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

From: Jingchang Lu
Date: Wed Oct 15 2014 - 02:33:07 EST


>-----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.
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;
>> }
>>