[PATCHv6 05/13] iommu/core: add ops->{bound,unbind}_driver()

[hdoyu@nvidia.com (Hiroshi Doyu)]

Hi Joerg,

Do you have some time to review this patch along with the following ones?

  [PATCHv6 02/13] iommu/of: introduce a global iommu device list
  http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007050.html

  [PATCHv6 03/13] iommu/of: check if dependee iommu is ready or not
  http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007051.html

With those patches, now I'm trying to populate iommu master devices
after an IOMMU device is populated. Originally [PATCHv6 02/13] was
proposed by Thierry. I'm a bit afraid of adding new IOMMU API as
this, but I think that this new {bound,unbind}_driver() is the right
timiing that depeding devices are populated instead of add_device()
since, even after add_device, a device won't be populated. I'm not so
sure how this affects on the existing IOMMUs.

It would be nice if you give some feedback on this.

On Thu, 21 Nov 2013 14:40:41 +0100
Hiroshi Doyu <hdoyu@nvidia.com> wrote:

> ops->{bound,unbind}_driver() functions are called at
> BUS_NOTIFY_{BOUND,UNBIND}_DRIVER respectively.
> 
> This is necessary to control the device population order. IOMMU master
> devices depend on an IOMMU device instanciation. IOMMU master devices
> can be registered to an IOMMU only after it's successfully
> populated. This IOMMU registration is done via
> ops->bound_driver(). Currently this population can be deferred if
> depending IOMMU device hasn't yet been populated in driver core. This
> cannot be done via ops->add_device() since after add_device() device's
> population/instanciation can be still deferred via probe().
> 
> Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
> ---
> v6:
> New for v6.
> ---
>  drivers/iommu/iommu.c | 13 +++++++++++--
>  include/linux/iommu.h |  4 ++++
>  2 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index e5555fc..5469d36 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -540,14 +540,23 @@ static int iommu_bus_notifier(struct notifier_block *nb,
>  	 * ADD/DEL call into iommu driver ops if provided, which may
>  	 * result in ADD/DEL notifiers to group->notifier
>  	 */
> -	if (action == BUS_NOTIFY_ADD_DEVICE) {
> +	switch (action) {
> +	case BUS_NOTIFY_ADD_DEVICE:
>  		if (ops->add_device)
>  			return ops->add_device(dev);
> -	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
> +	case BUS_NOTIFY_DEL_DEVICE:
>  		if (ops->remove_device && dev->iommu_group) {
>  			ops->remove_device(dev);
>  			return 0;
>  		}
> +	case BUS_NOTIFY_BOUND_DRIVER:
> +		if (ops->bound_driver)
> +			ops->bound_driver(dev);
> +		break;
> +	case BUS_NOTIFY_UNBIND_DRIVER:
> +		if (ops->unbind_driver)
> +			ops->unbind_driver(dev);
> +		break;
>  	}
>  
>  	/*
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index a444c79..a0e92be 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -96,6 +96,8 @@ enum iommu_attr {
>   * @domain_has_cap: domain capabilities query
>   * @add_device: add device to iommu grouping
>   * @remove_device: remove device from iommu grouping
> + * @bound_driver: called at BUS_NOTIFY_BOUND_DRIVER
> + * @unbind_driver: called at BUS_NOTIFY_UNBIND_DRIVER
>   * @domain_get_attr: Query domain attributes
>   * @domain_set_attr: Change domain attributes
>   * @pgsize_bitmap: bitmap of supported page sizes
> @@ -114,6 +116,8 @@ struct iommu_ops {
>  			      unsigned long cap);
>  	int (*add_device)(struct device *dev);
>  	void (*remove_device)(struct device *dev);
> +	int (*bound_driver)(struct device *dev);
> +	void (*unbind_driver)(struct device *dev);
>  	int (*device_group)(struct device *dev, unsigned int *groupid);
>  	int (*domain_get_attr)(struct iommu_domain *domain,
>  			       enum iommu_attr attr, void *data);
> -- 
> 1.8.1.5
>