powerpc/powernv/pseries: Rework device adding to IOMMU groups

The powernv platform registers IOMMU groups and adds devices to them
from the pci_controller_ops::setup_bridge() hook except one case when
virtual functions (SRIOV VFs) are added from a bus notifier.

The pseries platform registers IOMMU groups from
the pci_controller_ops::dma_bus_setup() hook and adds devices from
the pci_controller_ops::dma_dev_setup() hook. The very same bus notifier
used for powernv does not add devices for pseries though as
__of_scan_bus() adds devices first, then it does the bus/dev DMA setup.

Both platforms use iommu_add_device() which takes a device and expects
it to have a valid IOMMU table struct with an iommu_table_group pointer
which in turn points the iommu_group struct (which represents
an IOMMU group). Although the helper seems easy to use, it relies on
some pre-existing device configuration and associated data structures
which it does not really need.

This simplifies iommu_add_device() to take the table_group pointer
directly. Pseries already has a table_group pointer handy and the bus
notified is not used anyway. For powernv, this copies the existing bus
notifier, makes it work for powernv only which means an easy way of
getting to the table_group pointer. This was tested on VFs but should
also support physical PCI hotplug.

Since iommu_add_device() receives the table_group pointer directly,
pseries does not do TCE cache invalidation (the hypervisor does) nor
allow multiple groups per a VFIO container (in other words sharing
an IOMMU table between partitionable endpoints), this removes
iommu_table_group_link from pseries.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 4 insertions, 8 deletions

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index a8aeac0db01c..e847ff69cb2b 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -215,9 +215,9 @@ struct iommu_table_group {
 
 extern void iommu_register_group(struct iommu_table_group *table_group,
 				 int pci_domain_number, unsigned long pe_num);
-extern int iommu_add_device(struct device *dev);
+extern int iommu_add_device(struct iommu_table_group *table_group,
+		struct device *dev);
 extern void iommu_del_device(struct device *dev);
-extern int __init tce_iommu_bus_notifier_init(void);
 extern long iommu_tce_xchg(struct mm_struct *mm, struct iommu_table *tbl,
 		unsigned long entry, unsigned long *hpa,
 		enum dma_data_direction *direction);
@@ -228,7 +228,8 @@ static inline void iommu_register_group(struct iommu_table_group *table_group,
 {
 }
 
-static inline int iommu_add_device(struct device *dev)
+static inline int iommu_add_device(struct iommu_table_group *table_group,
+		struct device *dev)
 {
 	return 0;
 }
@@ -236,11 +237,6 @@ static inline int iommu_add_device(struct device *dev)
 static inline void iommu_del_device(struct device *dev)
 {
 }
-
-static inline int __init tce_iommu_bus_notifier_init(void)
-{
-        return 0;
-}
 #endif /* !CONFIG_IOMMU_API */
 
 int dma_iommu_mapping_error(struct device *dev, dma_addr_t dma_addr);