On Fri, 14 Sep 2018 21:18:03 +0000
Sinan Kaya <okaya@xxxxxxxxxx> wrote:
> We need a contract between the reset API users and the PCI core about the
> types of reset that a user needs vs. what PCI core can do internally.
> If a platform supports hotplug, we need to do hotplug reset as an example.
>
> Expose the reset types to the drivers and try different reset types based
> on the new reset_type parameter.
>
> Most users are expected to use PCI_RESET_ANY, PCI_RESET_FUNC or
> PCI_RESET_LINK parameters.
>
> Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxx>
> ---
> .../net/ethernet/cavium/liquidio/lio_main.c | 2 +-
> drivers/pci/pci.c | 59 ++++++++++++-------
> drivers/xen/xen-pciback/pci_stub.c | 6 +-
> include/linux/pci.h | 13 +++-
> 4 files changed, 55 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> index 6fb13fa73b27..0ff76722734d 100644
> --- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
> +++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> @@ -989,7 +989,7 @@ static void octeon_pci_flr(struct octeon_device *oct)
> pci_write_config_word(oct->pci_dev, PCI_COMMAND,
> PCI_COMMAND_INTX_DISABLE);
>
> - rc = __pci_reset_function_locked(oct->pci_dev);
> + rc = __pci_reset_function_locked(oct->pci_dev, PCI_RESET_ANY);
>
> if (rc != 0)
> dev_err(&oct->pci_dev->dev, "Error %d resetting PCI function %d\n",
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 1835f3a7aa8d..8912c8ba3b2b 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4673,6 +4673,7 @@ static void pci_dev_restore(struct pci_dev *dev)
> * __pci_reset_function_locked - reset a PCI device function while holding
> * the @dev mutex lock.
> * @dev: PCI device to reset
> + * @reset_type: reset mask to try
> *
> * Some devices allow an individual function to be reset without affecting
> * other functions in the same device. The PCI device must be responsive
> @@ -4688,9 +4689,9 @@ static void pci_dev_restore(struct pci_dev *dev)
> * Returns 0 if the device function was successfully reset or negative if the
> * device doesn't support resetting a single function.
> */
> -int __pci_reset_function_locked(struct pci_dev *dev)
> +int __pci_reset_function_locked(struct pci_dev *dev, u32 reset_type)
> {
> - int rc;
> + int rc = 0;
What's the proper return value when a user passes zero for reset_type?
It seems to currently be: user provided no options, therefore we tried
none, therefore success. I'm torn whether that's entirely bogus to the
point of that we should WARN_ON (ie. caller bug), or simply return
-EINVAL, which the caller can ignore, or if there's some value to allow
the behavior here. Thanks,
Alex
>
> might_sleep();
>
> @@ -4702,24 +4703,42 @@ int __pci_reset_function_locked(struct pci_dev *dev)
> * other error, we're also finished: this indicates that further
> * reset mechanisms might be broken on the device.
> */
> - rc = pci_dev_specific_reset(dev, 0);
> - if (rc != -ENOTTY)
> - return rc;
> - if (pcie_has_flr(dev)) {
> - rc = pcie_flr(dev);
> + if (reset_type & PCI_RESET_DEV_SPECIFIC) {
> + rc = pci_dev_specific_reset(dev, 0);
> if (rc != -ENOTTY)
> return rc;
> }
> - rc = pci_af_flr(dev, 0);
> - if (rc != -ENOTTY)
> - return rc;
> - rc = pci_pm_reset(dev, 0);
> - if (rc != -ENOTTY)
> - return rc;
> - rc = pci_dev_reset_slot_function(dev, 0);
> - if (rc != -ENOTTY)
> - return rc;
> - return pci_parent_bus_reset(dev, 0);
> +
> + if (reset_type & PCI_RESET_FLR) {
> + if (pcie_has_flr(dev)) {
> + rc = pcie_flr(dev);
> + if (rc != -ENOTTY)
> + return rc;
> + }
> + rc = pci_af_flr(dev, 0);
> + if (rc != -ENOTTY)
> + return rc;
> + }
> +
> + if (reset_type & PCI_RESET_PM) {
> + rc = pci_pm_reset(dev, 0);
> + if (rc != -ENOTTY)
> + return rc;
> + }
> +
> + if (reset_type & PCI_RESET_SLOT) {
> + rc = pci_dev_reset_slot_function(dev, 0);
> + if (rc != -ENOTTY)
> + return rc;
> + }
> +
> + if (reset_type & PCI_RESET_BUS) {
> + rc = pci_parent_bus_reset(dev, 0);
> + if (rc != -ENOTTY)
> + return rc;
> + }
> +
> + return rc;
> }
> EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
>
> @@ -4784,7 +4803,7 @@ int pci_reset_function(struct pci_dev *dev)
> pci_dev_lock(dev);
> pci_dev_save_and_disable(dev);
>
> - rc = __pci_reset_function_locked(dev);
> + rc = __pci_reset_function_locked(dev, PCI_RESET_ANY);
>
> pci_dev_restore(dev);
> pci_dev_unlock(dev);
> @@ -4819,7 +4838,7 @@ int pci_reset_function_locked(struct pci_dev *dev)
>
> pci_dev_save_and_disable(dev);
>
> - rc = __pci_reset_function_locked(dev);
> + rc = __pci_reset_function_locked(dev, PCI_RESET_ANY);
>
> pci_dev_restore(dev);
>
> @@ -4844,7 +4863,7 @@ int pci_try_reset_function(struct pci_dev *dev)
> return -EAGAIN;
>
> pci_dev_save_and_disable(dev);
> - rc = __pci_reset_function_locked(dev);
> + rc = __pci_reset_function_locked(dev, PCI_RESET_ANY);
> pci_dev_restore(dev);
> pci_dev_unlock(dev);
>
> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
> index 59661db144e5..6dfb805bcb19 100644
> --- a/drivers/xen/xen-pciback/pci_stub.c
> +++ b/drivers/xen/xen-pciback/pci_stub.c
> @@ -105,7 +105,7 @@ static void pcistub_device_release(struct kref *kref)
> /* Call the reset function which does not take lock as this
> * is called from "unbind" which takes a device_lock mutex.
> */
> - __pci_reset_function_locked(dev);
> + __pci_reset_function_locked(dev, PCI_RESET_ANY);
> if (pci_load_and_free_saved_state(dev, &dev_data->pci_saved_state))
> dev_info(&dev->dev, "Could not reload PCI state\n");
> else
> @@ -283,7 +283,7 @@ void pcistub_put_pci_dev(struct pci_dev *dev)
> * (so it's ready for the next domain)
> */
> device_lock_assert(&dev->dev);
> - __pci_reset_function_locked(dev);
> + __pci_reset_function_locked(dev, PCI_RESET_ANY);
>
> dev_data = pci_get_drvdata(dev);
> ret = pci_load_saved_state(dev, dev_data->pci_saved_state);
> @@ -417,7 +417,7 @@ static int pcistub_init_device(struct pci_dev *dev)
> dev_err(&dev->dev, "Could not store PCI conf saved state!\n");
> else {
> dev_dbg(&dev->dev, "resetting (FLR, D3, etc) the device\n");
> - __pci_reset_function_locked(dev);
> + __pci_reset_function_locked(dev, PCI_RESET_ANY);
> pci_restore_state(dev);
> }
> /* Now disable the device (this also ensures some private device
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 6925828f9f25..d2e0a8c8177b 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -849,6 +849,17 @@ enum {
> PCI_SCAN_ALL_PCIE_DEVS = 0x00000040, /* Scan all, not just dev 0 */
> };
>
> +#define PCI_RESET_DEV_SPECIFIC (1 << 0)
> +#define PCI_RESET_FLR (1 << 1)
> +#define PCI_RESET_PM (1 << 2)
> +#define PCI_RESET_SLOT (1 << 3)
> +#define PCI_RESET_BUS (1 << 4)
> +
> +#define PCI_RESET_ANY (~0)
> +#define PCI_RESET_FUNC (PCI_RESET_DEV_SPECIFIC | \
> + PCI_RESET_FLR | PCI_RESET_PM)
> +#define PCI_RESET_LINK (PCI_RESET_SLOT | PCI_RESET_BUS)
> +
> /* These external functions are only available when PCI support is enabled */
> #ifdef CONFIG_PCI
>
> @@ -1111,7 +1122,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
> void pcie_print_link_status(struct pci_dev *dev);
> bool pcie_has_flr(struct pci_dev *dev);
> int pcie_flr(struct pci_dev *dev);
> -int __pci_reset_function_locked(struct pci_dev *dev);
> +int __pci_reset_function_locked(struct pci_dev *dev, u32 reset_type);
> int pci_reset_function(struct pci_dev *dev);
> int pci_reset_function_locked(struct pci_dev *dev);
> int pci_try_reset_function(struct pci_dev *dev);
