diff options
authorShawn Guo <shawn.guo@linaro.org>2012-01-09 21:54:08 +0000
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2012-02-27 21:19:24 +0100
commitfa34f6b25b3c92f27b245c52378a0d2af24aaa19 (patch)
parentba901df41b0d77088408c1f6aac65eaadd4d12a0 (diff)
common/image.c: align usage of fdt_high with initrd_high
The commit message of a28afca (Add uboot "fdt_high" enviroment variable) states that fdt_high behaves similarly to the existing initrd_high. But fdt_high actually has an outstanding difference from initrd_high. The former specifies the start address, while the later specifies the end address. As fdt_high and initrd_high will likely be used together, it'd be nice to have them behave same. The patch changes the behavior of fdt_high to have it aligned with initrd_high. The document of fdt_high in README is updated with an example to demonstrate the usage of this environment variable. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Acked-by: Simon Glass <sjg@chromium.org>
2 files changed, 13 insertions, 7 deletions
diff --git a/README b/README
index eba637853..89646725a 100644
--- a/README
+++ b/README
@@ -3665,6 +3665,14 @@ List of environment variables (most likely not complete):
fdt_high - if set this restricts the maximum address that the
flattened device tree will be copied into upon boot.
+ For example, if you have a system with 1 GB memory
+ at physical address 0x10000000, while Linux kernel
+ only recognizes the first 704 MB as low memory, you
+ may need to set fdt_high as 0x3C000000 to have the
+ device tree blob be copied to the maximum address
+ of the 704 MB low memory, so that Linux kernel can
+ access it during the boot procedure.
If this is set to the special value 0xFFFFFFFF then
the fdt will not be copied at all on boot. For this
to work it must reside in writable memory, have
diff --git a/common/image.c b/common/image.c
index 202c8a1ca..fbdc40a4b 100644
--- a/common/image.c
+++ b/common/image.c
@@ -1289,16 +1289,14 @@ int boot_relocate_fdt(struct lmb *lmb, char **of_flat_tree, ulong *of_size)
if (((ulong) desired_addr) == ~0UL) {
/* All ones means use fdt in place */
- desired_addr = fdt_blob;
+ of_start = fdt_blob;
+ lmb_reserve(lmb, (ulong)of_start, of_len);
disable_relocation = 1;
- }
- if (desired_addr) {
+ } else if (desired_addr) {
of_start =
(void *)(ulong) lmb_alloc_base(lmb, of_len, 0x1000,
- ((ulong)
- desired_addr)
- + of_len);
- if (desired_addr && of_start != desired_addr) {
+ (ulong)desired_addr);
+ if (of_start == 0) {
puts("Failed using fdt_high value for Device Tree");
goto error;