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Subject[PATCH 1/7] PCI: export pcie_flr
Date
Currently we opencode the FLR sequence in lots of place, export a core
helper instead. We split out the probing for FLR support as all the
non-core callers already know their hardware.

Note that in the new pci_has_flr function the quirk check has been moved
before the capability check as there is no point in reading the
capability in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pci.c | 39 ++++++++++++++++++++++++++++-----------
include/linux/pci.h | 1 +
2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bef14777bb30..957a11a6a840 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3773,27 +3773,41 @@ static void pci_flr_wait(struct pci_dev *dev)
(i - 1) * 100);
}

-static int pcie_flr(struct pci_dev *dev, int probe)
+/**
+ * pcie_has_flr - check if a device supports function level resets
+ * @dev: device to check
+ *
+ * Returns true if the device advertises support for PCIe function level
+ * resets.
+ */
+static bool pcie_has_flr(struct pci_dev *dev)
{
u32 cap;

- pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
- if (!(cap & PCI_EXP_DEVCAP_FLR))
- return -ENOTTY;
-
if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
- return -ENOTTY;
+ return false;

- if (probe)
- return 0;
+ pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+ return cap & PCI_EXP_DEVCAP_FLR;
+}

+/**
+ * pcie_flr - initiate a PCIe function level reset
+ * @dev: device to reset
+ *
+ * Initiate a function level reset on @dev. The caller should ensure the
+ * device supports FLR before calling this function, e.g. by using the
+ * pcie_has_flr() helper.
+ */
+void pcie_flr(struct pci_dev *dev)
+{
if (!pci_wait_for_pending_transaction(dev))
dev_err(&dev->dev, "timed out waiting for pending transaction; performing function level reset anyway\n");

pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
pci_flr_wait(dev);
- return 0;
}
+EXPORT_SYMBOL_GPL(pcie_flr);

static int pci_af_flr(struct pci_dev *dev, int probe)
{
@@ -3977,9 +3991,12 @@ static int __pci_dev_reset(struct pci_dev *dev, int probe)
if (rc != -ENOTTY)
goto done;

- rc = pcie_flr(dev, probe);
- if (rc != -ENOTTY)
+ if (pcie_has_flr(dev)) {
+ if (!probe)
+ pcie_flr(dev);
+ rc = 0;
goto done;
+ }

rc = pci_af_flr(dev, probe);
if (rc != -ENOTTY)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 20e1865233a4..60162f51227a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1054,6 +1054,7 @@ int pcie_get_mps(struct pci_dev *dev);
int pcie_set_mps(struct pci_dev *dev, int mps);
int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
enum pcie_link_width *width);
+void pcie_flr(struct pci_dev *dev);
int __pci_reset_function(struct pci_dev *dev);
int __pci_reset_function_locked(struct pci_dev *dev);
int pci_reset_function(struct pci_dev *dev);
--
2.11.0
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