ICP DAS LP-8x4x is an industrial data acquision device. It is based
on PXA270 CPU. The board containsi a lot of (up to 36) standard UARTi
8250i serial ports. System console on the board is provided with
an on-chip PXA serial port. Both modules use /dev/ttyS0 by default.
To solve the collision, PXA ports could be configured with different
name and device numbers.
Signed-off-by: Sergey Yanovich <[email protected]>
---
drivers/tty/serial/Kconfig | 14 ++++++++++++++
drivers/tty/serial/pxa.c | 22 ++++++++++++++++++----
2 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 59c23d0..09cf980 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -406,6 +406,20 @@ config SERIAL_PXA_CONSOLE
your boot loader (lilo or loadlin) about how to pass options to the
kernel at boot time.)
+config SERIAL_PXA_TTYSA_NAME
+ bool "as /dev/ttySA[0-3]"
+ depends on SERIAL_PXA
+ default N
+ help
+ If you have enabled the serial port on the Intel XScale PXA
+ CPU you can make it appear as /dev/ttySA[0-3] in the system.
+
+ If you say N here (default), the ports will use UART /dev/ttyS[0-3]
+ names and corresponding major and minor devices numbers.
+
+ If you say Y here, the ports will have SA-1100 style names and
+ numbers. It is reqired at least for one PXA based device.
+
config SERIAL_SA1100
bool "SA1100 serial port support"
depends on ARCH_SA1100
diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c
index 2764828..a7e5e40 100644
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c
@@ -619,6 +619,20 @@ serial_pxa_type(struct uart_port *port)
static struct uart_pxa_port *serial_pxa_ports[4];
static struct uart_driver serial_pxa_reg;
+#ifndef CONFIG_SERIAL_PXA_TTYSA_NAME
+
+#define PXA_TTY_NAME "ttyS"
+#define PXA_TTY_MAJOR TTY_MAJOR
+#define PXA_TTY_MINOR 64
+
+#else
+
+#define PXA_TTY_NAME "ttySA"
+#define PXA_TTY_MAJOR 204
+#define PXA_TTY_MINOR 5
+
+#endif
+
#ifdef CONFIG_SERIAL_PXA_CONSOLE
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
@@ -778,7 +792,7 @@ serial_pxa_console_setup(struct console *co, char *options)
}
static struct console serial_pxa_console = {
- .name = "ttyS",
+ .name = PXA_TTY_NAME,
.write = serial_pxa_console_write,
.device = uart_console_device,
.setup = serial_pxa_console_setup,
@@ -819,9 +833,9 @@ struct uart_ops serial_pxa_pops = {
static struct uart_driver serial_pxa_reg = {
.owner = THIS_MODULE,
.driver_name = "PXA serial",
- .dev_name = "ttyS",
- .major = TTY_MAJOR,
- .minor = 64,
+ .dev_name = PXA_TTY_NAME
+ .major = PXA_TTY_MAJOR,
+ .minor = PXA_TTY_MINOR,
.nr = 4,
.cons = PXA_CONSOLE,
};
--
1.7.10.4
On Wed, Mar 13, 2013 at 03:02:22AM +0400, Sergey Yanovich wrote:
> ICP DAS LP-8x4x is an industrial data acquision device. It is based
> on PXA270 CPU. The board containsi a lot of (up to 36) standard UARTi
> 8250i serial ports. System console on the board is provided with
> an on-chip PXA serial port. Both modules use /dev/ttyS0 by default.
>
> To solve the collision, PXA ports could be configured with different
> name and device numbers.
>
> Signed-off-by: Sergey Yanovich <[email protected]>
> ---
> drivers/tty/serial/Kconfig | 14 ++++++++++++++
> drivers/tty/serial/pxa.c | 22 ++++++++++++++++++----
> 2 files changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 59c23d0..09cf980 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -406,6 +406,20 @@ config SERIAL_PXA_CONSOLE
> your boot loader (lilo or loadlin) about how to pass options to the
> kernel at boot time.)
>
> +config SERIAL_PXA_TTYSA_NAME
> + bool "as /dev/ttySA[0-3]"
Does that config text really make sense? What does it look like when
you run "make oldconfig"?
> + depends on SERIAL_PXA
> + default N
> + help
> + If you have enabled the serial port on the Intel XScale PXA
> + CPU you can make it appear as /dev/ttySA[0-3] in the system.
> +
> + If you say N here (default), the ports will use UART /dev/ttyS[0-3]
> + names and corresponding major and minor devices numbers.
> +
> + If you say Y here, the ports will have SA-1100 style names and
> + numbers. It is reqired at least for one PXA based device.
Ugh, why does it matter what it is named?
Use udev, or a tool like it, to rename serial ports if you really need
it, don't do this in the kernel please.
thanks,
greg k-h
On 13 March 2013 03:10, Greg Kroah-Hartman <[email protected]> wrote:
> On Wed, Mar 13, 2013 at 03:02:22AM +0400, Sergey Yanovich wrote:
>> +config SERIAL_PXA_TTYSA_NAME
>> + bool "as /dev/ttySA[0-3]"
>
> Does that config text really make sense? What does it look like when
> you run "make oldconfig"?
--------------------
* Non-8250 serial port support
*
PXA serial port support (SERIAL_PXA) [Y/n/?] y
Console on PXA serial port (SERIAL_PXA_CONSOLE) [Y/n/?] y
as /dev/ttySA[0-3] (SERIAL_PXA_TTYSA_NAME) [N/y/?] (NEW)
---------------------
So the kernel will have PXA serial port, a console on it, and it will
have a name (and numbers) /dev/ttySA0 to /dev/ttySA3.
>> ICP DAS LP-8x4x is an industrial data acquision device. It is based
>> on PXA270 CPU. The board containsi a lot of (up to 36) standard UARTi
>> 8250i serial ports. System console on the board is provided with
>> an on-chip PXA serial port. Both modules use /dev/ttyS0 by default.
>>
>> To solve the collision, PXA ports could be configured with different
>> name and device numbers.
> Ugh, why does it matter what it is named?
>
> Use udev, or a tool like it, to rename serial ports if you really need
> it, don't do this in the kernel please.
It doesn't matter what it is named. It matters that both drivers try
to use the same major device number. I have to change major device
number for PXA tty, as a result I need a different name in /dev
Maybe I am missing something obvious, but it seems that such a
collision is a kernel bug. Someone assumed that PXA cannot have a 8250
tty device and used 8250's parameters in PXA tty driver.
On Wed, Mar 13, 2013 at 03:34:59AM +0400, Сергей Янович wrote:
> On 13 March 2013 03:10, Greg Kroah-Hartman <[email protected]> wrote:
> > On Wed, Mar 13, 2013 at 03:02:22AM +0400, Sergey Yanovich wrote:
> >> +config SERIAL_PXA_TTYSA_NAME
> >> + bool "as /dev/ttySA[0-3]"
> >
> > Does that config text really make sense? What does it look like when
> > you run "make oldconfig"?
>
> --------------------
> * Non-8250 serial port support
> *
> PXA serial port support (SERIAL_PXA) [Y/n/?] y
> Console on PXA serial port (SERIAL_PXA_CONSOLE) [Y/n/?] y
> as /dev/ttySA[0-3] (SERIAL_PXA_TTYSA_NAME) [N/y/?] (NEW)
Please make it sane for the single line it is on.
> So the kernel will have PXA serial port, a console on it, and it will
> have a name (and numbers) /dev/ttySA0 to /dev/ttySA3.
>
> >> ICP DAS LP-8x4x is an industrial data acquision device. It is based
> >> on PXA270 CPU. The board containsi a lot of (up to 36) standard UARTi
> >> 8250i serial ports. System console on the board is provided with
> >> an on-chip PXA serial port. Both modules use /dev/ttyS0 by default.
> >>
> >> To solve the collision, PXA ports could be configured with different
> >> name and device numbers.
>
> > Ugh, why does it matter what it is named?
> >
> > Use udev, or a tool like it, to rename serial ports if you really need
> > it, don't do this in the kernel please.
>
> It doesn't matter what it is named. It matters that both drivers try
> to use the same major device number. I have to change major device
> number for PXA tty, as a result I need a different name in /dev
>
> Maybe I am missing something obvious, but it seems that such a
> collision is a kernel bug. Someone assumed that PXA cannot have a 8250
> tty device and used 8250's parameters in PXA tty driver.
Yes, someone must have messed up, so care to find the root problem here?
thanks,
greg k-h
On 13 March 2013 03:39, Greg Kroah-Hartman <[email protected]> wrote:
> On Wed, Mar 13, 2013 at 03:34:59AM +0400, Сергей Янович wrote:
>> --------------------
>> * Non-8250 serial port support
>> *
>> PXA serial port support (SERIAL_PXA) [Y/n/?] y
>> Console on PXA serial port (SERIAL_PXA_CONSOLE) [Y/n/?] y
>> as /dev/ttySA[0-3] (SERIAL_PXA_TTYSA_NAME) [N/y/?] (NEW)
>
> Please make it sane for the single line it is on.
"PXA serial port with SA-1100 major"
"PXA serial port with SA-1100 major number"
"PXA serial port with SA-1100 major device number"
Could anything like that be acceptable?
How long a line could be?
>> Maybe I am missing something obvious, but it seems that such a
>> collision is a kernel bug. Someone assumed that PXA cannot have a 8250
>> tty device and used 8250's parameters in PXA tty driver.
>
> Yes, someone must have messed up, so care to find the root problem here?
Two drivers try to use the same resource. It was in pre-git era, so it
difficult to find out exactly. I would guess that that 8250 have
precedence by at least 5 years. But it is almost guaranteed that lots
of people depend on PXA console having ttyS0 name. So simple
s/ttyS/ttySA/ is not a solution. My patch preserves status quo by
default, but allows to have a correct workaround for those who face a
collision. By correct I mean that it will not create a new collision
since a system cannot run on both SA-1100 and PXA270 at the same time.
This assumption is already documented in
arch/arm/mach-pxa/include/mach/irqs.h line 94.