When movable BARs are enabled, and if a bridge contains a device with fixed
(IORESOURCE_PCI_FIXED) or immovable BARs, the corresponding windows can't
be moved too far away from their original positions - they must still
contain all the fixed/immovable BARs, like that:
1) Window position before a bus rescan:
| <-- root bridge window --> |
| |
| | <-- bridge window --> | |
| | movable BARs | **fixed BAR** | |
^^^^^^^^^^^^
2) Possible valid outcome after rescan and move:
| <-- root bridge window --> |
| |
| | <-- bridge window --> | |
| | **fixed BAR** | Movable BARs | |
^^^^^^^^^^^^
An immovable area of a bridge window is a range that covers all the fixed
and immovable BARs of direct children, and all the fixed area of children
bridges:
| <-- root bridge window --> |
| |
| | <-- bridge window level 1 --> | |
| | ******************** immovable area ******************* | |
| | | |
| | **fixed BAR** | <-- bridge window level 2 --> | BARs | |
| | | *********** immovable area *********** | | |
| | | | | |
| | | **fixed BAR** | BARs | **fixed BAR** | | |
^^^^
To store these areas, the .immovable_range field has been added to struct
pci_bus for every bridge window type: IO, MEM and PREFETCH. It is filled
recursively from leaves to the root before a rescan.
Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
---
drivers/pci/pci.h | 14 ++++++++
drivers/pci/probe.c | 88 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 6 ++++
3 files changed, 108 insertions(+)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 3b4c982772d3..5f2051c8531c 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -404,6 +404,20 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
return dev->error_state == pci_channel_io_perm_failure;
}
+static inline int pci_get_bridge_resource_idx(struct resource *r)
+{
+ int idx = 1;
+
+ if (r->flags & IORESOURCE_IO)
+ idx = 0;
+ else if (!(r->flags & IORESOURCE_PREFETCH))
+ idx = 1;
+ else if (r->flags & IORESOURCE_MEM_64)
+ idx = 2;
+
+ return idx;
+}
+
/* pci_dev priv_flags */
#define PCI_DEV_ADDED 0
#define PCI_DEV_DISABLED_BARS 1
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1e8bbf5c99f6..bb584038d5b4 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -546,6 +546,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
{
struct pci_bus *b;
+ int idx;
b = kzalloc(sizeof(*b), GFP_KERNEL);
if (!b)
@@ -562,6 +563,11 @@ static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
if (parent)
b->domain_nr = parent->domain_nr;
#endif
+ for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+ b->immovable_range[idx].start = 0;
+ b->immovable_range[idx].end = 0;
+ }
+
return b;
}
@@ -3228,6 +3234,87 @@ static void pci_setup_bridges(struct pci_bus *bus)
pci_setup_bridge(bus);
}
+static void pci_bus_update_immovable_range(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+ int idx;
+ resource_size_t start, end;
+
+ for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+ bus->immovable_range[idx].start = 0;
+ bus->immovable_range[idx].end = 0;
+ }
+
+ list_for_each_entry(dev, &bus->devices, bus_list)
+ if (dev->subordinate)
+ pci_bus_update_immovable_range(dev->subordinate);
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ int i;
+ struct pci_bus *child = dev->subordinate;
+
+ for (i = 0; i < PCI_BRIDGE_RESOURCES; ++i) {
+ struct resource *r = &dev->resource[i];
+
+ if (!r->flags || (r->flags & IORESOURCE_UNSET) || !r->parent)
+ continue;
+
+ if (!pci_dev_bar_movable(dev, r)) {
+ idx = pci_get_bridge_resource_idx(r);
+ start = bus->immovable_range[idx].start;
+ end = bus->immovable_range[idx].end;
+
+ if (!start || start > r->start)
+ start = r->start;
+ if (end < r->end)
+ end = r->end;
+
+ if (bus->immovable_range[idx].start != start ||
+ bus->immovable_range[idx].end != end) {
+ dev_dbg(&bus->dev, "Found fixed BAR%d 0x%llx-0x%llx in %s, expand the fixed bridge window %d to 0x%llx-0x%llx\n",
+ i,
+ (unsigned long long)r->start,
+ (unsigned long long)r->end,
+ dev_name(&dev->dev), idx,
+ (unsigned long long)start,
+ (unsigned long long)end);
+ bus->immovable_range[idx].start = start;
+ bus->immovable_range[idx].end = end;
+ }
+ }
+ }
+
+ if (child) {
+ for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+ struct resource *child_immovable_range =
+ &child->immovable_range[idx];
+
+ if (child_immovable_range->start >=
+ child_immovable_range->end)
+ continue;
+
+ start = bus->immovable_range[idx].start;
+ end = bus->immovable_range[idx].end;
+
+ if (!start || start > child_immovable_range->start)
+ start = child_immovable_range->start;
+ if (end < child_immovable_range->end)
+ end = child_immovable_range->end;
+
+ if (start < bus->immovable_range[idx].start ||
+ end > bus->immovable_range[idx].end) {
+ dev_dbg(&bus->dev, "Expand the fixed bridge window %d from %s to 0x%llx-0x%llx\n",
+ idx, dev_name(&child->dev),
+ (unsigned long long)start,
+ (unsigned long long)end);
+ bus->immovable_range[idx].start = start;
+ bus->immovable_range[idx].end = end;
+ }
+ }
+ }
+ }
+}
+
static struct pci_dev *pci_find_next_new_device(struct pci_bus *bus)
{
struct pci_dev *dev;
@@ -3324,6 +3411,7 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
if (pci_can_move_bars) {
pci_bus_rescan_prepare(root);
+ pci_bus_update_immovable_range(root);
pci_bus_release_root_bridge_resources(root);
max = pci_scan_child_bus(root);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a8f2c26757fe..d6eb498f7997 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -582,6 +582,12 @@ struct pci_bus {
struct list_head resources; /* Address space routed to this bus */
struct resource busn_res; /* Bus numbers routed to this bus */
+ /*
+ * If there are fixed or immovable resources in the bridge window, this range
+ * contains the lowest start address and highest end address of them.
+ */
+ struct resource immovable_range[PCI_BRIDGE_RESOURCE_NUM];
+
struct pci_ops *ops; /* Configuration access functions */
struct msi_controller *msi; /* MSI controller */
void *sysdata; /* Hook for sys-specific extension */
--
2.24.1
