Philips Semiconductors
AN10476
Getting started Linux with LPC3180
MPMCDynamicRefresh
MPMCDynamicRasCas0
MPMCDynamicConfig0
MPMCDynamicControl
MPMCAHBTimeOut0
MPMCAHBTimeOut2
MPMCAHBTimeOut3
MPMCAHBTimeOut4
MPMCStatus;
8.2 SDRAM definitions in U-boot
Before U-boot running, SIBL must have finished the SDRAM initialization. In U-boot,
there are no necessary SDRAM operations but only some parameter settings need to be
defined.
In
./u-boot/include/configs/phytec.h
, define the SDRAM start address and effective
size:
/*-----------------------------------------------------------------------
* Physical Memory Map
*/
#define CONFIG_NR_DRAM_BANKS 1
#define PHYS_SDRAM_1 0x80000000
#define PHYS_SDRAM_1_SIZE 0x02000000 /* 32 MB */
In
./u-boot/board/phytec/config.mk,
define the TEXT section start address of u-boot
image file:
#
# image should be loaded at 32M - 256k
#
TEXT_BASE = 0x81EC0000
In
./u-boot/board/phytec/u-boot.lds,
align the TEXT section start address with that
defined in
config.mk:
ENTRY(_start)
SECTIONS
{
. = 0x81EC0000;
. = ALIGN(4);
In
./u-boot/board/phytec/phytec.c
, there are SDRAM detection and initialization
routines
sdram_init
and
dram_init
. Actually the
sdram_init
wouldn’t be called at all. Have
a look at the
dram_init
may help you understand more about the U-boot process for
SDRAM. But neither need modification.
<12NC>
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
Application note
Rev.03 — 21 Dec 2006
25 of 28
