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PCI: Make specifying PCI devices in kernel parameters reusable

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Separate out the code to match a PCI device with a string (typically
originating from a kernel parameter) from the
pci_specified_resource_alignment() function into its own helper function.

While we are at it, this change fixes the kernel style of the function
(fixing a number of long lines and extra parentheses).

Additionally, make the analogous change to the kernel parameter
documentation: Separate the description of how to specify a PCI device
into its own section at the head of the "pci=" parameter.

This patch should have no functional alterations.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
[bhelgaas: use "device" instead of "slot" in documentation since that's the
usual language in the PCI specs]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
This commit is contained in:
Logan Gunthorpe 2018-07-30 10:18:37 -06:00 committed by Bjorn Helgaas
parent bd2e9567db
commit 07d8d7e57c
2 changed files with 126 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
Documentation/admin-guide/kernel-parameters.txt
View File

@ -2994,7 +2994,26 @@
See header of drivers/block/paride/pcd.c.
See also Documentation/blockdev/paride.txt.
pci=option[,option...] [PCI] various PCI subsystem options:
pci=option[,option...] [PCI] various PCI subsystem options.
Some options herein operate on a specific device
or a set of devices (<pci_dev>). These are
specified in one of the following formats:
[<domain>:]<bus>:<device>.<func>
pci:<vendor>:<device>[:<subvendor>:<subdevice>]
Note: the first format specifies a PCI
bus/device/function address which may change
if new hardware is inserted, if motherboard
firmware changes, or due to changes caused
by other kernel parameters. If the
domain is left unspecified, it is
taken to be zero. The second format
selects devices using IDs from the
configuration space which may match multiple
devices in the system.
earlydump [X86] dump PCI config space before the kernel
changes anything
off [X86] don't probe for the PCI bus
@ -3123,11 +3142,10 @@
window. The default value is 64 megabytes.
resource_alignment=
Format:
[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
[<order of align>@]pci:<vendor>:<device>\
[:<subvendor>:<subdevice>][; ...]
[<order of align>@]<pci_dev>[; ...]
Specifies alignment and device to reassign
aligned memory resources.
aligned memory resources. How to
specify the device is described above.
If <order of align> is not specified,
PAGE_SIZE is used as alignment.
PCI-PCI bridge can be specified, if resource

157
drivers/pci/pci.c
View File

@ -191,6 +191,92 @@ void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar)
EXPORT_SYMBOL_GPL(pci_ioremap_wc_bar);
#endif
/**
* pci_dev_str_match - test if a string matches a device
* @dev: the PCI device to test
* @p: string to match the device against
* @endptr: pointer to the string after the match
*
* Test if a string (typically from a kernel parameter) matches a specified
* PCI device. The string may be of one of the following formats:
*
* [<domain>:]<bus>:<device>.<func>
* pci:<vendor>:<device>[:<subvendor>:<subdevice>]
*
* The first format specifies a PCI bus/device/function address which
* may change if new hardware is inserted, if motherboard firmware changes,
* or due to changes caused in kernel parameters. If the domain is
* left unspecified, it is taken to be 0.
*
* The second format matches devices using IDs in the configuration
* space which may match multiple devices in the system. A value of 0
* for any field will match all devices. (Note: this differs from
* in-kernel code that uses PCI_ANY_ID which is ~0; this is for
* legacy reasons and convenience so users don't have to specify
* FFFFFFFFs on the command line.)
*
* Returns 1 if the string matches the device, 0 if it does not and
* a negative error code if the string cannot be parsed.
*/
static int pci_dev_str_match(struct pci_dev *dev, const char *p,
const char **endptr)
{
int ret;
int seg, bus, slot, func, count;
unsigned short vendor, device, subsystem_vendor, subsystem_device;
if (strncmp(p, "pci:", 4) == 0) {
/* PCI vendor/device (subvendor/subdevice) IDs are specified */
p += 4;
ret = sscanf(p, "%hx:%hx:%hx:%hx%n", &vendor, &device,
&subsystem_vendor, &subsystem_device, &count);
if (ret != 4) {
ret = sscanf(p, "%hx:%hx%n", &vendor, &device, &count);
if (ret != 2)
return -EINVAL;
subsystem_vendor = 0;
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))
goto found;
} else {
/* PCI Bus, Device, Function IDs are specified */
ret = sscanf(p, "%x:%x:%x.%x%n", &seg, &bus, &slot,
&func, &count);
if (ret != 4) {
seg = 0;
ret = sscanf(p, "%x:%x.%x%n", &bus, &slot,
&func, &count);
if (ret != 3)
return -EINVAL;
}
p += count;
if (seg == pci_domain_nr(dev->bus) &&
bus == dev->bus->number &&
slot == PCI_SLOT(dev->devfn) &&
func == PCI_FUNC(dev->devfn))
goto found;
}
*endptr = p;
return 0;
found:
*endptr = p;
return 1;
}
static int __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn,
u8 pos, int cap, int *ttl)
@ -5454,10 +5540,10 @@ static DEFINE_SPINLOCK(resource_alignment_lock);
static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
bool *resize)
{
int seg, bus, slot, func, align_order, count;
unsigned short vendor, device, subsystem_vendor, subsystem_device;
int align_order, count;
resource_size_t align = pcibios_default_alignment();
char *p;
const char *p;
int ret;
spin_lock(&resource_alignment_lock);
p = resource_alignment_param;
@ -5477,58 +5563,21 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
} else {
align_order = -1;
}
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))) {
*resize = true;
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)) {
*resize = true;
if (align_order == -1)
align = PAGE_SIZE;
else
align = 1 << align_order;
/* Found */
break;
}
ret = pci_dev_str_match(dev, p, &p);
if (ret == 1) {
*resize = true;
if (align_order == -1)
align = PAGE_SIZE;
else
align = 1 << align_order;
break;
} else if (ret < 0) {
pr_err("PCI: Can't parse resource_alignment parameter: %s\n",
p);
break;
}
if (*p != ';' && *p != ',') {
/* End of param or invalid format */
break;