On Mon, 2016-02-15 at 21:05 +0300, Aleksey Makarov wrote:

This patchset is based on the patchset by Leif Lindholm [1]

'ARM Server Base Boot Requirements' [2] mentions SPCR (Serial Port
Console Redirection Table) [3] as a mandatory ACPI table that
specifies the configuration of serial console.

SPCR support is included in QEMU's ARM mach-virt since 2.4 release.

Introduce a new function acpi_console_check().  At the uart port
registration, this function checks if the ACPI SPCR table specifies
its argument of type struct uart_port to be a console
and if so calls add_preferred_console().

Use SPCR to tell if SBSA serial driver should use 32-bit access to registers.

To be able to access SPCR table each time any console is registered
change __init to __ref for early_acpi_os_unmap_memory().

The patchset should be applied to tty-next.

On Mustang, m400, and Seattle:

Tested-by: Mark Salter <redacted>