Re: [PATCH v15 2/9] PCI: Add pcie_reset_flr to follow calling convention of other reset methods

From: Raphael Norwitz
Date: Mon Aug 09 2021 - 07:16:02 EST

On Thu, Aug 05, 2021 at 09:59:10PM +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.
>
> Signed-off-by: Amey Narkhede <ameynarkhede03@xxxxxxxxx>

Reviewed-by: Raphael Norwitz <raphael.norwitz@xxxxxxxxxxx>

> ---
> drivers/crypto/cavium/nitrox/nitrox_main.c | 4 +--
> drivers/pci/pci.c | 40 +++++++++++++++-------
> drivers/pci/pcie/aer.c | 12 +++----
> drivers/pci/quirks.c | 9 ++---
> include/linux/pci.h | 2 +-
> 5 files changed, 38 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/crypto/cavium/nitrox/nitrox_main.c b/drivers/crypto/cavium/nitrox/nitrox_main.c
> index facc8e6bc580..15d6c8452807 100644
> --- a/drivers/crypto/cavium/nitrox/nitrox_main.c
> +++ b/drivers/crypto/cavium/nitrox/nitrox_main.c
> @@ -306,9 +306,7 @@ static int nitrox_device_flr(struct pci_dev *pdev)
> return -ENOMEM;
> }
>
> - /* check flr support */
> - if (pcie_has_flr(pdev))
> - pcie_flr(pdev);
> + pcie_reset_flr(pdev, 0);
>
> pci_restore_state(pdev);
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 1fafd05caa41..7d1d9671160b 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4619,22 +4619,20 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction);
> * Returns true if the device advertises support for PCIe function level
> * resets.
> */
> -bool pcie_has_flr(struct pci_dev *dev)
> +static bool pcie_has_flr(struct pci_dev *dev)
> {
> if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
> return false;
>
> return FIELD_GET(PCI_EXP_DEVCAP_FLR, dev->devcap) == 1;
> }
> -EXPORT_SYMBOL_GPL(pcie_has_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.
> + * Initiate a function level reset unconditionally on @dev without
> + * checking any flags and DEVCAP
> */
> int pcie_flr(struct pci_dev *dev)
> {
> @@ -4657,6 +4655,25 @@ int pcie_flr(struct pci_dev *dev)
> }
> EXPORT_SYMBOL_GPL(pcie_flr);
>
> +/**
> + * 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)
> +{
> + if (!pcie_has_flr(dev))
> + return -ENOTTY;
> +
> + if (probe)
> + return 0;
> +
> + return pcie_flr(dev);
> +}
> +EXPORT_SYMBOL_GPL(pcie_reset_flr);
> +
> static int pci_af_flr(struct pci_dev *dev, int probe)
> {
> int pos;
> @@ -5137,11 +5154,9 @@ int __pci_reset_function_locked(struct pci_dev *dev)
> rc = pci_dev_specific_reset(dev, 0);
> if (rc != -ENOTTY)
> return rc;
> - if (pcie_has_flr(dev)) {
> - rc = pcie_flr(dev);
> - if (rc != -ENOTTY)
> - return rc;
> - }
> + rc = pcie_reset_flr(dev, 0);
> + if (rc != -ENOTTY)
> + return rc;
> rc = pci_af_flr(dev, 0);
> if (rc != -ENOTTY)
> return rc;
> @@ -5172,8 +5187,9 @@ int pci_probe_reset_function(struct pci_dev *dev)
> rc = pci_dev_specific_reset(dev, 1);
> if (rc != -ENOTTY)
> return rc;
> - if (pcie_has_flr(dev))
> - return 0;
> + rc = pcie_reset_flr(dev, 1);
> + if (rc != -ENOTTY)
> + return rc;
> rc = pci_af_flr(dev, 1);
> if (rc != -ENOTTY)
> return rc;
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index ec943cee5ecc..98077595a73e 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -1405,13 +1405,11 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
> }
>
> if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
> - if (pcie_has_flr(dev)) {
> - rc = pcie_flr(dev);
> - pci_info(dev, "has been reset (%d)\n", rc);
> - } else {
> - pci_info(dev, "not reset (no FLR support)\n");
> - rc = -ENOTTY;
> - }
> + rc = pcie_reset_flr(dev, 0);
> + if (!rc)
> + pci_info(dev, "has been reset\n");
> + else
> + pci_info(dev, "not reset (no FLR support: %d)\n", rc);
> } else {
> rc = pci_bus_error_reset(dev);
> pci_info(dev, "%s Port link has been reset (%d)\n",
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index d85914afe65a..b48e7ef8b641 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3819,7 +3819,7 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
> u32 cfg;
>
> if (dev->class != PCI_CLASS_STORAGE_EXPRESS ||
> - !pcie_has_flr(dev) || !pci_resource_start(dev, 0))
> + pcie_reset_flr(dev, 1) || !pci_resource_start(dev, 0))
> return -ENOTTY;
>
> if (probe)
> @@ -3888,13 +3888,10 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
> */
> static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
> {
> - if (!pcie_has_flr(dev))
> - return -ENOTTY;
> -
> if (probe)
> - return 0;
> + return pcie_reset_flr(dev, 1);
>
> - pcie_flr(dev);
> + pcie_reset_flr(dev, 0);
>
> msleep(250);
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 697b1f085c7b..aa85e7d3147e 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1226,7 +1226,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
> enum pci_bus_speed *speed,
> enum pcie_link_width *width);
> void pcie_print_link_status(struct pci_dev *dev);
> -bool pcie_has_flr(struct pci_dev *dev);
> +int pcie_reset_flr(struct pci_dev *dev, int probe);
> int pcie_flr(struct pci_dev *dev);
> int __pci_reset_function_locked(struct pci_dev *dev);
> int pci_reset_function(struct pci_dev *dev);
> --
> 2.32.0
>
>