/* * (C) Copyright 2003, Psyent Corporation <www.psyent.com> * Scott McNutt <smcnutt@psyent.com> * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <config.h> #include <version.h> #if !defined(CONFIG_IDENT_STRING) #define CONFIG_IDENT_STRING "" #endif #define STATUS_INIT 0x8600 /* IE=1, IPRI=2 */ /************************************************************************* * RESTART ************************************************************************/ .text .global _start _start: bsr 0f nop .long _start /* GERMS -- The "standard-32" configuration GERMS monitor looks * for the string "Nios" at flash_base + 0xc (actually it only * tests for 'N', 'i'). You can leave support for this in place * as it's only a few words. */ . = _start + 0x000c .string "Nios" .align 4 0: /* * Early setup -- set cwp = HI_LIMIT, IPRI = 2, IE = 1 to * enable underflow exceptions. Disable cache. * NOTE: %o7 has return addr -- save in %g7 use later. */ mov %g7, %o7 pfx 2 /* WVALID */ rdctl %g0 lsri %g0, 1 pfx %hi(STATUS_INIT) or %g0, %lo(STATUS_INIT) wrctl %g0 /* update status */ nop /* * STACK */ pfx %hi(CFG_INIT_SP) movi %sp, %lo(CFG_INIT_SP) pfx %xhi(CFG_INIT_SP) movhi %sp, %xlo(CFG_INIT_SP) mov %fp, %sp pfx %hi(4*16) subi %sp, %lo(4*16) /* Space for reg window mgmt */ /* * RELOCATE -- %g7 has return addr from bsr at _start. */ pfx %hi(__u_boot_cmd_end) movi %g5, %lo(__u_boot_cmd_end) pfx %xhi(__u_boot_cmd_end) movhi %g5, %xlo(__u_boot_cmd_end) /* %g5 <- end address */ lsli %g7, 1 /* mem = retaddr << 1 */ mov %g6, %g7 subi %g6, 4 /* %g6 <- src addr */ ld %g7, [%g7] /* %g7 <- dst addr */ /* No need to move text sections if we're already located * at the proper address. */ cmp %g7, %g6 ifs cc_z br reloc nop /* delay slot */ 1: cmp %g7, %g5 skps cc_nz br 2f nop /* delay slot */ ld %g0, [%g6] addi %g6, 4 /* src++ */ st [%g7], %g0 addi %g7, 4 /* dst++ */ br 1b nop /* delay slot */ 2: /* * Jump to relocation address */ pfx %hi(reloc@h) movi %g0, %lo(reloc@h) pfx %xhi(reloc@h) movhi %g0, %xlo(reloc@h) jmp %g0 nop /* delay slot */ reloc: /* * CLEAR BSS */ pfx %hi(__bss_end) movi %g5, %lo(__bss_end) pfx %xhi(__bss_end) movhi %g5, %xlo(__bss_end) /* %g5 <- end address */ pfx %hi(__bss_start) movi %g7, %lo(__bss_start) pfx %xhi(__bss_start) movhi %g7, %xlo(__bss_start) /* %g7 <- end address */ movi %g0, 0 3: cmp %g7, %g5 skps cc_nz br 4f nop /* delay slot */ st [%g7], %g0 addi %g7, 4 /* (delay slot) dst++ */ br 3b nop /* delay slot */ 4: /* * INIT VECTOR TABLE */ pfx %hi(CFG_VECT_BASE) movi %g0, %lo(CFG_VECT_BASE) pfx %xhi(CFG_VECT_BASE) movhi %g0, %xlo(CFG_VECT_BASE) /* dst */ mov %l0, %g0 pfx %hi(_vectors) movi %g1, %lo(_vectors) pfx %xhi(_vectors) movhi %g1, %xlo(_vectors) /* src */ bgen %g2, 6 /* cnt = 64 */ ldp %g3, [%l0, 3] /* bkpt vector */ ldp %g4, [%l0, 4] /* single step vector */ 5: ld %g7, [%g1] addi %g1, 4 /* src++ */ st [%g0], %g7 addi %g0, 4 /* dst++ */ subi %g2, 1 /* cnt-- */ ifrnz %g2 br 5b nop /* delay slot */ #if defined(CONFIG_ROM_STUBS) /* Restore the breakpoint and single step exception * vectors to their original values. */ stp [%l0,3], %g3 /* breakpoint */ stp [%l0,4], %g4 /* single step */ #endif /* For debug startup convenience ... software breakpoints * set prior to this point may not succeed ;-) */ .global __start __start: /* * Call board_init -- never returns */ pfx %hi(board_init@h) movi %g1, %lo(board_init@h) pfx %xhi(board_init@h) movhi %g1, %xlo(board_init@h) call %g1 nop /* Delaly slot */ /* NEVER RETURNS */ /* * dly_clks -- Nios doesn't have a time/clk reference for simple * delay loops, so we do our best by counting instruction cycles. * A control register that counts system clock cycles would be * a handy feature -- hint for Altera ;-) */ .globl dly_clks /* Each loop is 4 instructions as delay slot is always * executed. Each instruction is approximately 4 clocks * (according to some lame info from Altera). So ... * ... each loop is about 16 clocks. */ dly_clks: lsri %o0, 4 /* cnt/16 */ 8: skprnz %o0 br 9f subi %o0, 1 /* cnt--, Delay slot */ br 8b nop 9: lret nop /* Delay slot */ .data .globl version_string version_string: .ascii U_BOOT_VERSION .ascii " (", __DATE__, " - ", __TIME__, ")" .ascii CONFIG_IDENT_STRING, "\0"