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dmaengine: allow dma support for async_tx to be toggled
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Provide a config option for blocking the allocation of dma channels to
the async_tx api.

Signed-off-by: Dan Williams <[email protected]>
djbw committed Mar 25, 2009
1 parent 06164f3 commit 729b5d1
Showing 3 changed files with 32 additions and 3 deletions.
6 changes: 3 additions & 3 deletions crypto/async_tx/async_tx.c
Original file line number Diff line number Diff line change
@@ -30,7 +30,7 @@
#ifdef CONFIG_DMA_ENGINE
static int __init async_tx_init(void)
{
dmaengine_get();
async_dmaengine_get();

printk(KERN_INFO "async_tx: api initialized (async)\n");

@@ -39,7 +39,7 @@ static int __init async_tx_init(void)

static void __exit async_tx_exit(void)
{
dmaengine_put();
async_dmaengine_put();
}

/**
@@ -56,7 +56,7 @@ __async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
if (depend_tx &&
dma_has_cap(tx_type, depend_tx->chan->device->cap_mask))
return depend_tx->chan;
return dma_find_channel(tx_type);
return async_dma_find_channel(tx_type);
}
EXPORT_SYMBOL_GPL(__async_tx_find_channel);
#else
11 changes: 11 additions & 0 deletions drivers/dma/Kconfig
Original file line number Diff line number Diff line change
@@ -98,6 +98,17 @@ config NET_DMA
Say Y here if you enabled INTEL_IOATDMA or FSL_DMA, otherwise
say N.

config ASYNC_TX_DMA
bool "Async_tx: Offload support for the async_tx api"
depends on DMA_ENGINE
help
This allows the async_tx api to take advantage of offload engines for
memcpy, memset, xor, and raid6 p+q operations. If your platform has
a dma engine that can perform raid operations and you have enabled
MD_RAID456 say Y.

If unsure, say N.

config DMATEST
tristate "DMA Test client"
depends on DMA_ENGINE
18 changes: 18 additions & 0 deletions include/linux/dmaengine.h
Original file line number Diff line number Diff line change
@@ -288,6 +288,24 @@ static inline void net_dmaengine_put(void)
}
#endif

#ifdef CONFIG_ASYNC_TX_DMA
#define async_dmaengine_get() dmaengine_get()
#define async_dmaengine_put() dmaengine_put()
#define async_dma_find_channel(type) dma_find_channel(type)
#else
static inline void async_dmaengine_get(void)
{
}
static inline void async_dmaengine_put(void)
{
}
static inline struct dma_chan *
async_dma_find_channel(enum dma_transaction_type type)
{
return NULL;
}
#endif

dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
void *dest, void *src, size_t len);
dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,

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