linux-toradex.git/drivers/pci/pci-sysfs.c, branch v2.6.32.45

PCI: return correct value when writing to the "reset" attribute

2011-03-27T18:30:32+00:00

commit 447c5dd7338638f526e9bcf7dcf69b4da5835c7d upstream.

A successful write() to the "reset" sysfs attribute should return the
number of bytes written, not 0. Otherwise userspace (bash) retries the
write over and over again.

Acked-by: Michael S. Tsirkin 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Michal Schmidt 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

PCI: sysfs: Fix failure path for addition of "vpd" attribute

2011-03-23T20:16:50+00:00

commit 0f12a4e29368a9476076515881d9ef4e5876c6e2 upstream.

Commit 280c73d ("PCI: centralize the capabilities code in
pci-sysfs.c") changed the initialisation of the "rom" and "vpd"
attributes, and made the failure path for the "vpd" attribute
incorrect.  We must free the new attribute structure (attr), but
instead we currently free dev->vpd->attr.  That will normally be NULL,
resulting in a memory leak, but it might be a stale pointer, resulting
in a double-free.

Found by inspection; compile-tested only.

Signed-off-by: Ben Hutchings 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

PCI: fix offset check for sysfs mmapped files

2010-12-09T21:26:53+00:00

commit 8c05cd08a7504b855c265263e84af61aabafa329 upstream.

I just loaded 2.6.37-rc2 on my machines, and I noticed that X no longer starts.
Running an strace of the X server shows that it's doing this:

open("/sys/bus/pci/devices/0000:07:00.0/resource0", O_RDWR) = 10
mmap(NULL, 16777216, PROT_READ|PROT_WRITE, MAP_SHARED, 10, 0) = -1 EINVAL (Invalid argument)

This code seems to be asking for a shared read/write mapping of 16MB worth of
BAR0 starting at file offset 0, and letting the kernel assign a starting
address.  Unfortunately, this -EINVAL causes X not to start.  Looking into
dmesg, there's a complaint like so:

process "Xorg" tried to map 0x01000000 bytes at page 0x00000000 on 0000:07:00.0 BAR 0 (start 0x        96000000, size 0x         1000000)

...with the following code in pci_mmap_fits:

	pci_start = (mmap_api == PCI_MMAP_SYSFS) ?
		pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0;
        if (start >= pci_start && start < pci_start + size &&
                        start + nr <= pci_start + size)

It looks like the logic here is set up such that when the mmap call comes via
sysfs, the check in pci_mmap_fits wants vma->vm_pgoff to be between the
resource's start and end address, and the end of the vma to be no farther than
the end.  However, the sysfs PCI resource files always start at offset zero,
which means that this test always fails for programs that mmap the sysfs files.
Given the comment in the original commit
3b519e4ea618b6943a82931630872907f9ac2c2b, I _think_ the old procfs files
require that the file offset be equal to the resource's base address when
mmapping.

I think what we want here is for pci_start to be 0 when mmap_api ==
PCI_MMAP_PROCFS.  The following patch makes that change, after which the Matrox
and Mach64 X drivers work again.

Acked-by: Martin Wilck 
Signed-off-by: Darrick J. Wong 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

PCI: fix size checks for mmap() on /proc/bus/pci files

2010-12-09T21:26:53+00:00

commit 3b519e4ea618b6943a82931630872907f9ac2c2b upstream.

The checks for valid mmaps of PCI resources made through /proc/bus/pci files
that were introduced in 9eff02e2042f96fb2aedd02e032eca1c5333d767 have several
problems:

1. mmap() calls on /proc/bus/pci files are made with real file offsets > 0,
whereas under /sys/bus/pci/devices, the start of the resource corresponds
to offset 0. This may lead to false negatives in pci_mmap_fits(), which
implicitly assumes the /sys/bus/pci/devices layout.

2. The loop in proc_bus_pci_mmap doesn't skip empty resouces. This leads
to false positives, because pci_mmap_fits() doesn't treat empty resources
correctly (the calculated size is 1 << (8*sizeof(resource_size_t)-PAGE_SHIFT)
in this case!).

3. If a user maps resources with BAR > 0, pci_mmap_fits will emit bogus
WARNINGS for the first resources that don't fit until the correct one is found.

On many controllers the first 2-4 BARs are used, and the others are empty.
In this case, an mmap attempt will first fail on the non-empty BARs
(including the "right" BAR because of 1.) and emit bogus WARNINGS because
of 3., and finally succeed on the first empty BAR because of 2.
This is certainly not the intended behaviour.

This patch addresses all 3 issues.
Updated with an enum type for the additional parameter for pci_mmap_fits().

Signed-off-by: Martin Wilck 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

PCI: expose function reset capability in sysfs

2009-09-09T20:29:24+00:00

Some devices allow an individual function to be reset without affecting
other functions in the same device: that's what pci_reset_function does.
For devices that have this support, expose reset attribite in sysfs.

This is useful e.g. for virtualization, where a qemu userspace
process wants to reset the device when the guest is reset,
to emulate machine reboot as closely as possible.

Acked-by: Greg Kroah-Hartman 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Jesse Barnes

docbooks: add/fix PCI kernel-doc

2009-04-22T21:49:33+00:00

Add drivers/pci/*.c source files to DocBook/kernel-api.tmpl
and update those pci/*.c source files that need kernel-doc fixes.

Signed-off-by: Randy Dunlap 
Signed-off-by: Jesse Barnes

PCI: allow PCI core hotplug to remove PCI root bus

2009-04-06T18:30:02+00:00

There is no reason to prevent removal of root bus devices. A subsequent
rescan will find them just fine.

Reviewed-by: Kenji Kaneshige 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI: Setup disabled bridges even if buses are added

2009-04-06T18:25:06+00:00

This patch sets up disabled bridges even if buses have already been
added.

pci_assign_unassigned_resources is called after buses are added.
pci_assign_unassigned_resources calls pci_bus_assign_resources.
pci_bus_assign_resources calls pci_setup_bridge to configure BARs of
bridges.

Currently pci_setup_bridge returns immediately if the bus have already
been added. So pci_assign_unassigned_resources can't configure BARs of
bridges that were added in a disabled state; this patch fixes the issue.

On logical hot-add, we need to prevent the kernel from re-initializing
bridges that have already been initialized. To achieve this,
pci_setup_bridge returns immediately if the bridge have already been
enabled.

We don't need to check whether the specified bus is a root bus or not.
pci_setup_bridge is not called on a root bus, because a root bus does
not have a bridge.

The patch adds a new helper function, pci_is_enabled. I made the
function name similar to pci_is_managed. The codes which use
enable_cnt directly are changed to use pci_is_enabled.

Acked-by: Alex Chiang 
Signed-off-by: Yuji Shimada 
Signed-off-by: Jesse Barnes

PCI: Introduce /sys/bus/pci/devices/.../rescan

2009-03-20T21:59:07+00:00

This interface allows the user to force a rescan of the device's
parent bus and all subordinate buses, and rediscover devices removed
earlier from this part of the device tree.

Cc: Trent Piepho 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI: Introduce /sys/bus/pci/devices/.../remove

2009-03-20T21:58:48+00:00

This patch adds an attribute named "remove" to a PCI device's sysfs
directory.  Writing a non-zero value to this attribute will remove the PCI
device and any children of it.

Trent Piepho wrote the original implementation and documentation.

Thanks to Vegard Nossum for testing under kmemcheck and finding locking
issues with the sysfs interface.

Cc: Trent Piepho 
Tested-by: Vegard Nossum 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes