drivers/misc/bcm-vk/bcm_vk_sg.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright 2018-2020 Broadcom.
   4  */
   5
   6 #ifndef BCM_VK_SG_H
   7 #define BCM_VK_SG_H
   8
   9 #include <linux/dma-mapping.h>
  10
  11 struct bcm_vk_dma {
  12         /* for userland buffer */
  13         struct page **pages;
  14         int nr_pages;
  15
  16         /* common */
  17         dma_addr_t handle;
  18         /*
  19          * sglist is of the following LE format
  20          * [U32] num_sg  = number of sg addresses (N)
  21          * [U32] totalsize = totalsize of data being transferred in sglist
  22          * [U32] size[0] = size of data in address0
  23          * [U32] addr_l[0] = lower 32-bits of address0
  24          * [U32] addr_h[0] = higher 32-bits of address0
  25          * ..
  26          * [U32] size[N-1] = size of data in addressN-1
  27          * [U32] addr_l[N-1] = lower 32-bits of addressN-1
  28          * [U32] addr_h[N-1] = higher 32-bits of addressN-1
  29          */
  30         u32 *sglist;
  31 #define SGLIST_NUM_SG           0
  32 #define SGLIST_TOTALSIZE        1
  33 #define SGLIST_VKDATA_START     2
  34
  35         int sglen; /* Length (bytes) of sglist */
  36         int direction;
  37 };
  38
  39 struct _vk_data {
  40         u32 size;    /* data size in bytes */
  41         u64 address; /* Pointer to data     */
  42 } __packed;
  43
  44 /*
  45  * Scatter-gather DMA buffer API.
  46  *
  47  * These functions provide a simple way to create a page list and a
  48  * scatter-gather list from userspace address and map the memory
  49  * for DMA operation.
  50  */
  51 int bcm_vk_sg_alloc(struct device *dev,
  52                     struct bcm_vk_dma *dma,
  53                     int dir,
  54                     struct _vk_data *vkdata,
  55                     int num);
  56
  57 int bcm_vk_sg_free(struct device *dev, struct bcm_vk_dma *dma, int num,
  58                    int *proc_cnt);
  59
  60 #endif
  61