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Diffstat (limited to 'cpu/bf561/start.S')
| -rw-r--r-- | cpu/bf561/start.S | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/cpu/bf561/start.S b/cpu/bf561/start.S new file mode 100644 index 0000000..9333648 --- /dev/null +++ b/cpu/bf561/start.S @@ -0,0 +1,311 @@ +/* + * U-boot - start.S Startup file of u-boot for BF533/BF561 + * + * Copyright (c) 2005 blackfin.uclinux.org + * + * 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., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 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; |