The following 2 patches implement a PM hook for platform 8250
UARTs and a sample PM implementation for a MIPS SoC.

Patch #1 hooks a new .pm callback in struct plat_serial8250_port to
the rest of serial_core's PM infrastructure,

Patch #2 implements uart power gating for Alchemy line of mips socs
using the new hook.

With these 2 patches serial console on my test system survives
suspend/resume cycles without having to resort to platform-specific
hacks in the PM code.

Thanks,
     Manuel Lauss

Manuel Lauss (2):
  8250: allow platform uarts to install PM callback.
  Alchemy: UART PM through serial framework.

 arch/mips/alchemy/common/platform.c |   17 +++++++++++++++++
 arch/mips/alchemy/common/power.c    |   32 --------------------------------
 drivers/serial/8250.c               |   31 ++++++++++++++++++++++++++++---
 include/linux/serial_8250.h         |    6 ++++++
 4 files changed, 51 insertions(+), 35 deletions(-)

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The 8250 UART driver provides rudimentary UART PM support and
a callback for systems to do more sophisticated power management.
However, there is no way yet for platform_device uarts to assign
a function to this internal callback.

This patch adds a callback to plat_8250_port and a function to
register this callback with 8250 driver internals.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
---
 drivers/serial/8250.c       |   31 ++++++++++++++++++++++++++++---
 include/linux/serial_8250.h |    6 ++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index c3db16b..c0c8e9b 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2995,7 +2995,7 @@ static int __devinit serial8250_probe(struct platform_device *dev)
 		port.serial_out		= p->serial_out;
 		port.dev		= &dev->dev;
 		port.irqflags		|= irqflag;
-		ret = serial8250_register_port(&port);
+		ret = serial8250_register_port_with_pm(&port, p->pm);
 		if (ret < 0) {
 			dev_err(&dev->dev, "unable to register port at index %d "
 				"(IO%lx MEM%llx IRQ%d): %d\n", i,
@@ -3107,8 +3107,10 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *
 }
 
 /**
- *	serial8250_register_port - register a serial port
+ *	serial8250_register_port_with_pm - register a serial port and its
+ *					   power management callback.
  *	@port: serial port template
+ *	@pm:   PM callback for this port, can be NULL.
  *
  *	Configure the serial port specified by the request. If the
  *	port exists and is in use, it is hung up and unregistered
@@ -3119,7 +3121,9 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *
  *
  *	On success the port is ready to use and the line number is returned.
  */
-int serial8250_register_port(struct uart_port *port)
+int serial8250_register_port_with_pm(struct uart_port *port,
+	void(*pm)(struct uart_port *port, unsigned int state,
+		  unsigned int old))
 {
 	struct ...
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Hook up the Alchemy on-chip uarts with the platform 8250 PM callback
and enable/disable the uart blocks as needed.

Tested on Au1200.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
---
 arch/mips/alchemy/common/platform.c |   17 +++++++++++++++++
 arch/mips/alchemy/common/power.c    |   32 --------------------------------
 2 files changed, 17 insertions(+), 32 deletions(-)

diff --git a/arch/mips/alchemy/common/platform.c b/arch/mips/alchemy/common/platform.c
index 2580e77..70f4abd 100644
--- a/arch/mips/alchemy/common/platform.c
+++ b/arch/mips/alchemy/common/platform.c
@@ -21,6 +21,22 @@
 #include <asm/mach-au1x00/au1100_mmc.h>
 #include <asm/mach-au1x00/au1xxx_eth.h>
 
+static void alchemy_8250_pm(struct uart_port *port, unsigned int state,
+			    unsigned int old_state)
+{
+	if (state == 0) {		/* power on */
+		__raw_writel(0, port->membase + UART_MOD_CNTRL);
+		wmb();
+		__raw_writel(1, port->membase + UART_MOD_CNTRL);
+		wmb();
+		__raw_writel(3, port->membase + UART_MOD_CNTRL);
+		wmb();
+	} else if (state == 3) {	/* power off */
+		__raw_writel(0, port->membase + UART_MOD_CNTRL);
+		wmb();
+	}
+}
+
 #define PORT(_base, _irq)					\
 	{							\
 		.mapbase	= _base,			\
@@ -30,6 +46,7 @@
 		.flags		= UPF_SKIP_TEST | UPF_IOREMAP |	\
 				  UPF_FIXED_TYPE,		\
 		.type		= PORT_16550A,			\
+		.pm		= alchemy_8250_pm,		\
 	}
 
 static struct plat_serial8250_port au1x00_uart_data[] = {
diff --git a/arch/mips/alchemy/common/power.c b/arch/mips/alchemy/common/power.c
index 6ab7b42..8fbf6d0 100644
--- a/arch/mips/alchemy/common/power.c
+++ b/arch/mips/alchemy/common/power.c
@@ -52,11 +52,6 @@
  * We only have to save/restore registers that aren't otherwise
  * done as part of a driver pm_* function.
  */
-static unsigned int sleep_uart0_inten;
-static unsigned int sleep_uart0_fifoctl;
-static unsigned int sleep_uart0_linectl;
-static unsigned int sleep_uart0_clkdiv;
-static unsigned int sleep_uart0_enable;
 static unsigned int sleep_usb[2];
 ...
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Hello.


   A *switch* statement seems more fitting here...

WBR, Sergei

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Well, those are the only 2 values defined anyway, but I'll change it.

Thanks!
       Manuel Lauss
--

[ message continues ]

Ping?  Noone interested?

On Wed, Mar 24, 2010 at 7:16 PM, Manuel Lauss
--

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