Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned
PCI memory resources are not page aligned.
By using the kernel option "pci=resource_alignment" it is possible to force
single PCI boards to use page alignment for their memory resources.
However, this is fairly cumbersome if multiple of these boards are in use as
the specification of the cards has to be done via PCI bus/slot/function number
which might change e.g. by adding another board.
This patch extends the kernel option "pci=resource_alignment" to allow to
specify the relevant boards via PCI device/vendor (and subdevice/subvendor) ids.
The specification of the devices via device/vendor is indicated by a leading
string "pci:" as argument to "pci=resource_alignment".
The format of the specification is
pci:<vendor>:<device>[:<subvendor>:<subdevice>]
Examples:
pci=resource_alignment=4096@pci:1234:abcd:1234:bcde
pci=resource_alignment=pci:1234:abcd
Signed-off-by: Mathias Koehrer <mathias.koehrer@xxxxxxxx>
---
Documentation/kernel-parameters.txt | 2 +
drivers/pci/pci.c | 66 +++++++++++++++++++++++++-----------
2 files changed, 49 insertions(+), 19 deletions(-)
Index: linux-4.7-rc1/Documentation/kernel-parameters.txt
===================================================================
--- linux-4.7-rc1.orig/Documentation/kernel-parameters.txt
+++ linux-4.7-rc1/Documentation/kernel-parameters.txt
@@ -2998,12 +2998,17 @@ bytes respectively. Such letter suffixes
resource_alignment=
Format:
[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
+ [<order of align>@]pci:<vendor>:<device>\
+ [:<subvendor>:<subdevice>][; ...]
Specifies alignment and device to reassign
aligned memory resources.
If <order of align> is not specified,
PAGE_SIZE is used as alignment.
PCI-PCI bridge can be specified, if resource
windows need to be expanded.
+ To specify the alignment for certain types of devices, the
+ PCI vendor/device (and subvendor/subdevice) may be
+ specified. E.g. 4096@pci:1234:abcd:1234:bcde
ecrc= Enable/disable PCIe ECRC (transaction layer
end-to-end CRC checking).
bios: Use BIOS/firmware settings. This is the
Index: linux-4.7-rc1/drivers/pci/pci.c
===================================================================
--- linux-4.7-rc1.orig/drivers/pci/pci.c
+++ linux-4.7-rc1/drivers/pci/pci.c
@@ -4755,6 +4755,7 @@ static DEFINE_SPINLOCK(resource_alignmen
static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev)
{
int seg, bus, slot, func, align_order, count;
+ unsigned short vendor, device, subsystem_vendor, subsystem_device;
resource_size_t align = 0;
char *p;
@@ -4768,28 +4769,55 @@ static resource_size_t pci_specified_res
} else {
align_order = -1;
}
- if (sscanf(p, "%x:%x:%x.%x%n",
- &seg, &bus, &slot, &func, &count) != 4) {
- seg = 0;
- if (sscanf(p, "%x:%x.%x%n",
- &bus, &slot, &func, &count) != 3) {
- /* Invalid format */
- printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n",
- p);
+ if (strncmp(p, "pci:", 4) == 0) {
+ /* PCI vendor/device (subvendor/subdevice) ids are specified */
+ p += 4;
+ if (sscanf(p, "%hx:%hx:%hx:%hx%n",
+ &vendor, &device, &subsystem_vendor, &subsystem_device, &count) != 4) {
+ if (sscanf(p, "%hx:%hx%n", &vendor, &device, &count) != 2) {
+ printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: pci:%s\n",
+ p);
+ break;
+ }
+ subsystem_vendor = subsystem_device = 0;
+ }
+ p += count;
+ if ((!vendor || (vendor == dev->vendor)) &&
+ (!device || (device == dev->device)) &&
+ (!subsystem_vendor || (subsystem_vendor == dev->subsystem_vendor)) &&
+ (!subsystem_device || (subsystem_device == dev->subsystem_device))) {
+ if (align_order == -1)
+ align = PAGE_SIZE;
+ else
+ align = 1 << align_order;
+ /* Found */
break;
}
}
- p += count;
- if (seg == pci_domain_nr(dev->bus) &&
- bus == dev->bus->number &&
- slot == PCI_SLOT(dev->devfn) &&
- func == PCI_FUNC(dev->devfn)) {
- if (align_order == -1)
- align = PAGE_SIZE;
- else
- align = 1 << align_order;
- /* Found */
- break;
+ else {
+ if (sscanf(p, "%x:%x:%x.%x%n",
+ &seg, &bus, &slot, &func, &count) != 4) {
+ seg = 0;
+ if (sscanf(p, "%x:%x.%x%n",
+ &bus, &slot, &func, &count) != 3) {
+ /* Invalid format */
+ printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n",
+ p);
+ break;
+ }
+ }
+ p += count;
+ if (seg == pci_domain_nr(dev->bus) &&
+ bus == dev->bus->number &&
+ slot == PCI_SLOT(dev->devfn) &&
+ func == PCI_FUNC(dev->devfn)) {
+ if (align_order == -1)
+ align = PAGE_SIZE;
+ else
+ align = 1 << align_order;
+ /* Found */
+ break;
+ }
}
if (*p != ';' && *p != ',') {
/* End of param or invalid format */
--
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