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Diffstat (limited to 'arch/m68k/68000/head.S')
| -rw-r--r-- | arch/m68k/68000/head.S | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/arch/m68k/68000/head.S b/arch/m68k/68000/head.S new file mode 100644 index 000000000..140220662 --- /dev/null +++ b/arch/m68k/68000/head.S @@ -0,0 +1,241 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * head.S - Common startup code for 68000 core based CPU's + * + * 2012.10.21, Luis Alves <ljalvs@gmail.com>, Single head.S file for all + * 68000 core based CPU's. Based on the sources from: + * Coldfire by Greg Ungerer <gerg@snapgear.com> + * 68328 by D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>, + * Kenneth Albanowski <kjahds@kjahds.com>, + * The Silver Hammer Group, Ltd. + * + */ + +#include <linux/linkage.h> +#include <linux/init.h> +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> + + +/***************************************************************************** + * UCSIMM and UCDIMM use CONFIG_MEMORY_RESERVE to reserve some RAM + *****************************************************************************/ +#ifdef CONFIG_MEMORY_RESERVE +#define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE)-(CONFIG_MEMORY_RESERVE*0x100000) +#else +#define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE) +#endif +/*****************************************************************************/ + +.global _start +.global _rambase +.global _ramvec +.global _ramstart +.global _ramend + +#if defined(CONFIG_PILOT) || defined(CONFIG_INIT_LCD) +.global bootlogo_bits +#endif + +/* Defining DEBUG_HEAD_CODE, serial port in 68x328 is inited */ +/* #define DEBUG_HEAD_CODE */ +#undef DEBUG_HEAD_CODE + +.data + +/***************************************************************************** + * RAM setup pointers. Used by the kernel to determine RAM location and size. + *****************************************************************************/ + +_rambase: + .long 0 +_ramvec: + .long 0 +_ramstart: + .long 0 +_ramend: + .long 0 + +__HEAD + +/***************************************************************************** + * Entry point, where all begins! + *****************************************************************************/ + +_start: + +/* Pilot need this specific signature at the start of ROM */ +#ifdef CONFIG_PILOT + .byte 0x4e, 0xfa, 0x00, 0x0a /* bra opcode (jmp 10 bytes) */ + .byte 'b', 'o', 'o', 't' + .word 10000 + nop + moveq #0, %d0 + movew %d0, 0xfffff618 /* Watchdog off */ + movel #0x00011f07, 0xfffff114 /* CS A1 Mask */ +#endif /* CONFIG_PILOT */ + + movew #0x2700, %sr /* disable all interrupts */ + +/***************************************************************************** + * Setup PLL and wait for it to settle (in 68x328 cpu's). + * Also, if enabled, init serial port. + *****************************************************************************/ +#if defined(CONFIG_M68328) || \ + defined(CONFIG_M68EZ328) || \ + defined(CONFIG_M68VZ328) + +/* Serial port setup. Should only be needed if debugging this startup code. */ +#ifdef DEBUG_HEAD_CODE + movew #0x0800, 0xfffff906 /* Ignore CTS */ + movew #0x010b, 0xfffff902 /* BAUD to 9600 */ + movew #0xe100, 0xfffff900 /* enable */ +#endif /* DEBUG_HEAD */ + +#ifdef CONFIG_PILOT + movew #0x2410, 0xfffff200 /* PLLCR */ +#else + movew #0x2400, 0xfffff200 /* PLLCR */ +#endif + movew #0x0123, 0xfffff202 /* PLLFSR */ + moveq #0, %d0 + movew #16384, %d0 /* PLL settle wait loop */ +_pll_settle: + subw #1, %d0 + bne _pll_settle +#endif /* CONFIG_M68x328 */ + + +/***************************************************************************** + * If running kernel from ROM some specific initialization has to be done. + * (Assuming that everything is already init'ed when running from RAM) + *****************************************************************************/ +#ifdef CONFIG_ROMKERNEL + +/***************************************************************************** + * Init chip registers (uCsimm specific) + *****************************************************************************/ +#ifdef CONFIG_UCSIMM + moveb #0x00, 0xfffffb0b /* Watchdog off */ + moveb #0x10, 0xfffff000 /* SCR */ + moveb #0x00, 0xfffff40b /* enable chip select */ + moveb #0x00, 0xfffff423 /* enable /DWE */ + moveb #0x08, 0xfffffd0d /* disable hardmap */ + moveb #0x07, 0xfffffd0e /* level 7 interrupt clear */ + movew #0x8600, 0xfffff100 /* FLASH at 0x10c00000 */ + movew #0x018b, 0xfffff110 /* 2Meg, enable, 0ws */ + movew #0x8f00, 0xfffffc00 /* DRAM configuration */ + movew #0x9667, 0xfffffc02 /* DRAM control */ + movew #0x0000, 0xfffff106 /* DRAM at 0x00000000 */ + movew #0x068f, 0xfffff116 /* 8Meg, enable, 0ws */ + moveb #0x40, 0xfffff300 /* IVR */ + movel #0x007FFFFF, %d0 /* IMR */ + movel %d0, 0xfffff304 + moveb 0xfffff42b, %d0 + andb #0xe0, %d0 + moveb %d0, 0xfffff42b +#endif + +/***************************************************************************** + * Init LCD controller. + * (Assuming that LCD controller is already init'ed when running from RAM) + *****************************************************************************/ +#ifdef CONFIG_INIT_LCD +#ifdef CONFIG_PILOT + moveb #0, 0xfffffA27 /* LCKCON */ + movel #_start, 0xfffffA00 /* LSSA */ + moveb #0xa, 0xfffffA05 /* LVPW */ + movew #0x9f, 0xFFFFFa08 /* LXMAX */ + movew #0x9f, 0xFFFFFa0a /* LYMAX */ + moveb #9, 0xfffffa29 /* LBAR */ + moveb #0, 0xfffffa25 /* LPXCD */ + moveb #0x04, 0xFFFFFa20 /* LPICF */ + moveb #0x58, 0xfffffA27 /* LCKCON */ + moveb #0x85, 0xfffff429 /* PFDATA */ + moveb #0xd8, 0xfffffA27 /* LCKCON */ + moveb #0xc5, 0xfffff429 /* PFDATA */ + moveb #0xd5, 0xfffff429 /* PFDATA */ + movel #bootlogo_bits, 0xFFFFFA00 /* LSSA */ + moveb #10, 0xFFFFFA05 /* LVPW */ + movew #160, 0xFFFFFA08 /* LXMAX */ + movew #160, 0xFFFFFA0A /* LYMAX */ +#else /* CONFIG_PILOT */ + movel #bootlogo_bits, 0xfffffA00 /* LSSA */ + moveb #0x28, 0xfffffA05 /* LVPW */ + movew #0x280, 0xFFFFFa08 /* LXMAX */ + movew #0x1df, 0xFFFFFa0a /* LYMAX */ + moveb #0, 0xfffffa29 /* LBAR */ + moveb #0, 0xfffffa25 /* LPXCD */ + moveb #0x08, 0xFFFFFa20 /* LPICF */ + moveb #0x01, 0xFFFFFA21 /* -ve pol */ + moveb #0x81, 0xfffffA27 /* LCKCON */ + movew #0xff00, 0xfffff412 /* LCD pins */ +#endif /* CONFIG_PILOT */ +#endif /* CONFIG_INIT_LCD */ + +/***************************************************************************** + * Kernel is running from FLASH/ROM (XIP) + * Copy init text & data to RAM + *****************************************************************************/ + moveal #_etext, %a0 + moveal #_sdata, %a1 + moveal #__bss_start, %a2 +_copy_initmem: + movel %a0@+, %a1@+ + cmpal %a1, %a2 + bhi _copy_initmem +#endif /* CONFIG_ROMKERNEL */ + +/***************************************************************************** + * Setup basic memory information for kernel + *****************************************************************************/ + movel #CONFIG_VECTORBASE,_ramvec /* set vector base location */ + movel #CONFIG_RAMBASE,_rambase /* set the base of RAM */ + movel #RAMEND, _ramend /* set end ram addr */ + lea __bss_stop,%a1 + movel %a1,_ramstart + +/***************************************************************************** + * If the kernel is in RAM, move romfs to right above bss and + * adjust _ramstart to where romfs ends. + * + * (Do this only if CONFIG_MTD_UCLINUX is true) + *****************************************************************************/ + +#if defined(CONFIG_ROMFS_FS) && defined(CONFIG_RAMKERNEL) && \ + defined(CONFIG_MTD_UCLINUX) + lea __bss_start, %a0 /* get start of bss */ + lea __bss_stop, %a1 /* set up destination */ + movel %a0, %a2 /* copy of bss start */ + + movel 8(%a0), %d0 /* get size of ROMFS */ + addql #8, %d0 /* allow for rounding */ + andl #0xfffffffc, %d0 /* whole words */ + + addl %d0, %a0 /* copy from end */ + addl %d0, %a1 /* copy from end */ + movel %a1, _ramstart /* set start of ram */ +_copy_romfs: + movel -(%a0), -(%a1) /* copy dword */ + cmpl %a0, %a2 /* check if at end */ + bne _copy_romfs +#endif /* CONFIG_ROMFS_FS && CONFIG_RAMKERNEL && CONFIG_MTD_UCLINUX */ + +/***************************************************************************** + * Clear bss region + *****************************************************************************/ + lea __bss_start, %a0 /* get start of bss */ + lea __bss_stop, %a1 /* get end of bss */ +_clear_bss: + movel #0, (%a0)+ /* clear each word */ + cmpl %a0, %a1 /* check if at end */ + bne _clear_bss + +/***************************************************************************** + * Load the current task pointer and stack. + *****************************************************************************/ + lea init_thread_union,%a0 + lea THREAD_SIZE(%a0),%sp + jsr start_kernel /* start Linux kernel */ +_exit: + jmp _exit /* should never get here */ |