xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

PCI: Make specifying PCI devices in kernel parameters reusable

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

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;