RE: [PATCHv4] serial: of-serial: fix up PM ops on no_console_suspend and port type

[Jingchang Lu]

>-----Original Message-----
>From: Joseph Lo [mailto:josephl@xxxxxxxxxx]
>Sent: Wednesday, October 15, 2014 2:42 PM
>To: Lu Jingchang-B35083; gregkh@xxxxxxxxxxxxxxxxxxx
>Cc: peter@xxxxxxxxxxxxxxxxxx; arnd@xxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
>linux-serial@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>Subject: Re: [PATCHv4] serial: of-serial: fix up PM ops on
>no_console_suspend and port type
>
>On 10/15/2014 02:32 PM, Jingchang Lu wrote:
>>> -----Original Message-----
>>> From: Joseph Lo [mailto:josephl@xxxxxxxxxx]
>>> Sent: Wednesday, October 15, 2014 9:01 AM
>>> To: Lu Jingchang-B35083; gregkh@xxxxxxxxxxxxxxxxxxx
>>> Cc: peter@xxxxxxxxxxxxxxxxxx; arnd@xxxxxxxx;
>>> linux-kernel@xxxxxxxxxxxxxxx; linux-serial@xxxxxxxxxxxxxxx;
>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>>> 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@xxxxxxxxxxxxx>
>>>
>>> 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.
>I tested it on next-20141013 and k3.14, both of them need the fix. I can
>check it again against the latest linux-next tree later. Thanks.
Sorry, it is needed indeed, I have forgotten enable the PM in the next tree
due the lack of PM supporting of my board, I test the function on my 3.12 tree.
I will add it right now.

Best Regards,
Jingchang
>
>-Joseph
>
>> Thanks.
>>
>> Best Regards,
>> Jingchang
>>>
>>> Tested-by: Joseph Lo <josephl@xxxxxxxxxx>
>>>
>>> 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;
>>>>    }
>>>>