[PATCH V2 0/2] Use dynamic allocation for major number when uart ports > 4

[PATCH V2 0/2] Use dynamic allocation for major number when uart ports > 4

[Manikanta Guntupalli]

Update ttyUL major number allocation details in documentation.
Use dynamic allocation for major number when uart ports > 4.
---
Changes for V2:
Introduce 1/2 patch.
Update driver to use either static or dynamic major allocation.
Update commit description.
Update description of SERIAL_UARTLITE_NR_UARTS in Kconfig.

Manikanta Guntupalli (2):
  Documentation: devices.txt: Update ttyUL major number allocation
    details
  serial: uartlite: Use dynamic allocation for major number when uart
    ports > 4

 Documentation/admin-guide/devices.txt | 4 ++++
 drivers/tty/serial/Kconfig            | 2 ++
 drivers/tty/serial/uartlite.c         | 5 +++++
 3 files changed, 11 insertions(+)

-- 
2.25.1

[PATCH V2 1/2] Documentation: devices.txt: Update ttyUL major number allocation details

[Manikanta Guntupalli]

Describe when uartlite driver uses static/dynamic allocation for major
number based on maximum number of uartlite serial ports.

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
---
Changes for V2:
This patch introduced in V2.
---
 Documentation/admin-guide/devices.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt
index 839054923530..d2f2c9f436db 100644
--- a/Documentation/admin-guide/devices.txt
+++ b/Documentation/admin-guide/devices.txt
@@ -2707,6 +2707,10 @@
 		 187 = /dev/ttyUL0		Xilinx uartlite - port 0
 		    ...
 		 190 = /dev/ttyUL3		Xilinx uartlite - port 3
+
+		 If maximum number of uartlite serial ports more than 4, then driver uses
+		 dynamic allocation instead of static allocation for major number.
+
 		 191 = /dev/xvc0		Xen virtual console - port 0
 		 192 = /dev/ttyPZ0		pmac_zilog - port 0
 		    ...
-- 
2.25.1

[PATCH V2 2/2] serial: uartlite: Use dynamic allocation for major number when uart ports > 4

[Manikanta Guntupalli]

Device number 204 has a range of minors on major number.
uart_register_driver is failing due to lack of minor numbers
when more number of uart ports used. So, to avoid minor number
limitation on 204 major number use dynamic major allocation
when more than 4 uart ports used otherwise use static major
allocation.

https://docs.kernel.org/arch/arm/sa1100/serial_uart.html

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
---
Changes for V2:
Update logic to use either static or dynamic major allocation.
Update commit description.
Update description of SERIAL_UARTLITE_NR_UARTS in Kconfig.
---
 drivers/tty/serial/Kconfig    | 2 ++
 drivers/tty/serial/uartlite.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 732c893c8d16..368c63066a86 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -532,6 +532,8 @@ config SERIAL_UARTLITE_NR_UARTS
 	help
 	  Set this to the number of uartlites in your system, or the number
 	  you think you might implement.
+	  If maximum number of uartlite serial ports more than 4, then driver uses
+	  dynamic allocation instead of static allocation for major number.
 
 config SERIAL_SUNCORE
 	bool
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index 404c14acafa5..517f1f34143d 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -24,8 +24,13 @@
 #include <linux/pm_runtime.h>
 
 #define ULITE_NAME		"ttyUL"
+#if (CONFIG_SERIAL_UARTLITE_NR_UARTS > 4)
+#define ULITE_MAJOR             0       /* use dynamic node allocation */
+#define ULITE_MINOR             0
+#else
 #define ULITE_MAJOR		204
 #define ULITE_MINOR		187
+#endif
 #define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
 
 /* ---------------------------------------------------------------------
-- 
2.25.1

Re: [PATCH V2 2/2] serial: uartlite: Use dynamic allocation for major number when uart ports > 4

[Jiri Slaby]

On 14. 11. 23, 10:33, Manikanta Guntupalli wrote:
> Device number 204 has a range of minors on major number.
> uart_register_driver is failing due to lack of minor numbers
> when more number of uart ports used. So, to avoid minor number
> limitation on 204 major number use dynamic major allocation
> when more than 4 uart ports used otherwise use static major
> allocation.
> 
> https://docs.kernel.org/arch/arm/sa1100/serial_uart.html
> 
> Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
> ---
> Changes for V2:
> Update logic to use either static or dynamic major allocation.
> Update commit description.
> Update description of SERIAL_UARTLITE_NR_UARTS in Kconfig.
> ---
>   drivers/tty/serial/Kconfig    | 2 ++
>   drivers/tty/serial/uartlite.c | 5 +++++
>   2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 732c893c8d16..368c63066a86 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -532,6 +532,8 @@ config SERIAL_UARTLITE_NR_UARTS
>   	help
>   	  Set this to the number of uartlites in your system, or the number
>   	  you think you might implement.
> +	  If maximum number of uartlite serial ports more than 4,

A verb is missing. The same in patch 1/2.

> then driver uses
> +	  dynamic allocation instead of static allocation for major number.
>   
>   config SERIAL_SUNCORE
>   	bool
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index 404c14acafa5..517f1f34143d 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -24,8 +24,13 @@
>   #include <linux/pm_runtime.h>
>   
>   #define ULITE_NAME		"ttyUL"
> +#if (CONFIG_SERIAL_UARTLITE_NR_UARTS > 4)

The parentheses are unneeded, right?

> +#define ULITE_MAJOR             0       /* use dynamic node allocation */
> +#define ULITE_MINOR             0
> +#else
>   #define ULITE_MAJOR		204
>   #define ULITE_MINOR		187
> +#endif
>   #define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
>   
>   /* ---------------------------------------------------------------------

-- 
js
suse labs

Re: [PATCH V2 1/2] Documentation: devices.txt: Update ttyUL major number allocation details

[Jiri Slaby]

On 14. 11. 23, 10:33, Manikanta Guntupalli wrote:
> Describe when uartlite driver uses static/dynamic allocation for major
> number based on maximum number of uartlite serial ports.
> 
> Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
> ---
> Changes for V2:
> This patch introduced in V2.
> ---
>   Documentation/admin-guide/devices.txt | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt
> index 839054923530..d2f2c9f436db 100644
> --- a/Documentation/admin-guide/devices.txt
> +++ b/Documentation/admin-guide/devices.txt
> @@ -2707,6 +2707,10 @@
>   		 187 = /dev/ttyUL0		Xilinx uartlite - port 0
>   		    ...
>   		 190 = /dev/ttyUL3		Xilinx uartlite - port 3
> +
> +		 If maximum number of uartlite serial ports more than 4, then driver uses
> +		 dynamic allocation instead of static allocation for major number.

I am not sure about the placement of this comment. This looks like it 
holds for xvc below.

>   		 191 = /dev/xvc0		Xen virtual console - port 0
>   		 192 = /dev/ttyPZ0		pmac_zilog - port 0
>   		    ...

-- 
js
suse labs