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