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Diffstat (limited to 'c/src/lib/libbsp/powerpc/mpc8260ads/start/start.S')
| -rw-r--r-- | c/src/lib/libbsp/powerpc/mpc8260ads/start/start.S | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/powerpc/mpc8260ads/start/start.S b/c/src/lib/libbsp/powerpc/mpc8260ads/start/start.S new file mode 100644 index 0000000000..b517c175c9 --- /dev/null +++ b/c/src/lib/libbsp/powerpc/mpc8260ads/start/start.S @@ -0,0 +1,191 @@ +/* start.S + * + * $Id$ + * + * Modified for the Motorola PQII ADS board by + * Andy Dachs <a.dachs@sstl.co.uk> 23-11-00. + * Surrey Satellite Technology Limited + * + * I have a proprietary bootloader programmed into the flash + * on the board which initialises the SDRAM prior to calling + * this function. + * + * This file is based on the one by Jay Monkman (jmonkman@fracsa.com) + * which in turn was based on the dlentry.s file for the Papyrus BSP, + * written by: + * + * Author: Andrew Bray <andy@i-cubed.co.uk> + * + * COPYRIGHT (c) 1995 by i-cubed ltd. + * + * To anyone who acknowledges that this file is provided "AS IS" + * without any express or implied warranty: + * permission to use, copy, modify, and distribute this file + * for any purpose is hereby granted without fee, provided that + * the above copyright notice and this notice appears in all + * copies, and that the name of i-cubed limited not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * i-cubed limited makes no representations about the suitability + * of this software for any purpose. + * + */ + +#include "asm.h" + +/* + * The initial stack is set to run BELOW the code base address. + * (between the vectors and text sections) + * + * The entry veneer has to clear the BSS and copy the read only + * version of the data segment to the correct location. + */ + + + .section ".entry" /* This might have to be the first thing in the + * text section. At one time, it had to be + * first, but I don't believe it is true + * any more. */ + PUBLIC_VAR (start) +SYM(start): + bl .startup +base_addr: + +/* + * Parameters from linker + */ +toc_pointer: + .long s.got +bss_length: + .long bss.size +bss_addr: + .long bss.start + +PUBLIC_VAR (data_length ) +data_length: + .long data.size +PUBLIC_VAR (data_addr ) +data_addr: + .long data.start + + + +PUBLIC_VAR (text_addr) +text_addr: + .long text.start + +PUBLIC_VAR (text_length) +text_length: + .long text.size + + +/* + * Initialization code + */ +.startup: + /* Get start address */ + mflr r1 + + + /* -------------------------------------------------- + * Clear MSR[EE] to disable interrupts + * Clear MSR[IP] bit to put vectors at 0x00000000 + * Set MSR[FP] to enable FPU - not on my eval board! + * -------------------------------------------------- */ + mfmsr r5 + lis r13, 0xFFFF + ori r13, r13, 0x7FBF + and r5, r5, r13 /* Clear EE and IP */ +#if 1 + ori r5, r5, 0x2000 /* Enable FPU */ +#endif + mtmsr r5 + + + + +#ifdef ENABLE_CACHE + /* Enable caches */ + mfspr r5, 1008 + ori r5, r5, 0x8000 + isync + mtspr 1008, r5 + +/* Leave D-cache disabled for now */ +#if 0 + ori r5, r5, 0x4000 + sync + mtspr 1008, r5 +#endif +#endif + + + /*-------------------------------------------------- + * Set up the power management modes + * The 8260 has a dynamic power management mode that + * is automatically invoked if the unit is idle. + * We invoke the NAP mode in the RTEMS idle task. + *-------------------------------------------------- */ + + lis r13, 0x0050 /* set nap mode and DPM */ + or r5, r5, r13 + mtspr 1008, r5 + + /*-------------------------------------------------- + * + *-------------------------------------------------- */ + + + + /* clear the bss section */ + bl bssclr + + +/* + * C_setup. + */ + + /* set toc */ + lwz r2, toc_pointer-base_addr(r1) + + /* Set up stack pointer = beginning of text section - 56 */ + addi r1, r1, -56-4 + + + /* clear argc and argv */ + xor r3, r3, r3 + xor r4, r4, r4 + + .extern SYM (boot_card) + bl SYM (boot_card) /* call the first C routine */ + + + + /* we don't expect to return from boot_card but if we do */ + /* wait here for watchdog to kick us into hard reset */ + + +twiddle: + b twiddle + + +/* + * bssclr - zero out bss + */ +bssclr: + lwz r4, bss_addr-base_addr(r1) /* Start of bss */ + lwz r5, bss_length-base_addr(r1) /* Length of bss */ + + rlwinm. r5,r5,30,0x3FFFFFFF /* form length/4 */ + beqlr /* no bss */ + mtctr r5 /* set ctr reg */ + xor r6,r6,r6 /* r6 = 0 */ +clear_bss: + stswi r6,r4,0x4 /* store r6 */ + addi r4,r4,0x4 /* update r2 */ + + bdnz clear_bss /* dec counter and loop */ + blr /* return */ + + + |