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

[Joseph Lo]

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.

-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;
> > >    }
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