PPC: POWERNV: move iommu_add_device earlier

The current implementation of IOMMU on sPAPR does not use iommu_ops
and therefore does not call IOMMU API's bus_set_iommu() which
1) sets iommu_ops for a bus
2) registers a bus notifier
Instead, PCI devices are added to IOMMU groups from
subsys_initcall_sync(tce_iommu_init) which does basically the same
thing without using iommu_ops callbacks.

However Freescale PAMU driver (https://lkml.org/lkml/2013/7/1/158)
implements iommu_ops and when tce_iommu_init is called, every PCI device
is already added to some group so there is a conflict.

This patch does 2 things:
1. removes the loop in which PCI devices were added to groups and
adds explicit iommu_add_device() calls to add devices as soon as they get
the iommu_table pointer assigned to them.
2. moves a bus notifier to powernv code in order to avoid conflict with
the notifier from Freescale driver.

iommu_add_device() and iommu_del_device() are public now.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 4 insertions, 44 deletions

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 572bb5b95f35..d22abe0b08e3 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1105,7 +1105,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 }
 EXPORT_SYMBOL_GPL(iommu_release_ownership);
 
-static int iommu_add_device(struct device *dev)
+int iommu_add_device(struct device *dev)
 {
 	struct iommu_table *tbl;
 	int ret = 0;
@@ -1134,52 +1134,12 @@ static int iommu_add_device(struct device *dev)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(iommu_add_device);
 
-static void iommu_del_device(struct device *dev)
+void iommu_del_device(struct device *dev)
 {
 	iommu_group_remove_device(dev);
 }
-
-static int iommu_bus_notifier(struct notifier_block *nb,
-			      unsigned long action, void *data)
-{
-	struct device *dev = data;
-
-	switch (action) {
-	case BUS_NOTIFY_ADD_DEVICE:
-		return iommu_add_device(dev);
-	case BUS_NOTIFY_DEL_DEVICE:
-		iommu_del_device(dev);
-		return 0;
-	default:
-		return 0;
-	}
-}
-
-static struct notifier_block tce_iommu_bus_nb = {
-	.notifier_call = iommu_bus_notifier,
-};
-
-static int __init tce_iommu_init(void)
-{
-	struct pci_dev *pdev = NULL;
-
-	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
-
-	for_each_pci_dev(pdev)
-		iommu_add_device(&pdev->dev);
-
-	bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
-	return 0;
-}
-
-subsys_initcall_sync(tce_iommu_init);
-
-#else
-
-void iommu_register_group(struct iommu_table *tbl,
-		int pci_domain_number, unsigned long pe_num)
-{
-}
+EXPORT_SYMBOL_GPL(iommu_del_device);
 
 #endif /* CONFIG_IOMMU_API */