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authorStephen Warren <swarren@nvidia.com>2013-11-26 12:40:51 -0700
committerVinod Koul <vinod.koul@intel.com>2013-12-10 17:48:33 +0530
commit8010dad55a0ab0e829f3733854e5235eef4e2734 (patch)
tree1a853cb6960763860227891b1324ab9467d6e8c9 /drivers/dma
parent6ce4eac1f600b34f2f7f58f9cd8f0503d79e42ae (diff)
downloadlinux-8010dad55a0ab0e829f3733854e5235eef4e2734.tar.bz2
dma: add dma_get_any_slave_channel(), for use in of_xlate()
mmp_pdma.c implements a custom of_xlate() function that is 95% identical to what Tegra will need. Create a function to implement the common part, so everyone doesn't just cut/paste the implementation. Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vinod Koul <vinod.koul@intel.com> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: dmaengine@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/dmaengine.c28
-rw-r--r--drivers/dma/mmp_pdma.c30
2 files changed, 35 insertions, 23 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ea806bdc12ef..4f08ee8c17b4 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -535,6 +535,34 @@ struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
}
EXPORT_SYMBOL_GPL(dma_get_slave_channel);
+struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
+{
+ dma_cap_mask_t mask;
+ struct dma_chan *chan;
+ int err;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ /* lock against __dma_request_channel */
+ mutex_lock(&dma_list_mutex);
+
+ chan = private_candidate(&mask, device, NULL, NULL);
+ if (chan) {
+ err = dma_chan_get(chan);
+ if (err) {
+ pr_debug("%s: failed to get %s: (%d)\n",
+ __func__, dma_chan_name(chan), err);
+ chan = NULL;
+ }
+ }
+
+ mutex_unlock(&dma_list_mutex);
+
+ return chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
+
/**
* __dma_request_channel - try to allocate an exclusive channel
* @mask: capabilities that the channel must satisfy
diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
index dcb1e05149a7..2998f1bffac1 100644
--- a/drivers/dma/mmp_pdma.c
+++ b/drivers/dma/mmp_pdma.c
@@ -893,33 +893,17 @@ static struct dma_chan *mmp_pdma_dma_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct mmp_pdma_device *d = ofdma->of_dma_data;
- struct dma_chan *chan, *candidate;
+ struct dma_chan *chan;
+ struct mmp_pdma_chan *c;
-retry:
- candidate = NULL;
-
- /* walk the list of channels registered with the current instance and
- * find one that is currently unused */
- list_for_each_entry(chan, &d->device.channels, device_node)
- if (chan->client_count == 0) {
- candidate = chan;
- break;
- }
-
- if (!candidate)
+ chan = dma_get_any_slave_channel(&d->device);
+ if (!chan)
return NULL;
- /* dma_get_slave_channel will return NULL if we lost a race between
- * the lookup and the reservation */
- chan = dma_get_slave_channel(candidate);
-
- if (chan) {
- struct mmp_pdma_chan *c = to_mmp_pdma_chan(chan);
- c->drcmr = dma_spec->args[0];
- return chan;
- }
+ c = to_mmp_pdma_chan(chan);
+ c->drcmr = dma_spec->args[0];
- goto retry;
+ return chan;
}
static int mmp_pdma_probe(struct platform_device *op)