Howdy, I'm a beginner of embedded system. I'm working on a board of Walnut PPC405GP which use PPCBOOT 1.1.2. One day I tried to write some data into unused area of the flash:
fli
Bank # 1: AMD AM29F040 (512 Kbit, uniform sector size) Size: 512 KB in 8 Sectors Sector Start Addresses: FFF80000 RO FFF90000 RO FFFA0000 RO FFFB0000 FFFC0000 FFFD0000 FFFE0000 FFFF0000
I use the last sector:
md ffff0000
ffff0000: 00000000 00000000 00000000 00000000 ................ ffff0010: 00000000 00000000 00000000 00000000 ................ ffff0020: 00000000 00000000 00000000 00000000 ................ ffff0030: 00000000 00000000 00000000 00000000 ................ ffff0040: 00000000 00000000 00000000 00000000 ................ ffff0050: 00000000 00000000 00000000 00000000 ................ ffff0060: 00000000 00000000 00000000 00000000 ................ ffff0070: 00000000 00000000 00000000 00000000 ................ ffff0080: 00000000 00000000 00000000 00000000 ................ ffff0090: 00000000 00000000 00000000 00000000 ................ ffff00a0: 00000000 00000000 00000000 00000000 ................ ffff00b0: 00000000 00000000 00000000 00000000 ................ ffff00c0: 00000000 00000000 00000000 00000000 ................ ffff00d0: 00000000 00000000 00000000 00000000 ................ ffff00e0: 00000000 00000000 00000000 00000000 ................ ffff00f0: 00000000 00000000 00000000 00000000 ................
protected off ffff0000 ffffffff
Un-Protected 1 sectors
erase ffff0000 ffffffff
Erase Flash from 0xffff0000 to 0xffffffff Erasing sector ffff0000 . done Erased 1 sectors
!! Now I tried to copy a small file data to this area by using tftp.
tftp ffff0000 data_file
405GP Eth Status: data len error 0 rx frames 0 rx 0 rx_prot_err 0 int_err 0 tx_err_log: [0] 0 [1] 0 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 [8] 0 [9] 0 rx_err_log: [0] 0 [1] 0 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 [8] 0 [9] 0
ENET Speed is 100 Mbps - FULL duplex connection *** ERROR: `ipaddr' not set Well, set the target addr first, then:
dhcp
405GP Eth Status: data len error 0 rx frames 0 rx 0 rx_prot_err 0 int_err 0 tx_err_log: [0] 0 [1] 0 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 [8] 0 [9] 0 rx_err_log: [0] 0 [1] 0 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 [8] 0 [9] 0
ENET Speed is 100 Mbps - FULL duplex connection BOOTP broadcast 1 DHCPHandler: got packet: (src=67, dst=68, len=548) state: 3 Filtering pkt = 0 DHCPHandler: got DHCP packet: (src=67, dst=68, len=548) state: 3 DHCP: state=SELECTING bp_file: "uImage" TRANSITIONING TO REQUESTING STATE Bootfile: uImage DhcpSendRequestPkt: Sending DHCPREQUEST Transmitting DHCPREQUEST packet: len = 308 DHCPHandler: got packet: (src=67, dst=68, len=548) state: 4 Filtering pkt = 0 DHCPHandler: got DHCP packet: (src=67, dst=68, len=548) state: 4 DHCP State: REQUESTING Bootfile: uImage DHCP client bound to address 192.168.1.201 ARP broadcast 1 Got good ARP - start TFTP TFTP from server 192.168.1.200; our IP address is 192.168.1.201 Filename 'uImage'. Load address: 0xffff0000 Loading: *##############NIP: 00000200 XER: 00000000 LR: 67E12A71 REGS: 01faea48 TRAP: 0700 DAR: 00080000 MSR: 00000000 EE: 0 PR: 0 FP: 0 ME: 0 IR/DR: 00
GPR00: 00000001 01FAEB38 40000000 01FAEB48 80000000 00000002 01FB016D 01C80764 GPR08: 01FF5060 01FF5074 FFFFFFFF 01FF54B4 00000000 7C6BFE6C 01FF4400 02050000 GPR16: E45EA284 DC212086 02CACA22 F3844306 00001000 01FAEB38 00000000 67E12A71 GPR24: 76585F5E 00000001 00000000 01FAEF8C 00000004 00000000 01FF44CC 01FF52A4 ** Illegal Instruction ** Call backtrace: Program Check Exception
======================== You can see my mistake...>_< A big uImage file is copied to flash, rather than data_file. After that, the Walnut board cannot boot anymore... I wonder why. The data is simply copied to the unused sector, while other sectors are under protection. It should be safe even if I made mistakes.
Thank you very much. --- ShenLei