From 0077a845f7e31a6eabafaefc99540903b65439d4 Mon Sep 17 00:00:00 2001 From: Stuart Hayes Date: Fri, 5 Jan 2018 12:51:55 -0600 Subject: PCI: Expose ari_enabled in sysfs Some multifunction PCI devices with more than 8 functions use "alternative routing-ID interpretation" (ARI), which means the 8-bit device/function number field will be interpreted as 8 bits specifying the function number (the device number is 0 implicitly), rather than the upper 5 bits specifying the device number and the lower 3 bits specifying the function number. The kernel can enable and use this. Expose in a sysfs attribute whether the kernel has enabled ARI, so that a program in userspace won't have to parse PCI devices and PCI configuration space to figure out if it is enabled. This will allow better predictable network naming using PCI function numbers without using PCI bus or device numbers, which is desirable because bus and device numbers can change with system configuration but function numbers will not. Signed-off-by: Stuart Hayes Signed-off-by: Bjorn Helgaas --- drivers/pci/pci-sysfs.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/pci') diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 06c7f0b85cd2..707a4b46b97a 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -278,6 +278,16 @@ static ssize_t subordinate_bus_number_show(struct device *dev, } static DEVICE_ATTR_RO(subordinate_bus_number); +static ssize_t ari_enabled_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + + return sprintf(buf, "%u\n", pci_ari_enabled(pci_dev->bus)); +} +static DEVICE_ATTR_RO(ari_enabled); + static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -786,6 +796,7 @@ static struct attribute *pci_dev_attrs[] = { &dev_attr_devspec.attr, #endif &dev_attr_driver_override.attr, + &dev_attr_ari_enabled.attr, NULL, }; -- cgit v1.2.3