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kernel/linux-imx6_3.14.28/arch/arm/mach-omap1/sram.S 1.52 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * linux/arch/arm/plat-omap/sram-fn.S
   *
   * Functions that need to be run in internal SRAM
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/linkage.h>
  
  #include <asm/assembler.h>
  
  #include <mach/hardware.h>
  
  #include "iomap.h"
  
  	.text
  
  /*
   * Reprograms ULPD and CKCTL.
   */
  	.align	3
  ENTRY(omap1_sram_reprogram_clock)
  	stmfd	sp!, {r0 - r12, lr}		@ save registers on stack
  
  	mov	r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0xff000000
  	orr	r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x00ff0000
  	orr	r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x0000ff00
  
  	mov	r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0xff000000
  	orr	r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
  	orr	r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
  
  	tst	r0, #1 << 4			@ want lock mode?
  	beq	newck				@ nope
  	bic	r0, r0, #1 << 4			@ else clear lock bit
  	strh	r0, [r2]			@ set dpll into bypass mode
  	orr	r0, r0, #1 << 4			@ set lock bit again
  
  newck:
  	strh	r1, [r3]			@ write new ckctl value
  	strh	r0, [r2]			@ write new dpll value
  
  	mov	r4, #0x0700			@ let the clocks settle
  	orr	r4, r4, #0x00ff
  delay:	sub	r4, r4, #1
  	cmp	r4, #0
  	bne	delay
  
  lock:	ldrh	r4, [r2], #0			@ read back dpll value
  	tst	r0, #1 << 4			@ want lock mode?
  	beq	out				@ nope
  	tst	r4, #1 << 0			@ dpll rate locked?
  	beq	lock				@ try again
  
  out:
  	ldmfd	sp!, {r0 - r12, pc}		@ restore regs and return
  ENTRY(omap1_sram_reprogram_clock_sz)
  	.word	. - omap1_sram_reprogram_clock