lowlevel_init.s

UBOOT 源码

/*
 * Most of this taken from Redboot hal_platform_setup.h with cleanup
 *
 * NOTE: I haven't clean this up considerably, just enough to get it
 * running. See hal_platform_setup.h for the source. See
 * board/cradle/lowlevel_init.S for another PXA250 setup that is
 * much cleaner.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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/pxa-regs.h>

DRAM_SIZE:  .long   CFG_DRAM_SIZE

/* wait for coprocessor write complete */
.macro CPWAIT reg
	mrc	p15,0,\reg,c2,c0,0
	mov	\reg,\reg
	sub	pc,pc,#4
.endm


.macro wait time
	ldr		r2, =OSCR
	mov		r3, #0
	str		r3, [r2]
0:
	ldr		r3, [r2]
	cmp		r3, \time
	bls		0b
.endm

/*
 *	Memory setup
 */

.globl lowlevel_init
lowlevel_init:
	/* Set up GPIO pins first ----------------------------------------- */
	mov	 r10, lr

	/*  Configure GPIO Pins 41 - 48 as UART1 / altern. Fkt. 2 */
	ldr		r0, =0x40E10438 @ GPIO41 FFRXD
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E1043C @ GPIO42 FFTXD
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E10440 @ GPIO43 FFCTS
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E10444 @ GPIO 44 FFDCD
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E10448 @ GPIO 45 FFDSR
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E1044C @ GPIO 46 FFRI
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E10450 @ GPIO 47 FFDTR
	ldr		r1, =0x802
	str		r1, [r0]

	ldr		r0, =0x40E10454 @ GPIO 48
	ldr		r1, =0x802
	str		r1, [r0]

	/* tebrandt - ASCR, clear the RDH bit */
	ldr		r0, =ASCR
	ldr		r1, [r0]
	bic		r1, r1, #0x80000000
	str		r1, [r0]

	/* ---------------------------------------------------------------- */
	/* Enable memory interface					    */
	/*								    */
	/* The sequence below is based on the recommended init steps	    */
	/* detailed in the Intel PXA250 Operating Systems Developers Guide, */
	/* Chapter 10.							    */
	/* ---------------------------------------------------------------- */

	/* ---------------------------------------------------------------- */
	/* Step 1: Wait for at least 200 microsedonds to allow internal	    */
	/*	   clocks to settle. Only necessary after hard reset...	    */
	/*	   FIXME: can be optimized later			    */
	/* ---------------------------------------------------------------- */

	/* mk:	 replaced with wait macro */
/*	ldr r3, =OSCR			/\* reset the OS Timer Count to zero *\/ */
/*	mov r2, #0 */
/*	str r2, [r3] */
/*	ldr r4, =0x300			/\* really 0x2E1 is about 200usec,   *\/ */
/*					/\* so 0x300 should be plenty	     *\/ */
/* 1: */
/*	ldr r2, [r3] */
/*	cmp r4, r2 */
/*	bgt 1b */
	wait #300

mem_init:

	/* configure the MEMCLKCFG register */
	ldr		r1, =MEMCLKCFG
	ldr		r2, =0x00010001
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set CSADRCFG[0] to data flash SRAM mode */
	ldr		r1, =CSADRCFG0
	ldr		r2, =0x00320809
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set CSADRCFG[1] to data flash SRAM mode */
	ldr		r1, =CSADRCFG1
	ldr		r2, =0x00320809
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set MSC 0 register for SRAM memory */
	ldr		r1, =MSC0
	ldr		r2, =0x11191119
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set CSADRCFG[2] to data flash SRAM mode */
	ldr		r1, =CSADRCFG2
	ldr		r2, =0x00320809
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set CSADRCFG[3] to VLIO mode */
	ldr		r1, =CSADRCFG3
	ldr		r2, =0x0032080B
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

	/* set MSC 1 register for VLIO memory */
	ldr		r1, =MSC1
	ldr		r2, =0x123C1119
	str		r2, [r1]	     @ WRITE
	ldr		r2, [r1]	     @ DELAY UNTIL WRITTEN

#if 0
	/* This does not work in Zylonite. -SC */
	ldr		r0, =0x15fffff0
	ldr		r1, =0xb10b
	str		r1, [r0]
	str		r1, [r0, #4]
#endif

	/* Configure ACCR Register */
	ldr		r0, =ACCR		@ ACCR
	ldr		r1, =0x0180b108
	str		r1, [r0]
	ldr		r1, [r0]

	/* Configure MDCNFG Register */
	ldr		r0, =MDCNFG		@ MDCNFG
	ldr		r1, =0x403
	str		r1, [r0]
	ldr		r1, [r0]

	/* Perform Resistive Compensation by configuring RCOMP register */
	ldr		r1, =RCOMP		@ RCOMP
	ldr		r2, =0x000000ff
	str		r2, [r1]
	ldr		r2, [r1]

	/* Configure MDMRS Register for SDCS0 */
	ldr		r1, =MDMRS		@ MDMRS
	ldr		r2, =0x60000023
	ldr		r3, [r1]
	orr		r2, r2, r3
	str		r2, [r1]
	ldr		r2, [r1]

	/* Configure MDMRS Register for SDCS1 */
	ldr		r1, =MDMRS		@ MDMRS
	ldr		r2, =0xa0000023
	ldr		r3, [r1]
	orr		r2, r2, r3
	str		r2, [r1]
	ldr		r2, [r1]

	/* Configure MDREFR */
	ldr		r1, =MDREFR		@ MDREFR
	ldr		r2, =0x00000006
	str		r2, [r1]
	ldr		r2, [r1]

	/* Configure EMPI */
	ldr		r1, =EMPI		@ EMPI
	ldr		r2, =0x80000000
	str		r2, [r1]
	ldr		r2, [r1]

	/* Hardware DDR Read-Strobe Delay Calibration */
	ldr		r0, =DDR_HCAL		@ DDR_HCAL
	ldr		r1, =0x803ffc07	    @ the offset is correct? -SC
	str		r1, [r0]
	wait		#5
	ldr		r1, [r0]

	/* Here we assume the hardware calibration alwasy be successful. -SC */
	/* Set DMCEN bit in MDCNFG Register */
	ldr		r0, =MDCNFG		@ MDCNFG
	ldr		r1, [r0]
	orr		r1, r1, #0x40000000	@ enable SDRAM for Normal Access
	str		r1, [r0]

#ifndef CFG_SKIP_DRAM_SCRUB
	/* scrub/init SDRAM if enabled/present */
/*	ldr	r11, =0xa0000000 /\* base address of SDRAM (CFG_DRAM_BASE) *\/ */
/*	ldr	r12, =0x04000000 /\* size of memory to scrub (CFG_DRAM_SIZE) *\/ */
/*	mov	r8,r12		 /\* save DRAM size (mk: why???) *\/ */
	ldr	r8, =0xa0000000	 /* base address of SDRAM (CFG_DRAM_BASE) */
	ldr	r9, =0x04000000	 /* size of memory to scrub (CFG_DRAM_SIZE) */
	mov	r0, #0		 /* scrub with 0x0000:0000 */
	mov	r1, #0
	mov	r2, #0
	mov	r3, #0
	mov	r4, #0
	mov	r5, #0
	mov	r6, #0
	mov	r7, #0
10:	/* fastScrubLoop */
	subs	r9, r9, #32	/* 32 bytes/line */
	stmia	r8!, {r0-r7}
	beq	15f
	b	10b
#endif /* CFG_SKIP_DRAM_SCRUB */

15:
	/* Mask all interrupts */
	mov	r1, #0
	mcr	p6, 0, r1, c1, c0, 0	@ ICMR

	/* Disable software and data breakpoints */
	mov	r0, #0
	mcr	p15,0,r0,c14,c8,0  /* ibcr0 */
	mcr	p15,0,r0,c14,c9,0  /* ibcr1 */
	mcr	p15,0,r0,c14,c4,0  /* dbcon */

	/* Enable all debug functionality */
	mov	r0,#0x80000000
	mcr	p14,0,r0,c10,c0,0  /* dcsr */

	/* We are finished with Intel's memory controller initialisation    */

	/* ---------------------------------------------------------------- */
	/* End lowlevel_init							 */
	/* ---------------------------------------------------------------- */

endlowlevel_init:

	mov	pc, lr

/*
@********************************************************************************
@ DDR calibration
@
@  This function is used to calibrate DQS delay lines.
@ Monahans supports three ways to do it. One is software
@ calibration. Two is hardware calibration. Three is hybrid
@ calibration.
@
@ TBD
@ -SC
ddr_calibration:

	@ Case 1:	Write the correct delay value once
	@ Configure DDR_SCAL Register
	ldr	r0, =DDR_SCAL		@ DDR_SCAL
q	ldr	r1, =0xaf2f2f2f
	str	r1, [r0]
	ldr	r1, [r0]
*/
/*	@ Case 2:	Software Calibration
	@ Write test pattern to memory
	ldr	r5, =0x0faf0faf		@ Data Pattern
	ldr	r4, =0xa0000000		@ DDR ram
	str	r5, [r4]

	mov	r1, =0x0		@ delay count
	mov	r6, =0x0
	mov	r7, =0x0
ddr_loop1:
	add	r1, r1, =0x1
	cmp	r1, =0xf
	ble	end_loop
	mov	r3, r1
	mov	r0, r1, lsl #30
	orr	r3, r3, r0
	mov	r0, r1, lsl #22
	orr	r3, r3, r0
	mov	r0, r1, lsl #14
	orr	r3, r3, r0
	orr	r3, r3, =0x80000000
	ldr	r2, =DDR_SCAL
	str	r3, [r2]

	ldr	r2, [r4]
	cmp	r2, r5
	bne	ddr_loop1
	mov	r6, r1
ddr_loop2:
	add	r1, r1, =0x1
	cmp	r1, =0xf
	ble	end_loop
	mov	r3, r1
	mov	r0, r1, lsl #30
	orr	r3, r3, r0
	mov	r0, r1, lsl #22
	orr	r3, r3, r0
	mov	r0, r1, lsl #14
	orr	r3, r3, r0
	orr	r3, r3, =0x80000000
	ldr	r2, =DDR_SCAL
	str	r3, [r2]

	ldr	r2, [r4]
	cmp	r2, r5
	be	ddr_loop2
	mov	r7, r2

	add	r3, r6, r7
	lsr	r3, r3, =0x1
	mov	r0, r1, lsl #30
	orr	r3, r3, r0
	mov	r0, r1, lsl #22
	orr	r3, r3, r0
	mov	r0, r1, lsl #14
	orr	r3, r3, r0
	orr	r3, r3, =0x80000000
	ldr	r2, =DDR_SCAL

end_loop:

	@ Case 3:	Hardware Calibratoin
	ldr	r0, =DDR_HCAL		@ DDR_HCAL
	ldr	r1, =0x803ffc07	    @ the offset is correct? -SC
	str	r1, [r0]
	wait	#5
	ldr	r1, [r0]
	mov	pc, lr
*/