This board has an 8MB soldered on flash, and a 64MB SODIMM
flash module. Normally the board boots from the 8MB flash,
but the hardware can be configured for booting from the 64MB
flash as well by swapping CS0 and CS6. This can be handy
for recovery purposes, or for supporting u-boot and VxBoot
at the same time.
To support this in u-boot, we need to have different BR0/OR0
and BR6/OR6 settings in place for when the board is configured
in this way, and a different TEXT_BASE needs to be used due
to the larger sector size of the 64MB flash module.
We introduce the suffix _8M and _64M for the BR0/BR6 and the
OR0/OR6 values so it is clear which is being used to map what
specific device.
The larger sector size (512k) of the alternate flash needs
a larger malloc pool, otherwise you'll get failures when
running saveenv, so bump it up accordingly.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
The current situation has the 64MB user flash at an awkward
alignment; shifted back from 0xfc00_0000 by 8M, to leave an 8MB hole
for the soldered on boot flash @ EOM. But to switch to optionally
supporting booting off the 64MB flash, the 64MB will then be mapped
at the sane address of 0xfc00_0000.
This leads to awkward things when programming the 64MB flash prior
to transitioning to it -- i.e. even though the chip spans from
0xfb80_0000 to 0xff7f_ffff, you would have to program a u-boot image
into the two sectors from 0xfbf0_0000 --> 0xfbff_ffff so that it was
in the right place when JP12/SW2.8 were switched to make the 64MB on
/CS0. (i.e. the chip is only looking at the bits in mask 0x3ff_ffff)
We also have to have three TLB entries responsible for dealing with
mapping the 64MB flash due to this 8MB of misalignment.
In the end, there is address space from 0xec00_0000 to 0xefff_ffff
where we can map it, and then the transition from booting from one
config to the other will be a simple 0xec --> 0xfc mapping. Plus we
can toss out a TLB entry.
Note that TLB0 is kept at 64MB and not shrunk down to the 8MB boot
flash; this means we won't have to change it when the alternate
config uses the full 64MB for booting, in TLB0.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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>
The previous README.sbc8548 was pretty much content-free. Replace
it with something that actually gives the end user some relevant
hardware details, and also lists the u-boot configuration choices.
Also in the cosmetic department, fix the bogus line in the Makefile
that was carried over from the SBC8560 Makefile, and the typo in
the sbc8548.c copyright.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
