u-boot/arch/arm/cpu/arm926ejs/mx28
Marek Vasut 8f975865be i.MX28: Add delay after CPU bypass is cleared
This solves issues when larger amount of DRAM is used, like 256MB.
Behave the same in case of CPU bypass as we do in case of EMI
bypass, but wait 15 ms. We need to wait until the clock domain
stabilizes.

This issue seemed to have been caused by not waiting after frobbing
with the CPU bypass, it was unrelated to memory, but had a direct
impact, causing trouble. This was yet another X-File of the
imx-bootlets, sigh. The conclusion is, trying a semi-random delay
(there is delay after the EMI bypass change), the issue is fixed.

Another possible explanation is that we do not do the "simple memory
test" FSL does in their imx-bootlets (1000 R/W cycles to/from piece of
the memory, while also outputing something on the serial port). This
might have caused the similar delay in the imx-bootlets and therefore
they didn't need to add this explicitly.

For now, this seems good fix enough, but to me, whole that memory
init code in imx-bootlets is completely flunked and it'd need deeper
investigation.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
2012-05-15 08:31:35 +02:00
..
clock.c Fix erroneous 32-bit access to hw_clkctrl_frac0 and hw_clkctrl_frac1 registers 2012-03-26 23:09:24 +02:00
iomux.c Renamed mx28_register to mx28_register_32 to prepare for mx28_register_8 2012-03-26 23:09:24 +02:00
Makefile M28: Cleanup memsize.o OOT build 2011-12-09 17:30:10 +01:00
mx28.c DMA: Split the APBH DMA init into block and channel init 2012-04-16 14:53:59 +02:00
mx28_init.h i.MX28: Move SPL to arch/arm/cpu/arm926ejs/mx28 2011-12-09 17:30:10 +01:00
spl_boot.c M28: Cleanup memsize.o OOT build 2011-12-09 17:30:10 +01:00
spl_mem_init.c i.MX28: Add delay after CPU bypass is cleared 2012-05-15 08:31:35 +02:00
spl_power_init.c i.MX28: Make the stabilization delays shorter 2012-03-27 09:41:16 +02:00
start.S mx28: fix SPL code to make USB booting work 2012-02-27 21:19:23 +01:00
timer.c MX28: Fix get_timer() / get_tbclk() issue 2012-02-27 21:19:23 +01:00
u-boot-spl.lds M28: Cleanup memsize.o OOT build 2011-12-09 17:30:10 +01:00