On 11/16/2016 10:54 AM, Marek Vasut wrote: > Valid Altera SoCFPGA preloader image must contain special data at > offsets 0x40, 0x44, 0x48 and valid instructions at address 0x4c or > 0x50. These addresses are by default used by U-Boot's vector table > and a piece of reset handler, thus a valid preloader corrupts those > addresses slightly. While this works most of the time, this can and > does prevent the board from rebooting sometimes and triggering this > issue may even depend on compiler. > > The problem is that when SoCFPGA performs warm reset, it checks the > addresses 0x40..0x4b in SRAM for a valid preloader signature and > header checksum. If those are found, it jumps to address 0x4c or > 0x50 (this is unclear). These addresses are populated by the first > few instructions of arch/arm/cpu/armv7/start.S: > > ffff0040 <data_abort>: > ffff0040: ebfffffe bl ffff0040 <data_abort> > > ffff0044 <reset>: > ffff0044: ea000012 b ffff0094 <save_boot_params> > > ffff0048 <save_boot_params_ret>: > ffff0048: e10f0000 mrs r0, CPSR > ffff004c: e200101f and r1, r0, #31 > ffff0050: e331001a teq r1, #26 > > Without this patch, the CPU will enter the code at 0xffff004c or > 0xffff0050 , at which point the value of r0 and r1 registers is > undefined. Moreover, jumping directly to the preloader entry point > at address 0xffff0000 will also fail, because address 0xffff004. > is invalid and contains the preloader magic. > > Add BOOT0 hook which reserves the area at offset 0x40..0x5f and > populates offset 0x50 with jump to the entry point. This way, the > preloader signature is stored in reserved space and can not corrupt > the SPL code. > > Signed-off-by: Marek Vasut <ma...@denx.de> > Cc: Chin Liang See <cl...@altera.com> > Cc: Dinh Nguyen <dingu...@opensource.altera.com> > Cc: Stefan Roese <s...@denx.de> > --- > arch/arm/Kconfig | 1 + > arch/arm/mach-socfpga/include/mach/boot0.h | 28 ++++++++++++++++++++++++++++ > 2 files changed, 29 insertions(+) > create mode 100644 arch/arm/mach-socfpga/include/mach/boot0.h
With this patch, I can properly do a soft reset on an Atlas DE0 Nano board. So feel free to add: Tested-by: Dinh Nguyen <dingu...@opensource.altera.com> Dinh _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
