MIPS: Octeon: Add PCIe link status check

The standard PCIe configuration read-write interface is used to
access the configuration space of the peripheral PCIe devices
of the mips processor after the PCIe link surprise down, it can
generate kernel panic caused by "Data bus error". So it is
necessary to add PCIe link status check for system protection.
When the PCIe link is down or in training, assigning a value
of 0 to the configuration address can prevent read-write behavior
to the configuration space of peripheral PCIe devices, thereby
preventing kernel panic.

Signed-off-by: Songyang Li <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

Author: Songyang Li

arch/mips/pci/pcie-octeon.c

@@ -230,12 +230,18 @@ static inline uint64_t __cvmx_pcie_build_config_addr(int pcie_port, int bus,
 {
 	union cvmx_pcie_address pcie_addr;
 	union cvmx_pciercx_cfg006 pciercx_cfg006;
+	union cvmx_pciercx_cfg032 pciercx_cfg032;
 
 	pciercx_cfg006.u32 =
 	    cvmx_pcie_cfgx_read(pcie_port, CVMX_PCIERCX_CFG006(pcie_port));
 	if ((bus <= pciercx_cfg006.s.pbnum) && (dev != 0))
 		return 0;
 
+	pciercx_cfg032.u32 =
+		cvmx_pcie_cfgx_read(pcie_port, CVMX_PCIERCX_CFG032(pcie_port));
+	if ((pciercx_cfg032.s.dlla == 0) || (pciercx_cfg032.s.lt == 1))
+		return 0;
+
 	pcie_addr.u64 = 0;
 	pcie_addr.config.upper = 2;
 	pcie_addr.config.io = 1;