diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 71645d568986..47ceb8567b2b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4857,6 +4857,55 @@ static int pci_pm_reset(struct pci_dev *dev, bool probe) } /** + * pcie_wait_for_link_status - Wait for link training end + * @pdev: Device whose link to wait for. + * + * Return TRUE if successful, or FALSE if training has not completed + * within PCIE_LINK_RETRAIN_TIMEOUT_MS milliseconds. + */ +static bool pcie_wait_for_link_status(struct pci_dev *pdev) +{ + unsigned long end_jiffies; + u16 lnksta; + + end_jiffies = jiffies + msecs_to_jiffies(PCIE_LINK_RETRAIN_TIMEOUT_MS); + do { + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta); + if (!(lnksta & PCI_EXP_LNKSTA_LT)) + break; + msleep(1); + } while (time_before(jiffies, end_jiffies)); + return !(lnksta & PCI_EXP_LNKSTA_LT); +} + +/** + * pcie_retrain_link - Request a link retrain and wait for it to complete + * @pdev: Device whose link to retrain. + * + * Return TRUE if successful, or FALSE if training has not completed + * within PCIE_LINK_RETRAIN_TIMEOUT_MS milliseconds. + */ +bool pcie_retrain_link(struct pci_dev *pdev) +{ + u16 lnkctl; + + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnkctl); + lnkctl |= PCI_EXP_LNKCTL_RL; + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); + if (pdev->clear_retrain_link) { + /* + * Due to an erratum in some devices the Retrain Link bit + * needs to be cleared again manually to allow the link + * training to succeed. + */ + lnkctl &= ~PCI_EXP_LNKCTL_RL; + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnkctl); + } + + return pcie_wait_for_link_status(pdev); +} + +/** * pcie_wait_for_link_delay - Wait until link is active or inactive * @pdev: Bridge device * @active: waiting for active or inactive? |