/* * armboot - Startup Code for ARM926EJS CPU-core * * Copyright (c) 2003 Texas Instruments * * ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------ * * Copyright (c) 2001 Marius Groger * Copyright (c) 2002 Alex Zupke * Copyright (c) 2002 Gary Jennejohn * Copyright (c) 2003 Richard Woodruff * Copyright (c) 2003 Kshitij * Copyright (c) 2010 Albert Aribaud * * Change to support call back into iMX28 bootrom * Copyright (c) 2011 Marek Vasut * on behalf of DENX Software Engineering GmbH * * SPDX-License-Identifier: GPL-2.0+ */ #include #include #include #include /* ************************************************************************* * * Startup Code (reset vector) * * do important init only if we don't start from memory! * setup Memory and board specific bits prior to relocation. * relocate armboot to ram * setup stack * ************************************************************************* */ .globl reset reset: /* * If the CPU is configured in "Wait JTAG connection mode", the stack * pointer is not configured and is zero. This will cause crash when * trying to push data onto stack right below here. Load the SP and make * it point to the end of OCRAM if the SP is zero. */ cmp sp, #0x00000000 ldreq sp, =CONFIG_SYS_INIT_SP_ADDR /* * Store all registers on old stack pointer, this will allow us later to * return to the BootROM and let the BootROM load U-Boot into RAM. * * WARNING: Register r0 and r1 are used by the BootROM to pass data * to the called code. Register r0 will contain arbitrary * data that are set in the BootStream. In case this code * was started with CALL instruction, register r1 will contain * pointer to the return value this function can then set. * The code below MUST NOT CHANGE register r0 and r1 ! */ push {r0-r12,r14} /* Save control register c1 */ mrc p15, 0, r2, c1, c0, 0 push {r2} /* Set the cpu to SVC32 mode and store old CPSR register content. */ mrs r2, cpsr push {r2} bic r2, r2, #0x1f orr r2, r2, #0xd3 msr cpsr, r2 bl board_init_ll /* Restore BootROM's CPU mode (especially FIQ). */ pop {r2} msr cpsr,r2 /* * Restore c1 register. Especially set exception vector location * back to BootROM space which is required by bootrom for USB boot. */ pop {r2} mcr p15, 0, r2, c1, c0, 0 pop {r0-r12,r14} /* * In case this code was started by the CALL instruction, the register * r0 is examined by the BootROM after this code returns. The value in * r0 must be set to 0 to indicate successful return. */ mov r0, #0 bx lr