arch/arm/mach-omap2/cm4xxx.c

   1 /*
   2  * OMAP4 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 <plat/common.h>
  25
  26 #include "cm.h"
  27 #include "cm-regbits-44xx.h"
  28
  29 /**
  30  * omap4_cm_wait_module_ready - wait for a module to be in 'func' state
  31  * @clkctrl_reg: CLKCTRL module address
  32  *
  33  * Wait for the module IDLEST to be functional. If the idle state is in any
  34  * the non functional state (trans, idle or disabled), module and thus the
  35  * sysconfig cannot be accessed and will probably lead to an "imprecise
  36  * external abort"
  37  *
  38  * Module idle state:
  39  *   0x0 func:     Module is fully functional, including OCP
  40  *   0x1 trans:    Module is performing transition: wakeup, or sleep, or sleep
  41  *                 abortion
  42  *   0x2 idle:     Module is in Idle mode (only OCP part). It is functional if
  43  *                 using separate functional clock
  44  *   0x3 disabled: Module is disabled and cannot be accessed
  45  *
  46  * TODO: Need to handle module accessible in idle state
  47  */
  48 int omap4_cm_wait_module_ready(void __iomem *clkctrl_reg)
  49 {
  50         int i = 0;
  51
  52         if (!clkctrl_reg)
  53                 return 0;
  54
  55         omap_test_timeout(((__raw_readl(clkctrl_reg) &
  56                             OMAP4430_IDLEST_MASK) == 0),
  57                           MAX_MODULE_READY_TIME, i);
  58
  59         return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
  60 }
  61