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custom PM support for 8250

PATCH In review Vitaly Wool 4 participants 7 messages Aug 31, 2005 – Sep 6, 2005 8250/16?50 (and clone uarts) serial driver

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Vitaly Wool

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#0 lore raw

PATCH 1/1 custom PM support for 8250

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 <[email protected]>
drivers/serial/8250.c +40 -7
Index: 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 ERR_PTR(-EINVAL);
 
 	/* Avoid re-registering platform based ports if KGDB active */
 	if (port->line == kgdb8250_ttyS)
-		return -EBUSY;
+		return ERR_PTR(-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 : ERR_PTR(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);
include/linux/serial_8250.h +4 -0
Index: 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
author
#1 lore raw

Sorry for format. Attached is the better one :)

Quoted 6 lines · Vitaly Wool

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 <[email protected]>
drivers/serial/8250.c +40 -7
Index: 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);
include/linux/serial_8250.h +4 -0
Index: 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
#2 lore raw
In reply to Vitaly Wool
Quoted 4 lines · Vitaly Wool

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.

I'd rather change the structure passed via the platform device to something like:

struct platform_serial_data {
	void	(*pm)(struct uart_port *port, unsigned int state, unsigned int old);
	int	nr_ports;
	struct plat_serial8250_port *ports;
};

which also eliminates the empty plat_serial8250_port terminator from all the serial8250 platform devices (which appears to have caused some folk problems.)

It does mean that a set of 8250 ports (grouped by each platform device) have a common power management method - which seems a logical restriction.

Signature · 3 lines
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
author
#3 lore raw

Yes, that's also something I was thinking of, but I wasn't sure enough in this radical change :)
Anyway, I do agree that this way looks better than the current one.
So, if you don't object against other changes (say, the suggested approach to set uart->pm), I can proceed with the changes you suggest and work it out to the new patch. ;)

Best regards,
Vitaly

Quoted 26 lines · Russell King
Quoted 4 lines · Vitaly Wool

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.

I'd rather change the structure passed via the platform device to something like:

struct platform_serial_data {
	void	(*pm)(struct uart_port *port, unsigned int state, unsigned int old);
	int	nr_ports;
	struct plat_serial8250_port *ports;
};

which also eliminates the empty plat_serial8250_port terminator from all the serial8250 platform devices (which appears to have caused some folk problems.)

It does mean that a set of 8250 ports (grouped by each platform device) have a common power management method - which seems a logical restriction.

#4 lore raw
In reply to Russell King

Hi Russel,

I tried the patch provided by Vitaly Wool. And it works correctly. And now I'm successful with the PM support for my own serial8250 driver. Are you planning to commit the Vitlaly's changes into the mainstream? I guess it'll be helpful for the other people too. What I want is to know whether this changes will be supported by the Community or not. It's important for the project I'm worin on, cause I'm planning to push it into Open Source ;)

Thanks,
Grigory.

Quoted 26 lines · Russell King
Quoted 4 lines · Vitaly Wool

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.

I'd rather change the structure passed via the platform device to something like:

struct platform_serial_data {
	void	(*pm)(struct uart_port *port, unsigned int state, unsigned int old);
	int	nr_ports;
	struct plat_serial8250_port *ports;
};

which also eliminates the empty plat_serial8250_port terminator from all the serial8250 platform devices (which appears to have caused some folk problems.)

It does mean that a set of 8250 ports (grouped by each platform device) have a common power management method - which seems a logical restriction.

author
#5 lore raw

Russell,

what I'd suggest is to separate the changes that allow to provide PM callbacks and generic changes in the interface/structures as the latter will result in changing a lot of code that uses 8250 serial driver, otherwise that code will stop working. Namely, is it posible to have the first patch I've sent for 8250 in place first?
I'll continue to work on 8250 PM/platform_serial_data changes then.

Vitaly

Quoted 37 lines · Grigory Tolstolytkin

Hi Russel,

I tried the patch provided by Vitaly Wool. And it works correctly. And now I'm successful with the PM support for my own serial8250 driver. Are you planning to commit the Vitlaly's changes into the mainstream? I guess it'll be helpful for the other people too. What I want is to know whether this changes will be supported by the Community or not. It's important for the project I'm worin on, cause I'm planning to push it into Open Source ;)

Thanks,
Grigory.

Quoted 27 lines · Russell King
Quoted 3 lines · Vitaly Wool

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.

I'd rather change the structure passed via the platform device to something like:

struct platform_serial_data {
void (*pm)(struct uart_port *port, unsigned int state,

unsigned int old);
    int    nr_ports;
    struct plat_serial8250_port *ports;
};

which also eliminates the empty plat_serial8250_port terminator from all the serial8250 platform devices (which appears to have caused some folk problems.)

It does mean that a set of 8250 ports (grouped by each platform device) have a common power management method - which seems a logical restriction.

#6 lore raw
In reply to Vitaly Wool

Hi!

Quoted 5 lines

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.

No. Current state needs to be pm_message_t, not int.
Pavel

Signature · 1 line
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms