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;