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 <[email protected]>
ndreys · Apr 4, 2018 · d4ff9c4 · d4ff9c4
1 parent 41dd040
commit d4ff9c4
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diff --git 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
@@ -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