diff mbox series

serial: sprd: Support 12 uart ports

Message ID 20230807080726.7190-1-Wenhua.Lin@unisoc.com
State New
Headers show
Series serial: sprd: Support 12 uart ports | expand

Commit Message

Wenhua Lin Aug. 7, 2023, 8:07 a.m. UTC 
From: Wenhua Lin <wenhua.lin@unisoc.com>

Support 12 uart ports, which can solve the problem
of insufficient uart ports.

Signed-off-by: Wenhua Lin <wenhua.lin@unisoc.com>
---
 drivers/tty/serial/sprd_serial.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

wenhua lin Aug. 9, 2023, 5:52 a.m. UTC | #1 
The change of the max ports is to adapt to an new
SPRD serial hardware,also is backward-compatibility with old hardware.

Baolin Wang <baolin.wang@linux.alibaba.com> 于2023年8月7日周一 16:41写道：
>
>
>
> On 8/7/2023 4:07 PM, Wenhua Lin wrote:
> > From: Wenhua Lin <wenhua.lin@unisoc.com>
> >
> > Support 12 uart ports, which can solve the problem
> > of insufficient uart ports.
>
> This sounds incorrect to me.
> If this is a software bug, please add a Fixes tag to backport for stable
> kernels. If the change of the max ports is only avaliable on the new
> SPRD serial hardware, you should ensure the change is
> backward-compatibility with old hardware.
>
> > Signed-off-by: Wenhua Lin <wenhua.lin@unisoc.com>
> > ---
> >   drivers/tty/serial/sprd_serial.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
> > index b58f51296ace..2774df490899 100644
> > --- a/drivers/tty/serial/sprd_serial.c
> > +++ b/drivers/tty/serial/sprd_serial.c
> > @@ -22,7 +22,7 @@
> >   #include <linux/tty_flip.h>
> >
> >   /* device name */
> > -#define UART_NR_MAX          8
> > +#define UART_NR_MAX          12
> >   #define SPRD_TTY_NAME               "ttyS"
> >   #define SPRD_FIFO_SIZE              128
> >   #define SPRD_DEF_RATE               26000000
Chunyan Zhang Aug. 9, 2023, 6:23 a.m. UTC | #2 
On Wed, 9 Aug 2023 at 13:52, wenhua lin <wenhua.lin1994@gmail.com> wrote:
>
> The change of the max ports is to adapt to an new
> SPRD serial hardware,also is backward-compatibility with old hardware.

This change seems not backward-compatible if the serial devices on
some old Unisoc SoCs can support 8 ports only.

BTW, please do not top-post your reply.

Thanks,
Chunyan

>
> Baolin Wang <baolin.wang@linux.alibaba.com> 于2023年8月7日周一 16:41写道：
> >
> >
> >
> > On 8/7/2023 4:07 PM, Wenhua Lin wrote:
> > > From: Wenhua Lin <wenhua.lin@unisoc.com>
> > >
> > > Support 12 uart ports, which can solve the problem
> > > of insufficient uart ports.
> >
> > This sounds incorrect to me.
> > If this is a software bug, please add a Fixes tag to backport for stable
> > kernels. If the change of the max ports is only avaliable on the new
> > SPRD serial hardware, you should ensure the change is
> > backward-compatibility with old hardware.
> >
> > > Signed-off-by: Wenhua Lin <wenhua.lin@unisoc.com>
> > > ---
> > >   drivers/tty/serial/sprd_serial.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
> > > index b58f51296ace..2774df490899 100644
> > > --- a/drivers/tty/serial/sprd_serial.c
> > > +++ b/drivers/tty/serial/sprd_serial.c
> > > @@ -22,7 +22,7 @@
> > >   #include <linux/tty_flip.h>
> > >
> > >   /* device name */
> > > -#define UART_NR_MAX          8
> > > +#define UART_NR_MAX          12
> > >   #define SPRD_TTY_NAME               "ttyS"
> > >   #define SPRD_FIFO_SIZE              128
> > >   #define SPRD_DEF_RATE               26000000
Baolin Wang Aug. 9, 2023, 6:26 a.m. UTC | #3 
On 8/9/2023 1:52 PM, wenhua lin wrote:
> The change of the max ports is to adapt to an new
> SPRD serial hardware,also is backward-compatibility with old hardware.

Again, DO NOT top-posting! Thanks.

>>
>> On 8/7/2023 4:07 PM, Wenhua Lin wrote:
>>> From: Wenhua Lin <wenhua.lin@unisoc.com>
>>>
>>> Support 12 uart ports, which can solve the problem
>>> of insufficient uart ports.
>>
>> This sounds incorrect to me.
>> If this is a software bug, please add a Fixes tag to backport for stable
>> kernels. If the change of the max ports is only avaliable on the new
>> SPRD serial hardware, you should ensure the change is
>> backward-compatibility with old hardware.

This is not backward-compatibility. Please see 'sprd_uart_driver' 
structure as below:

static struct uart_driver sprd_uart_driver = {
	.owner = THIS_MODULE,
	.driver_name = "sprd_serial",
	.dev_name = SPRD_TTY_NAME,
	.major = 0,
	.minor = 0,
	.nr = UART_NR_MAX,
	.cons = SPRD_CONSOLE,
};

That means you will still register 12 UART ports in the tty for old 
serial hardwares which actually only support 8 UART ports, and if users 
want to use another 4 ports which are not supported in the hardware, 
then system crashes.

So I think you should add a SoC data in 'serial_ids' to change the 
number of UART port according to different SoC.

>>> Signed-off-by: Wenhua Lin <wenhua.lin@unisoc.com>
>>> ---
>>>    drivers/tty/serial/sprd_serial.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
>>> index b58f51296ace..2774df490899 100644
>>> --- a/drivers/tty/serial/sprd_serial.c
>>> +++ b/drivers/tty/serial/sprd_serial.c
>>> @@ -22,7 +22,7 @@
>>>    #include <linux/tty_flip.h>
>>>
>>>    /* device name */
>>> -#define UART_NR_MAX          8
>>> +#define UART_NR_MAX          12
>>>    #define SPRD_TTY_NAME               "ttyS"
>>>    #define SPRD_FIFO_SIZE              128
>>>    #define SPRD_DEF_RATE               26000000
wenhua lin Aug. 9, 2023, 11:27 a.m. UTC | #4 
On Wed, Aug 9, 2023 at 2:27 PM Baolin Wang
<baolin.wang@linux.alibaba.com> wrote:
>
>
>
> On 8/9/2023 1:52 PM, wenhua lin wrote:
> > The change of the max ports is to adapt to an new
> > SPRD serial hardware,also is backward-compatibility with old hardware.
>
> Again, DO NOT top-posting! Thanks.

Thank you for your correction.


>
> >>
> >> On 8/7/2023 4:07 PM, Wenhua Lin wrote:
> >>> From: Wenhua Lin <wenhua.lin@unisoc.com>
> >>>
> >>> Support 12 uart ports, which can solve the problem
> >>> of insufficient uart ports.
> >>
> >> This sounds incorrect to me.
> >> If this is a software bug, please add a Fixes tag to backport for stable
> >> kernels. If the change of the max ports is only avaliable on the new
> >> SPRD serial hardware, you should ensure the change is
> >> backward-compatibility with old hardware.
>
> This is not backward-compatibility. Please see 'sprd_uart_driver'
> structure as below:
>
> static struct uart_driver sprd_uart_driver = {
>         .owner = THIS_MODULE,
>         .driver_name = "sprd_serial",
>         .dev_name = SPRD_TTY_NAME,
>         .major = 0,
>         .minor = 0,
>         .nr = UART_NR_MAX,
>         .cons = SPRD_CONSOLE,
> };
>
> That means you will still register 12 UART ports in the tty for old
> serial hardwares which actually only support 8 UART ports, and if users
> want to use another 4 ports which are not supported in the hardware,
> then system crashes.
>
> So I think you should add a SoC data in 'serial_ids' to change the
> number of UART port according to different SoC.
>

Thank you for your valuable comments, we should probably consider
how to make changes based on your suggestions.

> >>> Signed-off-by: Wenhua Lin <wenhua.lin@unisoc.com>
> >>> ---
> >>>    drivers/tty/serial/sprd_serial.c | 2 +-
> >>>    1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
> >>> index b58f51296ace..2774df490899 100644
> >>> --- a/drivers/tty/serial/sprd_serial.c
> >>> +++ b/drivers/tty/serial/sprd_serial.c
> >>> @@ -22,7 +22,7 @@
> >>>    #include <linux/tty_flip.h>
> >>>
> >>>    /* device name */
> >>> -#define UART_NR_MAX          8
> >>> +#define UART_NR_MAX          12
> >>>    #define SPRD_TTY_NAME               "ttyS"
> >>>    #define SPRD_FIFO_SIZE              128
> >>>    #define SPRD_DEF_RATE               26000000
diff mbox series

Patch

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index b58f51296ace..2774df490899 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -22,7 +22,7 @@ 
 #include <linux/tty_flip.h>
 
 /* device name */
-#define UART_NR_MAX		8
+#define UART_NR_MAX		12
 #define SPRD_TTY_NAME		"ttyS"
 #define SPRD_FIFO_SIZE		128
 #define SPRD_DEF_RATE		26000000