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u-boot/cpu/bf561/start.S

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/*
* U-boot - start.S Startup file of u-boot for BF533/BF561
*
* Copyright (c) 2005-2007 Analog Devices Inc.
*
* This file is based on head.S
* Copyright (c) 2003 Metrowerks/Motorola
* Copyright (C) 1998 D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,
* Kenneth Albanowski <kjahds@kjahds.com>,
* The Silver Hammer Group, Ltd.
* (c) 1995, Dionne & Associates
* (c) 1995, DKG Display Tech.
*
* 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., 51 Franklin St, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
/*
* Note: A change in this file subsequently requires a change in
* board/$(board_name)/config.mk for a valid u-boot.bin
*/
#define ASSEMBLY
#include <linux/config.h>
#include <config.h>
#include <asm/blackfin.h>
.global _stext;
.global __bss_start;
.global start;
.global _start;
.global _rambase;
.global _ramstart;
.global _ramend;
.global edata;
.global _initialize;
.global _exit;
.global flashdataend;
.global init_sdram;
.text
_start:
start:
_stext:
R0 = 0x32;
SYSCFG = R0;
SSYNC;
/*
* As per HW reference manual DAG registers,
* DATA and Address resgister shall be zero'd
* in initialization, after a reset state
*/
r1 = 0; /* Data registers zero'd */
r2 = 0;
r3 = 0;
r4 = 0;
r5 = 0;
r6 = 0;
r7 = 0;
p0 = 0; /* Address registers zero'd */
p1 = 0;
p2 = 0;
p3 = 0;
p4 = 0;
p5 = 0;
i0 = 0; /* DAG Registers zero'd */
i1 = 0;
i2 = 0;
i3 = 0;
m0 = 0;
m1 = 0;
m3 = 0;
m3 = 0;
l0 = 0;
l1 = 0;
l2 = 0;
l3 = 0;
b0 = 0;
b1 = 0;
b2 = 0;
b3 = 0;
/*
* Set loop counters to zero, to make sure that
* hw loops are disabled.
*/
r0 = 0;
lc0 = r0;
lc1 = r0;
SSYNC;
/* Check soft reset status */
p0.h = SWRST >> 16;
p0.l = SWRST & 0xFFFF;
r0.l = w[p0];
cc = bittst(r0, 15);
if !cc jump no_soft_reset;
/* Clear Soft reset */
r0 = 0x0000;
w[p0] = r0;
ssync;
no_soft_reset:
nop;
/* Clear EVT registers */
p0.h = (EVT_EMULATION_ADDR >> 16);
p0.l = (EVT_EMULATION_ADDR & 0xFFFF);
p0 += 8;
p1 = 14;
r1 = 0;
LSETUP(4,4) lc0 = p1;
[ p0 ++ ] = r1;
p0.h = hi(SIC_IWR);
p0.l = lo(SIC_IWR);
r0.l = 0x1;
w[p0] = r0.l;
SSYNC;
sp.l = (0xffb01000 & 0xFFFF);
sp.h = (0xffb01000 >> 16);
/*
* Check if the code is in SDRAM
* If the code is in SDRAM, skip SDRAM initializaiton
*/
call get_pc;
r3.l = 0x0;
r3.h = 0x2000;
cc = r0 < r3 (iu);
if cc jump sdram_initialized;
call init_sdram;
/* relocate into to RAM */
sdram_initialized:
call get_pc;
offset:
r2.l = offset;
r2.h = offset;
r3.l = start;
r3.h = start;
r1 = r2 - r3;
r0 = r0 - r1;
p1 = r0;
p2.l = (CFG_MONITOR_BASE & 0xffff);
p2.h = (CFG_MONITOR_BASE >> 16);
p3 = 0x04;
p4.l = ((CFG_MONITOR_BASE + CFG_MONITOR_LEN) & 0xffff);
p4.h = ((CFG_MONITOR_BASE + CFG_MONITOR_LEN) >> 16);
loop1:
r1 = [p1 ++ p3];
[p2 ++ p3] = r1;
cc=p2==p4;
if !cc jump loop1;
/*
* configure STACK
*/
r0.h = (CONFIG_STACKBASE >> 16);
r0.l = (CONFIG_STACKBASE & 0xFFFF);
sp = r0;
fp = sp;
/*
* This next section keeps the processor in supervisor mode
* during kernel boot. Switches to user mode at end of boot.
* See page 3-9 of Hardware Reference manual for documentation.
*/
/* To keep ourselves in the supervisor mode */
p0.l = (EVT_IVG15_ADDR & 0xFFFF);
p0.h = (EVT_IVG15_ADDR >> 16);
p1.l = _real_start;
p1.h = _real_start;
[p0] = p1;
p0.l = (IMASK & 0xFFFF);
p0.h = (IMASK >> 16);
r0.l = LO(IVG15_POS);
r0.h = HI(IVG15_POS);
[p0] = r0;
raise 15;
p0.l = WAIT_HERE;
p0.h = WAIT_HERE;
reti = p0;
rti;
WAIT_HERE:
jump WAIT_HERE;
.global _real_start;
_real_start:
[ -- sp ] = reti;
#ifdef CONFIG_EZKIT561
p0.l = (WDOG_CTL & 0xFFFF);
p0.h = (WDOG_CTL >> 16);
r0 = WATCHDOG_DISABLE(z);
w[p0] = r0;
#endif
/* DMA reset code to Hi of L1 SRAM */
copy:
P1.H = hi(SYSMMR_BASE); /* P1 Points to the beginning of SYSTEM MMR Space */
P1.L = lo(SYSMMR_BASE);
R0.H = reset_start; /* Source Address (high) */
R0.L = reset_start; /* Source Address (low) */
R1.H = reset_end;
R1.L = reset_end;
R2 = R1 - R0; /* Count */
R1.H = hi(L1_ISRAM); /* Destination Address (high) */
R1.L = lo(L1_ISRAM); /* Destination Address (low) */
R3.L = DMAEN; /* Source DMAConfig Value (8-bit words) */
R4.L = (DI_EN | WNR | DMAEN); /* Destination DMAConfig Value (8-bit words) */
DMA:
R6 = 0x1 (Z);
W[P1+OFFSET_(MDMA_S0_X_MODIFY)] = R6; /* Source Modify = 1 */
W[P1+OFFSET_(MDMA_D0_X_MODIFY)] = R6; /* Destination Modify = 1 */
[P1+OFFSET_(MDMA_S0_START_ADDR)] = R0; /* Set Source Base Address */
W[P1+OFFSET_(MDMA_S0_X_COUNT)] = R2; /* Set Source Count */
/* Set Source DMAConfig = DMA Enable,
Memory Read, 8-Bit Transfers, 1-D DMA, Flow - Stop */
W[P1+OFFSET_(MDMA_S0_CONFIG)] = R3;
[P1+OFFSET_(MDMA_D0_START_ADDR)] = R1; /* Set Destination Base Address */
W[P1+OFFSET_(MDMA_D0_X_COUNT)] = R2; /* Set Destination Count */
/* Set Destination DMAConfig = DMA Enable,
Memory Write, 8-Bit Transfers, 1-D DMA, Flow - Stop, IOC */
W[P1+OFFSET_(MDMA_D0_CONFIG)] = R4;
WAIT_DMA_DONE:
p0.h = hi(MDMA_D0_IRQ_STATUS);
p0.l = lo(MDMA_D0_IRQ_STATUS);
R0 = W[P0](Z);
CC = BITTST(R0, 0);
if ! CC jump WAIT_DMA_DONE
R0 = 0x1;
W[P1+OFFSET_(MDMA_D0_IRQ_STATUS)] = R0; /* Write 1 to clear DMA interrupt */
/* Initialize BSS Section with 0 s */
p1.l = __bss_start;
p1.h = __bss_start;
p2.l = _end;
p2.h = _end;
r1 = p1;
r2 = p2;
r3 = r2 - r1;
r3 = r3 >> 2;
p3 = r3;
lsetup (_clear_bss, _clear_bss_end ) lc1 = p3;
CC = p2<=p1;
if CC jump _clear_bss_skip;
r0 = 0;
_clear_bss:
_clear_bss_end:
[p1++] = r0;
_clear_bss_skip:
p0.l = _start1;
p0.h = _start1;
jump (p0);
reset_start:
p0.h = WDOG_CNT >> 16;
p0.l = WDOG_CNT & 0xffff;
r0 = 0x0010;
w[p0] = r0;
p0.h = WDOG_CTL >> 16;
p0.l = WDOG_CTL & 0xffff;
r0 = 0x0000;
w[p0] = r0;
reset_wait:
jump reset_wait;
reset_end: nop;
_exit:
jump.s _exit;
get_pc:
r0 = rets;
rts;
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