In case the MX23/MX28 is switched into JTAG mode via the BootMode select
switches, the BootROM bypasses the CPU core registers initialization.
This in turn means that the Stack Pointer (SP) register is not set as
it is in every other mode of operation, but instead is only zeroed out.
To prevent U-Boot SPL from crashing in this obscure JTAG mode, configure
the SP to point at the CONFIG_SYS_INIT_SP_ADDR if the SP is zeroed out.
Note that in case the SP is already configured, we must preserve that exact
SP value and must not modify it. This is important since in every other mode
but the JTAG mode, the SPL returns into the BootROM and BootROM in turn loads
U-Boot itself. If the SP were to be corrupted, the BootROM won't be able to
continue it's operation after returned from SPL and the system would crash.
Finally, add the JTAG mode switch identifier, so it's not recognised as
Unknown mode.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Make sure value in register r0 and r1 is preserved and passed to
the board_init_ll() and mxs_common_spl_init() where it can be
processed further. The value in r0 can be configured during the
BootStream generation to arbitary value, r1 contains pointer to
return value from CALL'd function.
This patch also clears the value in r0 before returning to BootROM
to make sure the BootROM is not confused by this value.
Finally, this patch cleans up some comments in the start.S file.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
_TEXT_BASE must be set to CONFIG_SPL_TEXT_BASE for generic SPL, and to
CONFIG_SYS_TEXT_BASE for non-SPL builds.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Reviewed-by: Tom Rini <trini@ti.com>
Note this is a tree-wide change affecting multiple architectures.
At present we use __bss_start, but mostly __bss_end__. This seems
inconsistent and in a number of places __bss_end is used instead.
Change to use __bss_end for the BSS end symbol throughout U-Boot. This
makes it possible to use the asm-generic/sections.h file on all
archs.
Signed-off-by: Simon Glass <sjg@chromium.org>
The SPL doesn't need the CP15 reconfiguration, as that's what the
BootROM does for us already. Moreover, when the CP15 is reconfigured
and the code returns control to BootROM, the USB boot works no more.
Remove the code and allow [1] to work properly as well.
[1] http://git.bfuser.eu/?p=marex/mxsldr.git;a=summary
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Most code can be shared between i.MX23 and i.MX28 as both are from
i.MXS family; this source directory structure makes easy to share code
among them.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Stefano Babic <sbabic@denx.de>
2012-09-01 14:58:17 +02:00
Renamed from arch/arm/cpu/arm926ejs/mx28/start.S (Browse further)
