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PCI: Export pcie_flr()

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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>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Christoph Hellwig 2017-04-14 21:11:25 +02:00 committed by Bjorn Helgaas
parent 0e7df22401
commit a60a2b73ba
2 changed files with 29 additions and 11 deletions
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39
drivers/pci/pci.c
View File

@ -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)

1
include/linux/pci.h
View File

@ -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);