From 8010dad55a0ab0e829f3733854e5235eef4e2734 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 26 Nov 2013 12:40:51 -0700 Subject: [PATCH] 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 Cc: Vinod Koul Cc: Lars-Peter Clausen Cc: dmaengine@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Stephen Warren Signed-off-by: Vinod Koul --- drivers/dma/dmaengine.c | 28 ++++++++++++++++++++++++++++ drivers/dma/mmp_pdma.c | 30 +++++++----------------------- include/linux/dmaengine.h | 1 + 3 files changed, 36 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) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 41cf0c399288..09ef23ee8bce 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -1079,6 +1079,7 @@ int dma_async_device_register(struct dma_device *device); void dma_async_device_unregister(struct dma_device *device); void dma_run_dependencies(struct dma_async_tx_descriptor *tx); struct dma_chan *dma_get_slave_channel(struct dma_chan *chan); +struct dma_chan *dma_get_any_slave_channel(struct dma_device *device); struct dma_chan *net_dma_find_channel(void); #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y) #define dma_request_slave_channel_compat(mask, x, y, dev, name) \ -- 2.20.1