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PCI: Add pcie_get_width_cap() to find max supported link width 

Add pcie_get_width_cap() to find the max link width supported by a device.
Change max_link_width_show() to use pcie_get_width_cap().

Signed-off-by: Tal Gilboa <talgi@mellanox.com>
[bhelgaas: return width directly instead of error and *width, don't export
outside drivers/pci]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
This commit is contained in:
Tal Gilboa 2018-03-30 08:24:36 -05:00 committed by Bjorn Helgaas
parent 6cf57be0f7
commit c70b65fb7f
3 changed files with 21 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/pci/pci-sysfs.c
View File

@ -167,15 +167,9 @@ static DEVICE_ATTR_RO(max_link_speed);
static ssize_t max_link_width_show(struct device *dev, static ssize_t max_link_width_show(struct device *dev,
struct device_attribute *attr, char *buf) struct device_attribute *attr, char *buf)
{ {
struct pci_dev *pci_dev = to_pci_dev(dev); struct pci_dev *pdev = to_pci_dev(dev);
u32 linkcap;
int err;
err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap); return sprintf(buf, "%u\n", pcie_get_width_cap(pdev));
if (err)
return -EINVAL;
return sprintf(buf, "%u\n", (linkcap & PCI_EXP_LNKCAP_MLW) >> 4);
} }
static DEVICE_ATTR_RO(max_link_width); static DEVICE_ATTR_RO(max_link_width);

18
drivers/pci/pci.c
View File

@ -5190,6 +5190,24 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
return PCI_SPEED_UNKNOWN; return PCI_SPEED_UNKNOWN;
} }
/**
* pcie_get_width_cap - query for the PCI device's link width capability
* @dev: PCI device to query
*
* Query the PCI device width capability. Return the maximum link width
* supported by the device.
*/
enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev)
{
u32 lnkcap;
pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
if (lnkcap)
return (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4;
return PCIE_LNK_WIDTH_UNKNOWN;
}
/** /**
* pci_select_bars - Make BAR mask from the type of resource * pci_select_bars - Make BAR mask from the type of resource
* @dev: the PCI device for which BAR mask is made * @dev: the PCI device for which BAR mask is made

1
drivers/pci/pci.h
View File

@ -262,6 +262,7 @@ void pci_disable_bridge_window(struct pci_dev *dev);
"Unknown speed") "Unknown speed")
enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev); enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev);
enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev);
/* Single Root I/O Virtualization */ /* Single Root I/O Virtualization */
struct pci_sriov { struct pci_sriov {