| /* 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 */ |
