[POWERPC] 86xx: Avoid system halt if link training isn't at least L0.

We check the Link Training and State Status register to make sure we
are at least at the L0 state.

Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Acked-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/86xx/pci.c b/arch/powerpc/platforms/86xx/pci.c
index 0db51e8ab5d4..3825e1ac5312 100644
--- a/arch/powerpc/platforms/86xx/pci.c
+++ b/arch/powerpc/platforms/86xx/pci.c
@@ -122,7 +122,6 @@ static void __init
 mpc86xx_setup_pcie(struct pci_controller *hose, u32 pcie_offset, u32 pcie_size)
 {
         u16 cmd;
-        unsigned int temps;
 
         DBG("PCIE host controller register offset 0x%08x, size 0x%08x.\n",
                         pcie_offset, pcie_size);
@@ -135,6 +134,9 @@ mpc86xx_setup_pcie(struct pci_controller *hose, u32 pcie_offset, u32 pcie_size)
         early_write_config_byte(hose, 0, 0, PCI_LATENCY_TIMER, 0x80);
 }
 
+#define PCIE_LTSSM      0x404   /* PCIe Link Training and Status */
+#define PCIE_LTSSM_L0   0x16    /* L0 state */
+
 int __init mpc86xx_add_bridge(struct device_node *dev)
 {
         int len;
@@ -143,6 +145,7 @@ int __init mpc86xx_add_bridge(struct device_node *dev)
         const int *bus_range;
         int has_address = 0;
         int primary = 0;
+        u16 val;
 
         DBG("Adding PCIE host bridge %s\n", dev->full_name);
 
@@ -159,12 +162,18 @@ int __init mpc86xx_add_bridge(struct device_node *dev)
         if (!hose)
                 return -ENOMEM;
         hose->arch_data = dev;
+        hose->indirect_type = PPC_INDIRECT_TYPE_EXT_REG;
 
         hose->first_busno = bus_range ? bus_range[0] : 0x0;
         hose->last_busno = bus_range ? bus_range[1] : 0xff;
 
         setup_indirect_pci(hose, rsrc.start, rsrc.start + 0x4);
 
+        /* Probe the hose link training status */
+        early_read_config_word(hose, 0, 0, PCIE_LTSSM, &val);
+        if (val < PCIE_LTSSM_L0)
+                return -ENXIO;
+
         /* Setup the PCIE host controller. */
         mpc86xx_setup_pcie(hose, rsrc.start, rsrc.end - rsrc.start + 1);