common: Add functions to find free RAM

The bootm code needs to put the Kernel image and initrd into free
RAM. Add some functions to find free RAM chunks to help this code.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 56 insertions, 0 deletions

diff --git a/common/memory.c b/common/memory.c
index ff5bdc14e2..00fa7c50ff 100644
--- a/common/memory.c
+++ b/common/memory.c
@@ -171,6 +171,57 @@ int release_sdram_region(struct resource *res)
 	return release_region(res);
 }
 
+void memory_bank_find_space(struct memory_bank *bank, resource_size_t *retstart,
+			   resource_size_t *retend)
+{
+	resource_size_t freeptr, size, maxfree = 0;
+	struct resource *last, *child;
+
+	if (list_empty(&bank->res->children)) {
+		/* No children - return the whole bank */
+		*retstart = bank->res->start;
+		*retend = bank->res->end;
+		return;
+	}
+
+	freeptr = bank->res->start;
+
+	list_for_each_entry(child, &bank->res->children, sibling) {
+		/* Check gaps between child resources */
+		size = child->start - freeptr;
+		if (size > maxfree) {
+			*retstart = freeptr;
+			*retend = child->start - 1;
+			maxfree = size;
+		}
+		freeptr = child->start + resource_size(child);
+	}
+
+	last = list_last_entry(&bank->res->children, struct resource, sibling);
+
+	/* Check gap between last child and end of memory bank */
+	freeptr = last->start + resource_size(last);
+	size = bank->res->start + resource_size(bank->res) - freeptr;
+
+	if (size > maxfree) {
+		*retstart = freeptr;
+		*retend = bank->res->end;
+	}
+}
+
+int memory_bank_first_find_space(resource_size_t *retstart,
+				 resource_size_t *retend)
+{
+	struct memory_bank *bank;
+
+	for_each_memory_bank(bank) {
+		memory_bank_find_space(bank, retstart, retend);
+		return 0;
+	}
+
+	return -ENOENT;
+}
+
 #ifdef CONFIG_OFTREE
 
 static int of_memory_fixup(struct device_node *node, void *unused)
diff --git a/include/memory.h b/include/memory.h
index 165d2dc52a..56d16d20c8 100644
--- a/include/memory.h
+++ b/include/memory.h
@@ -27,4 +27,9 @@ struct resource *request_sdram_region(const char *name, resource_size_t start,
 		resource_size_t size);
 int release_sdram_region(struct resource *res);
 
+void memory_bank_find_space(struct memory_bank *bank, resource_size_t *retstart,
+			    resource_size_t *retend);
+int memory_bank_first_find_space(resource_size_t *retstart,
+				 resource_size_t *retend);
+
 #endif