PCI: Add support for AGP in cur/max bus speed

Take advantage of some gaps in the table to fit in support for AGP speeds.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 188ee9cf0605..2803ab96a98c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -437,11 +437,56 @@ void pcie_update_link_speed(struct pci_bus *bus, u16 linksta)
 }
 EXPORT_SYMBOL_GPL(pcie_update_link_speed);
 
+static unsigned char agp_speeds[] = {
+        AGP_UNKNOWN,
+        AGP_1X,
+        AGP_2X,
+        AGP_4X,
+        AGP_8X
+};
+
+static enum pci_bus_speed agp_speed(int agp3, int agpstat)
+{
+        int index = 0;
+
+        if (agpstat & 4)
+                index = 3;
+        else if (agpstat & 2)
+                index = 2;
+        else if (agpstat & 1)
+                index = 1;
+        else
+                goto out;
+        
+        if (agp3) {
+                index += 2;
+                if (index == 5)
+                        index = 0;
+        }
+
+ out:
+        return agp_speeds[index];
+}
+
+
 static void pci_set_bus_speed(struct pci_bus *bus)
 {
         struct pci_dev *bridge = bus->self;
         int pos;
 
+        pos = pci_find_capability(bridge, PCI_CAP_ID_AGP);
+        if (!pos)
+                pos = pci_find_capability(bridge, PCI_CAP_ID_AGP3);
+        if (pos) {
+                u32 agpstat, agpcmd;
+
+                pci_read_config_dword(bridge, pos + PCI_AGP_STATUS, &agpstat);
+                bus->max_bus_speed = agp_speed(agpstat & 8, agpstat & 7);
+
+                pci_read_config_dword(bridge, pos + PCI_AGP_COMMAND, &agpcmd);
+                bus->cur_bus_speed = agp_speed(agpstat & 8, agpcmd & 7);
+        }
+
         pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX);
         if (pos) {
                 u16 status;