PCI: rockchip: Use normal register bank for config accessors
commit dc8cca5e upstream. Rockchip's RC has two banks of registers for the root port: a normal bank that is strictly compatible with the PCIe spec, and a privileged bank that can be used to change RO bits of root port registers. When probing the RC driver, we use the privileged bank to do some basic setup work as some RO bits are hw-inited to wrong value. But we didn't change to the normal bank after probing the driver. This leads to a serious problem when the PME code tries to clear the PME status by writing PCI_EXP_RTSTA_PME to the register of PCI_EXP_RTSTA. Per PCIe 3.0 spec, section 7.8.14, the PME status bit is RW1C. So the PME code is doing the right thing to clear the PME status but we find the RC doesn't clear it but actually setting it to one. So finally the system trap in pcie_pme_work_fn() as PCI_EXP_RTSTA_PME is true now forever. This issue can be reproduced by booting kernel with pci=nomsi. Use the normal register bank for the PCI config accessors. The privileged bank is used only internally by this driver. Fixes: e77f847d ("PCI: rockchip: Add Rockchip PCIe controller support") Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Jeffy Chen <jeffy.chen@rock-chips.com> Cc: Brian Norris <briannorris@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing
Please register or sign in to comment