arch/powerpc/include/asm/fsldma.h

   1 /*
   2  * Freescale MPC83XX / MPC85XX DMA Controller
   3  *
   4  * Copyright (c) 2009 Ira W. Snyder <iws@ovro.caltech.edu>
   5  *
   6  * This file is licensed under the terms of the GNU General Public License
   7  * version 2. This program is licensed "as is" without any warranty of any
   8  * kind, whether express or implied.
   9  */
  10
  11 #ifndef __ARCH_POWERPC_ASM_FSLDMA_H__
  12 #define __ARCH_POWERPC_ASM_FSLDMA_H__
  13
  14 #include <linux/dmaengine.h>
  15
  16 /*
  17  * Definitions for the Freescale DMA controller's DMA_SLAVE implemention
  18  *
  19  * The Freescale DMA_SLAVE implementation was designed to handle many-to-many
  20  * transfers. An example usage would be an accelerated copy between two
  21  * scatterlists. Another example use would be an accelerated copy from
  22  * multiple non-contiguous device buffers into a single scatterlist.
  23  *
  24  * A DMA_SLAVE transaction is defined by a struct fsl_dma_slave. This
  25  * structure contains a list of hardware addresses that should be copied
  26  * to/from the scatterlist passed into device_prep_slave_sg(). The structure
  27  * also has some fields to enable hardware-specific features.
  28  */
  29
  30 /**
  31  * struct fsl_dma_hw_addr
  32  * @entry: linked list entry
  33  * @address: the hardware address
  34  * @length: length to transfer
  35  *
  36  * Holds a single physical hardware address / length pair for use
  37  * with the DMAEngine DMA_SLAVE API.
  38  */
  39 struct fsl_dma_hw_addr {
  40         struct list_head entry;
  41
  42         dma_addr_t address;
  43         size_t length;
  44 };
  45
  46 /**
  47  * struct fsl_dma_slave
  48  * @addresses: a linked list of struct fsl_dma_hw_addr structures
  49  * @request_count: value for DMA request count
  50  * @src_loop_size: setup and enable constant source-address DMA transfers
  51  * @dst_loop_size: setup and enable constant destination address DMA transfers
  52  * @external_start: enable externally started DMA transfers
  53  * @external_pause: enable externally paused DMA transfers
  54  *
  55  * Holds a list of address / length pairs for use with the DMAEngine
  56  * DMA_SLAVE API implementation for the Freescale DMA controller.
  57  */
  58 struct fsl_dma_slave {
  59
  60         /* List of hardware address/length pairs */
  61         struct list_head addresses;
  62
  63         /* Support for extra controller features */
  64         unsigned int request_count;
  65         unsigned int src_loop_size;
  66         unsigned int dst_loop_size;
  67         bool external_start;
  68         bool external_pause;
  69 };
  70
  71 /**
  72  * fsl_dma_slave_append - add an address/length pair to a struct fsl_dma_slave
  73  * @slave: the &struct fsl_dma_slave to add to
  74  * @address: the hardware address to add
  75  * @length: the length of bytes to transfer from @address
  76  *
  77  * Add a hardware address/length pair to a struct fsl_dma_slave. Returns 0 on
  78  * success, -ERRNO otherwise.
  79  */
  80 static inline int fsl_dma_slave_append(struct fsl_dma_slave *slave,
  81                                        dma_addr_t address, size_t length)
  82 {
  83         struct fsl_dma_hw_addr *addr;
  84
  85         addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
  86         if (!addr)
  87                 return -ENOMEM;
  88
  89         INIT_LIST_HEAD(&addr->entry);
  90         addr->address = address;
  91         addr->length = length;
  92
  93         list_add_tail(&addr->entry, &slave->addresses);
  94         return 0;
  95 }
  96
  97 /**
  98  * fsl_dma_slave_free - free a struct fsl_dma_slave
  99  * @slave: the struct fsl_dma_slave to free
 100  *
 101  * Free a struct fsl_dma_slave and all associated address/length pairs
 102  */
 103 static inline void fsl_dma_slave_free(struct fsl_dma_slave *slave)
 104 {
 105         struct fsl_dma_hw_addr *addr, *tmp;
 106
 107         if (slave) {
 108                 list_for_each_entry_safe(addr, tmp, &slave->addresses, entry) {
 109                         list_del(&addr->entry);
 110                         kfree(addr);
 111                 }
 112
 113                 kfree(slave);
 114         }
 115 }
 116
 117 /**
 118  * fsl_dma_slave_alloc - allocate a struct fsl_dma_slave
 119  * @gfp: the flags to pass to kmalloc when allocating this structure
 120  *
 121  * Allocate a struct fsl_dma_slave for use by the DMA_SLAVE API. Returns a new
 122  * struct fsl_dma_slave on success, or NULL on failure.
 123  */
 124 static inline struct fsl_dma_slave *fsl_dma_slave_alloc(gfp_t gfp)
 125 {
 126         struct fsl_dma_slave *slave;
 127
 128         slave = kzalloc(sizeof(*slave), gfp);
 129         if (!slave)
 130                 return NULL;
 131
 132         INIT_LIST_HEAD(&slave->addresses);
 133         return slave;
 134 }
 135
 136 #endif /* __ARCH_POWERPC_ASM_FSLDMA_H__ */