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Merge branch 'topic/sprd' into for-linus

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This commit is contained in:
Vinod Koul
2018-10-24 09:16:27 +01:00
parent 8e75ab9bd8 4ac6954647
commit 4b4447bfad
2 changed files with 143 additions and 7 deletions
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69
include/linux/dma/sprd-dma.h
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@@ -58,4 +58,73 @@ enum sprd_dma_int_type {
SPRD_DMA_CFGERR_INT,
};
/*
* struct sprd_dma_linklist - DMA link-list address structure
* @virt_addr: link-list virtual address to configure link-list node
* @phy_addr: link-list physical address to link DMA transfer
*
* The Spreadtrum DMA controller supports the link-list mode, that means slaves
* can supply several groups configurations (each configuration represents one
* DMA transfer) saved in memory, and DMA controller will link these groups
* configurations by writing the physical address of each configuration into the
* link-list register.
*
* Just as shown below, the link-list pointer register will be pointed to the
* physical address of 'configuration 1', and the 'configuration 1' link-list
* pointer will be pointed to 'configuration 2', and so on.
* Once trigger the DMA transfer, the DMA controller will load 'configuration
* 1' to its registers automatically, after 'configuration 1' transaction is
* done, DMA controller will load 'configuration 2' automatically, until all
* DMA transactions are done.
*
* Note: The last link-list pointer should point to the physical address
* of 'configuration 1', which can avoid DMA controller loads incorrect
* configuration when the last configuration transaction is done.
*
* DMA controller linklist memory
* ====================== -----------------------
*| | | configuration 1 |<---
*| DMA controller | ------->| | |
*| | | | | |
*| | | | | |
*| | | | | |
*| linklist pointer reg |---- ----| linklist pointer | |
* ====================== | ----------------------- |
* | |
* | ----------------------- |
* | | configuration 2 | |
* --->| | |
* | | |
* | | |
* | | |
* ----| linklist pointer | |
* | ----------------------- |
* | |
* | ----------------------- |
* | | configuration 3 | |
* --->| | |
* | | |
* | . | |
* . |
* . |
* . |
* | . |
* | ----------------------- |
* | | configuration n | |
* --->| | |
* | | |
* | | |
* | | |
* | linklist pointer |----
* -----------------------
*
* To support the link-list mode, DMA slaves should allocate one segment memory
* from always-on IRAM or dma coherent memory to store these groups of DMA
* configuration, and pass the virtual and physical address to DMA controller.
*/
struct sprd_dma_linklist {
unsigned long virt_addr;
phys_addr_t phy_addr;
};
#endif