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SubjectRe: [PATCH v2 1/8] pci: Create pci_reset_bridge_secondary_bus()
On 05/07/2013 10:57 PM, Alex Williamson wrote:
> Move the secondary bus reset code from pci_parent_bus_reset() into its own
> function. Export it as we'll later be calling it from hotplug controllers.
>
> Signed-off-by: Alex Williamson<alex.williamson@redhat.com>
> ---
> drivers/pci/pci.c | 32 +++++++++++++++++++++++---------
> include/linux/pci.h | 1 +
> 2 files changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b099e00..d0f313f 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3210,9 +3210,30 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
> return 0;
> }
>
> -static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> +/**
> + * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
> + * @dev: Bridge device
> + *
> + * Use the bridge control register to assert reset on the secondary bus.
> + * Devices on the secondary bus are left in power-on state.
> + */
> +void pci_reset_bridge_secondary_bus(struct pci_dev *dev)
see recommended api change below...

> {
> u16 ctrl;
> +
> + pci_read_config_word(dev, PCI_BRIDGE_CONTROL,&ctrl);
> + ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> + msleep(100);
> +
> + ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> + msleep(100);
> +}
> +EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
> +
> +static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> +{
> struct pci_dev *pdev;
>
> if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
> @@ -3225,14 +3246,7 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> if (probe)
> return 0;
>
> - pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL,&ctrl);
> - ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> - pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> - msleep(100);
> -
> - ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> - pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> - msleep(100);
> + pci_reset_bridge_secondary_bus(dev->bus->self);
>
It makes more sense to pass the pci-bus struct of the bus you want to reset,
instead of the pdev of the bridge that bus is sourced by.
i.e, dev->bus, and above, extract the pdev from the bus-struct.
That way, devices asking for bus-reset, don't have to know the bus-struct details
to make the call right... just their own pdev->bus reference.
(more object-like/clean).

> return 0;
> }
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 710067f..695620c 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -905,6 +905,7 @@ int pcie_set_mps(struct pci_dev *dev, int mps);
> 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);
> +void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
and final tweak.

> void pci_update_resource(struct pci_dev *dev, int resno);
> int __must_check pci_assign_resource(struct pci_dev *dev, int i);
> int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
>
> --
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