I'm trying to unify the way we handle unassigned PCI BARs, i.e., resources
where we know the type and size, but we haven't assigned an address yet.
The PCI core and the various architectures don't really have a consistent
way of dealing with these.
Many places currently use "res->start == 0" to indicate unassigned
resources. I don't think that's a good idea in general, because it's
possible for a resource to actually start at zero. Zero is also a
perfectly good BAR value, especially for a host bridge that translates
addresses, so I want to support that, too.
The IORESOURCE_UNSET flag exists already, but is hardly used at all. In
drivers/pci, we set it for an obscure error case, and clear it when
updating a BAR. The microblaze and powerpc architectures use it the same
way I want to use it here: to indicate a resource with no assigned address.
Here's the outline of what this series does:
- Add resource_contains(): true iff r1 contains r2 (for minor cleanup)
- Make %pR print resource size, not address, when IORESOURCE_UNSET
- Stop advertising pci_find_parent_resource() for use in allocation
- Mark PCI resources IORESOURCE_UNSET when BIOS left decoding disabled
- Mark PCI resources IORESOURCE_UNSET while we're trying to assign addresses
- Don't enable PCI decoding when no address has been assigned to BARs
It might be too aggressive to ignore the initial value of a BAR and try to
reassign it when the BIOS left decoding disabled. If the BIOS left
decoding *enabled*, we can have some confidence that the BAR value is
valid. It's possible the BAR is also valid even if the BIOS turned off
decoding. We could conceivably try to use BAR values that are inside
upstream bridge windows, even if the BAR was initially disabled. But this
first pass just ignores the values in BARs that are disabled.
I welcome any comments :)
---
Bjorn Helgaas (9):
resource: Add resource_contains()
vsprintf: Add support for IORESOURCE_UNSET in %pR
PCI: Remove pci_find_parent_resource() use for allocation
PCI: Mark resources as IORESOURCE_UNSET if we can't assign them
PCI: Don't clear IORESOURCE_UNSET when updating BAR
PCI: Check IORESOURCE_UNSET before updating BAR
PCI: Don't try to claim IORESOURCE_UNSET resources
PCI: Ignore BAR contents when firmware left decoding disabled
PCI: Don't enable decoding if BAR hasn't been assigned an address
drivers/pci/host-bridge.c | 8 --------
drivers/pci/pci.c | 41 +++++++++++++++++++++++++----------------
drivers/pci/probe.c | 8 +++++++-
drivers/pci/quirks.c | 5 +++++
drivers/pci/rom.c | 2 ++
drivers/pci/setup-res.c | 37 +++++++++++++++++++++++++------------
include/linux/ioport.h | 12 +++++++++++-
kernel/resource.c | 8 ++------
lib/vsprintf.c | 13 +++++++++----
9 files changed, 86 insertions(+), 48 deletions(-)
We have two identical copies of resource_contains() already, and more
places that could use it. This moves it to ioport.h where it can be
shared.
resource_contains(struct resource *r1, struct resource *r2) returns true
iff r1 and r2 are the same type (most callers already checked this
separately) and the r1 address range completely contains r2.
In addition, the new resource_contains() checks that both r1 and r2 have
addresses assigned to them. If a resource is IORESOURCE_UNSET, it doesn't
have a valid address and can't contain or be contained by another resource.
Some callers already check this or for res->start.
No functional change.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/host-bridge.c | 8 --------
include/linux/ioport.h | 10 ++++++++++
kernel/resource.c | 8 ++------
3 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 06ace6248c61..47aaf22d814e 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -32,11 +32,6 @@ void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
bridge->release_data = release_data;
}
-static bool resource_contains(struct resource *res1, struct resource *res2)
-{
- return res1->start <= res2->start && res1->end >= res2->end;
-}
-
void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
struct resource *res)
{
@@ -45,9 +40,6 @@ void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
resource_size_t offset = 0;
list_for_each_entry(window, &bridge->windows, list) {
- if (resource_type(res) != resource_type(window->res))
- continue;
-
if (resource_contains(window->res, res)) {
offset = window->offset;
break;
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 89b7c24a36e9..9fcaac8bc4f6 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -169,6 +169,16 @@ static inline unsigned long resource_type(const struct resource *res)
{
return res->flags & IORESOURCE_TYPE_BITS;
}
+/* True iff r1 completely contains r2 */
+static inline bool resource_contains(struct resource *r1, struct resource *r2)
+{
+ if (resource_type(r1) != resource_type(r2))
+ return false;
+ if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
+ return false;
+ return r1->start <= r2->start && r1->end >= r2->end;
+}
+
/* Convenience shorthand with allocation */
#define request_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), 0)
diff --git a/kernel/resource.c b/kernel/resource.c
index 3f285dce9347..a8344dda7049 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -432,11 +432,6 @@ static void resource_clip(struct resource *res, resource_size_t min,
res->end = max;
}
-static bool resource_contains(struct resource *res1, struct resource *res2)
-{
- return res1->start <= res2->start && res1->end >= res2->end;
-}
-
/*
* Find empty slot in the resource tree with the given range and
* alignment constraints
@@ -471,10 +466,11 @@ static int __find_resource(struct resource *root, struct resource *old,
arch_remove_reservations(&tmp);
/* Check for overflow after ALIGN() */
- avail = *new;
avail.start = ALIGN(tmp.start, constraint->align);
avail.end = tmp.end;
+ avail.flags = new->flags & ~IORESOURCE_UNSET;
if (avail.start >= tmp.start) {
+ alloc.flags = avail.flags;
alloc.start = constraint->alignf(constraint->alignf_data, &avail,
size, constraint->align);
alloc.end = alloc.start + size - 1;
Sometimes we have a struct resource where we know the type (MEM/IO/etc.)
and the size, but we haven't assigned address space for it. The
IORESOURCE_UNSET flag is a way to indicate this situation. For these
"unset" resources, the start address is meaningless, so print only the
size, e.g.,
- pci 0000:0c:00.0: reg 184: [mem 0x00000000-0x00001fff 64bit]
+ pci 0000:0c:00.0: reg 184: [mem size 0x2000 64bit]
For %pr (printing with raw flags), we still print the address range,
because %pr is mostly used for debugging anyway.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
include/linux/ioport.h | 2 +-
lib/vsprintf.c | 13 +++++++++----
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 9fcaac8bc4f6..5e3a906cc089 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -51,7 +51,7 @@ struct resource {
#define IORESOURCE_EXCLUSIVE 0x08000000 /* Userland may not map this resource */
#define IORESOURCE_DISABLED 0x10000000
-#define IORESOURCE_UNSET 0x20000000
+#define IORESOURCE_UNSET 0x20000000 /* No address assigned yet */
#define IORESOURCE_AUTO 0x40000000
#define IORESOURCE_BUSY 0x80000000 /* Driver has marked this resource busy */
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 185b6d300ebc..c14669f4ffc4 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -719,10 +719,15 @@ char *resource_string(char *buf, char *end, struct resource *res,
specp = &mem_spec;
decode = 0;
}
- p = number(p, pend, res->start, *specp);
- if (res->start != res->end) {
- *p++ = '-';
- p = number(p, pend, res->end, *specp);
+ if (decode && res->flags & IORESOURCE_UNSET) {
+ p = string(p, pend, "size ", str_spec);
+ p = number(p, pend, res->end - res->start + 1, *specp);
+ } else {
+ p = number(p, pend, res->start, *specp);
+ if (res->start != res->end) {
+ *p++ = '-';
+ p = number(p, pend, res->end, *specp);
+ }
}
if (decode) {
if (res->flags & IORESOURCE_MEM_64)
Check to make sure we don't update a BAR with an address we haven't
assigned.
If we haven't assigned an address to a resource, we shouldn't write it to a
BAR. This isn't a problem for the usual path via pci_assign_resource(),
which clears IORESOURCE_UNSET before calling pci_update_resource(), but
paths like pci_restore_bars() can call this for resources we haven't
assigned.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/setup-res.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 725d5b28398c..7f7652176fc5 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -44,6 +44,9 @@ void pci_update_resource(struct pci_dev *dev, int resno)
if (!res->flags)
return;
+ if (res->flags & IORESOURCE_UNSET)
+ return;
+
/*
* Ignore non-moveable resources. This might be legacy resources for
* which no functional BAR register exists or another important
If the IORESOURCE_UNSET bit is set, it means we haven't assigned an address
yet, so don't try to claim the region.
Also, make the error messages more uniform and add info about which BAR is
involved.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/setup-res.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 7f7652176fc5..6e443135ba24 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -111,18 +111,23 @@ int pci_claim_resource(struct pci_dev *dev, int resource)
struct resource *res = &dev->resource[resource];
struct resource *root, *conflict;
+ if (res->flags & IORESOURCE_UNSET) {
+ dev_info(&dev->dev, "can't claim BAR %d %pR: no address assigned\n",
+ resource, res);
+ return -EINVAL;
+ }
+
root = pci_find_parent_resource(dev, res);
if (!root) {
- dev_info(&dev->dev, "no compatible bridge window for %pR\n",
- res);
+ dev_info(&dev->dev, "can't claim BAR %d %pR: no compatible bridge window\n",
+ resource, res);
return -EINVAL;
}
conflict = request_resource_conflict(root, res);
if (conflict) {
- dev_info(&dev->dev,
- "address space collision: %pR conflicts with %s %pR\n",
- res, conflict->name, conflict);
+ dev_info(&dev->dev, "can't claim BAR %d %pR: address conflict with %s %pR\n",
+ resource, res, conflict->name, conflict);
return -EBUSY;
}
Don't rely on BAR contents when the command register says the BAR is
disabled.
If we receive a PCI device from firmware (or a hot-added device that was
just powered up) with the MEMORY or IO enable bits in the PCI command
register cleared, there's no reason to believe the BARs contain valid
addresses.
In that case, we still know the type and size of the BAR, but this
patch marks the resource as "unset" so we have a chance to reassign it.
Historically, we often used "BAR == 0" to decide the BAR is invalid. But 0
is a legal BAR value, especially if the host bridge translates addresses,
so I think it's better to decide based on the PCI command register, and
store the conclusion in the IORESOURCE_UNSET bit.
Reference: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=679545
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=48451
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/probe.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6e34498ec9f0..02654b5ec1b9 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -177,9 +177,10 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
+ pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
+
/* No printks while decoding is disabled! */
if (!dev->mmio_always_on) {
- pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
if (orig_cmd & PCI_COMMAND_DECODE_ENABLE) {
pci_write_config_word(dev, PCI_COMMAND,
orig_cmd & ~PCI_COMMAND_DECODE_ENABLE);
@@ -215,9 +216,13 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
if (res->flags & IORESOURCE_IO) {
l &= PCI_BASE_ADDRESS_IO_MASK;
mask = PCI_BASE_ADDRESS_IO_MASK & (u32) IO_SPACE_LIMIT;
+ if (!(orig_cmd & PCI_COMMAND_IO))
+ res->flags |= IORESOURCE_UNSET;
} else {
l &= PCI_BASE_ADDRESS_MEM_MASK;
mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
+ if (!(orig_cmd & PCI_COMMAND_MEMORY))
+ res->flags |= IORESOURCE_UNSET;
}
} else {
res->flags |= (l & IORESOURCE_ROM_ENABLE);
@@ -252,6 +257,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
/* Address above 32-bit boundary; disable the BAR */
pci_write_config_dword(dev, pos, 0);
pci_write_config_dword(dev, pos + 4, 0);
+ res->flags |= IORESOURCE_UNSET;
region.start = 0;
region.end = sz64;
bar_disabled = true;
Don't enable memory or I/O decoding if we haven't assigned or claimed the
BAR's resource.
If we enable decoding for a BAR that hasn't been assigned an address, we'll
likely cause bus conflicts. This declines to enable decoding for resources
with IORESOURCE_UNSET.
Note that drivers can use pci_enable_device_io() or pci_enable_device_mem()
if they only care about specific types of BARs. In that case, we don't
bother checking whether the corresponding resources are assigned or
claimed.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/setup-res.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 6e443135ba24..7eed671d5586 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -343,9 +343,15 @@ int pci_enable_resources(struct pci_dev *dev, int mask)
(!(r->flags & IORESOURCE_ROM_ENABLE)))
continue;
+ if (r->flags & IORESOURCE_UNSET) {
+ dev_err(&dev->dev, "can't enable device: BAR %d %pR not assigned\n",
+ i, r);
+ return -EINVAL;
+ }
+
if (!r->parent) {
- dev_err(&dev->dev, "device not available "
- "(can't reserve %pR)\n", r);
+ dev_err(&dev->dev, "can't enable device: BAR %d %pR not claimed\n",
+ i, r);
return -EINVAL;
}
Clear IORESOURCE_UNSET when we assign an address to a resource, not when we
write the address to the BAR.
Also, drop the "BAR %d: set to %pR" message; this is mostly redundant with
the "BAR %d: assigned %pR" message from pci_assign_resource().
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/setup-res.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 0474b0217fdf..725d5b28398c 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -101,11 +101,6 @@ void pci_update_resource(struct pci_dev *dev, int resno)
if (disable)
pci_write_config_word(dev, PCI_COMMAND, cmd);
-
- res->flags &= ~IORESOURCE_UNSET;
- dev_dbg(&dev->dev, "BAR %d: set to %pR (PCI address [%#llx-%#llx])\n",
- resno, res, (unsigned long long)region.start,
- (unsigned long long)region.end);
}
int pci_claim_resource(struct pci_dev *dev, int resource)
When assigning addresses to resources, mark them with IORESOURCE_UNSET
before we start and clear IORESOURCE_UNSET if assignment is successful.
That means that if we print the resource during assignment, we will show
the size, not a meaningless address.
Also, clear IORESOURCE_UNSET if we do assign an address, so we print the
address when it is valid.
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/pci.c | 2 ++
drivers/pci/quirks.c | 5 +++++
drivers/pci/rom.c | 2 ++
drivers/pci/setup-res.c | 4 ++++
4 files changed, 13 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 99293fa40db9..dc9ce62be7aa 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4244,6 +4244,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
"Rounding up size of resource #%d to %#llx.\n",
i, (unsigned long long)size);
}
+ r->flags |= IORESOURCE_UNSET;
r->end = size - 1;
r->start = 0;
}
@@ -4257,6 +4258,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
r = &dev->resource[i];
if (!(r->flags & IORESOURCE_MEM))
continue;
+ r->flags |= IORESOURCE_UNSET;
r->end = resource_size(r) - 1;
r->start = 0;
}
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 5cb726c193de..6e596ab77fb9 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -296,6 +296,7 @@ static void quirk_s3_64M(struct pci_dev *dev)
struct resource *r = &dev->resource[0];
if ((r->start & 0x3ffffff) || r->end != r->start + 0x3ffffff) {
+ r->flags |= IORESOURCE_UNSET;
r->start = 0;
r->end = 0x3ffffff;
}
@@ -937,6 +938,8 @@ DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_FE_GATE_700C
static void quirk_dunord(struct pci_dev *dev)
{
struct resource *r = &dev->resource [1];
+
+ r->flags |= IORESOURCE_UNSET;
r->start = 0;
r->end = 0xffffff;
}
@@ -1740,6 +1743,7 @@ static void quirk_tc86c001_ide(struct pci_dev *dev)
struct resource *r = &dev->resource[0];
if (r->start & 0x8) {
+ r->flags |= IORESOURCE_UNSET;
r->start = 0;
r->end = 0xf;
}
@@ -1769,6 +1773,7 @@ static void quirk_plx_pci9050(struct pci_dev *dev)
dev_info(&dev->dev,
"Re-allocating PLX PCI 9050 BAR %u to length 256 to avoid bit 7 bug\n",
bar);
+ r->flags |= IORESOURCE_UNSET;
r->start = 0;
r->end = 0xff;
}
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index 5d595724e5f4..c1839450d4d6 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -197,8 +197,10 @@ void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
void pci_cleanup_rom(struct pci_dev *pdev)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
+
if (res->flags & IORESOURCE_ROM_COPY) {
kfree((void*)(unsigned long)res->start);
+ res->flags |= IORESOURCE_UNSET;
res->flags &= ~IORESOURCE_ROM_COPY;
res->start = 0;
res->end = 0;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 5c060b152ce6..0474b0217fdf 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -263,6 +263,7 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
resource_size_t align, size;
int ret;
+ res->flags |= IORESOURCE_UNSET;
align = pci_resource_alignment(dev, res);
if (!align) {
dev_info(&dev->dev, "BAR %d: can't assign %pR "
@@ -282,6 +283,7 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
ret = pci_revert_fw_address(res, dev, resno, size);
if (!ret) {
+ res->flags &= ~IORESOURCE_UNSET;
res->flags &= ~IORESOURCE_STARTALIGN;
dev_info(&dev->dev, "BAR %d: assigned %pR\n", resno, res);
if (resno < PCI_BRIDGE_RESOURCES)
@@ -297,6 +299,7 @@ int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsiz
resource_size_t new_size;
int ret;
+ res->flags |= IORESOURCE_UNSET;
if (!res->parent) {
dev_info(&dev->dev, "BAR %d: can't reassign an unassigned resource %pR "
"\n", resno, res);
@@ -307,6 +310,7 @@ int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsiz
new_size = resource_size(res) + addsize;
ret = _pci_assign_resource(dev, resno, new_size, min_align);
if (!ret) {
+ res->flags &= ~IORESOURCE_UNSET;
res->flags &= ~IORESOURCE_STARTALIGN;
dev_info(&dev->dev, "BAR %d: reassigned %pR\n", resno, res);
if (resno < PCI_BRIDGE_RESOURCES)
If the resource hasn't been allocated yet, pci_find_parent_resource() is
documented as returning the region "where it should be allocated from."
This is impossible in general because there may be several candidates: a
prefetchable BAR can be put in either a prefetchable or non-prefetchable
window, a transparent bridge may have overlapping positively- and
subtractively-decoded windows, and a root bus may have several windows of
the same type.
Allocation should be done by pci_bus_alloc_resource(), which iterates
through all bus resources and looks for the best match, e.g., one with the
desired prefetchability attributes, and falls back to less-desired
possibilities.
The only valid use of pci_find_parent_resource() is to find the parent of
an already-allocated resource so we can claim it via request_resource(),
and all we need for that is a bus region of the correct type that contains
the resource.
Note that like 8c8def26bfaa ("PCI: allow matching of prefetchable resources
to non-prefetchable windows"), this depends on pci_bus_for_each_resource()
iterating through positively-decoded regions before subtractively-decoded
ones. We prefer not to return a subtractively-decoded region because
requesting from it will likely conflict with the overlapping positively-
decoded window (see Launchpad report below).
Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/424142
Signed-off-by: Bjorn Helgaas <[email protected]>
CC: Linus Torvalds <[email protected]>
---
drivers/pci/pci.c | 39 +++++++++++++++++++++++----------------
1 file changed, 23 insertions(+), 16 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1febe90831b4..99293fa40db9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -401,33 +401,40 @@ EXPORT_SYMBOL_GPL(pci_find_ht_capability);
* @res: child resource record for which parent is sought
*
* For given resource region of given device, return the resource
- * region of parent bus the given region is contained in or where
- * it should be allocated from.
+ * region of parent bus the given region is contained in.
*/
struct resource *
pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
{
const struct pci_bus *bus = dev->bus;
+ struct resource *r;
int i;
- struct resource *best = NULL, *r;
pci_bus_for_each_resource(bus, r, i) {
if (!r)
continue;
- if (res->start && !(res->start >= r->start && res->end <= r->end))
- continue; /* Not contained */
- if ((res->flags ^ r->flags) & (IORESOURCE_IO | IORESOURCE_MEM))
- continue; /* Wrong type */
- if (!((res->flags ^ r->flags) & IORESOURCE_PREFETCH))
- return r; /* Exact match */
- /* We can't insert a non-prefetch resource inside a prefetchable parent .. */
- if (r->flags & IORESOURCE_PREFETCH)
- continue;
- /* .. but we can put a prefetchable resource inside a non-prefetchable one */
- if (!best)
- best = r;
+ if (res->start && resource_contains(r, res)) {
+
+ /*
+ * If the window is prefetchable but the BAR is
+ * not, the allocator made a mistake.
+ */
+ if (r->flags & IORESOURCE_PREFETCH &&
+ !(res->flags & IORESOURCE_PREFETCH))
+ return NULL;
+
+ /*
+ * If we're below a transparent bridge, there may
+ * be both a positively-decoded aperture and a
+ * subtractively-decoded region that contain the BAR.
+ * We want the positively-decoded one, so this depends
+ * on pci_bus_for_each_resource() giving us those
+ * first.
+ */
+ return r;
+ }
}
- return best;
+ return NULL;
}
/**