lowlevel_init.S
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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* (C) Copyright 2011
* Matthias Weisser <weisserm@arcor.de>
*
* (C) Copyright 2009 DENX Software Engineering
* Author: John Rigby <jrigby@gmail.com>
*
* Based on U-Boot and RedBoot sources for several different i.mx
* platforms.
*/
#include <asm/macro.h>
#include <asm/arch/macro.h>
#include <asm/arch/imx-regs.h>
#include <generated/asm-offsets.h>
/*
* clocks
*/
.macro init_clocks
/* disable clock output */
write32 IMX_CCM_BASE + CCM_MCR, 0x00000000
write32 IMX_CCM_BASE + CCM_CCTL, 0x50030000
/*
* enable all implemented clocks in all three
* clock control registers
*/
write32 IMX_CCM_BASE + CCM_CGCR0, 0x1fffffff
write32 IMX_CCM_BASE + CCM_CGCR1, 0xffffffff
write32 IMX_CCM_BASE + CCM_CGCR2, 0xfffff
/* Devide NAND clock by 32 */
write32 IMX_CCM_BASE + CCM_PCDR2, 0x0101011F
.endm
/*
* sdram controller init
*/
.macro init_lpddr
ldr r0, =IMX_ESDRAMC_BASE
ldr r2, =IMX_SDRAM_BANK0_BASE
/*
* reset SDRAM controller
* then wait for initialization to complete
*/
ldr r1, =(1 << 1) | (1 << 2)
str r1, [r0, #ESDRAMC_ESDMISC]
1: ldr r3, [r0, #ESDRAMC_ESDMISC]
tst r3, #(1 << 31)
beq 1b
ldr r1, =(1 << 2)
str r1, [r0, #ESDRAMC_ESDMISC]
ldr r1, =0x002a7420
str r1, [r0, #ESDRAMC_ESDCFG0]
/* control | precharge */
ldr r1, =0x92216008
str r1, [r0, #ESDRAMC_ESDCTL0]
/* dram command encoded in address */
str r1, [r2, #0x400]
/* auto refresh */
ldr r1, =0xa2216008
str r1, [r0, #ESDRAMC_ESDCTL0]
/* read dram twice to auto refresh */
ldr r3, [r2]
ldr r3, [r2]
/* control | load mode */
ldr r1, =0xb2216008
str r1, [r0, #ESDRAMC_ESDCTL0]
/* mode register of lpddram */
strb r1, [r2, #0x33]
/* extended mode register of lpddrram */
ldr r2, =0x81000000
strb r1, [r2]
/* control | normal */
ldr r1, =0x82216008
str r1, [r0, #ESDRAMC_ESDCTL0]
.endm
.globl lowlevel_init
lowlevel_init:
init_aips
init_max
init_clocks
init_lpddr
mov pc, lr