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>

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;

drivers/pci/slot.c

@@ -61,11 +61,11 @@ static char *pci_bus_speed_strings[] = {
 	"66 MHz PCI-X 266",	/* 0x09 */
 	"100 MHz PCI-X 266",	/* 0x0a */
 	"133 MHz PCI-X 266",	/* 0x0b */
-	NULL,			/* 0x0c */
-	NULL,			/* 0x0d */
-	NULL,			/* 0x0e */
-	NULL,			/* 0x0f */
-	NULL,			/* 0x10 */
+	"Unknown AGP",		/* 0x0c */
+	"1x AGP",		/* 0x0d */
+	"2x AGP",		/* 0x0e */
+	"4x AGP",		/* 0x0f */
+	"8x AGP",		/* 0x10 */
 	"66 MHz PCI-X 533",	/* 0x11 */
 	"100 MHz PCI-X 533",	/* 0x12 */
 	"133 MHz PCI-X 533",	/* 0x13 */

include/linux/pci.h

@@ -200,6 +200,11 @@ enum pci_bus_speed {
 	PCI_SPEED_66MHz_PCIX_266	= 0x09,
 	PCI_SPEED_100MHz_PCIX_266	= 0x0a,
 	PCI_SPEED_133MHz_PCIX_266	= 0x0b,
+	AGP_UNKNOWN			= 0x0c,
+	AGP_1X				= 0x0d,
+	AGP_2X				= 0x0e,
+	AGP_4X				= 0x0f,
+	AGP_8X				= 0x10,
 	PCI_SPEED_66MHz_PCIX_533	= 0x11,
 	PCI_SPEED_100MHz_PCIX_533	= 0x12,
 	PCI_SPEED_133MHz_PCIX_533	= 0x13,