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Diffstat (limited to 'board/mx1fs2/lowlevel_init.S')
| -rw-r--r-- | board/mx1fs2/lowlevel_init.S | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/board/mx1fs2/lowlevel_init.S b/board/mx1fs2/lowlevel_init.S new file mode 100644 index 0000000..8211beb --- /dev/null +++ b/board/mx1fs2/lowlevel_init.S @@ -0,0 +1,188 @@ +/* + * Copyright (C) 2004 Sascha Hauer, Pengutronix + * + * 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 MCU PLL Control Register 1 */ + + ldr r0, =MPCTL1 + ldr r1, =CFG_MPCTL1_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 System PLL Control Register 1 */ + + ldr r0, =SPCTL1 + ldr r1, =CFG_SPCTL1_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] + + ldr r0, =GPCR + ldr r1, =CFG_GPCR_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 async mode */ +/* ORR r0,r0,#0x40000000 sync mode */ + ORR r0,r0,#0xC0000000 + MCR p15,0,r0,c1,c0,0 + + ldr r0, =GIUS(0) + ldr r1, =CFG_GIUS_A_VAL + str r1, [r0] + + 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, =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 r1,=0x00221000 /* adr of SDCTRL0 */ + ldr r0,=0x92120200 + str r0,[r1,#0] /* put in precharge command mode */ + ldr r2,=0x08200000 /* adr for precharge cmd */ + ldr r0,[r2,#0] /* precharge */ + ldr r0,=0xA2120200 + ldr r2,=0x08000000 /* start of SDRAM */ + str r0,[r1,#0] /* put in auto-refresh mode */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,[r2,#0] /* auto-refresh */ + ldr r0,=0xB2120200 + ldr r2,=0x08111800 + str r0,[r1,#0] /* setup for mode register of SDRAM */ + ldr r0,[r2,#0] /* program mode register */ + ldr r0,=0x82124267 + str r0,[r1,#0] /* back to normal operation */ + + mov pc,r10 |