diff options
Diffstat (limited to 'drivers/dma/mmp_pdma.c')
| -rw-r--r-- | drivers/dma/mmp_pdma.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c index dd024d4759e7..76884c48ea85 100644 --- a/drivers/dma/mmp_pdma.c +++ b/drivers/dma/mmp_pdma.c @@ -18,6 +18,7 @@ #include <linux/platform_data/mmp_dma.h> #include <linux/dmapool.h> #include <linux/of_device.h> +#include <linux/of_dma.h> #include <linux/of.h> #include <linux/dma/mmp-pdma.h> @@ -777,6 +778,39 @@ static struct of_device_id mmp_pdma_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, mmp_pdma_dt_ids); +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; + +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) + 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; + } + + goto retry; +} + static int mmp_pdma_probe(struct platform_device *op) { struct mmp_pdma_device *pdev; @@ -863,6 +897,16 @@ static int mmp_pdma_probe(struct platform_device *op) return ret; } + if (op->dev.of_node) { + /* Device-tree DMA controller registration */ + ret = of_dma_controller_register(op->dev.of_node, + mmp_pdma_dma_xlate, pdev); + if (ret < 0) { + dev_err(&op->dev, "of_dma_controller_register failed\n"); + return ret; + } + } + dev_info(pdev->device.dev, "initialized\n"); return 0; } |