Re: [PATCH] custom PM support for 8250

[Vitaly Wool]

Sorry for format. Attached is the better one :)

Vitaly Wool wrote:

> Greetings,
> please find the patch that allows passing the pointer to custom power 
> management routine (via platform_device) to 8250 serial driver.
> Please note that the interface to the outer world (i. e. exported 
> functions) remained the same.
>
> Best regards,
>   Vitaly


Currently 8250 serial driver doesn't have means to register custom
(i. e. board-specific) power management functions.
This patch modifies the driver to provide such facility.

 drivers/serial/8250.c       |   47 +++++++++++++++++++++++++++++++++++++-------
 include/linux/serial_8250.h |    4 +++
 2 files changed, 44 insertions(+), 7 deletions(-)
 
Signed-off-by: Vitaly Wool <vitalhome@xxxxxxxxxx>

Index: linux-2.6.10/drivers/serial/8250.c
===================================================================
--- linux-2.6.10.orig/drivers/serial/8250.c
+++ linux-2.6.10/drivers/serial/8250.c
@@ -2360,6 +2360,8 @@
 	uart_resume_port(&serial8250_reg, &serial8250_ports[line].port);
 }
 
+static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line);
+
 /*
  * Register a set of serial devices attached to a platform device.  The
  * list is terminated with a zero flags entry, which means we expect
@@ -2369,6 +2371,8 @@
 {
 	struct plat_serial8250_port *p = dev->platform_data;
 	struct uart_port port;
+	struct uart_8250_port *uart;
+	int line;
 
 	memset(&port, 0, sizeof(struct uart_port));
 
@@ -2386,7 +2390,9 @@
 		if (share_irqs)
 			port.flags |= UPF_SHARE_IRQ;
 
-		serial8250_register_port(&port);
+		uart = uart_8250_register_port(&port, &line);
+		if (!IS_ERR(uart))
+			uart->pm = p->pm;
 	}
 	return 0;
 }
@@ -2516,8 +2522,9 @@
 }
 
 /**
- *	serial8250_register_port - register a serial port
+ *	uart_8250_register_port - register a serial port
  *	@port: serial port template
+ *	@line: returned (on success) value of the line number
  *
  *	Configure the serial port specified by the request. If the
  *	port exists and is in use, it is hung up and unregistered
@@ -2526,19 +2533,20 @@
  *	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.
+ *	On success the port is ready to use and the pointer to the 
+ *	corresponding struct uart_8250_port is returned.
  */
-int serial8250_register_port(struct uart_port *port)
+static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line)
 {
 	struct uart_8250_port *uart;
 	int ret = -ENOSPC;
 
 	if (port->uartclk == 0)
-		return -EINVAL;
+		return PTR_ERR(-EINVAL);
 
 	/* Avoid re-registering platform based ports if KGDB active */
 	if (port->line == kgdb8250_ttyS)
-		return -EBUSY;
+		return PTR_ERR(-EBUSY);
 
 	down(&serial_sem);
 
@@ -2560,10 +2568,35 @@
 
 		ret = uart_add_one_port(&serial8250_reg, &uart->port);
 		if (ret == 0)
-			ret = uart->port.line;
+			*line = uart->port.line;
 	}
 	up(&serial_sem);
 
+	return ret == 0 ? uart : PTR_ERR(ret);
+
+}
+
+/**
+ *	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)
+{
+	int ret = 0;
+	struct uart_8250_port *uart = uart_8250_register_port(port, &ret);
+
+	if (IS_ERR(uart))
+		ret = PTR_ERR(uart);
+
 	return ret;
 }
 EXPORT_SYMBOL(serial8250_register_port);
Index: linux-2.6.10/include/linux/serial_8250.h
===================================================================
--- linux-2.6.10.orig/include/linux/serial_8250.h
+++ linux-2.6.10/include/linux/serial_8250.h
@@ -24,6 +24,10 @@
 	unsigned char	iotype;		/* UPIO_* */
 	unsigned int	flags;		/* UPF_* flags */
 	unsigned int	line;		/* uart # */
+
+	/* per-port pm hook */
+	void			(*pm)(struct uart_port *port,
+				      unsigned int state, unsigned int old);
 };
 
 #endif