PCI: altera: Check TLP completion status

Check TLP packet successful completion status.  This fix the issue when
accessing multi-function devices in enumeration process, TLP will return
error when accessing non-exist function number.  Returns PCI error code
instead of generic errno.

Tested on Ethernet adapter card with multi-functions.

[bhelgaas: simplify completion status checking code]
Signed-off-by: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
index ed736a94eade..072255d5b31c 100644
--- a/drivers/pci/host/pcie-altera.c
+++ b/drivers/pci/host/pcie-altera.c
@@ -55,6 +55,7 @@
 #define TLP_CFG_DW2(bus, devfn, offset) \
                                 (((bus) << 24) | ((devfn) << 16) | (offset))
 #define TLP_REQ_ID(bus, devfn)          (((bus) << 8) | (devfn))
+#define TLP_COMP_STATUS(s)              (((s) >> 12) & 7)
 #define TLP_HDR_SIZE                    3
 #define TLP_LOOP                        500
 #define RP_DEVFN                        0
@@ -171,6 +172,7 @@ static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
         bool sop = 0;
         u32 ctrl;
         u32 reg0, reg1;
+        u32 comp_status = 1;
 
         /*
          * Minimum 2 loops to read TLP headers and 1 loop to read data
@@ -182,19 +184,25 @@ static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
                         reg0 = cra_readl(pcie, RP_RXCPL_REG0);
                         reg1 = cra_readl(pcie, RP_RXCPL_REG1);
 
-                        if (ctrl & RP_RXCPL_SOP)
+                        if (ctrl & RP_RXCPL_SOP) {
                                 sop = true;
+                                comp_status = TLP_COMP_STATUS(reg1);
+                        }
 
                         if (ctrl & RP_RXCPL_EOP) {
+                                if (comp_status)
+                                        return PCIBIOS_DEVICE_NOT_FOUND;
+
                                 if (value)
                                         *value = reg0;
+
                                 return PCIBIOS_SUCCESSFUL;
                         }
                 }
                 udelay(5);
         }
 
-        return -ENOENT;
+        return PCIBIOS_DEVICE_NOT_FOUND;
 }
 
 static void tlp_write_packet(struct altera_pcie *pcie, u32 *headers,