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