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Diffstat (limited to 'arch/cris/arch-v10/boot/rescue/head.S')
| -rw-r--r-- | arch/cris/arch-v10/boot/rescue/head.S | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/arch/cris/arch-v10/boot/rescue/head.S b/arch/cris/arch-v10/boot/rescue/head.S new file mode 100644 index 00000000000..8689ea972c4 --- /dev/null +++ b/arch/cris/arch-v10/boot/rescue/head.S @@ -0,0 +1,333 @@ +/* $Id: head.S,v 1.6 2003/04/09 08:12:43 pkj Exp $ + * + * Rescue code, made to reside at the beginning of the + * flash-memory. when it starts, it checks a partition + * table at the first sector after the rescue sector. + * the partition table was generated by the product builder + * script and contains offsets, lengths, types and checksums + * for each partition that this code should check. + * + * If any of the checksums fail, we assume the flash is so + * corrupt that we cant use it to boot into the ftp flash + * loader, and instead we initialize the serial port to + * receive a flash-loader and new flash image. we dont include + * any flash code here, but just accept a certain amount of + * bytes from the serial port and jump into it. the downloaded + * code is put in the cache. + * + * The partitiontable is designed so that it is transparent to + * code execution - it has a relative branch opcode in the + * beginning that jumps over it. each entry contains extra + * data so we can add stuff later. + * + * Partition table format: + * + * Code transparency: + * + * 2 bytes [opcode 'nop'] + * 2 bytes [opcode 'di'] + * 4 bytes [opcode 'ba <offset>', 8-bit or 16-bit version] + * 2 bytes [opcode 'nop', delay slot] + * + * Table validation (at +10): + * + * 2 bytes [magic/version word for partitiontable - 0xef, 0xbe] + * 2 bytes [length of all entries plus the end marker] + * 4 bytes [checksum for the partitiontable itself] + * + * Entries, each with the following format, last has offset -1: + * + * 4 bytes [offset in bytes, from start of flash] + * 4 bytes [length in bytes of partition] + * 4 bytes [checksum, simple longword sum] + * 2 bytes [partition type] + * 2 bytes [flags, only bit 0 used, ro/rw = 1/0] + * 16 bytes [reserved for future use] + * + * End marker + * + * 4 bytes [-1] + * + * 10 bytes [0, padding] + * + * Bit 0 in flags signifies RW or RO. The rescue code only bothers + * to check the checksum for RO partitions, since the others will + * change their data without updating the checksums. A 1 in bit 0 + * means RO, 0 means RW. That way, it is possible to set a partition + * in RO mode initially, and later mark it as RW, since you can always + * write 0's to the flash. + * + * During the wait for serial input, the status LED will flash so the + * user knows something went wrong. + * + * Copyright (C) 1999, 2000, 2001, 2002, 2003 Axis Communications AB + */ + +#include <linux/config.h> +#define ASSEMBLER_MACROS_ONLY +#include <asm/arch/sv_addr_ag.h> + + ;; The partitiontable is looked for at the first sector after the boot + ;; sector. Sector size is 65536 bytes in all flashes we use. + +#define PTABLE_START CONFIG_ETRAX_PTABLE_SECTOR +#define PTABLE_MAGIC 0xbeef + + ;; The normal Etrax100 on-chip boot ROM does serial boot at 0x380000f0. + ;; That is not where we put our downloaded serial boot-code. The length is + ;; enough for downloading code that loads the rest of itself (after + ;; having setup the DRAM etc). It is the same length as the on-chip + ;; ROM loads, so the same host loader can be used to load a rescued + ;; product as well as one booted through the Etrax serial boot code. + +#define CODE_START 0x40000000 +#define CODE_LENGTH 784 + +#ifdef CONFIG_ETRAX_RESCUE_SER0 +#define SERXOFF R_SERIAL0_XOFF +#define SERBAUD R_SERIAL0_BAUD +#define SERRECC R_SERIAL0_REC_CTRL +#define SERRDAT R_SERIAL0_REC_DATA +#define SERSTAT R_SERIAL0_STATUS +#endif +#ifdef CONFIG_ETRAX_RESCUE_SER1 +#define SERXOFF R_SERIAL1_XOFF +#define SERBAUD R_SERIAL1_BAUD +#define SERRECC R_SERIAL1_REC_CTRL +#define SERRDAT R_SERIAL1_REC_DATA +#define SERSTAT R_SERIAL1_STATUS +#endif +#ifdef CONFIG_ETRAX_RESCUE_SER2 +#define SERXOFF R_SERIAL2_XOFF +#define SERBAUD R_SERIAL2_BAUD +#define SERRECC R_SERIAL2_REC_CTRL +#define SERRDAT R_SERIAL2_REC_DATA +#define SERSTAT R_SERIAL2_STATUS +#endif +#ifdef CONFIG_ETRAX_RESCUE_SER3 +#define SERXOFF R_SERIAL3_XOFF +#define SERBAUD R_SERIAL3_BAUD +#define SERRECC R_SERIAL3_REC_CTRL +#define SERRDAT R_SERIAL3_REC_DATA +#define SERSTAT R_SERIAL3_STATUS +#endif + +#define NOP_DI 0xf025050f +#define RAM_INIT_MAGIC 0x56902387 + + .text + + ;; This is the entry point of the rescue code + ;; 0x80000000 if loaded in flash (as it should be) + ;; since etrax actually starts at address 2 when booting from flash, we + ;; put a nop (2 bytes) here first so we dont accidentally skip the di + + nop + di + + jump in_cache ; enter cached area instead +in_cache: + + ;; first put a jump test to give a possibility of upgrading the rescue code + ;; without erasing/reflashing the sector. we put a longword of -1 here and if + ;; it is not -1, we jump using the value as jump target. since we can always + ;; change 1's to 0's without erasing the sector, it is possible to add new + ;; code after this and altering the jumptarget in an upgrade. + +jtcd: move.d [jumptarget], $r0 + cmp.d 0xffffffff, $r0 + beq no_newjump + nop + + jump [$r0] + +jumptarget: + .dword 0xffffffff ; can be overwritten later to insert new code + +no_newjump: +#ifdef CONFIG_ETRAX_ETHERNET + ;; Start MII clock to make sure it is running when tranceiver is reset + move.d 0x3, $r0 ; enable = on, phy = mii_clk + move.d $r0, [R_NETWORK_GEN_CONFIG] +#endif + + ;; We need to setup the bus registers before we start using the DRAM +#include "../../lib/dram_init.S" + + ;; we now should go through the checksum-table and check the listed + ;; partitions for errors. + + move.d PTABLE_START, $r3 + move.d [$r3], $r0 + cmp.d NOP_DI, $r0 ; make sure the nop/di is there... + bne do_rescue + nop + + ;; skip the code transparency block (10 bytes). + + addq 10, $r3 + + ;; check for correct magic + + move.w [$r3+], $r0 + cmp.w PTABLE_MAGIC, $r0 + bne do_rescue ; didn't recognize - trig rescue + nop + + ;; check for correct ptable checksum + + movu.w [$r3+], $r2 ; ptable length + move.d $r2, $r8 ; save for later, length of total ptable + addq 28, $r8 ; account for the rest + move.d [$r3+], $r4 ; ptable checksum + move.d $r3, $r1 + jsr checksum ; r1 source, r2 length, returns in r0 + + cmp.d $r0, $r4 + bne do_rescue ; didn't match - trig rescue + nop + + ;; ptable is ok. validate each entry. + + moveq -1, $r7 + +ploop: move.d [$r3+], $r1 ; partition offset (from ptable start) + bne notfirst ; check if it is the partition containing ptable + nop ; yes.. + move.d $r8, $r1 ; for its checksum check, skip the ptable + move.d [$r3+], $r2 ; partition length + sub.d $r8, $r2 ; minus the ptable length + ba bosse + nop +notfirst: + cmp.d -1, $r1 ; the end of the ptable ? + beq flash_ok ; if so, the flash is validated + move.d [$r3+], $r2 ; partition length +bosse: move.d [$r3+], $r5 ; checksum + move.d [$r3+], $r4 ; type and flags + addq 16, $r3 ; skip the reserved bytes + btstq 16, $r4 ; check ro flag + bpl ploop ; rw partition, skip validation + nop + btstq 17, $r4 ; check bootable flag + bpl 1f + nop + move.d $r1, $r7 ; remember boot partition offset +1: + + add.d PTABLE_START, $r1 + + jsr checksum ; checksum the partition + + cmp.d $r0, $r5 + beq ploop ; checksums matched, go to next entry + nop + + ;; otherwise fall through to the rescue code. + +do_rescue: + ;; setup port PA and PB default initial directions and data + ;; (so we can flash LEDs, and so that DTR and others are set) + + move.b CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0 + move.b $r0, [R_PORT_PA_DIR] + move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0 + move.b $r0, [R_PORT_PA_DATA] + + move.b CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0 + move.b $r0, [R_PORT_PB_DIR] + move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0 + move.b $r0, [R_PORT_PB_DATA] + + ;; setup the serial port at 115200 baud + + moveq 0, $r0 + move.d $r0, [SERXOFF] + + move.b 0x99, $r0 + move.b $r0, [SERBAUD] ; 115.2kbaud for both transmit and receive + + move.b 0x40, $r0 ; rec enable + move.b $r0, [SERRECC] + + moveq 0, $r1 ; "timer" to clock out a LED red flash + move.d CODE_START, $r3 ; destination counter + movu.w CODE_LENGTH, $r4; length + +wait_ser: + addq 1, $r1 +#ifndef CONFIG_ETRAX_NO_LEDS +#ifdef CONFIG_ETRAX_PA_LEDS + move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r2 +#endif +#ifdef CONFIG_ETRAX_PB_LEDS + move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r2 +#endif + move.d (1 << CONFIG_ETRAX_LED1R) | (1 << CONFIG_ETRAX_LED2R), $r0 + btstq 16, $r1 + bpl 1f + nop + or.d $r0, $r2 ; set bit + ba 2f + nop +1: not $r0 ; clear bit + and.d $r0, $r2 +2: +#ifdef CONFIG_ETRAX_PA_LEDS + move.b $r2, [R_PORT_PA_DATA] +#endif +#ifdef CONFIG_ETRAX_PB_LEDS + move.b $r2, [R_PORT_PB_DATA] +#endif +#ifdef CONFIG_ETRAX_90000000_LEDS + move.b $r2, [0x90000000] +#endif +#endif + + ;; check if we got something on the serial port + + move.b [SERSTAT], $r0 + btstq 0, $r0 ; data_avail + bpl wait_ser + nop + + ;; got something - copy the byte and loop + + move.b [SERRDAT], $r0 + move.b $r0, [$r3+] + + subq 1, $r4 ; decrease length + bne wait_ser + nop + + ;; jump into downloaded code + + move.d RAM_INIT_MAGIC, $r8 ; Tell next product that DRAM is initialized + jump CODE_START + +flash_ok: + ;; check r7, which contains either -1 or the partition to boot from + + cmp.d -1, $r7 + bne 1f + nop + move.d PTABLE_START, $r7; otherwise use the ptable start +1: + move.d RAM_INIT_MAGIC, $r8 ; Tell next product that DRAM is initialized + jump $r7 ; boot! + + + ;; Helper subroutines + + ;; Will checksum by simple addition + ;; r1 - source + ;; r2 - length in bytes + ;; result will be in r0 +checksum: + moveq 0, $r0 +1: addu.b [$r1+], $r0 + subq 1, $r2 + bne 1b + nop + ret + nop |