include/smem.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * The shared memory system is an allocate-only heap structure that
   4  * consists of one of more memory areas that can be accessed by the processors
   5  * in the SoC.
   6  *
   7  * Allocation can be done globally for all processors or to an individual processor.
   8  * This is controlled by the @host parameter.
   9  *
  10  * Allocation and management of heap can be implemented in various ways,
  11  * The @item parameter should be used as an index/hash to the memory region.
  12  *
  13  * Copyright (c) 2018 Ramon Fried <ramon.fried@gmail.com>
  14  */
  15
  16 #ifndef _smemh_
  17 #define _smemh_
  18
  19 /* struct smem_ops: Operations for the SMEM uclass */
  20 struct smem_ops {
  21         /**
  22          * alloc() - allocate space for a smem item
  23          *
  24          * @host:       remote processor id, or -1 for all processors.
  25          * @item:       smem item handle
  26          * @size:       number of bytes to be allocated
  27          * @return 0 if OK, -ve on error
  28          */
  29         int (*alloc)(unsigned int host,
  30                 unsigned int item, size_t size);
  31
  32         /**
  33          * get() - Resolve ptr of size of a smem item
  34          *
  35          * @host:       the remote processor, of -1 for all processors.
  36          * @item:       smem item handle
  37          * @size:       pointer to be filled out with the size of the item
  38          * @return      pointer on success, NULL on error
  39          */
  40         void *(*get)(unsigned int host,
  41                 unsigned int item, size_t *size);
  42
  43         /**
  44          * get_free_space() - Get free space in smem in bytes
  45          *
  46          * @host:   the remote processor identifying a partition, or -1
  47          *                      for all processors.
  48          * @return      free space, -ve on error
  49          */
  50         int (*get_free_space)(unsigned int host);
  51 };
  52
  53 #define smem_get_ops(dev)       ((struct smem_ops *)(dev)->driver->ops)
  54
  55 /**
  56  * smem_alloc() - allocate space for a smem item
  57  * @host:       remote processor id, or -1
  58  * @item:       smem item handle
  59  * @size:       number of bytes to be allocated
  60  * @return 0 if OK, -ve on error
  61  *
  62  * Allocate space for a given smem item of size @size, given that the item is
  63  * not yet allocated.
  64  */
  65 int smem_alloc(struct udevice *dev, unsigned int host, unsigned int item, size_t size);
  66
  67 /**
  68  * smem_get() - resolve ptr of size of a smem item
  69  * @host:       the remote processor, or -1 for all processors.
  70  * @item:       smem item handle
  71  * @size:       pointer to be filled out with size of the item
  72  * @return      pointer on success, NULL on error
  73  *
  74  * Looks up smem item and returns pointer to it. Size of smem
  75  * item is returned in @size.
  76  */
  77 void *smem_get(struct udevice *dev, unsigned int host, unsigned int item, size_t *size);
  78
  79 /**
  80  * smem_get_free_space() - retrieve amount of free space in a partition
  81  * @host:       the remote processor identifying a partition, or -1
  82  *                      for all processors.
  83  * @return      size in bytes, -ve on error
  84  *
  85  * To be used by smem clients as a quick way to determine if any new
  86  * allocations has been made.
  87  */
  88 int smem_get_free_space(struct udevice *dev, unsigned int host);
  89
  90 #endif /* _smem_h_ */
  91