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-rw-r--r--lib/swiotlb.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 9def738af4f4..975b8fc4f1e1 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -83,6 +83,12 @@ static unsigned int *io_tlb_list;
 static unsigned int io_tlb_index;
 
 /*
+ * Max segment that we can provide which (if pages are contingous) will
+ * not be bounced (unless SWIOTLB_FORCE is set).
+ */
+unsigned int max_segment;
+
+/*
  * We need to save away the original address corresponding to a mapped entry
  * for the sync operations.
  */
@@ -124,6 +130,20 @@ unsigned long swiotlb_nr_tbl(void)
 }
 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
 
+unsigned int swiotlb_max_segment(void)
+{
+	return max_segment;
+}
+EXPORT_SYMBOL_GPL(swiotlb_max_segment);
+
+void swiotlb_set_max_segment(unsigned int val)
+{
+	if (swiotlb_force == SWIOTLB_FORCE)
+		max_segment = 1;
+	else
+		max_segment = rounddown(val, PAGE_SIZE);
+}
+
 /* default to 64MB */
 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
 unsigned long swiotlb_size_or_default(void)
@@ -205,6 +225,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 	if (verbose)
 		swiotlb_print_info();
 
+	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
 	return 0;
 }
 
@@ -283,6 +304,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
 	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
 	if (rc)
 		free_pages((unsigned long)vstart, order);
+
 	return rc;
 }
 
@@ -337,6 +359,8 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 
 	late_alloc = 1;
 
+	swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+
 	return 0;
 
 cleanup4:
@@ -351,6 +375,7 @@ cleanup2:
 	io_tlb_end = 0;
 	io_tlb_start = 0;
 	io_tlb_nslabs = 0;
+	max_segment = 0;
 	return -ENOMEM;
 }
 
@@ -379,6 +404,7 @@ void __init swiotlb_free(void)
 				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
 	}
 	io_tlb_nslabs = 0;
+	max_segment = 0;
 }
 
 int is_swiotlb_buffer(phys_addr_t paddr)