On Tue, Aug 20, 2013 at 8:41 AM, Sebastian Ott
<sebott@xxxxxxxxxxxxxxxxxx> wrote:
> Hello Bjorn,
>
> I'm currently trying to implement hibernate support for pci on s390. To access
> the config space of a pci function on s390 the function has to be enabled first.
> So I need some kind of callback to achieve this before the pci core or the device
> driver tries to access the function after a resume from hibernate.
>
> Would you be OK with the following patch?
I think doing something like this is fine.
What would it look like if we provided empty weak definitions of the
eight functions you need to hook: pcibios_pm_freeze(),
pcibios_pm_freeze_noirq(), etc.? Then the callers wouldn't have to do
a test before making the call. Not sure which would be better, but it
might be more obvious that this is a build-time binding rather than a
dynamic binding.
Should we check return values from the arch code?
> ---
> PCI: add hibernation hooks
>
> Platforms may want to provide architecture-specific functionality when
> a PCI device is doing a hibernate transition. Add a weak symbol
> pcibios_pm_ops that architectures can override to do so.
>
> Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci-driver.c | 30 ++++++++++++++++++++++++++++++
> include/linux/pci.h | 4 ++++
> 2 files changed, 34 insertions(+)
>
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -763,6 +763,13 @@ static int pci_pm_resume(struct device *
>
> #ifdef CONFIG_HIBERNATE_CALLBACKS
>
> +
> +/*
> + * pcibios_pm_ops - provide arch specific hooks when a pci device is doing
> + * a hibernate transition
> + */
> +struct dev_pm_ops __weak pcibios_pm_ops;
For example:
int __weak pcibios_pm_freeze(struct device *) { return 0; }
> static int pci_pm_freeze(struct device *dev)
> {
> struct pci_dev *pci_dev = to_pci_dev(dev);
> @@ -786,6 +793,9 @@ static int pci_pm_freeze(struct device *
> return error;
> }
>
> + if (pcibios_pm_ops.freeze)
> + pcibios_pm_ops.freeze(dev);
return pcibios_pm_freeze(dev);
> return 0;
> }
>
> @@ -811,6 +821,9 @@ static int pci_pm_freeze_noirq(struct de
>
> pci_pm_set_unknown_state(pci_dev);
>
> + if (pcibios_pm_ops.freeze_noirq)
> + pcibios_pm_ops.freeze_noirq(dev);
> +
> return 0;
> }
>
> @@ -820,6 +833,9 @@ static int pci_pm_thaw_noirq(struct devi
> struct device_driver *drv = dev->driver;
> int error = 0;
>
> + if (pcibios_pm_ops.thaw_noirq)
> + pcibios_pm_ops.thaw_noirq(dev);
> +
> if (pci_has_legacy_pm_support(pci_dev))
> return pci_legacy_resume_early(dev);
>
> @@ -837,6 +853,9 @@ static int pci_pm_thaw(struct device *de
> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> int error = 0;
>
> + if (pcibios_pm_ops.thaw)
> + pcibios_pm_ops.thaw(dev);
> +
> if (pci_has_legacy_pm_support(pci_dev))
> return pci_legacy_resume(dev);
>
> @@ -878,6 +897,9 @@ static int pci_pm_poweroff(struct device
> Fixup:
> pci_fixup_device(pci_fixup_suspend, pci_dev);
>
> + if (pcibios_pm_ops.poweroff)
> + pcibios_pm_ops.poweroff(dev);
> +
> return 0;
> }
>
> @@ -911,6 +933,9 @@ static int pci_pm_poweroff_noirq(struct
> if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
> pci_write_config_word(pci_dev, PCI_COMMAND, 0);
>
> + if (pcibios_pm_ops.poweroff_noirq)
> + pcibios_pm_ops.poweroff_noirq(dev);
> +
> return 0;
> }
>
> @@ -920,6 +945,9 @@ static int pci_pm_restore_noirq(struct d
> struct device_driver *drv = dev->driver;
> int error = 0;
>
> + if (pcibios_pm_ops.restore_noirq)
> + pcibios_pm_ops.restore_noirq(dev);
> +
> pci_pm_default_resume_early(pci_dev);
>
> if (pci_has_legacy_pm_support(pci_dev))
> @@ -937,6 +965,8 @@ static int pci_pm_restore(struct device
> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> int error = 0;
>
> + if (pcibios_pm_ops.restore)
> + pcibios_pm_ops.restore(dev);
> /*
> * This is necessary for the hibernation error path in which restore is
> * called without restoring the standard config registers of the device.
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1648,6 +1648,10 @@ int pcibios_set_pcie_reset_state(struct
> int pcibios_add_device(struct pci_dev *dev);
> void pcibios_release_device(struct pci_dev *dev);
>
> +#ifdef CONFIG_HIBERNATE_CALLBACKS
> +extern struct dev_pm_ops pcibios_pm_ops;
> +#endif
> +
> #ifdef CONFIG_PCI_MMCONFIG
> void __init pci_mmcfg_early_init(void);
> void __init pci_mmcfg_late_init(void);
>
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