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Diffstat (limited to 'board/scb9328/lowlevel_init.S')
| -rw-r--r-- | board/scb9328/lowlevel_init.S | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/board/scb9328/lowlevel_init.S b/board/scb9328/lowlevel_init.S new file mode 100644 index 0000000..ba3b6d2 --- /dev/null +++ b/board/scb9328/lowlevel_init.S @@ -0,0 +1,203 @@ +/* + * Copyright (C) 2004 Sascha Hauer, Synertronixx GmbH + * + * 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. + * + */ + +#include <config.h> +#include <version.h> +#include <asm/arch/imx-regs.h> + +.globl lowlevel_init +lowlevel_init: + + mov r10, lr + +/* Change PERCLK1DIV to 14 ie 14+1 */ + ldr r0, =PCDR + ldr r1, =CFG_PCDR_VAL + str r1, [r0] + +/* set MCU PLL Control Register 0 */ + + ldr r0, =MPCTL0 + ldr r1, =CFG_MPCTL0_VAL + str r1, [r0] + +/* set mpll restart bit */ + ldr r0, =CSCR + ldr r1, [r0] + orr r1,r1,#(1<<21) + str r1, [r0] + + mov r2,#0x10 +1: + mov r3,#0x2000 +2: + subs r3,r3,#1 + bne 2b + + subs r2,r2,#1 + bne 1b + +/* set System PLL Control Register 0 */ + + ldr r0, =SPCTL0 + ldr r1, =CFG_SPCTL0_VAL + str r1, [r0] + +/* set spll restart bit */ + ldr r0, =CSCR + ldr r1, [r0] + orr r1,r1,#(1<<22) + str r1, [r0] + + mov r2,#0x10 +1: + mov r3,#0x2000 +2: + subs r3,r3,#1 + bne 2b + + subs r2,r2,#1 + bne 1b + + ldr r0, =CSCR + ldr r1, =CFG_CSCR_VAL + str r1, [r0] + +/* I have now read the ARM920 DataSheet back-to-Back, and have stumbled upon + *this..... + * + * It would appear that from a Cold-Boot the ARM920T enters "FastBus" mode CP15 + * register 1, this stops it using the output of the PLL and thus runs at the + * slow rate. Unless you place the Core into "Asynch" mode, the CPU will never + * use the value set in the CM_OSC registers...regardless of what you set it + * too! Thus, although i thought i was running at 140MHz, i'm actually running + * at 40!.. + + * Slapping this into my bootloader does the trick... + + * MRC p15,0,r0,c1,c0,0 ; read core configuration register + * ORR r0,r0,#0xC0000000 ; set asynchronous clocks and not fastbus mode + * MCR p15,0,r0,c1,c0,0 ; write modified value to core configuration + * register + */ + MRC p15,0,r0,c1,c0,0 + ORR r0,r0,#0xC0000000 + MCR p15,0,r0,c1,c0,0 + + ldr r0, =GPR(0) + ldr r1, =CFG_GPR_A_VAL + str r1, [r0] + + ldr r0, =GIUS(0) + ldr r1, =CFG_GIUS_A_VAL + str r1, [r0] + +/* CS3 becomes CS3 by clearing reset default bit 1 in FMCR */ + + ldr r0, =FMCR + ldr r1, =CFG_FMCR_VAL + str r1, [r0] + + ldr r0, =CS0U + ldr r1, =CFG_CS0U_VAL + str r1, [r0] + + ldr r0, =CS0L + ldr r1, =CFG_CS0L_VAL + str r1, [r0] + + ldr r0, =CS1U + ldr r1, =CFG_CS1U_VAL + str r1, [r0] + + ldr r0, =CS1L + ldr r1, =CFG_CS1L_VAL + str r1, [r0] + + ldr r0, =CS2U + ldr r1, =CFG_CS2U_VAL + str r1, [r0] + + ldr r0, =CS2L + ldr r1, =CFG_CS2L_VAL + str r1, [r0] + + ldr r0, =CS3U + ldr r1, =CFG_CS3U_VAL + str r1, [r0] + + ldr r0, =CS3L + ldr r1, =CFG_CS3L_VAL + str r1, [r0] + + ldr r0, =CS4U + ldr r1, =CFG_CS4U_VAL + str r1, [r0] + + ldr r0, =CS4L + ldr r1, =CFG_CS4L_VAL + str r1, [r0] + + ldr r0, =CS5U + ldr r1, =CFG_CS5U_VAL + str r1, [r0] + + ldr r0, =CS5L + ldr r1, =CFG_CS5L_VAL + str r1, [r0] + +/* SDRAM Setup */ + + ldr r0, =SDCTL0 + ldr r1, =PRECHARGE_CMD + str r1, [r0] + + ldr r0, =0x08200000 + ldr r1, =0x0 /* Issue Precharge all Command */ + str r1, [r0] + + ldr r0, =SDCTL0 + ldr r1, =AUTOREFRESH_CMD + str r1, [r0] + + ldr r0, =0x08000000 + ldr r1, =0x0 /* Issue AutoRefresh Command */ + str r1, [r0] + str r1, [r0] + str r1, [r0] + str r1, [r0] + str r1, [r0] + str r1, [r0] + str r1, [r0] + str r1, [r0] + + ldr r0, =SDCTL0 + ldr r1, =0xb10a8300 + str r1, [r0] + + ldr r0, =0x08223000 /* CAS Latency 2 */ + ldr r1, =0x0 /* Issue Mode Register Command, Burst Length = 8 */ + str r1, [r0] + + ldr r0, =SDCTL0 + ldr r1, =0x810a8200 /* Set to Normal Mode CAS 2 */ + str r1, [r0] + + mov pc,r10 |