When movable BARs are enabled, and if a bridge contains a device with fixed
BARs, the corresponding windows can't be moved too far away from their
original positions - they must still contain all the fixed 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 | |
^^^^^^^^^^^^
A fixed area of a bridge window is a range that covers all the fixed BARs
of direct children, and all the fixed area of children bridges:
| <-- root bridge window --> |
| |
| | <-- bridge window level 1 --> | |
| | ********************** fixed area ********************* | |
| | | |
| | **fixed BAR** | <-- bridge window level 2 --> | BARs | |
| | | ************* fixed area ************* | | |
| | | | | |
| | | **fixed BAR** | BARs | **fixed BAR** | | |
^^^^
To store these areas, the .fixed_range field has been added to the 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 | 23 ++++++++++++
drivers/pci/probe.c | 89 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 6 +++
3 files changed, 118 insertions(+)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 2ef72741e8e5..869398a62e5f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -297,6 +297,17 @@ bool pci_dev_bar_fixed(struct pci_dev *dev, struct resource *res);
bool pci_dev_bar_enabled(const struct pci_dev *dev, int idx);
bool pci_bus_check_bars_assigned(struct pci_bus *bus, bool complete_set);
+static inline void pci_set_fixed_range(struct resource *res)
+{
+ res->start = (resource_size_t)-1;
+ res->end = 0;
+}
+
+static inline bool pci_fixed_range_valid(struct resource *res)
+{
+ return res->start <= res->end;
+}
+
extern bool pci_init_done;
/* PCIe link information from Link Capabilities 2 */
@@ -414,6 +425,18 @@ 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)
+{
+ if (r->flags & IORESOURCE_IO)
+ return 0;
+ else if (!(r->flags & IORESOURCE_PREFETCH))
+ return 1;
+ else if (r->flags & IORESOURCE_MEM_64)
+ return 2;
+
+ return 1;
+}
+
/* 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 0c681bb767cc..2ec3f80f2711 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -589,6 +589,7 @@ 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)
@@ -605,6 +606,13 @@ 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)
+ pci_set_fixed_range(&b->fixed_range[idx]);
+
+ b->fixed_range[0].flags = IORESOURCE_IO;
+ b->fixed_range[1].flags = IORESOURCE_MEM;
+ b->fixed_range[2].flags = IORESOURCE_MEM | IORESOURCE_PREFETCH;
+
return b;
}
@@ -3338,6 +3346,86 @@ static void pci_setup_bridges(struct pci_bus *bus)
pci_setup_bridge(bus);
}
+static void pci_bus_update_fixed_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)
+ pci_set_fixed_range(&bus->fixed_range[idx]);
+
+ list_for_each_entry(dev, &bus->devices, bus_list)
+ if (dev->subordinate)
+ pci_bus_update_fixed_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];
+ struct resource *fixed_range;
+
+ if (!r->flags || (r->flags & IORESOURCE_UNSET) ||
+ !r->parent || !pci_dev_bar_fixed(dev, r))
+ continue;
+
+ idx = pci_get_bridge_resource_idx(r);
+ fixed_range = &bus->fixed_range[idx];
+ start = fixed_range->start;
+ end = fixed_range->end;
+
+ if (!pci_fixed_range_valid(fixed_range) ||
+ start > r->start)
+ start = r->start;
+
+ if (end < r->end)
+ end = r->end;
+
+ if (fixed_range->start != start ||
+ fixed_range->end != end) {
+ fixed_range->start = start;
+ fixed_range->end = end;
+ dev_dbg(&bus->dev, "Found fixed BAR %d %pR in %s, expand the fixed bridge window %d to %pR\n",
+ i, r, dev_name(&dev->dev), idx,
+ fixed_range);
+ }
+ }
+
+ if (child) {
+ for (idx = 0; idx < PCI_BRIDGE_RESOURCE_NUM; ++idx) {
+ struct resource *fixed_range = &bus->fixed_range[idx];
+ struct resource *child_fixed_range =
+ &child->fixed_range[idx];
+
+ if (!pci_fixed_range_valid(child_fixed_range))
+ continue;
+
+ start = fixed_range->start;
+ end = fixed_range->end;
+
+ if (!pci_fixed_range_valid(fixed_range) ||
+ start > child_fixed_range->start)
+ start = child_fixed_range->start;
+
+ if (end < child_fixed_range->end)
+ end = child_fixed_range->end;
+
+ if (start < fixed_range->start ||
+ end > fixed_range->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);
+ fixed_range->start = start;
+ fixed_range->end = end;
+ }
+ }
+ }
+ }
+}
+
static struct pci_dev *pci_find_next_new_device(struct pci_bus *bus)
{
struct pci_dev *dev;
@@ -3469,6 +3557,7 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
if (pci_can_move_bars) {
pci_bus_rescan_prepare(root);
+ pci_bus_update_fixed_range(root);
max = pci_scan_child_bus(root);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6a0a919a3cdb..b2d766ed425c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -596,6 +596,12 @@ 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 resources in the bridge window, this range contains
+ * the lowest start address and the highest end address of them.
+ */
+ struct resource fixed_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
