diff options
Diffstat (limited to 'drivers/pci/doe.c')
| -rw-r--r-- | drivers/pci/doe.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c index 652d63df9d22..7bd7892c5222 100644 --- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -146,6 +146,7 @@ static int pci_doe_send_req(struct pci_doe_mb *doe_mb, { struct pci_dev *pdev = doe_mb->pdev; int offset = doe_mb->cap_offset; + unsigned long timeout_jiffies; size_t length, remainder; u32 val; int i; @@ -155,8 +156,19 @@ static int pci_doe_send_req(struct pci_doe_mb *doe_mb, * someone other than Linux (e.g. firmware) is using the mailbox. Note * it is expected that firmware and OS will negotiate access rights via * an, as yet to be defined, method. + * + * Wait up to one PCI_DOE_TIMEOUT period to allow the prior command to + * finish. Otherwise, simply error out as unable to field the request. + * + * PCIe r6.2 sec 6.30.3 states no interrupt is raised when the DOE Busy + * bit is cleared, so polling here is our best option for the moment. */ - pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + timeout_jiffies = jiffies + PCI_DOE_TIMEOUT; + do { + pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); + } while (FIELD_GET(PCI_DOE_STATUS_BUSY, val) && + !time_after(jiffies, timeout_jiffies)); + if (FIELD_GET(PCI_DOE_STATUS_BUSY, val)) return -EBUSY; |