[PATCH 12/21] AMD IOMMU: add device detach helper functions

[Joerg Roedel <joerg.roedel@amd.com>]

Impact: add helper functions to detach a device from a domain

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 61584d5..47158e3 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1469,3 +1469,44 @@ free_domains:
 
 	return ret;
 }
+
+/*****************************************************************************
+ *
+ * The following functions belong to the exported interface of AMD IOMMU
+ *
+ * This interface allows access to lower level functions of the IOMMU
+ * like protection domain handling and assignement of devices to domains
+ * which is not possible with the dma_ops interface.
+ *
+ *****************************************************************************/
+
+static void __detach_device(struct protection_domain *domain, u16 devid)
+{
+
+	/* lock domain */
+	spin_lock(&domain->lock);
+
+	/* remove domain from the lookup table */
+	amd_iommu_pd_table[devid] = NULL;
+
+	/* remove entry from the device table seen by the hardware */
+	amd_iommu_dev_table[devid].data[0] = IOMMU_PTE_P | IOMMU_PTE_TV;
+	amd_iommu_dev_table[devid].data[1] = 0;
+	amd_iommu_dev_table[devid].data[2] = 0;
+
+	/* decrease reference counter */
+	domain->dev_cnt -= 1;
+
+	/* ready */
+	spin_unlock(&domain->lock);
+}
+
+static void detach_device(struct protection_domain *domain, u16 devid)
+{
+	unsigned long flags;
+
+	/* lock device table */
+	write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+	__detach_device(domain, devid);
+	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+}
-- 
1.5.6.4