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Diffstat (limited to 'arch/powerpc/include/asm/fsldma.h')
| -rw-r--r-- | arch/powerpc/include/asm/fsldma.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/fsldma.h b/arch/powerpc/include/asm/fsldma.h new file mode 100644 index 000000000000..a67aeed17d40 --- /dev/null +++ b/arch/powerpc/include/asm/fsldma.h @@ -0,0 +1,136 @@ +/* + * 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/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__ */ |