linux/dma/sprd-dma.h

1 /* SPDX-License-Identifier: GPL-2.0 */
15  * The Spreadtrum DMA controller supports channel 2-stage tansfer, that means
19  * trigger the destination channel's transaction automatically by hardware
22  * To support 2-stage tansfer, we must configure the channel mode and trigger
27  * enum sprd_dma_chn_mode: define the DMA channel mode for 2-stage transfer
29  * support the 2-stage transfer.
35  * Now the DMA controller can supports 2 groups 2-stage transfer.
46  * enum sprd_dma_trg_mode: define the DMA channel trigger mode for 2-stage
48  * @SPRD_DMA_NO_TRG: No trigger setting.
49  * @SPRD_DMA_FRAG_DONE_TRG: Trigger the transaction of destination channel
51  * @SPRD_DMA_BLOCK_DONE_TRG: Trigger the transaction of destination channel
53  * @SPRD_DMA_TRANS_DONE_TRG: Trigger the transaction of destination channel
55  * @SPRD_DMA_LIST_DONE_TRG: Trigger the transaction of destination channel
56  * automatically once the source channel's link-list request is done.
71  * @SPRD_DMA_LIST_REQ: link-list request mode
75  * contain several fragments. Link-list mode means we can save several DMA
100  * @SPRD_DMA_LIST_INT: link-list done interrupt when one link-list request
118  * struct sprd_dma_linklist - DMA link-list address structure
119  * @virt_addr: link-list virtual address to configure link-list node
120  * @phy_addr: link-list physical address to link DMA transfer
121  * @wrap_addr: the wrap address for link-list mode, which means once the
122  * transfer address reaches the wrap address, the next transfer address
123  * will jump to the address specified by wrap_to register.
125  * The Spreadtrum DMA controller supports the link-list mode, that means slaves
128  * configurations by writing the physical address of each configuration into the
129  * link-list register.
131  * Just as shown below, the link-list pointer register will be pointed to the
132  * physical address of 'configuration 1', and the 'configuration 1' link-list
134  * Once trigger the DMA transfer, the DMA controller will load 'configuration
139  * Note: The last link-list pointer should point to the physical address
144  * ======================             -----------------------
145  *|                      |           |    configuration 1    |<---
146  *|   DMA controller     |   ------->|                       |   |
150  *| linklist pointer reg |----   ----|    linklist pointer   |   |
151  * ======================        |    -----------------------    |
153  *                               |    -----------------------    |
155  *                               --->|                       |   |
159  *                               ----|    linklist pointer   |   |
160  *                               |    -----------------------    |
162  *                               |    -----------------------    |
164  *                               --->|                       |   |
171  *                               |    -----------------------    |
173  *                               --->|                       |   |
177  *                                   |    linklist pointer   |----
178  *                                    -----------------------
180  * To support the link-list mode, DMA slaves should allocate one segment memory
181  * from always-on IRAM or dma coherent memory to store these groups of DMA
182  * configuration, and pass the virtual and physical address to DMA controller.