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kernel/linux-imx6_3.14.28/arch/arm/mach-pxa/sleep.S 4.14 KB
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  /*
   * Low-level PXA250/210 sleep/wakeUp support
   *
   * Initial SA1110 code:
   * Copyright (c) 2001 Cliff Brake <cbrake@accelent.com>
   *
   * Adapted for PXA by Nicolas Pitre:
   * Copyright (c) 2002 Monta Vista Software, Inc.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License.
   */
  
  #include <linux/linkage.h>
  #include <asm/assembler.h>
  #include <mach/hardware.h>
  #include <mach/smemc.h>
  #include <mach/pxa2xx-regs.h>
  
  #define MDREFR_KDIV	0x200a4000	// all banks
  #define CCCR_SLEEP	0x00000107	// L=7 2N=2 A=0 PPDIS=0 CPDIS=0
  
  		.text
  
  #ifdef CONFIG_PXA3xx
  /*
   * pxa3xx_finish_suspend() - forces CPU into sleep state (S2D3C4)
   */
  ENTRY(pxa3xx_finish_suspend)
  	mov	r0, #0x06		@ S2D3C4 mode
  	mcr	p14, 0, r0, c7, c0, 0	@ enter sleep
  
  20:	b	20b			@ waiting for sleep
  #endif /* CONFIG_PXA3xx */
  
  #ifdef CONFIG_PXA27x
  /*
   * pxa27x_finish_suspend()
   *
   * Forces CPU into sleep state.
   *
   * r0 = value for PWRMODE M field for desired sleep state
   */
  ENTRY(pxa27x_finish_suspend)
  	@ Put the processor to sleep
  	@ (also workaround for sighting 28071)
  
  	@ prepare value for sleep mode
  	mov	r1, r0				@ sleep mode
  
  	@ prepare pointer to physical address 0 (virtual mapping in generic.c)
  	mov	r2, #UNCACHED_PHYS_0
  
  	@ prepare SDRAM refresh settings
  	ldr	r4, =MDREFR
  	ldr	r5, [r4]
  
  	@ enable SDRAM self-refresh mode
  	orr	r5, r5, #MDREFR_SLFRSH
  
  	@ set SDCLKx divide-by-2 bits (this is part of a workaround for Errata 50)
  	ldr	r6, =MDREFR_KDIV
  	orr	r5, r5, r6
  
  	@ Intel PXA270 Specification Update notes problems sleeping
  	@ with core operating above 91 MHz
  	@ (see Errata 50, ...processor does not exit from sleep...)
  
  	ldr	r6, =CCCR
  	ldr	r8, [r6]		@ keep original value for resume
  
  	ldr	r7, =CCCR_SLEEP		@ prepare CCCR sleep value
  	mov	r0, #0x2		@ prepare value for CLKCFG
  
  	@ align execution to a cache line
  	b	pxa_cpu_do_suspend
  #endif
  
  #ifdef CONFIG_PXA25x
  /*
   * pxa25x_finish_suspend()
   *
   * Forces CPU into sleep state.
   *
   * r0 = value for PWRMODE M field for desired sleep state
   */
  
  ENTRY(pxa25x_finish_suspend)
  	@ prepare value for sleep mode
  	mov	r1, r0				@ sleep mode
  
  	@ prepare pointer to physical address 0 (virtual mapping in generic.c)
  	mov	r2, #UNCACHED_PHYS_0
  
  	@ prepare SDRAM refresh settings
  	ldr	r4, =MDREFR
  	ldr	r5, [r4]
  
  	@ enable SDRAM self-refresh mode
  	orr	r5, r5, #MDREFR_SLFRSH
  
  	@ Intel PXA255 Specification Update notes problems
  	@ about suspending with PXBus operating above 133MHz
  	@ (see Errata 31, GPIO output signals, ... unpredictable in sleep
  	@
  	@ We keep the change-down close to the actual suspend on SDRAM
  	@ as possible to eliminate messing about with the refresh clock
  	@ as the system will restore with the original speed settings
  	@
  	@ Ben Dooks, 13-Sep-2004
  
  	ldr	r6, =CCCR
  	ldr	r8, [r6]		@ keep original value for resume
  
  	@ ensure x1 for run and turbo mode with memory clock
  	bic	r7, r8, #CCCR_M_MASK | CCCR_N_MASK
  	orr	r7, r7, #(1<<5) | (2<<7)
  
  	@ check that the memory frequency is within limits
  	and	r14, r7, #CCCR_L_MASK
  	teq	r14, #1
  	bicne	r7, r7, #CCCR_L_MASK
  	orrne	r7, r7, #1			@@ 99.53MHz
  
  	@ get ready for the change
  
  	@ note, turbo is not preserved over sleep so there is no
  	@ point in preserving it here. we save it on the stack with the
  	@ other CP registers instead.
  	mov	r0, #0
  	mcr	p14, 0, r0, c6, c0, 0
  	orr	r0, r0, #2			@ initiate change bit
  	b	pxa_cpu_do_suspend
  #endif
  
  	.ltorg
  	.align	5
  pxa_cpu_do_suspend:
  
  	@ All needed values are now in registers.
  	@ These last instructions should be in cache
  
  	@ initiate the frequency change...
  	str	r7, [r6]
  	mcr	p14, 0, r0, c6, c0, 0
  
  	@ restore the original cpu speed value for resume
  	str	r8, [r6]
  
  	@ need 6 13-MHz cycles before changing PWRMODE
  	@ just set frequency to 91-MHz... 6*91/13 = 42
  
  	mov	r0, #42
  10:	subs	r0, r0, #1
  	bne	10b
  
  	@ Do not reorder...
  	@ Intel PXA270 Specification Update notes problems performing
  	@ external accesses after SDRAM is put in self-refresh mode
  	@ (see Errata 39 ...hangs when entering self-refresh mode)
  
  	@ force address lines low by reading at physical address 0
  	ldr	r3, [r2]
  
  	@ put SDRAM into self-refresh
  	str	r5, [r4]
  
  	@ enter sleep mode
  	mcr	p14, 0, r1, c7, c0, 0		@ PWRMODE
  
  20:	b	20b				@ loop waiting for sleep