diff mbox

[uboot,v2] Add uboot "fdt_high" enviroment variable

Message ID CAHCtNCD9UwY9b2qC+sR_AMHxWULv9JcEvRpQQUQ2Hc_PzQM-og@mail.gmail.com
State New
Headers show

Commit Message

David Long July 18, 2011, 7:30 p.m. UTC
---------- Forwarded message ----------
From: David A. Long <dave.long@linaro.org>
Date: 9 July 2011 16:40
Subject: [uboot PATCH v2] Add uboot "fdt_high" enviroment variable
To: linaro-dev@lists.linaro.org
Cc: grant.likely@linaro.org, u-boot@lists.denx.de, john.rigby@linaro.org


From: David A. Long <dave.long@linaro.org>

Add a new "fdt_high" enviroment variable. This can be used to control (or
prevent) the
relocation of the flattened device tree on boot. It can be used to prevent
relocation
of the fdt into highmem.  The variable behaves similarly to the existing
"initrd_high"
variable.

Signed-off-by: David A. Long <dave.long@linaro.org>
---
 README         |    9 ++++++++
 common/image.c |   60
++++++++++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 58 insertions(+), 11 deletions(-)

       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;
diff mbox

Patch

diff --git a/README b/README
index 8bb9c8d..5b95246 100644
--- a/README
+++ b/README
@@ -3281,6 +3281,15 @@  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 e542a57..7853de0 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 */