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authorIra Snyder <iws@ovro.caltech.edu>2009-09-08 17:53:04 -0700
committerDan Williams <dan.j.williams@intel.com>2009-09-08 17:53:04 -0700
commitbbea0b6e0d214ef1511b9c6ccf3af26b38f0af7d (patch)
tree5f2145c023b9145d1461ecb63c839fd32f762378 /arch/powerpc/include/asm
parente6c7ecb64e08ef346cb7062b4a5421f00bc602bd (diff)
fsldma: Add DMA_SLAVE support
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>
Diffstat (limited to 'arch/powerpc/include/asm')
-rw-r--r--arch/powerpc/include/asm/fsldma.h136
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 00000000000..a67aeed17d4
--- /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__ */