When testing a u-boot binary that hasn't been booted from the bootrom, we have to make sure the bootstruct structure has sane storage space. If we don't, the initcode will crash when it tries to dereference an invalid pointer. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
235 lines
6.5 KiB
ArmAsm
235 lines
6.5 KiB
ArmAsm
/*
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* U-boot - start.S Startup file for Blackfin u-boot
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*
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* Copyright (c) 2005-2008 Analog Devices Inc.
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*
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* This file is based on head.S
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* Copyright (c) 2003 Metrowerks/Motorola
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* Copyright (C) 1998 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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* (c) 1995, Dionne & Associates
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* (c) 1995, DKG Display Tech.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#include <config.h>
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#include <asm/blackfin.h>
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#include <asm/mach-common/bits/core.h>
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#include <asm/mach-common/bits/dma.h>
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#include <asm/mach-common/bits/pll.h>
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#include "serial.h"
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/* It may seem odd that we make calls to functions even though we haven't
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* relocated ourselves yet out of {flash,ram,wherever}. This is OK because
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* the "call" instruction in the Blackfin architecture is actually PC
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* relative. So we can call functions all we want and not worry about them
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* not being relocated yet.
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*/
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.text
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ENTRY(_start)
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/* Set our initial stack to L1 scratch space */
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sp.l = LO(L1_SRAM_SCRATCH_END - 20);
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sp.h = HI(L1_SRAM_SCRATCH_END - 20);
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#ifdef CONFIG_HW_WATCHDOG
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# ifndef CONFIG_HW_WATCHDOG_TIMEOUT_START
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# define CONFIG_HW_WATCHDOG_TIMEOUT_START 5000
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# endif
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/* Program the watchdog with an initial timeout of ~5 seconds.
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* That should be long enough to bootstrap ourselves up and
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* then the common u-boot code can take over.
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*/
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P0.L = LO(WDOG_CNT);
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P0.H = HI(WDOG_CNT);
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R0.L = 0;
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R0.H = HI(MSEC_TO_SCLK(CONFIG_HW_WATCHDOG_TIMEOUT_START));
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[P0] = R0;
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/* fire up the watchdog - R0.L above needs to be 0x0000 */
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W[P0 + (WDOG_CTL - WDOG_CNT)] = R0;
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#endif
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/* Turn on the serial for debugging the init process */
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serial_early_init
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serial_early_set_baud
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serial_early_puts("Init Registers");
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/* Disable self-nested interrupts and enable CYCLES for udelay() */
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R0 = CCEN | 0x30;
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SYSCFG = R0;
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/* Zero out registers required by Blackfin ABI.
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* http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
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*/
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r1 = 0 (x);
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/* Disable circular buffers */
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l0 = r1;
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l1 = r1;
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l2 = r1;
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l3 = r1;
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/* Disable hardware loops in case we were started by 'go' */
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lc0 = r1;
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lc1 = r1;
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/* Save RETX so we can pass it while booting Linux */
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r7 = RETX;
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/* Figure out where we are currently executing so that we can decide
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* how to best reprogram and relocate things. We'll pass below:
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* R4: load address of _start
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* R5: current (not load) address of _start
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*/
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serial_early_puts("Find ourselves");
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call _get_pc;
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.Loffset:
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r1.l = .Loffset;
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r1.h = .Loffset;
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r4.l = _start;
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r4.h = _start;
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r3 = r1 - r4;
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r5 = r0 - r3;
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/* Inform upper layers if we had to do the relocation ourselves.
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* This allows us to detect whether we were loaded by 'go 0x1000'
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* or by the bootrom from an LDR. "R6" is "loaded_from_ldr".
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*/
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r6 = 1 (x);
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cc = r4 == r5;
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if cc jump .Lnorelocate;
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r6 = 0 (x);
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/* In bypass mode, we don't have an LDR with an init block
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* so we need to explicitly call it ourselves. This will
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* reprogram our clocks, memory, and setup our async banks.
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*/
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serial_early_puts("Program Clocks");
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/* if we're executing >=0x20000000, then we dont need to dma */
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r3 = 0x0;
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r3.h = 0x2000;
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cc = r5 < r3 (iu);
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if cc jump .Ldma_and_reprogram;
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r0 = 0 (x); /* set bootstruct to NULL */
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call _initcode;
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jump .Lprogrammed;
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/* we're sitting in external memory, so dma into L1 and reprogram */
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.Ldma_and_reprogram:
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r0.l = LO(L1_INST_SRAM);
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r0.h = HI(L1_INST_SRAM);
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r1.l = __initcode_start;
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r1.h = __initcode_start;
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r2.l = __initcode_end;
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r2.h = __initcode_end;
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r2 = r2 - r1; /* convert r2 into length of initcode */
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r1 = r1 - r4; /* convert r1 from load address of initcode ... */
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r1 = r1 + r5; /* ... to current (not load) address of initcode */
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p3 = r0;
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call _dma_memcpy_nocache;
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r0 = 0 (x); /* set bootstruct to NULL */
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call (p3);
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/* Since we reprogrammed SCLK, we need to update the serial divisor */
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.Lprogrammed:
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serial_early_set_baud
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/* Relocate from wherever we are (FLASH/RAM/etc...) to the hardcoded
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* monitor location in the end of RAM. We know that memcpy() only
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* uses registers, so it is safe to call here. Note that this only
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* copies to external memory ... we do not start executing out of
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* it yet (see "lower to 15" below).
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*/
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serial_early_puts("Relocate");
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r0 = r4;
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r1 = r5;
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r2.l = LO(CONFIG_SYS_MONITOR_LEN);
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r2.h = HI(CONFIG_SYS_MONITOR_LEN);
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call _memcpy_ASM;
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/* Initialize BSS section ... we know that memset() does not
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* use the BSS, so it is safe to call here. The bootrom LDR
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* takes care of clearing things for us.
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*/
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serial_early_puts("Zero BSS");
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r0.l = __bss_start;
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r0.h = __bss_start;
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r1 = 0 (x);
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r2.l = __bss_end;
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r2.h = __bss_end;
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r2 = r2 - r0;
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call _memset;
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.Lnorelocate:
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/* Setup the actual stack in external memory */
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sp.h = HI(CONFIG_STACKBASE);
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sp.l = LO(CONFIG_STACKBASE);
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fp = sp;
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/* Now lower ourselves from the highest interrupt level to
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* the lowest. We do this by masking all interrupts but 15,
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* setting the 15 handler to ".Lenable_nested", raising the 15
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* interrupt, and then returning from the highest interrupt
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* level to the dummy "jump" until the interrupt controller
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* services the pending 15 interrupt. If executing out of
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* flash, these steps also changes the code flow from flash
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* to external memory.
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*/
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serial_early_puts("Lower to 15");
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r0 = r7;
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r1 = r6;
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p0.l = LO(EVT15);
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p0.h = HI(EVT15);
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p1.l = .Lenable_nested;
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p1.h = .Lenable_nested;
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[p0] = p1;
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r7 = EVT_IVG15 (z);
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sti r7;
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raise 15;
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p4.l = .LWAIT_HERE;
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p4.h = .LWAIT_HERE;
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reti = p4;
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rti;
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/* Enable nested interrupts before continuing with cpu init */
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.Lenable_nested:
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cli r7;
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[--sp] = reti;
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jump.l _cpu_init_f;
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.LWAIT_HERE:
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jump .LWAIT_HERE;
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ENDPROC(_start)
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LENTRY(_get_pc)
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r0 = rets;
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#if ANOMALY_05000371
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NOP;
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NOP;
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NOP;
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#endif
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rts;
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ENDPROC(_get_pc)
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