PCI: Make specifying PCI devices in kernel parameters reusable

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>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index efc7aa7..ab36fb3 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -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

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 97acba7..1574b2d 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -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;