linux-kernel - RE: [PATCHv4] serial: of-serial: fix up PM ops on no_console

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Message-ID: <67564f37252242079bcd4c65827b8352@BL2PR03MB467.namprd03.prod.outlook.com>
Date:	Wed, 15 Oct 2014 06:32:57 +0000
From:	Jingchang Lu <jingchang.lu@...escale.com>
To:	Joseph Lo <josephl@...dia.com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:	"peter@...leysoftware.com" <peter@...leysoftware.com>,
	"arnd@...db.de" <arnd@...db.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCHv4] serial: of-serial: fix up PM ops on no_console_suspend
 and port type

>-----Original Message-----
>From: Joseph Lo [mailto:josephl@...dia.com]
>Sent: Wednesday, October 15, 2014 9:01 AM
>To: Lu Jingchang-B35083; gregkh@...uxfoundation.org
>Cc: peter@...leysoftware.com; arnd@...db.de; linux-kernel@...r.kernel.org;
>linux-serial@...r.kernel.org; linux-arm-kernel@...ts.infradead.org
>Subject: Re: [PATCHv4] serial: of-serial: fix up PM ops on
>no_console_suspend and port type
>
>On 10/14/2014 04:42 PM, Jingchang Lu wrote:
>> This patch fixes commit 2dea53bf57783f243c892e99c10c6921e956aa7e,
>> "serial: of-serial: add PM suspend/resume support", which disables the
>> uart clock on suspend, but also causes a hardware hang on register
>> access if no_console_suspend command line option is used.
>>
>> Also, not every of_serial device is an 8250 port, so the serial8250
>> suspend/resume functions should only be applied to a real 8250 port.
>>
>> Signed-off-by: Jingchang Lu <jingchang.lu@...escale.com>
>
>If you can make sure this patch can build without include
><linux/console.h>, then this patch
The build passes on my cloned linux-next tree, include next-20141014,
but is required on my another kernel-3.12+ based tree, then I didn't
add this header file when upstream. 
Is the build broken on your source tree, and is the tree latest?
If the header is needed, I will add it.
Thanks.

Best Regards,
Jingchang
>
>Tested-by: Joseph Lo <josephl@...dia.com>
>
>And thanks for your fix.
>
>> ---
>> changes in v4:
>>   separate 8250 port suspend/resume from of_serial_suspend/resume.
>>
>> changes in v3:
>>   fix up point reference and deference.
>>
>> changes in v2:
>>   add switch selection on uart type.
>>
>>   drivers/tty/serial/of_serial.c | 52
>++++++++++++++++++++++++++++++++++++------
>>   1 file changed, 45 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/tty/serial/of_serial.c
>> b/drivers/tty/serial/of_serial.c index 8bc2563..5281f8f 100644
>> --- a/drivers/tty/serial/of_serial.c
>> +++ b/drivers/tty/serial/of_serial.c
>> @@ -241,13 +241,48 @@ static int of_platform_serial_remove(struct
>platform_device *ofdev)
>>   }
>>
>>   #ifdef CONFIG_PM_SLEEP
>> -static int of_serial_suspend(struct device *dev)
>> +#ifdef CONFIG_SERIAL_8250
>> +static void of_serial_suspend_8250(struct of_serial_info *info)
>>   {
>> -	struct of_serial_info *info = dev_get_drvdata(dev);
>> +	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
>> +	struct uart_port *port = &port8250->port;
>>
>>   	serial8250_suspend_port(info->line);
>> -	if (info->clk)
>> +	if (info->clk && (!uart_console(port) || console_suspend_enabled))
>>   		clk_disable_unprepare(info->clk);
>> +}
>> +
>> +static void of_serial_resume_8250(struct of_serial_info *info) {
>> +	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
>> +	struct uart_port *port = &port8250->port;
>> +
>> +	if (info->clk && (!uart_console(port) || console_suspend_enabled))
>> +		clk_prepare_enable(info->clk);
>> +
>> +	serial8250_resume_port(info->line);
>> +}
>> +#else
>> +static inline void of_serial_suspend_8250(struct of_serial_info
>> +*info) { }
>> +
>> +static inline void of_serial_resume_8250(struct of_serial_info *info)
>> +{ } #endif
>> +
>> +static int of_serial_suspend(struct device *dev) {
>> +	struct of_serial_info *info = dev_get_drvdata(dev);
>> +
>> +	switch(info->type) {
>> +	case PORT_8250 ... PORT_MAX_8250:
>> +		of_serial_suspend_8250(info);
>> +		break;
>> +	default:
>> +		break;
>> +	}
>>
>>   	return 0;
>>   }
>> @@ -256,10 +291,13 @@ static int of_serial_resume(struct device *dev)
>>   {
>>   	struct of_serial_info *info = dev_get_drvdata(dev);
>>
>> -	if (info->clk)
>> -		clk_prepare_enable(info->clk);
>> -
>> -	serial8250_resume_port(info->line);
>> +	switch(info->type) {
>> +	case PORT_8250 ... PORT_MAX_8250:
>> +		of_serial_resume_8250(info);
>> +		break;
>> +	default:
>> +		break;
>> +	}
>>
>>   	return 0;
>>   }
>>