Commit 73bdd730 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/doe' 

- Wait up to 1 second for DOE Busy bit to clear before writing a request to
  the mailbox to avoid failures if the mailbox is still busy from a
  previous transfer (Gregory Price)

* pci/doe:
  PCI/DOE: Poll DOE Busy bit for up to 1 second in pci_doe_send_req()
parents d957ff7a 86efc62d

drivers/pci/doe.c

+13 −1
Original line number Diff line number Diff line
@@ -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.

	 */

	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;