3 files changed, 87 insertions, 4 deletions

diff --git a/common/memory.c b/common/memory.c
index 612ed87168..95995bb6e3 100644
--- a/common/memory.c
+++ b/common/memory.c
@@ -111,15 +111,56 @@ void *sbrk(ptrdiff_t increment)
 
 LIST_HEAD(memory_banks);
 
+static int barebox_grow_memory_bank(struct memory_bank *bank, const char *name,
+				    const struct resource *newres)
+{
+	struct resource *res;
+	resource_size_t bank_end = bank->res->end;
+
+	if (newres->start < bank->start) {
+		res = request_iomem_region(name, newres->start, bank->start - 1);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+		__merge_regions(name, bank->res, res);
+	}
+
+	if (bank_end < newres->end) {
+		res = request_iomem_region(name, bank_end + 1, newres->end);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+		__merge_regions(name, bank->res, res);
+	}
+
+	bank->start = newres->start;
+	bank->size = resource_size(bank->res);
+
+	return 0;
+}
+
 int barebox_add_memory_bank(const char *name, resource_size_t start,
 				    resource_size_t size)
 {
-	struct memory_bank *bank = xzalloc(sizeof(*bank));
+	struct memory_bank *bank;
+	struct resource *res;
+	struct resource newres = {
+		.start = start,
+		.end = start + size - 1,
+	};
+
+	for_each_memory_bank(bank) {
+		if (resource_contains(bank->res, &newres))
+			return 0;
+		if (resource_contains(&newres, bank->res))
+			return barebox_grow_memory_bank(bank, name, &newres);
+	}
+
+	res = request_iomem_region(name, start, start + size - 1);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
 
-	bank->res = request_iomem_region(name, start, start + size - 1);
-	if (IS_ERR(bank->res))
-		return PTR_ERR(bank->res);
+	bank = xzalloc(sizeof(*bank));
 
+	bank->res = res;
 	bank->start = start;
 	bank->size = size;
 
diff --git a/common/resource.c b/common/resource.c
index ff4318a0d7..f96cb94b50 100644
--- a/common/resource.c
+++ b/common/resource.c
@@ -102,6 +102,28 @@ int release_region(struct resource *res)
 	return 0;
 }
 
+
+/*
+ * merge two adjacent sibling regions.
+ */
+int __merge_regions(const char *name,
+		struct resource *resa, struct resource *resb)
+{
+	if (!resource_adjacent(resa, resb))
+		return -EINVAL;
+
+	if (resa->start < resb->start)
+		resa->end = resb->end;
+	else
+		resa->start = resb->start;
+
+	free((char *)resa->name);
+	resa->name = xstrdup(name);
+	release_region(resb);
+
+	return 0;
+}
+
 /* The root resource for the whole memory-mapped io space */
 struct resource iomem_resource = {
 	.start = 0,
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 3d375a8740..295ab4a49d 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -130,6 +130,23 @@ static inline unsigned long resource_type(const struct resource *res)
 	return res->flags & IORESOURCE_TYPE_BITS;
 }
 
+/* True iff r1 completely contains r2 */
+static inline bool resource_contains(struct resource *r1, struct resource *r2)
+{
+	if (resource_type(r1) != resource_type(r2))
+		return false;
+	if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
+		return false;
+	return r1->start <= r2->start && r1->end >= r2->end;
+}
+
+/* True if r1 and r2 are adjacent to each other */
+static inline bool resource_adjacent(struct resource *r1, struct resource *r2)
+{
+	return (r1->end != ~(resource_size_t)0 && r1->end + 1 == r2->start) ||
+		(r2->end != ~(resource_size_t)0 && r2->end + 1 == r1->start);
+}
+
 struct resource *request_iomem_region(const char *name,
 		resource_size_t start, resource_size_t end);
 struct resource *request_ioport_region(const char *name,
@@ -139,6 +156,9 @@ struct resource *__request_region(struct resource *parent,
 		const char *name, resource_size_t end,
 		resource_size_t size);
 
+int __merge_regions(const char *name,
+		struct resource *resa, struct resource *resb);
+
 int release_region(struct resource *res);
 
 extern struct resource iomem_resource;