From: Russell King <rmk-pci@arm.linux.org.uk>

GregKH mentioned confirmed that people have been waiting for this patch.
Appologies, it had completely evaporated from my mind.

This patch introduces the "bridge_ctl" member of pci_bus, which allows
architectures to tweak the bridge control register (eg, for setting
fast back to back modes etc) in pcibios_fixup_bus().

Please note, though, that the value is only written back if
pci_setup_bridge() is called.  This will be called if an architecture
is using the generic PCI bus setup functionality in setup-bus.c.
If an architecture doesn't, then it is the responsibility of the
architecture to write this value to the bridge as appropriate.

(That said, the bridge control register is only ever changed if an
architecture is using setup-bus.c anyway, so there should be no
overall functional change.)



---

 25-akpm/drivers/pci/probe.c     |    4 ++++
 25-akpm/drivers/pci/setup-bus.c |   22 ++++++++++------------
 25-akpm/include/linux/pci.h     |    2 ++
 3 files changed, 16 insertions(+), 12 deletions(-)

diff -puN drivers/pci/probe.c~introduce-bus_bridge_ctl-member drivers/pci/probe.c
--- 25/drivers/pci/probe.c~introduce-bus_bridge_ctl-member	Fri Feb 20 16:08:52 2004
+++ 25-akpm/drivers/pci/probe.c	Fri Feb 20 16:08:52 2004
@@ -368,6 +368,8 @@ int __devinit pci_scan_bridge(struct pci
 		child = pci_alloc_child_bus(bus, dev, busnr);
 		child->primary = buses & 0xFF;
 		child->subordinate = (buses >> 16) & 0xFF;
+		child->bridge_ctl = bctl;
+
 		cmax = pci_scan_child_bus(child);
 		if (cmax > max) max = cmax;
 	} else {
@@ -402,6 +404,8 @@ int __devinit pci_scan_bridge(struct pci
 		pci_write_config_dword(dev, PCI_PRIMARY_BUS, buses);
 
 		if (!is_cardbus) {
+			child->bridge_ctl = PCI_BRIDGE_CTL_NO_ISA;
+
 			/* Now we can scan all subordinate buses... */
 			max = pci_scan_child_bus(child);
 		} else {
diff -puN drivers/pci/setup-bus.c~introduce-bus_bridge_ctl-member drivers/pci/setup-bus.c
--- 25/drivers/pci/setup-bus.c~introduce-bus_bridge_ctl-member	Fri Feb 20 16:08:52 2004
+++ 25-akpm/drivers/pci/setup-bus.c	Fri Feb 20 16:08:52 2004
@@ -43,13 +43,15 @@
 #define CARDBUS_IO_SIZE		(4096)
 #define CARDBUS_MEM_SIZE	(32*1024*1024)
 
-static int __devinit
+static void __devinit
 pbus_assign_resources_sorted(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 	struct resource *res;
 	struct resource_list head, *list, *tmp;
-	int idx, found_vga = 0;
+	int idx;
+
+	bus->bridge_ctl &= ~PCI_BRIDGE_CTL_VGA;
 
 	head.next = NULL;
 	list_for_each_entry(dev, &bus->devices, bus_list) {
@@ -57,7 +59,7 @@ pbus_assign_resources_sorted(struct pci_
 
 		if (class == PCI_CLASS_DISPLAY_VGA
 				|| class == PCI_CLASS_NOT_DEFINED_VGA)
-			found_vga = 1;
+			bus->bridge_ctl |= PCI_BRIDGE_CTL_VGA;
 
 		pdev_sort_resources(dev, &head);
 	}
@@ -70,8 +72,6 @@ pbus_assign_resources_sorted(struct pci_
 		list = list->next;
 		kfree(tmp);
 	}
-
-	return found_vga;
 }
 
 static void __devinit
@@ -211,10 +211,7 @@ pci_setup_bridge(struct pci_bus *bus)
 	/* Clear out the upper 32 bits of PREF base. */
 	pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, 0);
 
-	/* Check if we have VGA behind the bridge.
-	   Enable ISA in either case (FIXME!). */
-	l = (bus->resource[0]->flags & IORESOURCE_BUS_HAS_VGA) ? 0x0c : 0x04;
-	pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, l);
+	pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, bus->bridge_ctl);
 }
 
 /* Check whether the bridge supports optional I/O and
@@ -498,13 +495,14 @@ void __devinit
 pci_bus_assign_resources(struct pci_bus *bus)
 {
 	struct pci_bus *b;
-	int found_vga = pbus_assign_resources_sorted(bus);
 	struct pci_dev *dev;
 
-	if (found_vga) {
+	pbus_assign_resources_sorted(bus);
+
+	if (bus->bridge_ctl & PCI_BRIDGE_CTL_VGA) {
 		/* Propagate presence of the VGA to upstream bridges */
 		for (b = bus; b->parent; b = b->parent) {
-			b->resource[0]->flags |= IORESOURCE_BUS_HAS_VGA;
+			b->bridge_ctl |= PCI_BRIDGE_CTL_VGA;
 		}
 	}
 	list_for_each_entry(dev, &bus->devices, bus_list) {
diff -puN include/linux/pci.h~introduce-bus_bridge_ctl-member include/linux/pci.h
--- 25/include/linux/pci.h~introduce-bus_bridge_ctl-member	Fri Feb 20 16:08:52 2004
+++ 25-akpm/include/linux/pci.h	Fri Feb 20 16:08:52 2004
@@ -512,6 +512,8 @@ struct pci_bus {
 
 	char		name[48];
 
+	unsigned short  bridge_ctl;	/* manage NO_ISA/FBB/et al behaviors */
+	unsigned short  pad2;
 	struct device		*bridge;
 	struct class_device	class_dev;
 };

_