sbc8548: reclaim wasted sector in boot flash
By nature of being based off the MPC8548CDS board, this
board inherited an ENV_SIZE setting of 256k. But since
it has a smaller flash device (8MB soldered on), it has
a native sector size of 128k, and hence the ENV_SIZE was
causing 2 sectors to be used for the environment.
By removing the unused sector, we can push TEXT_BASE up
closer to the end of address space and reclaim that
sector for any other application. This also fixes the
mismatch between TEXT_BASE and MONITOR_LEN reported by
Kumar earlier.
Since this board also supports the ability to boot off
the 64MB SODIMM flash, this change is forward looking
with that in mind; i.e. the settings for MONITOR_LEN
and ENV_SIZE will work when the 512k sectors of the
SODIMM flash are used for alternate boot in the future.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/doc/README.sbc8548 b/doc/README.sbc8548
index d72d97d..6cbe12f 100644
--- a/doc/README.sbc8548
+++ b/doc/README.sbc8548
@@ -63,6 +63,30 @@
=>
+Updating U-boot with U-boot:
+============================
+
+Note that versions of u-boot up to and including 2009.08 had u-boot stored
+at 0xfff8_0000 -> 0xffff_ffff (512k). Currently it is being stored from
+0xfffa_0000 -> 0xffff_ffff (384k). If you use an old macro/script to
+update u-boot with u-boot and it uses the old address, you will render
+your board inoperable, and you will require JTAG recovery.
+
+The following steps list how to update with the current address:
+
+ tftp u-boot.bin
+ md 200000 10
+ protect off all
+ erase fffa0000 ffffffff
+ cp.b 200000 fffa0000 60000
+ md fffa0000 10
+ protect on all
+
+The "md" steps in the above are just a precautionary step that allow
+you to confirm the u-boot version that was downloaded, and then confirm
+that it was copied to flash.
+
+
Hardware Reference:
===================