[+cc Alex]
On Thu, Apr 13, 2017 at 04:53:33PM +0200, Christoph Hellwig wrote:
> 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.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/pci/pci.c | 34 +++++++++++++++++++++++++---------
> include/linux/pci.h | 1 +
> 2 files changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02ffdb9..3256a63c5d08 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3773,24 +3773,38 @@ 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 (probe)
> - return 0;
> + 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.
s/pcie_has_flr/pcie_has_flr()/
> + */
> +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)
> {
> @@ -3971,9 +3985,11 @@ 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)) {
> + pcie_flr(dev);
> + rc = 0;
> goto done;
> + }
This performs an FLR (if supported) always, regardless of "probe".
I think it should look something like this instead:
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 eb3da1a04e6c..f35e51eddad0 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1052,6 +1052,7 @@ 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
>
