arch/arm/mach-omap2/cm_common.c

   1 /*
   2  * OMAP2+ common Clock Management (CM) IP block functions
   3  *
   4  * Copyright (C) 2012 Texas Instruments, Inc.
   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  * XXX This code should eventually be moved to a CM driver.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/errno.h>
  17 #include <linux/bug.h>
  18
  19 #include "cm2xxx.h"
  20 #include "cm3xxx.h"
  21 #include "cm44xx.h"
  22
  23 /*
  24  * cm_ll_data: function pointers to SoC-specific implementations of
  25  * common CM functions
  26  */
  27 static struct cm_ll_data null_cm_ll_data;
  28 static struct cm_ll_data *cm_ll_data = &null_cm_ll_data;
  29
  30 /* cm_base: base virtual address of the CM IP block */
  31 void __iomem *cm_base;
  32
  33 /* cm2_base: base virtual address of the CM2 IP block (OMAP44xx only) */
  34 void __iomem *cm2_base;
  35
  36 /**
  37  * omap2_set_globals_cm - set the CM/CM2 base addresses (for early use)
  38  * @cm: CM base virtual address
  39  * @cm2: CM2 base virtual address (if present on the booted SoC)
  40  *
  41  * XXX Will be replaced when the PRM/CM drivers are completed.
  42  */
  43 void __init omap2_set_globals_cm(void __iomem *cm, void __iomem *cm2)
  44 {
  45         cm_base = cm;
  46         cm2_base = cm2;
  47 }
  48
  49 /**
  50  * cm_split_idlest_reg - split CM_IDLEST reg addr into its components
  51  * @idlest_reg: CM_IDLEST* virtual address
  52  * @prcm_inst: pointer to an s16 to return the PRCM instance offset
  53  * @idlest_reg_id: pointer to a u8 to return the CM_IDLESTx register ID
  54  *
  55  * Given an absolute CM_IDLEST register address @idlest_reg, passes
  56  * the PRCM instance offset and IDLEST register ID back to the caller
  57  * via the @prcm_inst and @idlest_reg_id.  Returns -EINVAL upon error,
  58  * or 0 upon success.  XXX This function is only needed until absolute
  59  * register addresses are removed from the OMAP struct clk records.
  60  */
  61 int cm_split_idlest_reg(void __iomem *idlest_reg, s16 *prcm_inst,
  62                         u8 *idlest_reg_id)
  63 {
  64         if (!cm_ll_data->split_idlest_reg) {
  65                 WARN_ONCE(1, "cm: %s: no low-level function defined\n",
  66                           __func__);
  67                 return -EINVAL;
  68         }
  69
  70         return cm_ll_data->split_idlest_reg(idlest_reg, prcm_inst,
  71                                            idlest_reg_id);
  72 }
  73
  74 /**
  75  * cm_wait_module_ready - wait for a module to leave idle or standby
  76  * @prcm_mod: PRCM module offset
  77  * @idlest_id: CM_IDLESTx register ID (i.e., x = 1, 2, 3)
  78  * @idlest_shift: shift of the bit in the CM_IDLEST* register to check
  79  *
  80  * Wait for the PRCM to indicate that the module identified by
  81  * (@prcm_mod, @idlest_id, @idlest_shift) is clocked.  Return 0 upon
  82  * success, -EBUSY if the module doesn't enable in time, or -EINVAL if
  83  * no per-SoC wait_module_ready() function pointer has been registered
  84  * or if the idlest register is unknown on the SoC.
  85  */
  86 int cm_wait_module_ready(s16 prcm_mod, u8 idlest_id, u8 idlest_shift)
  87 {
  88         if (!cm_ll_data->wait_module_ready) {
  89                 WARN_ONCE(1, "cm: %s: no low-level function defined\n",
  90                           __func__);
  91                 return -EINVAL;
  92         }
  93
  94         return cm_ll_data->wait_module_ready(prcm_mod, idlest_id, idlest_shift);
  95 }
  96
  97 /**
  98  * cm_register - register per-SoC low-level data with the CM
  99  * @cld: low-level per-SoC OMAP CM data & function pointers to register
 100  *
 101  * Register per-SoC low-level OMAP CM data and function pointers with
 102  * the OMAP CM common interface.  The caller must keep the data
 103  * pointed to by @cld valid until it calls cm_unregister() and
 104  * it returns successfully.  Returns 0 upon success, -EINVAL if @cld
 105  * is NULL, or -EEXIST if cm_register() has already been called
 106  * without an intervening cm_unregister().
 107  */
 108 int cm_register(struct cm_ll_data *cld)
 109 {
 110         if (!cld)
 111                 return -EINVAL;
 112
 113         if (cm_ll_data != &null_cm_ll_data)
 114                 return -EEXIST;
 115
 116         cm_ll_data = cld;
 117
 118         return 0;
 119 }
 120
 121 /**
 122  * cm_unregister - unregister per-SoC low-level data & function pointers
 123  * @cld: low-level per-SoC OMAP CM data & function pointers to unregister
 124  *
 125  * Unregister per-SoC low-level OMAP CM data and function pointers
 126  * that were previously registered with cm_register().  The
 127  * caller may not destroy any of the data pointed to by @cld until
 128  * this function returns successfully.  Returns 0 upon success, or
 129  * -EINVAL if @cld is NULL or if @cld does not match the struct
 130  * cm_ll_data * previously registered by cm_register().
 131  */
 132 int cm_unregister(struct cm_ll_data *cld)
 133 {
 134         if (!cld || cm_ll_data != cld)
 135                 return -EINVAL;
 136
 137         cm_ll_data = &null_cm_ll_data;
 138
 139         return 0;
 140 }