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-rw-r--r--README9
-rw-r--r--common/image.c60
2 files changed, 58 insertions, 11 deletions
diff --git a/README b/README
index 1e2d4d33c0..6a601d2688 100644
--- a/README
+++ b/README
@@ -3305,6 +3305,15 @@ List of environment variables (most likely not complete):
This can be used to load and uncompress arbitrary
data.
+ fdt_high - if set this restricts the maximum address that the
+ flattened device tree will be copied into upon boot.
+ 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
+ sufficient padding on the end of it for u-boot to
+ add the information it needs into it, and the memory
+ must be accessible by the kernel.
+
i2cfast - (PPC405GP|PPC405EP only)
if set to 'y' configures Linux I2C driver for fast
mode (400kHZ). This environment variable is used in
diff --git a/common/image.c b/common/image.c
index e542a57367..c6cd85ef91 100644
--- a/common/image.c
+++ b/common/image.c
@@ -1234,8 +1234,10 @@ int boot_relocate_fdt (struct lmb *lmb, char **of_flat_tree, ulong *of_size)
{
void *fdt_blob = *of_flat_tree;
void *of_start = 0;
+ char *fdt_high;
ulong of_len = 0;
int err;
+ int disable_relocation = 0;
/* nothing to do */
if (*of_size == 0)
@@ -1249,26 +1251,62 @@ int boot_relocate_fdt (struct lmb *lmb, char **of_flat_tree, ulong *of_size)
/* position on a 4K boundary before the alloc_current */
/* Pad the FDT by a specified amount */
of_len = *of_size + CONFIG_SYS_FDT_PAD;
- of_start = (void *)(unsigned long)lmb_alloc_base(lmb, of_len, 0x1000,
- getenv_bootm_mapsize() + getenv_bootm_low());
+
+ /* If fdt_high is set use it to select the relocation address */
+ fdt_high = getenv("fdt_high");
+ if (fdt_high) {
+ void *desired_addr = (void *)simple_strtoul(fdt_high, NULL, 16);
+
+ if (((ulong) desired_addr) == ~0UL) {
+ /* All ones means use fdt in place */
+ desired_addr = fdt_blob;
+ disable_relocation = 1;
+ }
+ 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) {
+ puts("Failed using fdt_high value for Device Tree");
+ goto error;
+ }
+ } else {
+ of_start =
+ (void *)(ulong) mb_alloc(lmb, of_len, 0x1000);
+ }
+ } else {
+ of_start =
+ (void *)(ulong) lmb_alloc_base(lmb, of_len, 0x1000,
+ getenv_bootm_mapsize()
+ + getenv_bootm_low());
+ }
if (of_start == 0) {
puts("device tree - allocation error\n");
goto error;
}
- debug ("## device tree at %p ... %p (len=%ld [0x%lX])\n",
- fdt_blob, fdt_blob + *of_size - 1, of_len, of_len);
+ if (disable_relocation) {
+ /* We assume there is space after the existing fdt to use for padding */
+ fdt_set_totalsize(of_start, of_len);
+ printf(" Using Device Tree in place at %p, end %p\n",
+ of_start, of_start + of_len - 1);
+ } else {
+ debug ("## device tree at %p ... %p (len=%ld [0x%lX])\n",
+ fdt_blob, fdt_blob + *of_size - 1, of_len, of_len);
- printf (" Loading Device Tree to %p, end %p ... ",
- of_start, of_start + of_len - 1);
+ printf (" Loading Device Tree to %p, end %p ... ",
+ of_start, of_start + of_len - 1);
- err = fdt_open_into (fdt_blob, of_start, of_len);
- if (err != 0) {
- fdt_error ("fdt move failed");
- goto error;
+ err = fdt_open_into (fdt_blob, of_start, of_len);
+ if (err != 0) {
+ fdt_error ("fdt move failed");
+ goto error;
+ }
+ puts ("OK\n");
}
- puts ("OK\n");
*of_flat_tree = of_start;
*of_size = of_len;