* [PATCH] serial: 8250_early: Setup divider when uartclk is passed
@ 2018-04-23 9:18 ` Michal Simek
0 siblings, 0 replies; 7+ messages in thread
From: Michal Simek @ 2018-04-23 9:18 UTC (permalink / raw)
To: linux-kernel, monstr
Cc: stable, Matt Redfearn, Jiri Slaby, Douglas Anderson,
linux-serial, Greg Kroah-Hartman, Jeffy Chen
device->baud is always non zero value because it is checked already in
early_serial8250_setup() before init_port is called.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---
drivers/tty/serial/8250/8250_early.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index ae6a256524d8..5cd8c36c8fcc 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -122,7 +122,7 @@ static void __init init_port(struct earlycon_device *device)
serial8250_early_out(port, UART_FCR, 0); /* no fifo */
serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */
- if (port->uartclk && device->baud) {
+ if (port->uartclk) {
divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
c = serial8250_early_in(port, UART_LCR);
serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
--
2.17.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH] serial: 8250_early: Setup divider when uartclk is passed
@ 2018-04-23 9:18 ` Michal Simek
0 siblings, 0 replies; 7+ messages in thread
From: Michal Simek @ 2018-04-23 9:18 UTC (permalink / raw)
To: linux-kernel, monstr
Cc: stable, Matt Redfearn, Jiri Slaby, Douglas Anderson,
linux-serial, Greg Kroah-Hartman, Jeffy Chen
device->baud is always non zero value because it is checked already in
early_serial8250_setup() before init_port is called.
Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---
drivers/tty/serial/8250/8250_early.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index ae6a256524d8..5cd8c36c8fcc 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -122,7 +122,7 @@ static void __init init_port(struct earlycon_device *device)
serial8250_early_out(port, UART_FCR, 0); /* no fifo */
serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */
- if (port->uartclk && device->baud) {
+ if (port->uartclk) {
divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
c = serial8250_early_in(port, UART_LCR);
serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
--
2.17.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] serial: 8250_early: Setup divider when uartclk is passed
2018-04-23 9:18 ` Michal Simek
@ 2018-04-23 13:21 ` Matt Redfearn
-1 siblings, 0 replies; 7+ messages in thread
From: Matt Redfearn @ 2018-04-23 13:21 UTC (permalink / raw)
To: Michal Simek, linux-kernel, monstr
Cc: stable, Jiri Slaby, Douglas Anderson, linux-serial,
Greg Kroah-Hartman, Jeffy Chen
Hi Michal
On 23/04/18 10:18, Michal Simek wrote:
> device->baud is always non zero value because it is checked already in
> early_serial8250_setup() before init_port is called.
True, currently init_port is only called from the one location and so
the test is a little redundant, though I don't see the harm in testing
both inputs to the divisor calculation immediately before use such that
any future call path avoids setting a bad divisor.
>
> Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud")
> Cc: stable <stable@vger.kernel.org>
Even if the test is dropped going forward, I wouldn't consider it's
presence a "bug" such that a fix needs to be backported.
Thanks,
Matt
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
>
> drivers/tty/serial/8250/8250_early.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
> index ae6a256524d8..5cd8c36c8fcc 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -122,7 +122,7 @@ static void __init init_port(struct earlycon_device *device)
> serial8250_early_out(port, UART_FCR, 0); /* no fifo */
> serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */
>
> - if (port->uartclk && device->baud) {
> + if (port->uartclk) {
> divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
> c = serial8250_early_in(port, UART_LCR);
> serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial: 8250_early: Setup divider when uartclk is passed
@ 2018-04-23 13:21 ` Matt Redfearn
0 siblings, 0 replies; 7+ messages in thread
From: Matt Redfearn @ 2018-04-23 13:21 UTC (permalink / raw)
To: Michal Simek, linux-kernel, monstr
Cc: stable, Jiri Slaby, Douglas Anderson, linux-serial,
Greg Kroah-Hartman, Jeffy Chen
Hi Michal
On 23/04/18 10:18, Michal Simek wrote:
> device->baud is always non zero value because it is checked already in
> early_serial8250_setup() before init_port is called.
True, currently init_port is only called from the one location and so
the test is a little redundant, though I don't see the harm in testing
both inputs to the divisor calculation immediately before use such that
any future call path avoids setting a bad divisor.
>
> Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud")
> Cc: stable <stable@vger.kernel.org>
Even if the test is dropped going forward, I wouldn't consider it's
presence a "bug" such that a fix needs to be backported.
Thanks,
Matt
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
>
> drivers/tty/serial/8250/8250_early.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
> index ae6a256524d8..5cd8c36c8fcc 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -122,7 +122,7 @@ static void __init init_port(struct earlycon_device *device)
> serial8250_early_out(port, UART_FCR, 0); /* no fifo */
> serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */
>
> - if (port->uartclk && device->baud) {
> + if (port->uartclk) {
> divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * device->baud);
> c = serial8250_early_in(port, UART_LCR);
> serial8250_early_out(port, UART_LCR, c | UART_LCR_DLAB);
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial: 8250_early: Setup divider when uartclk is passed
2018-04-23 13:21 ` Matt Redfearn
@ 2018-04-24 12:27 ` Michal Simek
-1 siblings, 0 replies; 7+ messages in thread
From: Michal Simek @ 2018-04-24 12:27 UTC (permalink / raw)
To: Matt Redfearn, Michal Simek, linux-kernel, monstr
Cc: stable, Jiri Slaby, Douglas Anderson, linux-serial,
Greg Kroah-Hartman, Jeffy Chen
Hi Matt,
On 23.4.2018 15:21, Matt Redfearn wrote:
> Hi Michal
>
> On 23/04/18 10:18, Michal Simek wrote:
>> device->baud is always non zero value because it is checked already in
>> early_serial8250_setup() before init_port is called.
>
> True, currently init_port is only called from the one location and so
> the test is a little redundant, though I don't see the harm in testing
> both inputs to the divisor calculation immediately before use such that
> any future call path avoids setting a bad divisor.
I will let others to decide.
>
>>
>> Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid
>> clk & baud")
>> Cc: stable <stable@vger.kernel.org>
>
> Even if the test is dropped going forward, I wouldn't consider it's
> presence a "bug" such that a fix needs to be backported.
Not a problem with not adding this to stable.
Thanks,
Michal
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial: 8250_early: Setup divider when uartclk is passed
@ 2018-04-24 12:27 ` Michal Simek
0 siblings, 0 replies; 7+ messages in thread
From: Michal Simek @ 2018-04-24 12:27 UTC (permalink / raw)
To: Matt Redfearn, Michal Simek, linux-kernel, monstr
Cc: stable, Jiri Slaby, Douglas Anderson, linux-serial,
Greg Kroah-Hartman, Jeffy Chen
Hi Matt,
On 23.4.2018 15:21, Matt Redfearn wrote:
> Hi Michal
>
> On 23/04/18 10:18, Michal Simek wrote:
>> device->baud is always non zero value because it is checked already in
>> early_serial8250_setup() before init_port is called.
>
> True, currently init_port is only called from the one location and so
> the test is a little redundant, though I don't see the harm in testing
> both inputs to the divisor calculation immediately before use such that
> any future call path avoids setting a bad divisor.
I will let others to decide.
>
>>
>> Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid
>> clk & baud")
>> Cc: stable <stable@vger.kernel.org>
>
> Even if the test is dropped going forward, I wouldn't consider it's
> presence a "bug" such that a fix needs to be backported.
Not a problem with not adding this to stable.
Thanks,
Michal
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] serial: 8250_early: Setup divider when uartclk is passed
2018-04-23 9:18 ` Michal Simek
(?)
(?)
@ 2018-04-25 12:51 ` Greg Kroah-Hartman
-1 siblings, 0 replies; 7+ messages in thread
From: Greg Kroah-Hartman @ 2018-04-25 12:51 UTC (permalink / raw)
To: Michal Simek
Cc: linux-kernel, monstr, stable, Matt Redfearn, Jiri Slaby,
Douglas Anderson, linux-serial, Jeffy Chen
On Mon, Apr 23, 2018 at 11:18:11AM +0200, Michal Simek wrote:
> device->baud is always non zero value because it is checked already in
> early_serial8250_setup() before init_port is called.
>
> Fixes: 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud")
> Cc: stable <stable@vger.kernel.org>
This isn't "fixing" anything, as the logic is identical before, or
after, this patch is committed. So I'll apply this, but will drop these
two tags.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-04-25 12:51 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-23 9:18 [PATCH] serial: 8250_early: Setup divider when uartclk is passed Michal Simek
2018-04-23 9:18 ` Michal Simek
2018-04-23 13:21 ` Matt Redfearn
2018-04-23 13:21 ` Matt Redfearn
2018-04-24 12:27 ` Michal Simek
2018-04-24 12:27 ` Michal Simek
2018-04-25 12:51 ` Greg Kroah-Hartman
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