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+/*
+ * 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