arch/arm/mach-omap2/cm.c

   1 /*
   2  * OMAP2/3 CM module functions
   3  *
   4  * Copyright (C) 2009 Nokia Corporation
   5  * Paul Walmsley
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/delay.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/list.h>
  18 #include <linux/errno.h>
  19 #include <linux/err.h>
  20 #include <linux/io.h>
  21
  22 #include <asm/atomic.h>
  23
  24 #include "cm.h"
  25 #include "cm-regbits-24xx.h"
  26 #include "cm-regbits-34xx.h"
  27
  28 /* MAX_MODULE_READY_TIME: max milliseconds for module to leave idle */
  29 #define MAX_MODULE_READY_TIME           20000
  30
  31 static const u8 cm_idlest_offs[] = {
  32         CM_IDLEST1, CM_IDLEST2, OMAP2430_CM_IDLEST3
  33 };
  34
  35 /**
  36  * omap2_cm_wait_idlest_ready - wait for a module to leave idle or standby
  37  * @prcm_mod: PRCM module offset
  38  * @idlest_id: CM_IDLESTx register ID (i.e., x = 1, 2, 3)
  39  * @idlest_shift: shift of the bit in the CM_IDLEST* register to check
  40  *
  41  * XXX document
  42  */
  43 int omap2_cm_wait_module_ready(s16 prcm_mod, u8 idlest_id, u8 idlest_shift)
  44 {
  45         int ena = 0, i = 0;
  46         u8 cm_idlest_reg;
  47         u32 mask;
  48
  49         if (!idlest_id || (idlest_id > ARRAY_SIZE(cm_idlest_offs)))
  50                 return -EINVAL;
  51
  52         cm_idlest_reg = cm_idlest_offs[idlest_id - 1];
  53
  54         if (cpu_is_omap24xx())
  55                 ena = idlest_shift;
  56         else if (cpu_is_omap34xx())
  57                 ena = 0;
  58         else
  59                 BUG();
  60
  61         mask = 1 << idlest_shift;
  62
  63         /* XXX should be OMAP2 CM */
  64         while (((cm_read_mod_reg(prcm_mod, cm_idlest_reg) & mask) != ena) &&
  65                (i++ < MAX_MODULE_READY_TIME))
  66                 udelay(1);
  67
  68         return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
  69 }
  70