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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 <vee.khee.wong@ni.com>
Signed-off-by: Hui Chun Ong <hui.chun.ong@ni.com>
[bhelgaas: changelog, return errors early to unindent usual case, return
errors with same style throughout]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Wong Vee Khee 2017-06-01 17:43:06 +08:00 committed by Bjorn Helgaas
parent 99b3c58f7b
commit 56c1af4606
2 changed files with 196 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

199
drivers/pci/pci-sysfs.c
View File

@ -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,
};

1
include/uapi/linux/pci_regs.h
View File

@ -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 */