On Tue, Jun 08, 2021 at 11:18:50AM +0530, Amey Narkhede wrote:

Currently there is separate function pcie_has_flr() to probe if pcie flr is
supported by the device which does not match the calling convention
followed by reset methods which use second function argument to decide
whether to probe or not.  Add new function pcie_reset_flr() that follows
the calling convention of reset methods.

+/**
+ * pcie_reset_flr - initiate a PCIe function level reset
+ * @dev: device to reset
+ * @probe: If set, only check if the device can be reset this way.
+ *
+ * Initiate a function level reset on @dev.
+ */
+int pcie_reset_flr(struct pci_dev *dev, int probe)
+{
+	u32 cap;
+
+	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
+		return -ENOTTY;
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+	if (!(cap & PCI_EXP_DEVCAP_FLR))
+		return -ENOTTY;
+
+	if (probe)
+		return 0;
+
+	return pcie_flr(dev);
+}

Tangent: I've been told before, but I can't remember why we need the
"probe" interface.  Since we're looking at this area again, can we add
a comment to clarify this?

Every time I read this, I wonder why we can't just get rid of the
probe and attempt a reset.  If it fails because it's not supported, we
could just try the next one in the list.