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Use the DMA_SLAVE capability of the DMAEngine API to copy/from a scatterlist into an arbitrary list of hardware address/length pairs. This allows a single DMA transaction to copy data from several different devices into a scatterlist at the same time. This also adds support to enable some controller-specific features such as external start and external pause for a DMA transaction. [dan.j.williams@intel.com: rebased on tx_list movement] Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Acked-by: Li Yang <leoli@freescale.com> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
136 lines
3.8 KiB
C
136 lines
3.8 KiB
C
/*
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* Freescale MPC83XX / MPC85XX DMA Controller
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*
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* Copyright (c) 2009 Ira W. Snyder <iws@ovro.caltech.edu>
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#ifndef __ARCH_POWERPC_ASM_FSLDMA_H__
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#define __ARCH_POWERPC_ASM_FSLDMA_H__
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#include <linux/dmaengine.h>
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/*
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* Definitions for the Freescale DMA controller's DMA_SLAVE implemention
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*
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* The Freescale DMA_SLAVE implementation was designed to handle many-to-many
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* transfers. An example usage would be an accelerated copy between two
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* scatterlists. Another example use would be an accelerated copy from
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* multiple non-contiguous device buffers into a single scatterlist.
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*
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* A DMA_SLAVE transaction is defined by a struct fsl_dma_slave. This
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* structure contains a list of hardware addresses that should be copied
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* to/from the scatterlist passed into device_prep_slave_sg(). The structure
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* also has some fields to enable hardware-specific features.
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*/
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/**
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* struct fsl_dma_hw_addr
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* @entry: linked list entry
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* @address: the hardware address
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* @length: length to transfer
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*
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* Holds a single physical hardware address / length pair for use
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* with the DMAEngine DMA_SLAVE API.
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*/
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struct fsl_dma_hw_addr {
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struct list_head entry;
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dma_addr_t address;
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size_t length;
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};
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/**
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* struct fsl_dma_slave
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* @addresses: a linked list of struct fsl_dma_hw_addr structures
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* @request_count: value for DMA request count
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* @src_loop_size: setup and enable constant source-address DMA transfers
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* @dst_loop_size: setup and enable constant destination address DMA transfers
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* @external_start: enable externally started DMA transfers
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* @external_pause: enable externally paused DMA transfers
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*
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* Holds a list of address / length pairs for use with the DMAEngine
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* DMA_SLAVE API implementation for the Freescale DMA controller.
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*/
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struct fsl_dma_slave {
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/* List of hardware address/length pairs */
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struct list_head addresses;
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/* Support for extra controller features */
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unsigned int request_count;
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unsigned int src_loop_size;
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unsigned int dst_loop_size;
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bool external_start;
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bool external_pause;
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};
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/**
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* fsl_dma_slave_append - add an address/length pair to a struct fsl_dma_slave
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* @slave: the &struct fsl_dma_slave to add to
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* @address: the hardware address to add
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* @length: the length of bytes to transfer from @address
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*
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* Add a hardware address/length pair to a struct fsl_dma_slave. Returns 0 on
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* success, -ERRNO otherwise.
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*/
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static inline int fsl_dma_slave_append(struct fsl_dma_slave *slave,
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dma_addr_t address, size_t length)
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{
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struct fsl_dma_hw_addr *addr;
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addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
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if (!addr)
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return -ENOMEM;
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INIT_LIST_HEAD(&addr->entry);
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addr->address = address;
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addr->length = length;
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list_add_tail(&addr->entry, &slave->addresses);
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return 0;
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}
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/**
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* fsl_dma_slave_free - free a struct fsl_dma_slave
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* @slave: the struct fsl_dma_slave to free
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*
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* Free a struct fsl_dma_slave and all associated address/length pairs
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*/
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static inline void fsl_dma_slave_free(struct fsl_dma_slave *slave)
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{
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struct fsl_dma_hw_addr *addr, *tmp;
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if (slave) {
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list_for_each_entry_safe(addr, tmp, &slave->addresses, entry) {
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list_del(&addr->entry);
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kfree(addr);
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}
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kfree(slave);
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}
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}
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/**
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* fsl_dma_slave_alloc - allocate a struct fsl_dma_slave
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* @gfp: the flags to pass to kmalloc when allocating this structure
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*
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* Allocate a struct fsl_dma_slave for use by the DMA_SLAVE API. Returns a new
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* struct fsl_dma_slave on success, or NULL on failure.
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*/
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static inline struct fsl_dma_slave *fsl_dma_slave_alloc(gfp_t gfp)
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{
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struct fsl_dma_slave *slave;
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slave = kzalloc(sizeof(*slave), gfp);
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if (!slave)
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return NULL;
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INIT_LIST_HEAD(&slave->addresses);
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return slave;
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}
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#endif /* __ARCH_POWERPC_ASM_FSLDMA_H__ */
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