Re: [PATCH] PCI: add hibernation hooks

[Sebastian Ott <sebott@linux.vnet.ibm.com>]

On Thu, 22 Aug 2013, Bjorn Helgaas wrote:

> On Thu, Aug 22, 2013 at 12:06:43AM +0200, Rafael J. Wysocki wrote:
> > -> the prevailing convention for representing platform options like that
> > seems to be to use a pointer to an object containing callback pointers.  This
> > is what we do for pci_platform_pm and for suspend_ops, hibernation_ops etc.
> > I think it is just more flexible, because it allows the pointer to be left
> > unset if there is an initialization error of some sort or a command line
> > option disabling something is set etc.
> 
> Good points.  I put merged the error checking into the original patch
> and put it in my pci/misc branch.  Here's the result; let me know if
> anything needs to be tweaked.

Great, thank you!

Sebastian

> 
> 
> PCI: Add pcibios_pm_ops for optional arch-specific hibernate functionality
> 
> From: Sebastian Ott <sebott@linux.vnet.ibm.com>
> 
> 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.
> 
> [bhelgaas: fold in return value checks from v2 patch]
> Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/pci/pci-driver.c |   43 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pci.h      |    4 ++++
>  2 files changed, 47 insertions(+)
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index e6515e2..98f7b9b 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -763,6 +763,13 @@ static int pci_pm_resume(struct device *dev)
> 
>  #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;
> +
>  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 *dev)
>  			return error;
>  	}
> 
> +	if (pcibios_pm_ops.freeze)
> +		return pcibios_pm_ops.freeze(dev);
> +
>  	return 0;
>  }
> 
> @@ -811,6 +821,9 @@ static int pci_pm_freeze_noirq(struct device *dev)
> 
>  	pci_pm_set_unknown_state(pci_dev);
> 
> +	if (pcibios_pm_ops.freeze_noirq)
> +		return pcibios_pm_ops.freeze_noirq(dev);
> +
>  	return 0;
>  }
> 
> @@ -820,6 +833,12 @@ static int pci_pm_thaw_noirq(struct device *dev)
>  	struct device_driver *drv = dev->driver;
>  	int error = 0;
> 
> +	if (pcibios_pm_ops.thaw_noirq) {
> +		error = pcibios_pm_ops.thaw_noirq(dev);
> +		if (error)
> +			return error;
> +	}
> +
>  	if (pci_has_legacy_pm_support(pci_dev))
>  		return pci_legacy_resume_early(dev);
> 
> @@ -837,6 +856,12 @@ static int pci_pm_thaw(struct device *dev)
>  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
>  	int error = 0;
> 
> +	if (pcibios_pm_ops.thaw) {
> +		error = pcibios_pm_ops.thaw(dev);
> +		if (error)
> +			return error;
> +	}
> +
>  	if (pci_has_legacy_pm_support(pci_dev))
>  		return pci_legacy_resume(dev);
> 
> @@ -878,6 +903,9 @@ static int pci_pm_poweroff(struct device *dev)
>   Fixup:
>  	pci_fixup_device(pci_fixup_suspend, pci_dev);
> 
> +	if (pcibios_pm_ops.poweroff)
> +		return pcibios_pm_ops.poweroff(dev);
> +
>  	return 0;
>  }
> 
> @@ -911,6 +939,9 @@ static int pci_pm_poweroff_noirq(struct device *dev)
>  	if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
>  		pci_write_config_word(pci_dev, PCI_COMMAND, 0);
> 
> +	if (pcibios_pm_ops.poweroff_noirq)
> +		return pcibios_pm_ops.poweroff_noirq(dev);
> +
>  	return 0;
>  }
> 
> @@ -920,6 +951,12 @@ static int pci_pm_restore_noirq(struct device *dev)
>  	struct device_driver *drv = dev->driver;
>  	int error = 0;
> 
> +	if (pcibios_pm_ops.restore_noirq) {
> +		error = pcibios_pm_ops.restore_noirq(dev);
> +		if (error)
> +			return error;
> +	}
> +
>  	pci_pm_default_resume_early(pci_dev);
> 
>  	if (pci_has_legacy_pm_support(pci_dev))
> @@ -937,6 +974,12 @@ static int pci_pm_restore(struct device *dev)
>  	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
>  	int error = 0;
> 
> +	if (pcibios_pm_ops.restore) {
> +		error = pcibios_pm_ops.restore(dev);
> +		if (error)
> +			return error;
> +	}
> +
>  	/*
>  	 * This is necessary for the hibernation error path in which restore is
>  	 * called without restoring the standard config registers of the device.
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 0fd1f15..89ed123 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1648,6 +1648,10 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev,
>  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);
> 
>