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 "cm.h"
  25 #include "cm-regbits-4xxx.h"
  26
  27 /* XXX move this to cm.h */
  28 /* MAX_MODULE_READY_TIME: max milliseconds for module to leave idle */
  29 #define MAX_MODULE_READY_TIME                   20000
  30
  31 /*
  32  * OMAP4_PRCM_CM_CLKCTRL_IDLEST_MASK: isolates the IDLEST field in the
  33  * CM_CLKCTRL register.
  34  */
  35 #define OMAP4_PRCM_CM_CLKCTRL_IDLEST_MASK       (0x2 << 16)
  36
  37 /*
  38  * OMAP4 prcm_mod u32 fields contain packed data: the CM ID in bit 16 and
  39  * the PRCM module offset address (from the CM module base) in bits 15-0.
  40  */
  41 #define OMAP4_PRCM_MOD_CM_ID_SHIFT              16
  42 #define OMAP4_PRCM_MOD_OFFS_MASK                0xffff
  43
  44 /**
  45  * omap4_cm_wait_idlest_ready - wait for a module to leave idle or standby
  46  * @prcm_mod: PRCM module offset (XXX example)
  47  * @prcm_dev_offs: PRCM device offset (e.g. MCASP XXX example)
  48  *
  49  * XXX document
  50  */
  51 int omap4_cm_wait_idlest_ready(u32 prcm_mod, u8 prcm_dev_offs)
  52 {
  53         int i = 0;
  54         u8 cm_id;
  55         u16 prcm_mod_offs;
  56         u32 mask = OMAP4_PRCM_CM_CLKCTRL_IDLEST_MASK;
  57
  58         cm_id = prcm_mod >> OMAP4_PRCM_MOD_CM_ID_SHIFT;
  59         prcm_mod_offs = prcm_mod & OMAP4_PRCM_MOD_OFFS_MASK;
  60
  61         while (((omap4_cm_read_mod_reg(cm_id, prcm_mod_offs, prcm_dev_offs,
  62                                        OMAP4_CM_CLKCTRL_DREG) & mask) != 0) &&
  63                (i++ < MAX_MODULE_READY_TIME))
  64                 udelay(1);
  65
  66         return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
  67 }
  68