From 07d8d7e57c28ca9a07dab4efd75dad3a654aeb85 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 30 Jul 2018 10:18:37 -0600 Subject: [PATCH] PCI: Make specifying PCI devices in kernel parameters reusable MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 [bhelgaas: use "device" instead of "slot" in documentation since that's the usual language in the PCI specs] Signed-off-by: Bjorn Helgaas Reviewed-by: Stephen Bates Reviewed-by: Alex Williamson Acked-by: Christian König --- Documentation/admin-guide/kernel-parameters.txt | 28 ++++- drivers/pci/pci.c | 157 ++++++++++++++++-------- 2 files changed, 126 insertions(+), 59 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index efc7aa7..ab36fb3 100644 --- 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 (). These are + specified in one of the following formats: + + [:]:. + pci::[::] + + 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: - [@][:]:.[; ...] - [@]pci::\ - [::][; ...] + [@][; ...] Specifies alignment and device to reassign - aligned memory resources. + aligned memory resources. How to + specify the device is described above. If 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 --- 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: + * + * [:]:. + * pci::[::] + * + * 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; -- 2.7.4