FROMLIST: PCI: mediatek-gen3: Don't reply AXI slave error

There are some circumstances where the EP device will not respond to
non-posted access from the root port (e.g., MMIO read). In such cases,
the root port will reply with an AXI slave error, which will be treated
as a System Error (SError), causing a kernel panic and preventing us
from obtaining any useful information for further debugging.

We have added a new bit in the PCIE_AXI_IF_CTRL_REG register to prevent
PCIe AXI0 from replying with a slave error. Setting this bit on an older
platform that does not support this feature will have no effect.

By preventing AXI0 from replying with a slave error, we can keep the
kernel alive and debug using the information from AER.

Signed-off-by: Jianjun Wang <jianjun.wang@mediatek.com>
(am from https://patchwork.kernel.org/patch/13925176/)
(also found at https://lore.kernel.org/r/20250103060035.30688-5-jianjun.wang@mediatek.com

)

BUG=b:383258443
TEST=build pass and boot to shell
UPSTREAM-TASK=b:379039276

Change-Id: Ibb18a9d780d3b009511632caeb9e7c4eb6b0173c
Signed-off-by: Hsin-Te Yuan <yuanhsinte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/6174700


Commit-Queue: Fei Shao <fshao@chromium.org>
Reviewed-by: Fei Shao <fshao@chromium.org>
Tested-by: Fei Shao <fshao@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Hubert Mazur <hmazur@google.com>