diff mbox series

[RFC,v2,12/21] PCI: Calculate boundaries for bridge windows

Message ID 20190111153707.10140-13-s.miroshnichenko@yadro.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show
Series PCI: Allow BAR movement during hotplug | expand

Commit Message

Sergei Miroshnichenko Jan. 11, 2019, 3:36 p.m. UTC
If a bridge window contains fixed areas (there are PCIe devices with
immovable BARs located on this bus), this window must be allocated
within the bound memory area, limited by windows size and by address
range of fixed resources, calculated as follows:

           | <--     bus's fixed_range_hard   --> |
  | <--  fixed_range_hard.end - window size   --> |
           | <--  fixed_range_hard.start + window size   --> |
  | <--                bus's fixed_range_soft            --> |

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/setup-bus.c | 56 +++++++++++++++++++++++++++++++++++++++++
 include/linux/pci.h     |  4 ++-
 2 files changed, 59 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 15554c80b745..09226a201119 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1838,6 +1838,61 @@  static enum enable_type pci_realloc_detect(struct pci_bus *bus,
 }
 #endif
 
+static void pci_bus_update_fixed_range_soft(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+	struct pci_bus *parent = bus->parent;
+	int idx;
+
+	list_for_each_entry(dev, &bus->devices, bus_list)
+		if (dev->subordinate)
+			pci_bus_update_fixed_range_soft(dev->subordinate);
+
+	if (!parent || !bus->self)
+		return;
+
+	for (idx = 0; idx < ARRAY_SIZE(bus->fixed_range_hard); ++idx) {
+		struct resource *r;
+		resource_size_t soft_start, soft_end;
+		resource_size_t hard_start = bus->fixed_range_hard[idx].start;
+		resource_size_t hard_end = bus->fixed_range_hard[idx].end;
+
+		if (hard_start > hard_end)
+			continue;
+
+		r = bus->resource[idx];
+
+		soft_start = hard_end - resource_size(r) + 1;
+		soft_end = hard_start + resource_size(r) - 1;
+
+		if (soft_start > hard_start)
+			soft_start = hard_start;
+
+		if (soft_end < hard_end)
+			soft_end = hard_end;
+
+		list_for_each_entry(dev, &parent->devices, bus_list) {
+			struct pci_bus *sibling = dev->subordinate;
+			resource_size_t s_start, s_end;
+
+			if (!sibling || sibling == bus)
+				continue;
+
+			s_start = sibling->fixed_range_hard[idx].start;
+			s_end = sibling->fixed_range_hard[idx].end;
+
+			if (s_start > s_end)
+				continue;
+
+			if (s_end < hard_start && s_end > soft_start)
+				soft_start = s_end;
+		}
+
+		bus->fixed_range_soft[idx].start = soft_start;
+		bus->fixed_range_soft[idx].end = soft_end;
+	}
+}
+
 /*
  * first try will not touch pci bridge res
  * second and later try will clear small leaf bridge res
@@ -1876,6 +1931,7 @@  void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
 	/* Depth first, calculate sizes and alignments of all
 	   subordinate buses. */
 	__pci_bus_size_bridges(bus, add_list);
+	pci_bus_update_fixed_range_soft(bus);
 
 	/* Depth last, allocate resources and update the hardware. */
 	__pci_bus_assign_resources(bus, add_list, &fail_head);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 11199717e4f5..161a9b8a854e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -570,9 +570,11 @@  struct pci_bus {
 
 	/*
 	 * If there are fixed resources in the bridge window, the hard range
-	 * contains the lowest and the highest addresses of them.
+	 * contains the lowest and the highest addresses of them, and this
+	 * bridge window must reside within the soft range.
 	 */
 	struct resource fixed_range_hard[PCI_BRIDGE_RESOURCE_NUM];
+	struct resource fixed_range_soft[PCI_BRIDGE_RESOURCE_NUM];
 
 	struct pci_ops	*ops;		/* Configuration access functions */
 	struct msi_controller *msi;	/* MSI controller */