[rtems commit] pc386: scan all functions of multi-function PCI devices

[Gedare Bloom]

Module:    rtems
Branch:    master
Commit:    2573e698d1a5f2e481b5b0520a949c4f590bacbd
Changeset: http://git.rtems.org/rtems/commit/?id=2573e698d1a5f2e481b5b0520a949c4f590bacbd

Author:    Till Strauman <strauman at slac.stanford.edu>
Date:      Tue Dec 23 22:27:25 2014 -0500

pc386: scan all functions of multi-function PCI devices

 The current algorithm scans all PCI busses (0..ff)
 and all devices (0..31) on each bus for bridges
 and determines the maximum of all subordinate
 busses encountered.

 However, the algorithm does not scan all functions
 present in multi-function devices -- I have a PCI express
 root complex (82801H) where multiple (non-zero index)
 functions are 'PCI bridges' whose subordinate bus number is
 missed by the original algorithm.

 This commit makes sure that the scan
 is extended to all functions of multi-function
 devices.

 See #2067

---

 c/src/lib/libbsp/i386/shared/pci/pcibios.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/c/src/lib/libbsp/i386/shared/pci/pcibios.c b/c/src/lib/libbsp/i386/shared/pci/pcibios.c
index 7767e7c..870721f 100644
--- a/c/src/lib/libbsp/i386/shared/pci/pcibios.c
+++ b/c/src/lib/libbsp/i386/shared/pci/pcibios.c
@@ -228,6 +228,8 @@ pci_bus_count(void)
   if ( ucBusCount == 0xff ) {
     unsigned char bus;
     unsigned char dev;
+    unsigned char fun;
+    unsigned char nfn;
     unsigned char hd = 0;
     uint32_t d = 0;
     int sig;
@@ -239,15 +241,29 @@ pci_bus_count(void)
         sig = PCIB_DEVSIG_MAKE(bus,dev,0);
         pcib_conf_read32(sig, PCI_VENDOR_ID, &d);
 
-        if ( d != -1 ) {
-           pcib_conf_read32(sig, PCI_CLASS_REVISION, &d);
+        if ( -1 == d ) {
+          continue;
+        }
+
+        pcib_conf_read8(sig, PCI_HEADER_TYPE, &hd);
+        nfn = (hd & 0x80) ? PCI_MAX_FUNCTIONS : 1;
+
+        for ( fun=0; fun<nfn; fun++ ) {
+
+          sig = PCIB_DEVSIG_MAKE(bus,dev,fun);
+          pcib_conf_read32(sig, PCI_VENDOR_ID, &d);
+          if ( -1 == d )
+            continue;
+
+          pcib_conf_read32(sig, PCI_CLASS_REVISION, &d);
+
+          if ( (d >> 16) == PCI_CLASS_BRIDGE_PCI ) {
+            pcib_conf_read8(sig, PCI_SUBORDINATE_BUS, &hd);
 
-           if ( (d >> 16) == PCI_CLASS_BRIDGE_PCI ) {
-             pcib_conf_read8(sig, PCI_SUBORDINATE_BUS, &hd);
+            if ( hd > ucBusCount )
+              ucBusCount = hd;
+          }
 
-             if ( hd > ucBusCount )
-               ucBusCount = hd;
-           }
         }
       }
     }