Yu Zhao wrote:
> PCI-to-PCI Bridge 1.2 specifies that the Secondary Bus Reset bit can
> force the assertion of RST# on the secondary interface, which can be
> used to reset all devices including subordinates under this bus. This
> can be used to reset a function if this function is the only device
> under this bus.
>
> Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>
> ---
> drivers/pci/pci.c | 31 +++++++++++++++++++++++++++++++
> 1 files changed, 31 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 19a5479..3711e74 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2160,6 +2160,33 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
> return 0;
> }
>
> +static int pci_secondary_bus_reset(struct pci_dev *dev, int probe)
> +{
I guess many people would imagine that pci_secondary_bus_reset()
receives the pointer to struct pci_dev corresponding to the bridge
and resets bridge's secondary bus, though it does quite different
things. So I think the function name should be changed.
Thanks,
Kenji Kaneshige
> + u16 ctrl;
> + struct pci_dev *pdev;
> +
> + if (dev->subordinate)
> + return -ENOTTY;
> +
> + list_for_each_entry(pdev, &dev->bus->devices, bus_list)
> + if (pdev != dev)
> + return -ENOTTY;
> +
> + 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);
> +
> + return 0;
> +}
> +
> static int pci_dev_reset(struct pci_dev *dev, int probe)
> {
> int rc;
> @@ -2181,6 +2208,10 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
> goto done;
>
> rc = pci_pm_reset(dev, probe);
> + if (rc != -ENOTTY)
> + goto done;
> +
> + rc = pci_secondary_bus_reset(dev, probe);
> done:
> if (!probe) {
> up(&dev->dev.sem);
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