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

[Wolfgang Denk]

Dear Vabhav,

In message <VI1PR04MB480032AF6B3C36FACA4318B6F3CF0 at VI1PR04MB4800.eurprd04.prod.outlook.com> you wrote:
> 
> > "enable" means we have all required information needed to initialize them,
> > if we need them.  The need arises only when someone wants to transfer
> > data over that UART.  If nobody uses the UArt, there is no need to ever
> > initialize it.
> On u-boot, only one console is used

Right.  And in any case, you can ALWAYS use only one serial driver
at a time, as U-Boot is strictly single-tasking.  It does not make a
difference whether you initialize one or twenty UARTS - you can use
always exactly one at any point of time.

> There is need to use multiple console for network firmware logging, linux boot

Yes, you repeat that. But you don't explain why you think this is
needed.

For example, why would you need a UART for "network logging"?
Why would LInux need a different console port than U-Boot?

This all makes no sense to me...

> > In which way is this a limitation?  We use only one UART (for the serial
> > console), so it works as supposed: only the used devices are fully initialized.
> Limitation for aforesaid example

You give no comprehensible example. You say you need it, but don't
explain why, or how you would actually use it with only one serial
port active at any time.

> > What do you mean "for Linux boot"?  If Linux needs the UART, it will
> > initialize it itself in the Linux dvice driver.
> Example is PL011 UART linux driver which expect initialization(integer and fractional baud date) done by bootloader

In this case the Linux driver is broken and needs to be fixed.

Alternatively, just _use_ this port in U-Boot before booting.
No need to initialize other ports, though.

> > And what exactly do you mean by "UART3 for ethernet firmware logging"?
> Different console than linux boot console.

I don't see why this would make sense.  But as metioned several
times before, you can always only use a single port at any time in
U-Boot.

Best regards,

Wolfgang Denk

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