Subject: [PATCH 2/5] powerpc/pci: Change how re-assigning resouces work

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 7 Nov 2011 15:55:58 +1100

When PCI_REASSIGN_ALL_RSRC is set, we used to clear all bus resources
at the beginning of survey and re-allocate them later.

This changes it so instead, during early fixup, we mark all resources
as IORESOURCE_UNSET and move them down to be 0-based.

Later, if bus resources are still unset at the beginning of the survey,
then we clear them.

This shouldn't impact the re-assignment case on 4xx, but will enable
us to have the platform do some custom resource assignment before the
survey, by clearing individual resources IORESOURCE_UNSET bit.

Also limits the clutter in the kernel log from fixup when re-assigning
since we don't care about the offset applied to the BAR values in this
case.

Signed-off-by: Benjamin Herrenschmidt <[email-masked]>
---
 arch/powerpc/kernel/pci-common.c |   66 ++++++++++++++++++++-----------------
 1 files changed, 36 insertions(+), 30 deletions(-)

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 855969f..d34ba7e 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -920,18 +920,22 @@ static void __devinit pcibios_fixup_resources(struct pci_dev *dev)
 		struct resource *res = dev->resource + i;
 		if (!res->flags)
 			continue;
-		/* On platforms that have PCI_PROBE_ONLY set, we don't
-		 * consider 0 as an unassigned BAR value. It's technically
-		 * a valid value, but linux doesn't like it... so when we can
-		 * re-assign things, we do so, but if we can't, we keep it
-		 * around and hope for the best...
+
+		/* If we're going to re-assign everything, we mark all resources
+		 * as unset (and 0-base them). In addition, we mark BARs starting
+		 * at 0 as unset as well, except if PCI_PROBE_ONLY is also set
+		 * since in that case, we don't want to re-assign anything
 		 */
-		if (res->start == 0 && !pci_has_flag(PCI_PROBE_ONLY)) {
-			pr_debug("PCI:%s Resource %d %016llx-%016llx [%x] is unassigned\n",
-				 pci_name(dev), i,
-				 (unsigned long long)res->start,
-				 (unsigned long long)res->end,
-				 (unsigned int)res->flags);
+		if (pci_has_flag(PCI_REASSIGN_ALL_RSRC) ||
+		    (res->start == 0 && !pci_has_flag(PCI_PROBE_ONLY))) {
+			/* Only print message if not re-assigning */
+			if (!pci_has_flag(PCI_REASSIGN_ALL_RSRC))
+				pr_debug("PCI:%s Resource %d %016llx-%016llx [%x] "
+					 "is unassigned\n",
+					 pci_name(dev), i,
+					 (unsigned long long)res->start,
+					 (unsigned long long)res->end,
+					 (unsigned int)res->flags);
 			res->end -= res->start;
 			res->start = 0;
 			res->flags |= IORESOURCE_UNSET;
@@ -1041,6 +1045,16 @@ static void __devinit pcibios_fixup_bridge(struct pci_bus *bus)
 		if (i >= 3 && bus->self->transparent)
 			continue;
 
+		/* If we are going to re-assign everything, mark the resource
+		 * as unset and move it down to 0
+		 */
+		if (pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {
+			res->flags |= IORESOURCE_UNSET;
+			res->end -= res->start;
+			res->start = 0;
+			continue;
+		}
+
 		pr_debug("PCI:%s Bus rsrc %d %016llx-%016llx [%x] fixup...\n",
 			 pci_name(dev), i,
 			 (unsigned long long)res->start,\
@@ -1261,18 +1275,15 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 	pci_bus_for_each_resource(bus, res, i) {
 		if (!res || !res->flags || res->start > res->end || res->parent)
 			continue;
+
+		/* If the resource was left unset at this point, we clear it */
+		if (res->flags & IORESOURCE_UNSET)
+			goto clear_resource;
+
 		if (bus->parent == NULL)
 			pr = (res->flags & IORESOURCE_IO) ?
 				&ioport_resource : &iomem_resource;
 		else {
-			/* Don't bother with non-root busses when
-			 * re-assigning all resources. We clear the
-			 * resource flags as if they were colliding
-			 * and as such ensure proper re-allocation
-			 * later.
-			 */
-			if (pci_has_flag(PCI_REASSIGN_ALL_RSRC))
-				goto clear_resource;
 			pr = pci_find_parent_resource(bus->self, res);
 			if (pr == res) {
 				/* this happens when the generic PCI
@@ -1303,9 +1314,9 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 			if (reparent_resources(pr, res) == 0)
 				continue;
 		}
-		printk(KERN_WARNING "PCI: Cannot allocate resource region "
-		       "%d of PCI bridge %d, will remap\n", i, bus->number);
-clear_resource:
+		pr_warning("PCI: Cannot allocate resource region "
+			   "%d of PCI bridge %d, will remap\n", i, bus->number);
+	clear_resource:
 		res->start = res->end = 0;
 		res->flags = 0;
 	}
@@ -1450,16 +1461,11 @@ void __init pcibios_resource_survey(void)
 {
 	struct pci_bus *b;
 
-	/* Allocate and assign resources. If we re-assign everything, then
-	 * we skip the allocate phase
-	 */
+	/* Allocate and assign resources */
 	list_for_each_entry(b, &pci_root_buses, node)
 		pcibios_allocate_bus_resources(b);
-
-	if (!pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {
-		pcibios_allocate_resources(0);
-		pcibios_allocate_resources(1);
-	}
+	pcibios_allocate_resources(0);
+	pcibios_allocate_resources(1);
 
 	/* Before we start assigning unassigned resource, we try to reserve
 	 * the low IO area and the VGA memory area if they intersect the
-- 
1.7.7.1