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>

diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
index ed736a9..072255d 100644 (file)
--- 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,