[PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Mehul Raninga]

While exiting deep sleep, serial port loses its configuration
hence it prints garbage characters on console.

Set serial port configuration while resume from deep sleep.

Signed-off-by: Mehul Raninga <quic_mraninga@quicinc.com>
---
 drivers/tty/serial/qcom_geni_serial.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 8582479f0211..c04b8fec30ba 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -20,6 +20,7 @@
 #include <linux/serial.h>
 #include <linux/serial_core.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <dt-bindings/interconnect/qcom,icc.h>
@@ -1737,6 +1738,8 @@ static int qcom_geni_serial_sys_resume(struct device *dev)
 	if (uart_console(uport)) {
 		geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
 		geni_icc_set_bw(&port->se);
+		if (pm_suspend_via_firmware())
+			qcom_geni_serial_port_setup(uport);
 	}
 	return ret;
 }
-- 
2.17.1

Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Bjorn Andersson]

On Tue, May 30, 2023 at 04:45:57PM +0530, Mehul Raninga wrote:
> While exiting deep sleep, serial port loses its configuration
> hence it prints garbage characters on console.

Presumably it lost its configuration sometime after suspend, rather than
while resuming the system?

> 
> Set serial port configuration while resume from deep sleep.
> 

What happens if you do this unconditionally?

> Signed-off-by: Mehul Raninga <quic_mraninga@quicinc.com>
> ---
>  drivers/tty/serial/qcom_geni_serial.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index 8582479f0211..c04b8fec30ba 100644
> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -20,6 +20,7 @@
>  #include <linux/serial.h>
>  #include <linux/serial_core.h>
>  #include <linux/slab.h>
> +#include <linux/suspend.h>
>  #include <linux/tty.h>
>  #include <linux/tty_flip.h>
>  #include <dt-bindings/interconnect/qcom,icc.h>
> @@ -1737,6 +1738,8 @@ static int qcom_geni_serial_sys_resume(struct device *dev)
>  	if (uart_console(uport)) {
>  		geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
>  		geni_icc_set_bw(&port->se);
> +		if (pm_suspend_via_firmware())

I'm not familiar with this api, but aren't all our systems implementing
firmware-assisted suspend?

Regards,
Bjorn

> +			qcom_geni_serial_port_setup(uport);
>  	}
>  	return ret;
>  }
> -- 
> 2.17.1
> 

RE: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Mehul Raninga (Temp) (QUIC)]

Hello Andersson,
Thanks for the review. Kindly find my reply inline below

> -----Original Message-----
> From: Bjorn Andersson <andersson@kernel.org>
> Sent: Tuesday, May 30, 2023 8:37 PM
> To: Mehul Raninga (Temp) (QUIC) <quic_mraninga@quicinc.com>
> Cc: agross@kernel.org; konrad.dybcio@linaro.org; gregkh@linuxfoundation.org;
> jirislaby@kernel.org; linux-arm-msm@vger.kernel.org; linux-
> serial@vger.kernel.org; linux-kernel@vger.kernel.org; Viken Dadhaniya (QUIC)
> <quic_vdadhani@quicinc.com>; Visweswara Tanuku (QUIC)
> <quic_vtanuku@quicinc.com>; Vijaya Krishna Nivarthi (Temp) (QUIC)
> <quic_vnivarth@quicinc.com>
> Subject: Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep
> 
> WARNING: This email originated from outside of Qualcomm. Please be wary of
> any links or attachments, and do not enable macros.
> 
> On Tue, May 30, 2023 at 04:45:57PM +0530, Mehul Raninga wrote:
> > While exiting deep sleep, serial port loses its configuration hence it
> > prints garbage characters on console.
> 
> Presumably it lost its configuration sometime after suspend, rather than while
> resuming the system?

I will reword commit message in V2 as below:
Serial port lost its configuration sometime after suspend hence it prints garbage characters on console after resuming.
> 
> >
> > Set serial port configuration while resume from deep sleep.
> >
> 
> What happens if you do this unconditionally?

pm_suspend_via_firmware returns true indicating system is resuming from deepsleep. In case we are not resuming from deepsleep, this serial port setup is not required.
> 
> > Signed-off-by: Mehul Raninga <quic_mraninga@quicinc.com>
> > ---
> >  drivers/tty/serial/qcom_geni_serial.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/tty/serial/qcom_geni_serial.c
> > b/drivers/tty/serial/qcom_geni_serial.c
> > index 8582479f0211..c04b8fec30ba 100644
> > --- a/drivers/tty/serial/qcom_geni_serial.c
> > +++ b/drivers/tty/serial/qcom_geni_serial.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/serial.h>
> >  #include <linux/serial_core.h>
> >  #include <linux/slab.h>
> > +#include <linux/suspend.h>
> >  #include <linux/tty.h>
> >  #include <linux/tty_flip.h>
> >  #include <dt-bindings/interconnect/qcom,icc.h>
> > @@ -1737,6 +1738,8 @@ static int qcom_geni_serial_sys_resume(struct
> device *dev)
> >       if (uart_console(uport)) {
> >               geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
> >               geni_icc_set_bw(&port->se);
> > +             if (pm_suspend_via_firmware())
> 
> I'm not familiar with this api, but aren't all our systems implementing firmware-
> assisted suspend?

Not all the platform supports deep sleep hence to differentiate if resume is from deep sleep suspend or normal suspend, this api is required.
> 
> Regards,
> Bjorn
> 
> > +                     qcom_geni_serial_port_setup(uport);
> >       }
> >       return ret;
> >  }
> > --
> > 2.17.1
> >

Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Bjorn Andersson]

On Wed, May 31, 2023 at 01:06:22PM +0000, Mehul Raninga (Temp) (QUIC) wrote:
> Hello Andersson,
> Thanks for the review. Kindly find my reply inline below
> 
> > -----Original Message-----
> > From: Bjorn Andersson <andersson@kernel.org>
> > Sent: Tuesday, May 30, 2023 8:37 PM
> > To: Mehul Raninga (Temp) (QUIC) <quic_mraninga@quicinc.com>
> > Cc: agross@kernel.org; konrad.dybcio@linaro.org; gregkh@linuxfoundation.org;
> > jirislaby@kernel.org; linux-arm-msm@vger.kernel.org; linux-
> > serial@vger.kernel.org; linux-kernel@vger.kernel.org; Viken Dadhaniya (QUIC)
> > <quic_vdadhani@quicinc.com>; Visweswara Tanuku (QUIC)
> > <quic_vtanuku@quicinc.com>; Vijaya Krishna Nivarthi (Temp) (QUIC)
> > <quic_vnivarth@quicinc.com>
> > Subject: Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep
> > 
> > WARNING: This email originated from outside of Qualcomm. Please be wary of
> > any links or attachments, and do not enable macros.
> > 
> > On Tue, May 30, 2023 at 04:45:57PM +0530, Mehul Raninga wrote:
> > > While exiting deep sleep, serial port loses its configuration hence it
> > > prints garbage characters on console.
> > 
> > Presumably it lost its configuration sometime after suspend, rather than while
> > resuming the system?
> 
> I will reword commit message in V2 as below:
> Serial port lost its configuration sometime after suspend hence it
> prints garbage characters on console after resuming.

Please wrap your replies to 72 chars wide

You can probably be more specific than "sometime after suspend" :)

> > 
> > >
> > > Set serial port configuration while resume from deep sleep.
> > >
> > 
> > What happens if you do this unconditionally?
> 
> pm_suspend_via_firmware returns true indicating system is resuming
> from deepsleep. In case we are not resuming from deepsleep, this
> serial port setup is not required.
> > 
> > > Signed-off-by: Mehul Raninga <quic_mraninga@quicinc.com>
> > > ---
> > >  drivers/tty/serial/qcom_geni_serial.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/tty/serial/qcom_geni_serial.c
> > > b/drivers/tty/serial/qcom_geni_serial.c
> > > index 8582479f0211..c04b8fec30ba 100644
> > > --- a/drivers/tty/serial/qcom_geni_serial.c
> > > +++ b/drivers/tty/serial/qcom_geni_serial.c
> > > @@ -20,6 +20,7 @@
> > >  #include <linux/serial.h>
> > >  #include <linux/serial_core.h>
> > >  #include <linux/slab.h>
> > > +#include <linux/suspend.h>
> > >  #include <linux/tty.h>
> > >  #include <linux/tty_flip.h>
> > >  #include <dt-bindings/interconnect/qcom,icc.h>
> > > @@ -1737,6 +1738,8 @@ static int qcom_geni_serial_sys_resume(struct
> > device *dev)
> > >       if (uart_console(uport)) {
> > >               geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
> > >               geni_icc_set_bw(&port->se);
> > > +             if (pm_suspend_via_firmware())
> > 
> > I'm not familiar with this api, but aren't all our systems implementing firmware-
> > assisted suspend?
> 
> Not all the platform supports deep sleep hence to differentiate if
> resume is from deep sleep suspend or normal suspend, this api is
> required.

Can you point me to where this difference in flags is coming from in the
upstream kernel?

Thanks,
Bjorn

> > 
> > Regards,
> > Bjorn
> > 
> > > +                     qcom_geni_serial_port_setup(uport);
> > >       }
> > >       return ret;
> > >  }
> > > --
> > > 2.17.1
> > >

RE: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Mehul Raninga (Temp) (QUIC)]

Hello Andersson,
Thanks for the review. Kindly find my reply inline below.

> -----Original Message-----
> From: Bjorn Andersson <andersson@kernel.org>
> Sent: Thursday, June 1, 2023 9:38 AM
> To: Mehul Raninga (Temp) (QUIC) <quic_mraninga@quicinc.com>
> Cc: agross@kernel.org; konrad.dybcio@linaro.org;
> gregkh@linuxfoundation.org; jirislaby@kernel.org; linux-arm-
> msm@vger.kernel.org; linux-serial@vger.kernel.org; linux-
> kernel@vger.kernel.org; Viken Dadhaniya (QUIC)
> <quic_vdadhani@quicinc.com>; Visweswara Tanuku (QUIC)
> <quic_vtanuku@quicinc.com>; Vijaya Krishna Nivarthi (Temp) (QUIC)
> <quic_vnivarth@quicinc.com>
> Subject: Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep
> sleep
> 
> WARNING: This email originated from outside of Qualcomm. Please be
> wary of any links or attachments, and do not enable macros.
> 
> On Wed, May 31, 2023 at 01:06:22PM +0000, Mehul Raninga (Temp)
> (QUIC) wrote:
> > Hello Andersson,
> > Thanks for the review. Kindly find my reply inline below
> >
> > > -----Original Message-----
> > > From: Bjorn Andersson <andersson@kernel.org>
> > > Sent: Tuesday, May 30, 2023 8:37 PM
> > > To: Mehul Raninga (Temp) (QUIC) <quic_mraninga@quicinc.com>
> > > Cc: agross@kernel.org; konrad.dybcio@linaro.org;
> > > gregkh@linuxfoundation.org; jirislaby@kernel.org;
> > > linux-arm-msm@vger.kernel.org; linux- serial@vger.kernel.org;
> > > linux-kernel@vger.kernel.org; Viken Dadhaniya (QUIC)
> > > <quic_vdadhani@quicinc.com>; Visweswara Tanuku (QUIC)
> > > <quic_vtanuku@quicinc.com>; Vijaya Krishna Nivarthi (Temp) (QUIC)
> > > <quic_vnivarth@quicinc.com>
> > > Subject: Re: [PATCH] serial: qcom_geni_serial: Setup serial port
> > > after Deep sleep
> > >
> > > WARNING: This email originated from outside of Qualcomm. Please be
> > > wary of any links or attachments, and do not enable macros.
> > >
> > > On Tue, May 30, 2023 at 04:45:57PM +0530, Mehul Raninga wrote:
> > > > While exiting deep sleep, serial port loses its configuration
> > > > hence it prints garbage characters on console.
> > >
> > > Presumably it lost its configuration sometime after suspend, rather
> > > than while resuming the system?
> >
> > I will reword commit message in V2 as below:
> > Serial port lost its configuration sometime after suspend hence it
> > prints garbage characters on console after resuming.
> 
> Please wrap your replies to 72 chars wide

Noted
> 
> You can probably be more specific than "sometime after suspend" :)

During deepsleep HW configurations are lost, hence it prints garbage
characters on console after resuming.
> 
> > >
> > > >
> > > > Set serial port configuration while resume from deep sleep.
> > > >
> > >
> > > What happens if you do this unconditionally?
> >
> > pm_suspend_via_firmware returns true indicating system is resuming
> > from deepsleep. In case we are not resuming from deepsleep, this
> > serial port setup is not required.
> > >
> > > > Signed-off-by: Mehul Raninga <quic_mraninga@quicinc.com>
> > > > ---
> > > >  drivers/tty/serial/qcom_geni_serial.c | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/drivers/tty/serial/qcom_geni_serial.c
> > > > b/drivers/tty/serial/qcom_geni_serial.c
> > > > index 8582479f0211..c04b8fec30ba 100644
> > > > --- a/drivers/tty/serial/qcom_geni_serial.c
> > > > +++ b/drivers/tty/serial/qcom_geni_serial.c
> > > > @@ -20,6 +20,7 @@
> > > >  #include <linux/serial.h>
> > > >  #include <linux/serial_core.h>
> > > >  #include <linux/slab.h>
> > > > +#include <linux/suspend.h>
> > > >  #include <linux/tty.h>
> > > >  #include <linux/tty_flip.h>
> > > >  #include <dt-bindings/interconnect/qcom,icc.h>
> > > > @@ -1737,6 +1738,8 @@ static int
> > > > qcom_geni_serial_sys_resume(struct
> > > device *dev)
> > > >       if (uart_console(uport)) {
> > > >               geni_icc_set_tag(&port->se, QCOM_ICC_TAG_ALWAYS);
> > > >               geni_icc_set_bw(&port->se);
> > > > +             if (pm_suspend_via_firmware())
> > >
> > > I'm not familiar with this api, but aren't all our systems
> > > implementing firmware- assisted suspend?
> >
> > Not all the platform supports deep sleep hence to differentiate if
> > resume is from deep sleep suspend or normal suspend, this api is
> > required.
> 
> Can you point me to where this difference in flags is coming from in the
> upstream kernel?

In upstream kernel by default the flag is false, and for deepsleep
support vendor kernel sets this flag true.
> 
> Thanks,
> Bjorn
> 
> > >
> > > Regards,
> > > Bjorn
> > >
> > > > +                     qcom_geni_serial_port_setup(uport);
> > > >       }
> > > >       return ret;
> > > >  }
> > > > --
> > > > 2.17.1
> > > >

Re: [PATCH] serial: qcom_geni_serial: Setup serial port after Deep sleep

[Bjorn Andersson]

On Fri, Jun 02, 2023 at 06:39:02AM +0000, Mehul Raninga (Temp) (QUIC) wrote:
[..]
> > On Wed, May 31, 2023 at 01:06:22PM +0000, Mehul Raninga (Temp)
> > (QUIC) wrote:
[..]
> > > > > +             if (pm_suspend_via_firmware())
> > > >
> > > > I'm not familiar with this api, but aren't all our systems
> > > > implementing firmware- assisted suspend?
> > >
> > > Not all the platform supports deep sleep hence to differentiate if
> > > resume is from deep sleep suspend or normal suspend, this api is
> > > required.
> > 
> > Can you point me to where this difference in flags is coming from in the
> > upstream kernel?
> 
> In upstream kernel by default the flag is false, and for deepsleep
> support vendor kernel sets this flag true.

I am questioning whether this is correct, given that we indeed "suspend
with the help of firmware". But I might be misinterpreting what that
statement means.

Regards,
Bjorn