[PATCH v2] drivers: serial: probe all uart devices

[Stefan Roese]

On 29.09.20 19:26, Vabhav Sharma wrote:
> From: Vabhav Sharma <vabhav.sharma at nxp.com>
> 
> U-Boot DM model probe only single device at a time
> which is enabled and configured using device tree
> or platform data method.
> 
> PL011 UART IP is SBSA compliant and firmware does the
> serial port set-up, initialization and let the kernel use
> UART port for sending and receiving characters.
> 
> Normally software talk to one serial port time but some
> LayerScape platform require all the UART devices enabled
> in Linux for various use case.
> 
> Adding support to probe all enabled serial devices like SBSA
> compliant PL011 UART ports probe and initialization by firmware.
> 
> Signed-off-by: Vabhav Sharma <vabhav.sharma at nxp.com>
> ---
> v2:
>     Incorporated Stefan review comment, Update #ifdef with macro
>     if (IS_ENABLED)..

Better, thanks. But...

> ---
> ---
>   drivers/serial/Kconfig         | 17 +++++++++++++++++
>   drivers/serial/serial-uclass.c | 30 ++++++++++++++++++++++++++++++
>   2 files changed, 47 insertions(+)
> 
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index e344677..b2e30f1 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -134,6 +134,23 @@ config SERIAL_SEARCH_ALL
>   
>   	  If unsure, say N.
>   
> +config SERIAL_PROBE_ALL
> +	bool "Probe all available serial devices"
> +	depends on DM_SERIAL
> +	default n
> +	help
> +	  The serial subsystem only probe for single serial device,
> +	  but does not probe for other remaining serial devices.
> +	  With this option set,we make probing and searching for
> +	  all available devices optional.
> +	  Normally, U-Boot talk to one serial port at a time but SBSA
> +	  compliant UART devices like PL011 require initialization
> +	  by firmware and let the kernel use serial port for sending
> +	  and receiving the characters.
> +
> +	  If probing is not required for all remaining available
> +	  devices other than default current console device, say N.
> +
>   config SPL_DM_SERIAL
>   	bool "Enable Driver Model for serial drivers in SPL"
>   	depends on DM_SERIAL && SPL_DM
> diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
> index 0027625..d303a66 100644
> --- a/drivers/serial/serial-uclass.c
> +++ b/drivers/serial/serial-uclass.c
> @@ -86,6 +86,11 @@ static void serial_find_console_or_panic(void)
>   		uclass_first_device(UCLASS_SERIAL, &dev);
>   		if (dev) {
>   			gd->cur_serial_dev = dev;
> +			if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +				/* Scanning uclass to probe all devices */
> +				for (; dev; uclass_next_device(&dev))
> +					;
> +			}
>   			return;
>   		}
>   	} else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
> @@ -96,11 +101,21 @@ static void serial_find_console_or_panic(void)
>   			if (np && !uclass_get_device_by_ofnode(UCLASS_SERIAL,
>   					np_to_ofnode(np), &dev)) {
>   				gd->cur_serial_dev = dev;
> +				if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +					/* Scanning uclass to probe devices */
> +					for (; dev; uclass_next_device(&dev))
> +						;
> +				}

This code sequence (incl. gd->cur_serial_dev = dev;) is repeated
multiple times (below as well). Could you instead move this into
a function and call this function to reduce code and binary size?

Thanks,
Stefan

>   				return;
>   			}
>   		} else {
>   			if (!serial_check_stdout(blob, &dev)) {
>   				gd->cur_serial_dev = dev;
> +				if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +					/* Scanning uclass to probe devices */
> +					for (; dev; uclass_next_device(&dev))
> +						;
> +				}
>   				return;
>   			}
>   		}
> @@ -125,6 +140,11 @@ static void serial_find_console_or_panic(void)
>   		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev)) {
>   			if (dev->flags & DM_FLAG_ACTIVATED) {
>   				gd->cur_serial_dev = dev;
> +				if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +					/* Scanning uclass to probe devices */
> +					for (; dev; uclass_next_device(&dev))
> +						;
> +				}
>   				return;
>   			}
>   		}
> @@ -136,6 +156,11 @@ static void serial_find_console_or_panic(void)
>   			if (!ret) {
>   				/* Device did succeed probing */
>   				gd->cur_serial_dev = dev;
> +				if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +					/* Scanning uclass to probe devices */
> +					for (; dev; uclass_next_device(&dev))
> +						;
> +				}
>   				return;
>   			}
>   		}
> @@ -144,6 +169,11 @@ static void serial_find_console_or_panic(void)
>   		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
>   		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
>   			gd->cur_serial_dev = dev;
> +			if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL)) {
> +				/* Scanning uclass to probe all devices */
> +				for (; dev; uclass_next_device(&dev))
> +					;
> +			}
>   			return;
>   		}
>   #endif
> 


Viele Grüße,
Stefan

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