ARM: bootm: locate zImage higher into RAM

The zImage should be placed where it won't be overwritten by the
uncompressed image, otherwise the kernel decompressing code has
to relocate the zImage before decompression. As Kernels tend to
become bigger put it into 32MiB into RAM if we have enough RAM
available.

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

1 files changed, 64 insertions, 8 deletions

diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index 56e42bc588..d2d5d26681 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -22,6 +22,49 @@
 #include <asm/armlinux.h>
 #include <asm/system.h>
 
+/*
+ * sdram_start_and_size() - determine place for putting the kernel/oftree/initrd
+ *
+ * @start:	returns the start address of the first RAM bank
+ * @size:	returns the usable space at the beginning of the first RAM bank
+ *
+ * This function returns the base address of the first RAM bank and the free
+ * space found there.
+ *
+ * return: 0 for success, negative error code otherwise
+ */
+static int sdram_start_and_size(unsigned long *start, unsigned long *size)
+{
+	struct memory_bank *bank;
+	struct resource *res;
+
+	/*
+	 * We use the first memory bank for the kernel and other resources
+	 */
+	bank = list_first_entry_or_null(&memory_banks, struct memory_bank,
+			list);
+	if (!bank) {
+		printf("cannot find first memory bank\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * If the first memory bank has child resources we can use the bank up
+	 * to the beginning of the first child resource, otherwise we can use
+	 * the whole bank.
+	 */
+	res = list_first_entry_or_null(&bank->res->children, struct resource,
+			sibling);
+	if (res)
+		*size = res->start - bank->start;
+	else
+		*size = bank->size;
+
+	*start = bank->start;
+
+	return 0;
+}
+
 static int __do_bootm_linux(struct image_data *data, int swap)
 {
 	unsigned long kernel;
@@ -80,16 +123,17 @@ static int __do_bootm_linux(struct image_data *data, int swap)
 
 static int do_bootm_linux(struct image_data *data)
 {
-	struct memory_bank *bank;
-	unsigned long load_address;
+	unsigned long load_address, mem_start, mem_size;
 	int ret;
 
+	ret = sdram_start_and_size(&mem_start, &mem_size);
+	if (ret)
+		return ret;
+
 	load_address = data->os_address;
 
 	if (load_address == UIMAGE_INVALID_ADDRESS) {
-		bank = list_first_entry(&memory_banks,
-				struct memory_bank, list);
-		load_address = bank->start + SZ_32K;
+		load_address = mem_start + SZ_32K;
 		if (bootm_verbose(data))
 			printf("no os load address, defaulting to 0x%08lx\n",
 				load_address);
@@ -192,11 +236,23 @@ static int do_bootz_linux(struct image_data *data)
 	void *zimage;
 	u32 end;
 	unsigned long load_address = data->os_address;
+	unsigned long mem_start, mem_size;
+
+	ret = sdram_start_and_size(&mem_start, &mem_size);
+	if (ret)
+		return ret;
 
 	if (load_address == UIMAGE_INVALID_ADDRESS) {
-		struct memory_bank *bank = list_first_entry(&memory_banks,
-				struct memory_bank, list);
-		data->os_address = bank->start + SZ_8M;
+		/*
+		 * The kernel should stay in the first 128MiB of RAM, recommended
+		 * is 32MiB into RAM so that relocation prior to decompression
+		 * can be avoided.
+		 */
+		if (mem_size > SZ_64M)
+			data->os_address = mem_start + SZ_32M;
+		else
+			data->os_address = mem_start + SZ_8M;
+
 		load_address = data->os_address;
 		if (bootm_verbose(data))
 			printf("no os load address, defaulting to 0x%08lx\n",