[PATCH V2] serial: qcom_geni_serial: To correct QUP Version detection logic

[PATCH V2] serial: qcom_geni_serial: To correct QUP Version detection logic

[Paras Sharma]

The current implementation reduces the sampling rate by half
if qup HW version greater is than 2.5 by checking if the geni
SE major version is greater than 2 and geni SE minor version
is greater than 5.

This implementation fails when the version is 3 or greater.

Hence by adding the another check for geni SE major version,
this problem can be solved.

Signed-off-by: Paras Sharma <parashar@codeaurora.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3aa29d2..a9f92d8 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -995,7 +995,8 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	sampling_rate = UART_OVERSAMPLING;
 	/* Sampling rate is halved for IP versions >= 2.5 */
 	ver = geni_se_get_qup_hw_version(&port->se);
-	if (GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5)
+	if ((GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5)
+		|| GENI_SE_VERSION_MAJOR(ver) >= 3)
 		sampling_rate /= 2;
 
 	clk_rate = get_clk_div_rate(baud, sampling_rate, &clk_div);
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH V2] serial: qcom_geni_serial: To correct QUP Version detection logic

[Greg Kroah-Hartman]

On Tue, Aug 11, 2020 at 01:13:14PM +0530, Paras Sharma wrote:
> The current implementation reduces the sampling rate by half
> if qup HW version greater is than 2.5 by checking if the geni
> SE major version is greater than 2 and geni SE minor version
> is greater than 5.
> 
> This implementation fails when the version is 3 or greater.
> 
> Hence by adding the another check for geni SE major version,
> this problem can be solved.
> 
> Signed-off-by: Paras Sharma <parashar@codeaurora.org>
> ---
>  drivers/tty/serial/qcom_geni_serial.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Should this go to stable kernels?  If so, how far back?  What git commit
id is this patch fixing?  And if so, why not put a Fixes: tag on this as
well?

thanks,

greg k-h

Re: [PATCH V2] serial: qcom_geni_serial: To correct QUP Version detection logic

[Felipe Balbi]

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Hi,

Paras Sharma <parashar@codeaurora.org> writes:
> The current implementation reduces the sampling rate by half
> if qup HW version greater is than 2.5 by checking if the geni
                    ^^^^^^^^^^^^^^^
                    is greater than

could, possibly, be fixed while applying.

> SE major version is greater than 2 and geni SE minor version
> is greater than 5.
>
> This implementation fails when the version is 3 or greater.
>
> Hence by adding the another check for geni SE major version,
> this problem can be solved.
>
> Signed-off-by: Paras Sharma <parashar@codeaurora.org>
> ---
>  drivers/tty/serial/qcom_geni_serial.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index 3aa29d2..a9f92d8 100644
> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -995,7 +995,8 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
>  	sampling_rate = UART_OVERSAMPLING;
>  	/* Sampling rate is halved for IP versions >= 2.5 */
>  	ver = geni_se_get_qup_hw_version(&port->se);
> -	if (GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5)
> +	if ((GENI_SE_VERSION_MAJOR(ver) >= 2 && GENI_SE_VERSION_MINOR(ver) >= 5)
> +		|| GENI_SE_VERSION_MAJOR(ver) >= 3)

it looks like having a single GENI_SE_VERSION() that returns MAJOR and
MINOR without STEP would look better here. Then you could use:

	if (GENI_SE_VERSION(ver) >= 0x20050000)

and it would work for any future version. Not a strong opinion, though

-- 
balbi

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Re: [PATCH V2] serial: qcom_geni_serial: To correct QUP Version detection logic

[Greg Kroah-Hartman]

On Tue, Aug 11, 2020 at 10:23:30AM +0200, Greg Kroah-Hartman wrote:
> On Tue, Aug 11, 2020 at 01:13:14PM +0530, Paras Sharma wrote:
> > The current implementation reduces the sampling rate by half
> > if qup HW version greater is than 2.5 by checking if the geni
> > SE major version is greater than 2 and geni SE minor version
> > is greater than 5.
> > 
> > This implementation fails when the version is 3 or greater.
> > 
> > Hence by adding the another check for geni SE major version,
> > this problem can be solved.
> > 
> > Signed-off-by: Paras Sharma <parashar@codeaurora.org>
> > ---
> >  drivers/tty/serial/qcom_geni_serial.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> Should this go to stable kernels?  If so, how far back?  What git commit
> id is this patch fixing?  And if so, why not put a Fixes: tag on this as
> well?

Dropped from my review queue due to lack of response, please fix up and
resend when you wish to have it reviewed again...

greg k-h