[PATCHv4 05/11] of: pci: add registry of MSI chips

[Bjorn Helgaas]

On Mon, Jul 1, 2013 at 7:42 AM, Thomas Petazzoni
<thomas.petazzoni at free-electrons.com> wrote:
> This commit adds a very basic registry of msi_chip structures, so that
> an IRQ controller driver can register an msi_chip, and a PCIe host
> controller can find it, based on a 'struct device_node'.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> ---
>  drivers/of/of_pci.c    | 40 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/msi.h    |  2 ++
>  include/linux/of_pci.h | 12 ++++++++++++
>  3 files changed, 54 insertions(+)
>
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 42c687a..f516632 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -89,3 +89,43 @@ int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
> +
> +#ifdef CONFIG_PCI_MSI
> +
> +static LIST_HEAD(msi_chip_list);
> +static DEFINE_MUTEX(msi_chip_mutex);
> +
> +int of_msi_chip_add(struct msi_chip *chip)
> +{
> +       if (! of_property_read_bool(chip->of_node, "msi-controller"))

The space between "! of_property..." is atypical.

> +               return -EINVAL;
> +
> +       mutex_lock(&msi_chip_mutex);
> +       list_add(&chip->list, &msi_chip_list);
> +       mutex_unlock(&msi_chip_mutex);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(of_msi_chip_add);
> +
> +void of_msi_chip_remove(struct msi_chip *chip)
> +{
> +       mutex_lock(&msi_chip_mutex);
> +       list_del(&chip->list);
> +       mutex_unlock(&msi_chip_mutex);
> +}
> +EXPORT_SYMBOL_GPL(of_msi_chip_remove);
> +
> +struct msi_chip *of_find_msi_chip_by_node(struct device_node *of_node)
> +{
> +       struct msi_chip *c;

Normally there's a blank line here.

The list traversal below isn't safe, is it?  A simultaneous remove,
e.g., of an MSI chip unrelated to the one we're looking up, might
change the list while we're traversing it.

> +       list_for_each_entry(c, &msi_chip_list, list) {
> +               if (c->of_node == of_node)
> +                       return c;
> +       }
> +
> +       return NULL;
> +}
> +EXPORT_SYMBOL_GPL(of_find_msi_chip_by_node);
> +
> +#endif /* CONFIG_PCI_MSI */
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 5b357d92..9e1a44b 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -66,6 +66,8 @@ void default_teardown_msi_irqs(struct pci_dev *dev);
>  struct msi_chip {
>         struct module *owner;
>         struct device *dev;
> +       struct device_node *of_node;
> +       struct list_head list;
>
>         int (*setup_irq)(struct msi_chip *chip, struct pci_dev *dev,
>                          struct msi_desc *desc);
> diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
> index 7a04826..99e4361 100644
> --- a/include/linux/of_pci.h
> +++ b/include/linux/of_pci.h
> @@ -2,6 +2,7 @@
>  #define __OF_PCI_H
>
>  #include <linux/pci.h>
> +#include <linux/msi.h>
>
>  struct pci_dev;
>  struct of_irq;
> @@ -13,4 +14,15 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
>  int of_pci_get_devfn(struct device_node *np);
>  int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
>
> +#if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
> +int of_msi_chip_add(struct msi_chip *chip);
> +void of_msi_chip_remove(struct msi_chip *chip);
> +struct msi_chip *of_find_msi_chip_by_node(struct device_node *of_node);
> +#else
> +static inline int of_msi_chip_add(struct msi_chip *chip) { return -EINVAL; }
> +static inline void of_msi_chip_remove(struct msi_chip *chip) { }
> +static inline struct msi_chip *
> +of_find_msi_chip_by_node(struct device_node *of_node) { return NULL };
> +#endif
> +
>  #endif
> --
> 1.8.1.2
>