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/*
* 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
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