My board is Intel Oxbohill CRB (Apollo lake). On my board UART are not connected to PCI.

I am using grub2 payload loaded by coreboot. UART works fine in coreboot by using memory mapped 8050 driver (https://github.com/coreboot/coreboot/blob/master/src/drivers/uart/uart8250mem.c), however when grub2 is loaded it refuses to recognize UART.

On Wed, Mar 1, 2017 at 3:08 PM, Matthias Lange <matthias.lange@kernkonzept.com> wrote:

Hi,

On 03/01/2017 08:00 AM, Andrei Borzenkov wrote:
> please test patches from Matthias Lange
>
> https://lists.gnu.org/archive/html/grub-devel/2017-02/msg00104.html
>
>
> On Wed, Mar 1, 2017 at 9:15 AM, Gailu Singh <gailu96@gmail.com> wrote:
>> Hi Experts,
>>
>> I am using GRUB2 on intel apollo lake board. This board does not have IO
>> mapped uart instead it has 8250 memory mapped UART.

Could you share some details about the board?

>> GRUB2 does not recognize memory mapped uart and gives error ("serial port
>> COM0 not found). There is a 8250 memory mapped driver available in coreboot.
>> Is it possible to port that driver to Grub2?

My patch set adds support for 8250 MMIO PCI cards. Is the UART on your
board connected via PCI?

Best,
Matthias.