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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 */
39struct 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 */
58struct 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 */
80static 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 */
103static 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 */
124static 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__ */