Patchwork [PATCHv8,05/21] iommu/core: add ops->{bound,unbind}_driver()

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Submitter Hiroshi Doyu
Date May 30, 2014, 11:20 a.m.
Message ID <1401448834-32659-6-git-send-email-hdoyu@nvidia.com>
Download mbox | patch
Permalink /patch/354077/
State Superseded, archived
Headers show

Comments

Hiroshi Doyu - May 30, 2014, 11:20 a.m.
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>
---
 drivers/iommu/iommu.c | 13 +++++++++++--
 include/linux/iommu.h |  4 ++++
 2 files changed, 15 insertions(+), 2 deletions(-)
Hiroshi Doyu - June 16, 2014, 11:02 a.m.
Hiroshi Doyu <hdoyu@nvidia.com> writes:

> 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>
> ---
>  drivers/iommu/iommu.c | 13 +++++++++++--
>  include/linux/iommu.h |  4 ++++
>  2 files changed, 15 insertions(+), 2 deletions(-)

I have just noticed that we could make use of IOMMU group for this
purpose so that we could avoid this iommu core part modification but
just tegra-smmu part modification which would be easier to merge.

> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index e5555fcfe703..5469d361e7bc 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 b96a5b2136e4..141eea25bdea 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -97,6 +97,8 @@ 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
> @@ -115,6 +117,8 @@ 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);
> -- 
> 2.0.0.rc1.15.g7e76a2f
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Patch

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index e5555fcfe703..5469d361e7bc 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 b96a5b2136e4..141eea25bdea 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -97,6 +97,8 @@  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
@@ -115,6 +117,8 @@  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);