[U-Boot] [U-Boot-DM] [PATCH] drivers: serial: probe all serial devices

[Marek Vasut]

On 10/16/2018 09:20 AM, Vabhav Sharma wrote:
> 
> 
>> -----Original Message-----
>> From: Marek Vasut <marex at denx.de>
>> Sent: Tuesday, October 16, 2018 12:29 PM
>> To: Vabhav Sharma <vabhav.sharma at nxp.com>; u-boot at lists.denx.de; u-boot-
>> dm at lists.denx.de; sjg at chromium.org
>> Cc: yamada.masahiro at socionext.com; bmeng.cn at gmail.com
>> Subject: Re: [U-Boot-DM] [PATCH] drivers: serial: probe all serial devices
>>
>> On 10/15/2018 02:09 AM, Vabhav Sharma wrote:
>>> Serial subsystem search and probe only one first serial device and
>>> unable to use remaining available UART devices
>>
>> The serial devices are bound and you can switch to them. What is the real
>> problem ?
> Yes, I understand switch is possible with change in DTS or platform data for choosing UART device to be used as boot console(e.g. UART0) with gd->cur_serial_dev is updated to chosen UART device.
> The problem was stated in email(attached 23 may) " [U-Boot-DM] QUERY:U-boot DM:SERIAL:Multiple On-chip UART Controller Support" with suggested solution from Simon which is sent as patch for review.
> Similar issue was faced by Andreas

You can also use setenv stdin/stdout/stderr to alternate between stdio
devices. So what is the problem ?

>>> This patch changes the logic to probe all available serial devices
>>> using platform data or device tree in DM model in order to use all
>>> UART devices
>>
>> Get rid of the ifdeffery and copied code please.
> This is case for using uclass_next_device() to iterate through them, Having CONFIG option doesn't make it mandatory for every platform to probe all serial devices.

Is this also the case for having 6 copies of exactly the same code ? You
can turn it into a function if needed.

>>> Signed-off-by: Vabhav Sharma <vabhav.sharma at nxp.com>
>>> ---
>>>  drivers/serial/Kconfig         | 12 ++++++++++++
>>>  drivers/serial/serial-uclass.c | 42
>>> ++++++++++++++++++++++++++++++++++++++++++
>>>  2 files changed, 54 insertions(+)
>>>
>>> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index
>>> 597db4b..d6451b1 100644
>>> --- a/drivers/serial/Kconfig
>>> +++ b/drivers/serial/Kconfig
>>> @@ -133,6 +133,18 @@ config SERIAL_SEARCH_ALL
>>>
>>>  	  If unsure, say N.
>>>
>>> +config SERIAL_PROBE_ALL
>>> +	bool "Probe all available serial devices"
>>> +	depends on DM_SERIAL
>>> +	help
>>> +	 The serial subsystem only probe for single serial device, but does
>>> +	 not probe for remaining available devices.
>>> +	 With this option set,we make probing for all available devices
>>> +	 mandatory.
>>> +
>>> +	 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 e50f0aa..405e60e 100644
>>> --- a/drivers/serial/serial-uclass.c
>>> +++ b/drivers/serial/serial-uclass.c
>>> @@ -82,6 +82,13 @@ static void serial_find_console_or_panic(void)
>>>  		uclass_first_device(UCLASS_SERIAL, &dev);
>>>  		if (dev) {
>>>  			gd->cur_serial_dev = dev;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +			/* Scanning uclass to probe all devices */
>>> +			for (;
>>> +			     dev;
>>> +			     uclass_next_device(&dev))
>>> +				;
>>> +#endif
>>>  			return;
>>>  		}
>>>  	} else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) { @@ -92,11
>> +99,25
>>> @@ 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;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +				/* Scanning uclass to probe all devices */
>>> +				for (;
>>> +				     dev;
>>> +				     uclass_next_device(&dev))
>>> +					;
>>> +#endif
>>>  				return;
>>>  			}
>>>  		} else {
>>>  			if (!serial_check_stdout(blob, &dev)) {
>>>  				gd->cur_serial_dev = dev;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +				/* Scanning uclass to probe all devices */
>>> +				for (;
>>> +				     dev;
>>> +				     uclass_next_device(&dev))
>>> +					;
>>> +#endif
>>>  				return;
>>>  			}
>>>  		}
>>> @@ -121,6 +142,13 @@ 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;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +				/* Scanning uclass to probe all devices */
>>> +				for (;
>>> +				     dev;
>>> +				     uclass_next_device(&dev))
>>> +					;
>>> +#endif
>>>  				return;
>>>  			}
>>>  		}
>>> @@ -132,6 +160,13 @@ static void serial_find_console_or_panic(void)
>>>  			if (!ret) {
>>>  				/* Device did succeed probing */
>>>  				gd->cur_serial_dev = dev;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +				/* Scanning uclass to probe all devices */
>>> +				for (;
>>> +				     dev;
>>> +				     uclass_next_device(&dev))
>>> +					;
>>> +#endif
>>>  				return;
>>>  			}
>>>  		}
>>> @@ -140,6 +175,13 @@ 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;
>>> +#ifdef CONFIG_SERIAL_PROBE_ALL
>>> +			/* Scanning uclass to probe all devices */
>>> +			for (;
>>> +			     dev;
>>> +			     uclass_next_device(&dev))
>>> +				;
>>> +#endif
>>>  			return;
>>>  		}
>>>  #endif
>>>
>>
>>
>> --
>> Best regards,
>> Marek Vasut


-- 
Best regards,
Marek Vasut