On 25.01.2016 20:14, Andy Shevchenko wrote:

On Mon, Jan 25, 2016 at 1:45 PM, Aleksey Makarov
[off-list ref] wrote:

quoted

'ARM Server Base Boot Requiremets' [1] mention SPCR
(Serial Port Console Redirection Table) [2] as a mandatory ACPI table
that specifies the configuration of serial console.

Parse this table and check if any registered console match
the description.  If it does, enable that console.

To implement that, introduce a new member
int (*acpi_match)(struct console *, struct acpi_table_spcr *)
of struct console.  It allows drivers to check if they provide
a matching console device.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
[2] http://msdn.microsoft.com/en-us/library/windows/hardware/dn639131(v=vs.85).aspx

Can you split this to several patches?

I am not sure I should.

I see preparatory patch in console code, i.e.
delete_from_console_list(), adding SPCR support to ACPI, enabling it.

It would be difficult to justify delete_from_console_list() in a 
separate patches before the rest of the changes. And enabling SPCR in a 
separate patch also looks oddly for me.

It would be great to have other comments on this before I fix this in 
the next version.

Thank you