drivers/gpu/drm/msm/disp/dpu1/dpu_hw_blk.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
   3  */
   4
   5 #define pr_fmt(fmt)     "[drm:%s:%d] " fmt, __func__, __LINE__
   6
   7 #include <linux/mutex.h>
   8 #include <linux/errno.h>
   9 #include <linux/slab.h>
  10
  11 #include "dpu_hw_mdss.h"
  12 #include "dpu_hw_blk.h"
  13
  14 /* Serialization lock for dpu_hw_blk_list */
  15 static DEFINE_MUTEX(dpu_hw_blk_lock);
  16
  17 /* List of all hw block objects */
  18 static LIST_HEAD(dpu_hw_blk_list);
  19
  20 /**
  21  * dpu_hw_blk_init - initialize hw block object
  22  * @type: hw block type - enum dpu_hw_blk_type
  23  * @id: instance id of the hw block
  24  * @ops: Pointer to block operations
  25  */
  26 void dpu_hw_blk_init(struct dpu_hw_blk *hw_blk, u32 type, int id,
  27                 struct dpu_hw_blk_ops *ops)
  28 {
  29         INIT_LIST_HEAD(&hw_blk->list);
  30         hw_blk->type = type;
  31         hw_blk->id = id;
  32         atomic_set(&hw_blk->refcount, 0);
  33
  34         if (ops)
  35                 hw_blk->ops = *ops;
  36
  37         mutex_lock(&dpu_hw_blk_lock);
  38         list_add(&hw_blk->list, &dpu_hw_blk_list);
  39         mutex_unlock(&dpu_hw_blk_lock);
  40 }
  41
  42 /**
  43  * dpu_hw_blk_destroy - destroy hw block object.
  44  * @hw_blk:  pointer to hw block object
  45  * return: none
  46  */
  47 void dpu_hw_blk_destroy(struct dpu_hw_blk *hw_blk)
  48 {
  49         if (!hw_blk) {
  50                 pr_err("invalid parameters\n");
  51                 return;
  52         }
  53
  54         if (atomic_read(&hw_blk->refcount))
  55                 pr_err("hw_blk:%d.%d invalid refcount\n", hw_blk->type,
  56                                 hw_blk->id);
  57
  58         mutex_lock(&dpu_hw_blk_lock);
  59         list_del(&hw_blk->list);
  60         mutex_unlock(&dpu_hw_blk_lock);
  61 }
  62
  63 /**
  64  * dpu_hw_blk_get - get hw_blk from free pool
  65  * @hw_blk: if specified, increment reference count only
  66  * @type: if hw_blk is not specified, allocate the next available of this type
  67  * @id: if specified (>= 0), allocate the given instance of the above type
  68  * return: pointer to hw block object
  69  */
  70 struct dpu_hw_blk *dpu_hw_blk_get(struct dpu_hw_blk *hw_blk, u32 type, int id)
  71 {
  72         struct dpu_hw_blk *curr;
  73         int rc, refcount;
  74
  75         if (!hw_blk) {
  76                 mutex_lock(&dpu_hw_blk_lock);
  77                 list_for_each_entry(curr, &dpu_hw_blk_list, list) {
  78                         if ((curr->type != type) ||
  79                                         (id >= 0 && curr->id != id) ||
  80                                         (id < 0 &&
  81                                                 atomic_read(&curr->refcount)))
  82                                 continue;
  83
  84                         hw_blk = curr;
  85                         break;
  86                 }
  87                 mutex_unlock(&dpu_hw_blk_lock);
  88         }
  89
  90         if (!hw_blk) {
  91                 pr_debug("no hw_blk:%d\n", type);
  92                 return NULL;
  93         }
  94
  95         refcount = atomic_inc_return(&hw_blk->refcount);
  96
  97         if (refcount == 1 && hw_blk->ops.start) {
  98                 rc = hw_blk->ops.start(hw_blk);
  99                 if (rc) {
 100                         pr_err("failed to start  hw_blk:%d rc:%d\n", type, rc);
 101                         goto error_start;
 102                 }
 103         }
 104
 105         pr_debug("hw_blk:%d.%d refcount:%d\n", hw_blk->type,
 106                         hw_blk->id, refcount);
 107         return hw_blk;
 108
 109 error_start:
 110         dpu_hw_blk_put(hw_blk);
 111         return ERR_PTR(rc);
 112 }
 113
 114 /**
 115  * dpu_hw_blk_put - put hw_blk to free pool if decremented refcount is zero
 116  * @hw_blk: hw block to be freed
 117  * @free_blk: function to be called when reference count goes to zero
 118  */
 119 void dpu_hw_blk_put(struct dpu_hw_blk *hw_blk)
 120 {
 121         if (!hw_blk) {
 122                 pr_err("invalid parameters\n");
 123                 return;
 124         }
 125
 126         pr_debug("hw_blk:%d.%d refcount:%d\n", hw_blk->type, hw_blk->id,
 127                         atomic_read(&hw_blk->refcount));
 128
 129         if (!atomic_read(&hw_blk->refcount)) {
 130                 pr_err("hw_blk:%d.%d invalid put\n", hw_blk->type, hw_blk->id);
 131                 return;
 132         }
 133
 134         if (atomic_dec_return(&hw_blk->refcount))
 135                 return;
 136
 137         if (hw_blk->ops.stop)
 138                 hw_blk->ops.stop(hw_blk);
 139 }