From 56c1af4606f04048e3ae9ab2027a708b9684ff37 Mon Sep 17 00:00:00 2001 From: Wong Vee Khee Date: Thu, 1 Jun 2017 17:43:06 +0800 Subject: [PATCH] PCI: Add sysfs max_link_speed/width, current_link_speed/width, etc Expose PCIe bridges attributes such as secondary bus number, subordinate bus number, max link speed and link width, current link speed and link width via sysfs in /sys/bus/pci/devices/... This information is available via lspci, but that requires root privilege. Signed-off-by: Wong Vee Khee Signed-off-by: Hui Chun Ong [bhelgaas: changelog, return errors early to unindent usual case, return errors with same style throughout] Signed-off-by: Bjorn Helgaas --- drivers/pci/pci-sysfs.c | 199 +++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/pci_regs.h | 1 + 2 files changed, 196 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 31e99613a12e..a3537cf58a20 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -154,6 +154,129 @@ static ssize_t resource_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RO(resource); +static ssize_t max_link_speed_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u32 linkcap; + int err; + const char *speed; + + err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap); + if (err) + return -EINVAL; + + switch (linkcap & PCI_EXP_LNKCAP_SLS) { + case PCI_EXP_LNKCAP_SLS_8_0GB: + speed = "8 GT/s"; + break; + case PCI_EXP_LNKCAP_SLS_5_0GB: + speed = "5 GT/s"; + break; + case PCI_EXP_LNKCAP_SLS_2_5GB: + speed = "2.5 GT/s"; + break; + default: + speed = "Unknown speed"; + } + + return sprintf(buf, "%s\n", speed); +} +static DEVICE_ATTR_RO(max_link_speed); + +static ssize_t max_link_width_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u32 linkcap; + int err; + + err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap); + if (err) + return -EINVAL; + + return sprintf(buf, "%u\n", (linkcap & PCI_EXP_LNKCAP_MLW) >> 4); +} +static DEVICE_ATTR_RO(max_link_width); + +static ssize_t current_link_speed_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u16 linkstat; + int err; + const char *speed; + + err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat); + if (err) + return -EINVAL; + + switch (linkstat & PCI_EXP_LNKSTA_CLS) { + case PCI_EXP_LNKSTA_CLS_8_0GB: + speed = "8 GT/s"; + break; + case PCI_EXP_LNKSTA_CLS_5_0GB: + speed = "5 GT/s"; + break; + case PCI_EXP_LNKSTA_CLS_2_5GB: + speed = "2.5 GT/s"; + break; + default: + speed = "Unknown speed"; + } + + return sprintf(buf, "%s\n", speed); +} +static DEVICE_ATTR_RO(current_link_speed); + +static ssize_t current_link_width_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u16 linkstat; + int err; + + err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat); + if (err) + return -EINVAL; + + return sprintf(buf, "%u\n", + (linkstat & PCI_EXP_LNKSTA_NLW) >> PCI_EXP_LNKSTA_NLW_SHIFT); +} +static DEVICE_ATTR_RO(current_link_width); + +static ssize_t secondary_bus_number_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u8 sec_bus; + int err; + + err = pci_read_config_byte(pci_dev, PCI_SECONDARY_BUS, &sec_bus); + if (err) + return -EINVAL; + + return sprintf(buf, "%u\n", sec_bus); +} +static DEVICE_ATTR_RO(secondary_bus_number); + +static ssize_t subordinate_bus_number_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u8 sub_bus; + int err; + + err = pci_read_config_byte(pci_dev, PCI_SUBORDINATE_BUS, &sub_bus); + if (err) + return -EINVAL; + + return sprintf(buf, "%u\n", sub_bus); +} +static DEVICE_ATTR_RO(subordinate_bus_number); + static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -629,12 +752,17 @@ static struct attribute *pci_dev_attrs[] = { NULL, }; -static const struct attribute_group pci_dev_group = { - .attrs = pci_dev_attrs, +static struct attribute *pci_bridge_attrs[] = { + &dev_attr_subordinate_bus_number.attr, + &dev_attr_secondary_bus_number.attr, + NULL, }; -const struct attribute_group *pci_dev_groups[] = { - &pci_dev_group, +static struct attribute *pcie_dev_attrs[] = { + &dev_attr_current_link_speed.attr, + &dev_attr_current_link_width.attr, + &dev_attr_max_link_width.attr, + &dev_attr_max_link_speed.attr, NULL, }; @@ -1557,6 +1685,57 @@ static umode_t pci_dev_hp_attrs_are_visible(struct kobject *kobj, return a->mode; } +static umode_t pci_bridge_attrs_are_visible(struct kobject *kobj, + struct attribute *a, int n) +{ + struct device *dev = kobj_to_dev(kobj); + struct pci_dev *pdev = to_pci_dev(dev); + + if (pci_is_bridge(pdev)) + return a->mode; + + return 0; +} + +static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj, + struct attribute *a, int n) +{ + struct device *dev = kobj_to_dev(kobj); + struct pci_dev *pdev = to_pci_dev(dev); + + if (pci_is_pcie(pdev)) + return a->mode; + + return 0; +} + +static const struct attribute_group pci_dev_group = { + .attrs = pci_dev_attrs, +}; + +const struct attribute_group *pci_dev_groups[] = { + &pci_dev_group, + NULL, +}; + +static const struct attribute_group pci_bridge_group = { + .attrs = pci_bridge_attrs, +}; + +const struct attribute_group *pci_bridge_groups[] = { + &pci_bridge_group, + NULL, +}; + +static const struct attribute_group pcie_dev_group = { + .attrs = pcie_dev_attrs, +}; + +const struct attribute_group *pcie_dev_groups[] = { + &pcie_dev_group, + NULL, +}; + static struct attribute_group pci_dev_hp_attr_group = { .attrs = pci_dev_hp_attrs, .is_visible = pci_dev_hp_attrs_are_visible, @@ -1592,12 +1771,24 @@ static struct attribute_group pci_dev_attr_group = { .is_visible = pci_dev_attrs_are_visible, }; +static struct attribute_group pci_bridge_attr_group = { + .attrs = pci_bridge_attrs, + .is_visible = pci_bridge_attrs_are_visible, +}; + +static struct attribute_group pcie_dev_attr_group = { + .attrs = pcie_dev_attrs, + .is_visible = pcie_dev_attrs_are_visible, +}; + static const struct attribute_group *pci_dev_attr_groups[] = { &pci_dev_attr_group, &pci_dev_hp_attr_group, #ifdef CONFIG_PCI_IOV &sriov_dev_attr_group, #endif + &pci_bridge_attr_group, + &pcie_dev_attr_group, NULL, }; diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index d56bb0051009..c22d3ebaca20 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -517,6 +517,7 @@ #define PCI_EXP_LNKCAP_SLS 0x0000000f /* Supported Link Speeds */ #define PCI_EXP_LNKCAP_SLS_2_5GB 0x00000001 /* LNKCAP2 SLS Vector bit 0 */ #define PCI_EXP_LNKCAP_SLS_5_0GB 0x00000002 /* LNKCAP2 SLS Vector bit 1 */ +#define PCI_EXP_LNKCAP_SLS_8_0GB 0x00000003 /* LNKCAP2 SLS Vector bit 2 */ #define PCI_EXP_LNKCAP_MLW 0x000003f0 /* Maximum Link Width */ #define PCI_EXP_LNKCAP_ASPMS 0x00000c00 /* ASPM Support */ #define PCI_EXP_LNKCAP_L0SEL 0x00007000 /* L0s Exit Latency */ -- 2.11.0