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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-10 13:37:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-10 13:37:36 -0700
commitec5b103ecfde929004b691f29183255aeeadecd5 (patch)
tree3b16d0654c074b5b36d06e56110c7218a8685655 /drivers/dma/dmaengine.c
parentd0048f0b91ee35ab940ec6cbdfdd238c55b12a14 (diff)
parent5622ff1a4dd7dcb1c09953d8066a4e7c4c350b2d (diff)
downloadlinux-ec5b103ecfde929004b691f29183255aeeadecd5.tar.bz2
Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma
Pull slave-dmaengine updates from Vinod Koul: "This pull brings: - Andy's DW driver updates - Guennadi's sh driver updates - Pl08x driver fixes from Tomasz & Alban - Improvements to mmp_pdma by Daniel - TI EDMA fixes by Joel - New drivers: - Hisilicon k3dma driver - Renesas rcar dma driver - New API for publishing slave driver capablities - Various fixes across the subsystem by Andy, Jingoo, Sachin etc..." * 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (94 commits) dma: edma: Remove limits on number of slots dma: edma: Leave linked to Null slot instead of DUMMY slot dma: edma: Find missed events and issue them ARM: edma: Add function to manually trigger an EDMA channel dma: edma: Write out and handle MAX_NR_SG at a given time dma: edma: Setup parameters to DMA MAX_NR_SG at a time dmaengine: pl330: use dma_set_max_seg_size to set the sg limit dmaengine: dma_slave_caps: remove sg entries dma: replace devm_request_and_ioremap by devm_ioremap_resource dma: ste_dma40: Fix potential null pointer dereference dma: ste_dma40: Remove duplicate const dma: imx-dma: Remove redundant NULL check dma: dmagengine: fix function names in comments dma: add driver for R-Car HPB-DMAC dma: k3dma: use devm_ioremap_resource() instead of devm_request_and_ioremap() dma: imx-sdma: Staticize sdma_driver_data structures pch_dma: Add MODULE_DEVICE_TABLE dmaengine: PL08x: Add cyclic transfer support dmaengine: PL08x: Fix reading the byte count in cctl dmaengine: PL08x: Add support for different maximum transfer size ...
Diffstat (limited to 'drivers/dma/dmaengine.c')
-rw-r--r--drivers/dma/dmaengine.c28
1 files changed, 27 insertions, 1 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index eee16b01fa89..9162ac80c18f 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -509,7 +509,33 @@ static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
}
/**
- * dma_request_channel - try to allocate an exclusive channel
+ * dma_request_slave_channel - try to get specific channel exclusively
+ * @chan: target channel
+ */
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
+{
+ int err = -EBUSY;
+
+ /* lock against __dma_request_channel */
+ mutex_lock(&dma_list_mutex);
+
+ if (chan->client_count == 0) {
+ err = dma_chan_get(chan);
+ if (err)
+ pr_debug("%s: failed to get %s: (%d)\n",
+ __func__, dma_chan_name(chan), err);
+ } else
+ chan = NULL;
+
+ mutex_unlock(&dma_list_mutex);
+
+
+ return chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_slave_channel);
+
+/**
+ * __dma_request_channel - try to allocate an exclusive channel
* @mask: capabilities that the channel must satisfy
* @fn: optional callback to disposition available channels
* @fn_param: opaque parameter to pass to dma_filter_fn