From d4ff9c40baf3cf64565c423d6f7622f27ec48a84 Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Wed, 14 Mar 2018 16:14:02 +0100
Subject: [PATCH] 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>
---
 common/memory.c  | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/memory.h |  5 +++++
 2 files changed, 56 insertions(+)

diff --git a/common/memory.c b/common/memory.c
index ff5bdc14e..00fa7c50f 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 165d2dc52..56d16d20c 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