On 11/16/2016 08:27 PM, Dinh Nguyen wrote: > > > 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 <[email protected]> >> Cc: Chin Liang See <[email protected]> >> Cc: Dinh Nguyen <[email protected]> >> Cc: Stefan Roese <[email protected]> >> --- >> 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 <[email protected]>
That's great, thanks for checking ! You probably want to propagate this fix to your downstream U-Boot mutation and also that MPL loader. -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
