iommu: Make IOVA domain low limit flexible

To share the IOVA allocator with other architectures, it needs to
accommodate more general aperture restrictions; move the lower limit
from a compile-time constant to a runtime domain property to allow
IOVA domains with different requirements to co-exist.

Also reword the slightly unclear description of alloc_iova since we're
touching it anyway.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 3 insertions, 4 deletions

diff --git a/include/linux/iova.h b/include/linux/iova.h
index ad0507c61cc7..591b19626b46 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -16,9 +16,6 @@
 #include <linux/rbtree.h>
 #include <linux/dma-mapping.h>
 
-/* IO virtual address start page frame number */
-#define IOVA_START_PFN          (1)
-
 /* iova structure */
 struct iova {
         struct rb_node  node;
@@ -31,6 +28,7 @@ struct iova_domain {
         spinlock_t      iova_rbtree_lock; /* Lock to protect update of rbtree */
         struct rb_root  rbroot;         /* iova domain rbtree root */
         struct rb_node  *cached32_node; /* Save last alloced node */
+        unsigned long   start_pfn;      /* Lower limit for this domain */
         unsigned long   dma_32bit_pfn;
 };
 
@@ -52,7 +50,8 @@ struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size,
 struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
         unsigned long pfn_hi);
 void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);
-void init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit);
+void init_iova_domain(struct iova_domain *iovad, unsigned long start_pfn,
+        unsigned long pfn_32bit);
 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
 void put_iova_domain(struct iova_domain *iovad);
 struct iova *split_and_remove_iova(struct iova_domain *iovad,