2 files changed, 31 insertions, 18 deletions

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 81a4e213c6cf..b406261d8887 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -23,6 +23,7 @@ extern int swiotlb_force;
 #define IO_TLB_SHIFT 11
 
 extern void swiotlb_init(int verbose);
+extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 
 extern void
 *swiotlb_alloc_coherent(struct device *hwdev, size_t size,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 783aff00024c..ec61e1507d0a 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -140,28 +140,14 @@ void swiotlb_print_info(void)
                (unsigned long long)pend);
 }
 
-/*
- * Statically reserve bounce buffer space and initialize bounce buffer data
- * structures for the software IO TLB used to implement the DMA API.
- */
-void __init
-swiotlb_init_with_default_size(size_t default_size, int verbose)
+void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 {
         unsigned long i, bytes;
 
-        if (!io_tlb_nslabs) {
-                io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-                io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
-        }
+        bytes = nslabs << IO_TLB_SHIFT;
 
-        bytes = io_tlb_nslabs << IO_TLB_SHIFT;
-
-        /*
-         * Get IO TLB memory from the low pages
-         */
-        io_tlb_start = alloc_bootmem_low_pages(bytes);
-        if (!io_tlb_start)
-                panic("Cannot allocate SWIOTLB buffer");
+        io_tlb_nslabs = nslabs;
+        io_tlb_start = tlb;
         io_tlb_end = io_tlb_start + bytes;
 
         /*
@@ -185,6 +171,32 @@ swiotlb_init_with_default_size(size_t default_size, int verbose)
                 swiotlb_print_info();
 }
 
+/*
+ * Statically reserve bounce buffer space and initialize bounce buffer data
+ * structures for the software IO TLB used to implement the DMA API.
+ */
+void __init
+swiotlb_init_with_default_size(size_t default_size, int verbose)
+{
+        unsigned long bytes;
+
+        if (!io_tlb_nslabs) {
+                io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
+                io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+        }
+
+        bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+
+        /*
+         * Get IO TLB memory from the low pages
+         */
+        io_tlb_start = alloc_bootmem_low_pages(bytes);
+        if (!io_tlb_start)
+                panic("Cannot allocate SWIOTLB buffer");
+
+        swiotlb_init_with_tbl(io_tlb_start, io_tlb_nslabs, verbose);
+}
+
 void __init
 swiotlb_init(int verbose)
 {