PCIEXP_PLUGIN_SUPPORT: Change dependency on PCI access

Some PCI-e capability registers are located starting from
0x100, these are not accessible using the conventional
PCI IO config operations at 0xcf8/0xcfc, unless PCI_CFG_EXT_IO
was selected.

Thus any feature that calls pciexp_find_extended_cap()
depends on either MMCONF_SUPPORT_DEFAULT or PCI_CFG_EXT_IO
being enabled on the platform.

In theory there can be system without MMCONF_SUPPORT, but
with complete PCI Express configuration space available
using PCI_CFG_EXT_IO. Do not use explicit PCI MMCONF
operations here, but rely on the default PCI access
method to be able to access all of the configuration space.

While at it, convert to IS_ENABLED() everywhere in the source
and organize Kconfig file better.

Change-Id: Ica6e16d2fb2adc532e644c4b2c47806490235715
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17546
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions