsa, ulong, probe_rsa_count, 0444);
 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
 #endif
 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
+
+/**
+ *	register_serial - configure a 16x50 serial port at runtime
+ *	@req: request structure
+ *
+ *	Configure the serial port specified by the request. If the
+ *	port exists and is in use an error is returned. If the port
+ *	is not currently in the table it is added.
+ *
+ *	The port is then probed and if necessary the IRQ is autodetected
+ *	If this fails an error is returned.
+ *
+ *	On success the port is ready to use and the line number is returned.
+ */
+int register_serial(struct serial_struct *req)
+{
+	struct uart_port port;
+
+	port.iobase   = req->port;
+	port.membase  = req->iomem_base;
+	port.irq      = req->irq;
+	port.uartclk  = req->baud_base * 16;
+	port.fifosize = req->xmit_fifo_size;
+	port.regshift = req->iomem_reg_shift;
+	port.iotype   = req->io_type;
+	port.flags    = req->flags | UPF_BOOT_AUTOCONF;
+	port.mapbase  = req->iomap_base;
+	port.dev      = NULL;
+
+	if (share_irqs)
+		port.flags |= UPF_SHARE_IRQ;
+
+	if (HIGH_BITS_OFFSET)
+		port.iobase |= (long) req->port_high << HIGH_BITS_OFFSET;
+
+	/*
+	 * If a clock rate wasn't specified by the low level
+	 * driver, then default to the standard clock rate.
+	 */
+	if (port.uartclk == 0)
+		port.uartclk = BASE_BAUD * 16;
+
+	return serial8250_register_port(&port);
+}
+EXPORT_SYMBOL(register_serial);
+
+/**
+ *	unregister_serial - remove a 16x50 serial port at runtime
+ *	@line: serial line number
+ *
+ *	Remove one serial port.  This may not be called from interrupt
+ *	context.  We hand the port back to our local PM control.
+ */
+void unregister_serial(int line)
+{
+	serial8250_unregister_port(line);
+}
+EXPORT_SYMBOL(unregister_serial);

drivers/serial/8250.h

@@ -17,6 +17,8 @@
 
 #include <linux/config.h>
 
+int serial8250_register_port(struct uart_port *);
+void serial8250_unregister_port(int line);
 void serial8250_get_irq_map(unsigned int *map);
 void serial8250_suspend_port(int line);
 void serial8250_resume_port(int line);