| /* |
| * 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 |
