Re: [Patch v2 1/4] PCI: Add hooks to allocate/free IRQ resources when binding/unbinding driver

Bjorn Helgaas
2015-06-05T21:17:41Z

On Tue, Jun 02, 2015 at 10:49:16AM +0800, Jiang Liu wrote:
> Add two hook points pcibios_{alloc|free}_irq() into PCI core, which will
> be called when binding/unbinding PCI device drivers. Then PCI arch code
> may hook into these two points to allocate IRQ resources on demand and
> free them when not used anymore.
>
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
> drivers/pci/pci-driver.c | 26 ++++++++++++++++++++------
> include/linux/pci.h | 2 ++
> 2 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 3cb2210de553..450ad36ffc77 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -388,18 +388,31 @@ static int __pci_device_probe(struct pci_driver *drv, struct pci_dev *pci_dev)
> return error;
> }
>
> +int __weak pcibios_alloc_irq(struct pci_dev *dev)
> +{
> + return dev->irq;

Based on your usage, pcibios_alloc_irq() returns either zero or a negative
errno. So I think you should return 0 here.

> +}
> +
> +void __weak pcibios_free_irq(struct pci_dev *dev)
> +{
> +}
> +
> static int pci_device_probe(struct device *dev)
> {
> - int error = 0;
> - struct pci_driver *drv;
> - struct pci_dev *pci_dev;
> + int error;
> + struct pci_dev *pci_dev = to_pci_dev(dev);
> + struct pci_driver *drv = to_pci_driver(dev->driver);
> +
> + error = pcibios_alloc_irq(pci_dev);
> + if (error < 0)
> + return error;
>
> - drv = to_pci_driver(dev->driver);
> - pci_dev = to_pci_dev(dev);
> pci_dev_get(pci_dev);
> error = __pci_device_probe(drv, pci_dev);
> - if (error)
> + if (error) {
> + pcibios_free_irq(pci_dev);
> pci_dev_put(pci_dev);
> + }
>
> return error;
> }
> @@ -415,6 +428,7 @@ static int pci_device_remove(struct device *dev)
> drv->remove(pci_dev);
> pm_runtime_put_noidle(dev);
> }
> + pcibios_free_irq(pci_dev);
> pci_dev->driver = NULL;
> }
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 353db8dc4c6e..f50d16a04abc 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1656,6 +1656,8 @@ 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);
> void pcibios_penalize_isa_irq(int irq, int active);
> +int pcibios_alloc_irq(struct pci_dev *dev);
> +void pcibios_free_irq(struct pci_dev *dev);
>
> #ifdef CONFIG_HIBERNATE_CALLBACKS
> extern struct dev_pm_ops pcibios_pm_ops;
> --
> 1.7.10.4
>