riscv: Move serial and rtc from IO port space to MMIO area.

The default serial and rtc IO region overlaps with PCI IO bar
region leading bar 0 activation to fail. Moving these devices
to MMIO region similar to ARM.

Given serial has been moved from 0x3f8 to 0x10000000, this
requires us to now pass earlycon=uart8250,mmio,0x10000000
from cmdline rather than earlycon=uart8250,mmio,0x3f8.

To avoid the need to change the address every time the tool
is updated, we can also just pass "earlycon" from cmdline
and guest then finds the type and base address by following
the Device Tree's stdout-path property.

Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20230203122934.18714-1-rkanwal@rivosinc.com
Signed-off-by: Will Deacon <will@kernel.org>
3 files changed