arch/arm/mach-omap2/prm2xxx_3xxx.c

   1 /*
   2  * OMAP2/3 PRM module functions
   3  *
   4  * Copyright (C) 2010 Texas Instruments, Inc.
   5  * Copyright (C) 2010 Nokia Corporation
   6  * Benoît Cousson
   7  * Paul Walmsley
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <linux/err.h>
  18
  19 #include <plat/common.h>
  20 #include <plat/cpu.h>
  21 #include <plat/prcm.h>
  22
  23 #include "prm.h"
  24 #include "prm-regbits-24xx.h"
  25 #include "prm-regbits-34xx.h"
  26
  27 /**
  28  * omap2_prm_is_hardreset_asserted - read the HW reset line state of
  29  * submodules contained in the hwmod module
  30  * @prm_mod: PRM submodule base (e.g. CORE_MOD)
  31  * @shift: register bit shift corresponding to the reset line to check
  32  *
  33  * Returns 1 if the (sub)module hardreset line is currently asserted,
  34  * 0 if the (sub)module hardreset line is not currently asserted, or
  35  * -EINVAL if called while running on a non-OMAP2/3 chip.
  36  */
  37 int omap2_prm_is_hardreset_asserted(s16 prm_mod, u8 shift)
  38 {
  39         if (!(cpu_is_omap24xx() || cpu_is_omap34xx()))
  40                 return -EINVAL;
  41
  42         return prm_read_mod_bits_shift(prm_mod, OMAP2_RM_RSTCTRL,
  43                                        (1 << shift));
  44 }
  45
  46 /**
  47  * omap2_prm_assert_hardreset - assert the HW reset line of a submodule
  48  * @prm_mod: PRM submodule base (e.g. CORE_MOD)
  49  * @shift: register bit shift corresponding to the reset line to assert
  50  *
  51  * Some IPs like dsp or iva contain processors that require an HW
  52  * reset line to be asserted / deasserted in order to fully enable the
  53  * IP.  These modules may have multiple hard-reset lines that reset
  54  * different 'submodules' inside the IP block.  This function will
  55  * place the submodule into reset.  Returns 0 upon success or -EINVAL
  56  * upon an argument error.
  57  */
  58 int omap2_prm_assert_hardreset(s16 prm_mod, u8 shift)
  59 {
  60         u32 mask;
  61
  62         if (!(cpu_is_omap24xx() || cpu_is_omap34xx()))
  63                 return -EINVAL;
  64
  65         mask = 1 << shift;
  66         prm_rmw_mod_reg_bits(mask, mask, prm_mod, OMAP2_RM_RSTCTRL);
  67
  68         return 0;
  69 }
  70
  71 /**
  72  * omap2_prm_deassert_hardreset - deassert a submodule hardreset line and wait
  73  * @prm_mod: PRM submodule base (e.g. CORE_MOD)
  74  * @shift: register bit shift corresponding to the reset line to deassert
  75  *
  76  * Some IPs like dsp or iva contain processors that require an HW
  77  * reset line to be asserted / deasserted in order to fully enable the
  78  * IP.  These modules may have multiple hard-reset lines that reset
  79  * different 'submodules' inside the IP block.  This function will
  80  * take the submodule out of reset and wait until the PRCM indicates
  81  * that the reset has completed before returning.  Returns 0 upon success or
  82  * -EINVAL upon an argument error, -EEXIST if the submodule was already out
  83  * of reset, or -EBUSY if the submodule did not exit reset promptly.
  84  */
  85 int omap2_prm_deassert_hardreset(s16 prm_mod, u8 shift)
  86 {
  87         u32 mask;
  88         int c;
  89
  90         if (!(cpu_is_omap24xx() || cpu_is_omap34xx()))
  91                 return -EINVAL;
  92
  93         mask = 1 << shift;
  94
  95         /* Check the current status to avoid de-asserting the line twice */
  96         if (prm_read_mod_bits_shift(prm_mod, OMAP2_RM_RSTCTRL, mask) == 0)
  97                 return -EEXIST;
  98
  99         /* Clear the reset status by writing 1 to the status bit */
 100         prm_rmw_mod_reg_bits(0xffffffff, mask, prm_mod, OMAP2_RM_RSTST);
 101         /* de-assert the reset control line */
 102         prm_rmw_mod_reg_bits(mask, 0, prm_mod, OMAP2_RM_RSTCTRL);
 103         /* wait the status to be set */
 104         omap_test_timeout(prm_read_mod_bits_shift(prm_mod, OMAP2_RM_RSTST,
 105                                                   mask),
 106                           MAX_MODULE_HARDRESET_WAIT, c);
 107
 108         return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
 109 }
 110