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Subject[PATCH 1/3] 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: Separating the description of how to specify a PCI device
into it's own section at the head of the pci= parameter.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
---
Documentation/admin-guide/kernel-parameters.txt | 26 +++-
drivers/pci/pci.c | 153 +++++++++++++++---------
2 files changed, 120 insertions(+), 59 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 11fc28ecdb6d..894aa516ceab 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2982,7 +2982,24 @@
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 two formats:
+
+ [<domain>:]<bus>:<slot>.<func>
+ pci:<vendor>:<device>[:<subvendor>:<subdevice>]
+
+ Note: the first format specifies a PCI
+ bus/slot/function address which may change
+ if new hardware is inserted, if motherboard
+ firmware changes, or due to changes caused
+ by other kernel parameters. 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
@@ -3111,11 +3128,10 @@
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 dbfe7c4f3776..85fec5e2640b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -183,6 +183,88 @@ 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. The string may be of one of two forms formats:
+ *
+ * [<domain>:]<bus>:<slot>.<func>
+ * pci:<vendor>:<device>[:<subvendor>:<subdevice>]
+ *
+ * The first format specifies a PCI bus/slot/function address which
+ * may change if new hardware is inserted, if motherboard firmware changes,
+ * or due to changes caused in kernel parameters.
+ *
+ * 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.
+ *
+ * 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,Slot,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)
@@ -5462,10 +5544,10 @@ 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;
@@ -5485,58 +5567,21 @@ 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_info("PCI: Can't parse resource_alignment parameter: pci:%s\n",
+ p);
+ break;
}
+
if (*p != ';' && *p != ',') {
/* End of param or invalid format */
break;
--
2.11.0
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