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Diffstat (limited to 'board/wepep250/lowlevel_init.S')
| -rw-r--r-- | board/wepep250/lowlevel_init.S | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/board/wepep250/lowlevel_init.S b/board/wepep250/lowlevel_init.S new file mode 100644 index 0000000..b172cea --- /dev/null +++ b/board/wepep250/lowlevel_init.S @@ -0,0 +1,145 @@ +/* + * Copyright (C) 2001, 2002 ETC s.r.o. + * + * 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. + * + * Written by Marcel Telka <marcel@telka.sk>, 2001, 2002. + * Changes for U-Boot Peter Figuli <peposh@etc.sk>, 2003. + * + * This file is taken from OpenWinCE project hosted by SourceForge.net + * + * Documentation: + * [1] Intel Corporation, "Intel PXA250 and PXA210 Application Processors + * Developer's Manual", February 2002, Order Number: 278522-001 + * [2] Samsung Electronics, "8Mx16 SDRAM 54CSP K4S281633D-RL/N/P", + * Revision 1.0, February 2002 + * [3] Samsung Electronics, "16Mx16 SDRAM 54CSP K4S561633C-RL(N)", + * Revision 1.0, February 2002 + * +*/ + +#include <config.h> +#include <version.h> +#include <asm/arch/pxa-regs.h> + +.globl lowlevel_init +lowlevel_init: + + mov r10, lr + +/* setup memory - see 6.12 in [1] + * Step 1 - wait 200 us + */ + mov r0,#0x2700 /* wait 200 us @ 99.5 MHz */ +1: subs r0, r0, #1 + bne 1b +/* TODO: complete step 1 for Synchronous Static memory*/ + + ldr r0, =0x48000000 /* MC_BASE */ + + +/* step 1.a - setup MSCx + */ + ldr r1, =0x000012B3 /* MSC0_RRR0(1) | MSC0_RDN0(2) | MSC0_RDF0(11) | MSC0_RT0(3) */ + str r1, [r0, #0x8] /* MSC0_OFFSET */ + +/* step 1.c - clear MDREFR:K1FREE, set MDREFR:DRI + * see AUTO REFRESH chapter in section D. in [2] and in [3] + * DRI = (64ms / 4096) * 99.53MHz / 32 = 48 for K4S281633 + * DRI = (64ms / 8192) * 99.52MHz / 32 = 24 for K4S561633 + * TODO: complete for Synchronous Static memory + */ + ldr r1, [r0, #4] /* MDREFR_OFFSET */ + ldr r2, =0x01000FFF /* MDREFR_K1FREE | MDREFR_DRI_MASK */ + bic r1, r1, r2 +#if defined( WEP_SDRAM_K4S281633 ) + orr r1, r1, #48 /* MDREFR_DRI(48) */ +#elif defined( WEP_SDRAM_K4S561633 ) + orr r1, r1, #24 /* MDREFR_DRI(24) */ +#else +#error SDRAM chip is not defined +#endif + + str r1, [r0, #4] /* MDREFR_OFFSET */ + +/* Step 2 - only for Synchronous Static memory (TODO) + * + * Step 3 - same as step 4 + * + * Step 4 + * + * Step 4.a - set MDREFR:K1RUN, clear MDREFR:K1DB2 + */ + orr r1, r1, #0x00010000 /* MDREFR_K1RUN */ + bic r1, r1, #0x00020000 /* MDREFR_K1DB2 */ + str r1, [r0, #4] /* MDREFR_OFFSET */ + +/* Step 4.b - clear MDREFR:SLFRSH */ + bic r1, r1, #0x00400000 /* MDREFR_SLFRSH */ + str r1, [r0, #4] /* MDREFR_OFFSET */ + +/* Step 4.c - set MDREFR:E1PIN */ + orr r1, r1, #0x00008000 /* MDREFR_E1PIN */ + str r1, [r0, #4] /* MDREFR_OFFSET */ + +/* Step 4.d - automatically done + * + * Steps 4.e and 4.f - configure SDRAM + */ +#if defined( WEP_SDRAM_K4S281633 ) + ldr r1, =0x00000AA8 /* MDCNFG_DTC0(2) | MDCNFG_DLATCH0 | MDCNFG_DCAC0(1) | MDCNFG_DRAC0(1) | MDCNFG_DNB0 */ +#elif defined( WEP_SDRAM_K4S561633 ) + ldr r1, =0x00000AC8 /* MDCNFG_DTC0(2) | MDCNFG_DLATCH0 | MDCNFG_DCAC0(1) | MDCNFG_DRAC0(2) | MDCNFG_DNB0 */ +#else +#error SDRAM chip is not defined +#endif + str r1, [r0, #0] /* MDCNFG_OFFSET */ + +/* Step 5 - wait at least 200 us for SDRAM + * see section B. in [2] + */ + mov r2,#0x2700 /* wait 200 us @ 99.5 MHz */ +1: subs r2, r2, #1 + bne 1b + +/* Step 6 - after reset dcache is disabled, so automatically done + * + * Step 7 - eight refresh cycles + */ + mov r2, #0xA0000000 + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + ldr r3, [r2] + +/* Step 8 - we don't need dcache now + * + * Step 9 - enable SDRAM partition 0 + */ + orr r1, r1, #1 /* MDCNFG_DE0 */ + str r1, [r0, #0] /* MDCNFG_OFFSET */ + +/* Step 10 - write MDMRS */ + mov r1, #0 + str r1, [r0, #0x40] /* MDMRS_OFFSET */ + +/* Step 11 - optional (TODO) */ + + mov pc,r10 |