diff options
author | Jon Hunter <jon-hunter@ti.com> | 2012-09-14 22:41:57 (GMT) |
---|---|---|
committer | Vinod Koul <vinod.koul@intel.com> | 2013-01-07 04:57:45 (GMT) |
commit | 9a6cecc846169159bfce511f4c0034bb96eea1ca (patch) | |
tree | e5d0dcef464741a0988e4355744a33cb55e6bcd4 | |
parent | d1c3ed669a2d452cacfb48c2d171a1f364dae2ed (diff) | |
download | linux-fsl-qoriq-9a6cecc846169159bfce511f4c0034bb96eea1ca.tar.xz |
dmaengine: add helper function to request a slave DMA channel
Currently slave DMA channels are requested by calling dma_request_channel()
and requires DMA clients to pass various filter parameters to obtain the
appropriate channel.
With device-tree being used by architectures such as arm and the addition of
device-tree helper functions to extract the relevant DMA client information
from device-tree, add a new function to request a slave DMA channel using
device-tree. This function is currently a simple wrapper that calls the
device-tree of_dma_request_slave_channel() function.
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <djbw@fb.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Reviewed-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
-rw-r--r-- | drivers/dma/dmaengine.c | 16 | ||||
-rw-r--r-- | include/linux/dmaengine.h | 6 |
2 files changed, 22 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index a815d44..d37cf95 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -62,6 +62,7 @@ #include <linux/rculist.h> #include <linux/idr.h> #include <linux/slab.h> +#include <linux/of_dma.h> static DEFINE_MUTEX(dma_list_mutex); static DEFINE_IDR(dma_idr); @@ -546,6 +547,21 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v } EXPORT_SYMBOL_GPL(__dma_request_channel); +/** + * dma_request_slave_channel - try to allocate an exclusive slave channel + * @dev: pointer to client device structure + * @name: slave channel name + */ +struct dma_chan *dma_request_slave_channel(struct device *dev, char *name) +{ + /* If device-tree is present get slave info from here */ + if (dev->of_node) + return of_dma_request_slave_channel(dev->of_node, name); + + return NULL; +} +EXPORT_SYMBOL_GPL(dma_request_slave_channel); + void dma_release_channel(struct dma_chan *chan) { mutex_lock(&dma_list_mutex); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index d3201e4..8cd0e25 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -974,6 +974,7 @@ enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie); enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx); void dma_issue_pending_all(void); struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param); +struct dma_chan *dma_request_slave_channel(struct device *dev, char *name); void dma_release_channel(struct dma_chan *chan); #else static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) @@ -988,6 +989,11 @@ static inline struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, { return NULL; } +static inline struct dma_chan *dma_request_slave_channel(struct device *dev, + char *name) +{ + return NULL +} static inline void dma_release_channel(struct dma_chan *chan) { } |