[RFC PATCH 0/2] serial 8250 platform PM hooks

[RFC PATCH 0/2] serial 8250 platform PM hooks

[Manuel Lauss]

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.

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    |   35 -----------------------------------
 drivers/serial/8250.c               |   31 ++++++++++++++++++++++++++++---
 include/linux/serial_8250.h         |    6 ++++++
 4 files changed, 51 insertions(+), 38 deletions(-)

[RFC PATCH 1/2] 8250: allow platform uarts to install PM callback.

[Manuel Lauss]

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
something this internal callback.

This patch adds a callback to struct plat_serial8250_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 a81ff7b..7802266 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2966,7 +2966,7 @@ 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,
@@ -3078,8 +3078,10 @@ 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
@@ -3090,7 +3092,9 @@ 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 uart_8250_port *uart;
 	int ret = -ENOSPC;
@@ -3115,6 +3119,7 @@ int serial8250_register_port(struct uart_port *port)
 		uart->port.flags        = port->flags | UPF_BOOT_AUTOCONF;
 		uart->port.mapbase      = port->mapbase;
 		uart->port.private_data = port->private_data;
+		uart->pm		= pm;
 		if (port->dev)
 			uart->port.dev = port->dev;
 
@@ -3140,6 +3145,26 @@ int serial8250_register_port(struct uart_port *port)
 
 	return ret;
 }
+EXPORT_SYMBOL(serial8250_register_port_with_pm);
+
+/**
+ *	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)
+{
+	return serial8250_register_port_with_pm(port, NULL);
+}
+
 EXPORT_SYMBOL(serial8250_register_port);
 
 /**
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index fb46aba..25cc3fb 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -14,6 +14,9 @@
 #include <linux/serial_core.h>
 #include <linux/platform_device.h>
 
+typedef void(*plat8250_pm_func_t)(struct uart_port *port, unsigned int state,
+				  unsigned int old_state);
+
 /*
  * This is the platform device platform_data structure
  */
@@ -32,6 +35,8 @@ struct plat_serial8250_port {
 	unsigned int	type;		/* If UPF_FIXED_TYPE */
 	unsigned int	(*serial_in)(struct uart_port *, int);
 	void		(*serial_out)(struct uart_port *, int, int);
+	void 		(*pm)(struct uart_port *port, unsigned int state,
+			      unsigned int old_state);
 };
 
 /*
@@ -62,6 +67,7 @@ enum {
 struct uart_port;
 
 int serial8250_register_port(struct uart_port *);
+int serial8250_register_port_with_pm(struct uart_port *, plat8250_pm_func_t);
 void serial8250_unregister_port(int line);
 void serial8250_suspend_port(int line);
 void serial8250_resume_port(int line);
-- 
1.7.0

[RFC PATCH 2/2] Alchemy: UART PM through serial framework.

[Manuel Lauss]

Hook up the Alchemy on-chip uarts with the platform 8250 PM callback
and enable/disable clocks to the uart blocks as needed.

This allows to get rid of the devboard-specific uart pm hack in the
Alchemy common code.

Tested on Au1200/DB1200.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
---
This patch applies against Ralf Baechle's mips-queue tree.

 arch/mips/alchemy/common/platform.c |   17 +++++++++++++++++
 arch/mips/alchemy/common/power.c    |   35 -----------------------------------
 2 files changed, 17 insertions(+), 35 deletions(-)

diff --git a/arch/mips/alchemy/common/platform.c b/arch/mips/alchemy/common/platform.c
index 3fbe30c..a85d515 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..cf37e27 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];
 static unsigned int sleep_sys_clocks[5];
 static unsigned int sleep_sys_pinfunc;
@@ -65,22 +60,6 @@ static unsigned int sleep_static_memctlr[4][3];
 
 static void save_core_regs(void)
 {
-	extern void save_au1xxx_intctl(void);
-	extern void pm_eth0_shutdown(void);
-
-	/*
-	 * Do the serial ports.....these really should be a pm_*
-	 * registered function by the driver......but of course the
-	 * standard serial driver doesn't understand our Au1xxx
-	 * unique registers.
-	 */
-	sleep_uart0_inten = au_readl(UART0_ADDR + UART_IER);
-	sleep_uart0_fifoctl = au_readl(UART0_ADDR + UART_FCR);
-	sleep_uart0_linectl = au_readl(UART0_ADDR + UART_LCR);
-	sleep_uart0_clkdiv = au_readl(UART0_ADDR + UART_CLK);
-	sleep_uart0_enable = au_readl(UART0_ADDR + UART_MOD_CNTRL);
-	au_sync();
-
 #ifndef CONFIG_SOC_AU1200
 	/* Shutdown USB host/device. */
 	sleep_usb[0] = au_readl(USB_HOST_CONFIG);
@@ -186,20 +165,6 @@ static void restore_core_regs(void)
 	au_writel(sleep_static_memctlr[3][1], MEM_STTIME3);
 	au_writel(sleep_static_memctlr[3][2], MEM_STADDR3);
 
-	/*
-	 * Enable the UART if it was enabled before sleep.
-	 * I guess I should define module control bits........
-	 */
-	if (sleep_uart0_enable & 0x02) {
-		au_writel(0, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(1, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(3, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(sleep_uart0_inten, UART0_ADDR + UART_IER); au_sync();
-		au_writel(sleep_uart0_fifoctl, UART0_ADDR + UART_FCR); au_sync();
-		au_writel(sleep_uart0_linectl, UART0_ADDR + UART_LCR); au_sync();
-		au_writel(sleep_uart0_clkdiv, UART0_ADDR + UART_CLK); au_sync();
-	}
-
 	restore_au1xxx_intctl();
 
 #if defined(CONFIG_SOC_AU1550) || defined(CONFIG_SOC_AU1200)
-- 
1.7.0

Re: [RFC PATCH 2/2] Alchemy: UART PM through serial framework.

[Manuel Lauss]

On Wed, Mar 24, 2010 at 6:40 PM, Sergei Shtylyov <sshtylyov@mvista.com> wrote:
> Hello.
>
> Manuel Lauss wrote:
>
>> 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();
>> +       }
>> +}
>
>  A *switch* statement seems more fitting here...

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

Thanks!
       Manuel Lauss

Re: [RFC PATCH 2/2] Alchemy: UART PM through serial framework.

[Manuel Lauss]

On Wed, Mar 24, 2010 at 6:40 PM, Sergei Shtylyov <sshtylyov@mvista.com> wrote:
> Hello.
>
> Manuel Lauss wrote:
>
>> 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();
>> +       }
>> +}
>
>  A *switch* statement seems more fitting here...

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

Thanks!
       Manuel Lauss
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Re: [RFC PATCH 2/2] Alchemy: UART PM through serial framework.

[Sergei Shtylyov]

Hello.

Manuel Lauss wrote:

> 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();
> +	}
> +}

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

WBR, Sergei

[RFC PATCH 2/2] Alchemy: UART PM through serial framework.

[Manuel Lauss]

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];
 static unsigned int sleep_sys_clocks[5];
 static unsigned int sleep_sys_pinfunc;
@@ -68,19 +63,6 @@ static void save_core_regs(void)
 	extern void save_au1xxx_intctl(void);
 	extern void pm_eth0_shutdown(void);
 
-	/*
-	 * Do the serial ports.....these really should be a pm_*
-	 * registered function by the driver......but of course the
-	 * standard serial driver doesn't understand our Au1xxx
-	 * unique registers.
-	 */
-	sleep_uart0_inten = au_readl(UART0_ADDR + UART_IER);
-	sleep_uart0_fifoctl = au_readl(UART0_ADDR + UART_FCR);
-	sleep_uart0_linectl = au_readl(UART0_ADDR + UART_LCR);
-	sleep_uart0_clkdiv = au_readl(UART0_ADDR + UART_CLK);
-	sleep_uart0_enable = au_readl(UART0_ADDR + UART_MOD_CNTRL);
-	au_sync();
-
 #ifndef CONFIG_SOC_AU1200
 	/* Shutdown USB host/device. */
 	sleep_usb[0] = au_readl(USB_HOST_CONFIG);
@@ -186,20 +168,6 @@ static void restore_core_regs(void)
 	au_writel(sleep_static_memctlr[3][1], MEM_STTIME3);
 	au_writel(sleep_static_memctlr[3][2], MEM_STADDR3);
 
-	/*
-	 * Enable the UART if it was enabled before sleep.
-	 * I guess I should define module control bits........
-	 */
-	if (sleep_uart0_enable & 0x02) {
-		au_writel(0, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(1, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(3, UART0_ADDR + UART_MOD_CNTRL); au_sync();
-		au_writel(sleep_uart0_inten, UART0_ADDR + UART_IER); au_sync();
-		au_writel(sleep_uart0_fifoctl, UART0_ADDR + UART_FCR); au_sync();
-		au_writel(sleep_uart0_linectl, UART0_ADDR + UART_LCR); au_sync();
-		au_writel(sleep_uart0_clkdiv, UART0_ADDR + UART_CLK); au_sync();
-	}
-
 	restore_au1xxx_intctl();
 
 #if defined(CONFIG_SOC_AU1550) || defined(CONFIG_SOC_AU1200)
-- 
1.7.0.2