Coreboot 4.5: No early serial output

[Naveed Ghori]

Hi all,

In Coreboot 4.4 (Intel baytrail FSP) early serial output use to work (first line being coreboot version followed by RTC Init)
In Coreboot 4.5 it seems that serial output only works once the FSP initializes the serial port (first line being romstage_main_continue).

Notes: Setup for spew output, using the debug serial port lines.
I am looking at what might have caused this but though I'd ask if this was a known issue, possibly already fixed with a patch or if it was an error on my part.

Note sure exactly where to search as I have already reviewed the changes in src/drivers/uart/uart8250io.c

Regards,
Naveed
Naveed Ghori | Lead Firmware & Driver Engineer
DTI Group Ltd | Transit Security & Surveillance
31 Affleck Road, Perth Airport, Western Australia 6105, Australia
P +61 8 9373 2905,151 | F [phone] | [e-mail]

Visit our website  www.dti.com.auhttp://www.dti.com.au
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[Zoran Stojsavljevic]

Hello Naveed,
> In Coreboot 4.4 (Intel baytrail FSP) early serial output use to work

(first line being coreboot version followed by RTC Init)
> In Coreboot 4.5 it seems that serial output only works once the FSP

initializes the serial port (first line being romstage_main_continue).

What entity initializes serial port in Coreboot 4.4 (BYT FSP or Coreboot
itself)? In which stage?

Once you get answer to this question, you should know what to do for/in
Coreboot 4.5 . ;-)

Zoran

On Wed, Mar 29, 2017 at 10:55 AM, Naveed Ghori 
wrote:
> Hi all,
>
> In Coreboot 4.4 (Intel baytrail FSP) early serial output use to work
> (first line being coreboot version followed by RTC Init)
>
> In Coreboot 4.5 it seems that serial output only works once the FSP
> initializes the serial port (first line being romstage_main_continue).
>
> Notes: Setup for spew output, using the debug serial port lines.
>
> I am looking at what might have caused this but though I’d ask if this was
> a known issue, possibly already fixed with a patch or if it was an error on
> my part.
>
> Note sure exactly where to search as I have already reviewed the changes
> in src/drivers/uart/uart8250io.c
>
> Regards,
>
> Naveed
> *Naveed Ghori* | Lead Firmware & Driver Engineer
> *DTI Group Ltd* | Transit Security & Surveillance
> 31 Affleck Road, Perth Airport, Western Australia 6105, Australia
> P [phone] <+61%208%209373%202905>,151 | F [phone]
> <+61%208%209479%201190> | [e-mail]
> Visit our website  www.dti.com.au
> The information contained in this email is confidential. If you receive
> this email in error, please inform DTI Group Ltd via the above contact
> details. If you are not the intended recipient, you may not use or disclose
> the information contained in this email or attachments.