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/*
* Copyright (c) 2010 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Ali Saidi
*/
/*************************************************************************
* Super simple bootloader
* Preserve loaded values that we need to pass to the kernel (r0, r1, r2)
* Additionally M5 puts the kernel start address in r3
*
* Upon executing this code:
* r0 = 0, r1 = machine number, r2 = atags ptr
* r3 = kernel start address
*
* CPU 0 should branch to the kernel start address and it's done with
* the boot loader. Other CPUs need to start in a wfi loop. When CPU0 sends
* an IPI the slave CPUs reads a register which CPU0 has programmed with the
* boot address for the secondary cpu
**************************************************************************/
.text
.globl _start
.extern main
_start:
_entry:
mrc p15, 0, r4, c0, c0, 5 // get the MPIDR register
uxtb r4, r4 // isolate the lower 8 bits (affinity lvl 1)
adds r4, r4, #0 // set flags for branch
bxeq r3 // if it's 0 (CPU 0), branch to kernel
pen:
wfi // otherwise wait for an interrupt
mov r4, #0x30 // Build address of the system controller
movt r4, #0x1000 // flag register r4 = 0x10000030
ldr r5, [r4] // load the value
movs r5, r5 // set the flags on this value
beq pen // if it's zero try again
bx r5 // Jump to where we've been told
bkpt // We should never get here
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