LXR linux/arch/arm/mach-omap1/sram.S

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * linux/arch/arm/plat-omap/sram-fn.S
   4 *
   5 * Functions that need to be run in internal SRAM
   6 */
   7
   8#include <linux/linkage.h>
   9
  10#include <asm/assembler.h>
  11
  12#include <mach/hardware.h>
  13
  14#include "iomap.h"
  15
  16        .text
  17
  18/*
  19 * Reprograms ULPD and CKCTL.
  20 */
  21        .align  3
  22ENTRY(omap1_sram_reprogram_clock)
  23        stmfd   sp!, {r0 - r12, lr}             @ save registers on stack
  24
  25        mov     r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0xff000000
  26        orr     r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x00ff0000
  27        orr     r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x0000ff00
  28
  29        mov     r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0xff000000
  30        orr     r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
  31        orr     r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
  32
  33        tst     r0, #1 << 4                     @ want lock mode?
  34        beq     newck                           @ nope
  35        bic     r0, r0, #1 << 4                 @ else clear lock bit
  36        strh    r0, [r2]                        @ set dpll into bypass mode
  37        orr     r0, r0, #1 << 4                 @ set lock bit again
  38
  39newck:
  40        strh    r1, [r3]                        @ write new ckctl value
  41        strh    r0, [r2]                        @ write new dpll value
  42
  43        mov     r4, #0x0700                     @ let the clocks settle
  44        orr     r4, r4, #0x00ff
  45delay:  sub     r4, r4, #1
  46        cmp     r4, #0
  47        bne     delay
  48
  49lock:   ldrh    r4, [r2], #0                    @ read back dpll value
  50        tst     r0, #1 << 4                     @ want lock mode?
  51        beq     out                             @ nope
  52        tst     r4, #1 << 0                     @ dpll rate locked?
  53        beq     lock                            @ try again
  54
  55out:
  56        ldmfd   sp!, {r0 - r12, pc}             @ restore regs and return
  57ENTRY(omap1_sram_reprogram_clock_sz)
  58        .word   . - omap1_sram_reprogram_clock
  59