Hello!
It seems that there might be some problem with relocation on P2020RDB-PC board when U-Boot is compiled with a relatively new toolchain. It is hard to detect because it seems that the relocation leaves only some constants on their old addresses but otherwise it works fine.
I have a Turris board which is a derivative of P2020RDB-PC (it differs only in minor aspects). I have a perfectly working U-Boot (current master) compiled with ELDK 5.2.1. But compiling the same tree with anything newer (ELDK 5.5+ or current OpenWRT buildroot) causes this
U-Boot 2015.04-00008-g2b3a8e8 (Apr 21 2015 - 06:18:55)
CPU0: P2020E, Version: 2.1, (0x80ea0021) Core: e500, Version: 5.1, (0x80211051) Clock Configuration: CPU0:1200 MHz, CPU1:1200 MHz, CCB:600 MHz, DDR:400 MHz (800 MT/s data rate) (Asynchronous), LBC:37.500 MHz L1: D-cache 32 KiB enabled I-cache 32 KiB enabled Board: P2020RDB-PCA CPLD: V4.1 PCBA: V4.0 Error reading i2c boot information! I2C: ready SPI: ready DRAM: DDR: failed to read SPD from address 82 SPD error on controller 0! Trying fallback to raw timing calculation Detected UDIMM Fixed DDR on board 1 GiB (DDR3, 64-bit, CL=6, ECC off) Flash: 16 MiB L2: 512 KiB enabled NAND: 256 MiB MMC: FSL_SDHC: 0 *** Warning - bad CRC, using default environment
PCIe1: Root Complex of mini PCIe SLOT, no link, regs @ 0xffe0a000 PCIe1: Bus 00 - 00 PCIe2: Root Complex of PCIe SLOT, no link, regs @ 0xffe09000 PCIe2: Bus 01 - 01 In: serial Out: serial Err: serial Net: No address specified for VSC7385 microcode. eTSEC1 [PRIME] Error: eTSEC1 address not set. , eTSEC2 Error: eTSEC2 address not set. , eTSEC3 Error: eTSEC3 address not set.
Hit any key to stop autoboot: 0 => protect off 0xEFF00000 0xEFFFFFFF Un-Protected 8 sectors => era 0xEFF00000 0xEFFFFFFF
........ done Erased 8 sectors Bad trap at PC: 3fef785c, SR: 29200, vector=d00 NIP: 3FEF785C XER: 00000000 LR: 3FF4C6C8 REGS: 3fdedc50 TRAP: 0d00 DAR: F0000000 MSR: 00029200 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 00
GPR00: 000000FF 3FDEDD40 3FDEDF08 EFFA5C28 EFFFFFFF 3FDEDD98 3FF6D5D4 00000000 GPR08: 00000080 3FDEDDD8 00000000 EFFFFFFF 44002084 49858508 3FFB0224 0000000A GPR16: 3FF55C40 3FF55C38 3FF55C30 0000000A 00000000 00000000 3FFB0220 EFFA5C28 GPR24: 00000000 00000002 00000000 00000000 3FDEDDD8 3FDEDD98 3FF689F4 3FF6D5D4 Call backtrace: 3FDF3668 3FF12D4C 3FEFAAA0 3FEFB15C 3FF186F4 3FEFB8F0 3FF46C34 3FEFBCAC 3FEF164C Exception in kernel pc 3fef785c signal 0
ERROR ### Please RESET the board
I looked into that and it seems that the exception occurs when hush calls getenv("IFS") (common/cli_hush.c:3133) in a subsequent strcat() because "IFS" is actually a pointer to already-erased flash (0xeff...).
I have to admit that I don't understand reloc code for this CPU so I am asking this question or requesting help since I was unable to fix it or find out what is wrong on my own yet.
Thanks, Tomas