dma: pl330: Use dma_get_slave_channel() in the of xlate callback

Currently the driver uses dma_request_channel() with a custom filter function to
find the requested channel. This will loop over all available channels until the
one we want has been found, but we already know which channel we want to
request, so we can dma_get_slave_channel(). This also makes the code a bit
shorter cleaner.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/pl330.c

@@ -589,6 +589,7 @@ struct dma_pl330_dmac {
 	spinlock_t pool_lock;
 
 	/* Peripheral channels connected to this DMAC */
+	unsigned int num_peripherals;
 	struct dma_pl330_chan *peripherals; /* keep at end */
 };
 
@@ -611,11 +612,6 @@ struct dma_pl330_desc {
 	struct dma_pl330_chan *pchan;
 };
 
-struct dma_pl330_filter_args {
-	struct dma_pl330_dmac *pdmac;
-	unsigned int chan_id;
-};
-
 static inline void _callback(struct pl330_req *r, enum pl330_op_err err)
 {
 	if (r && r->xfer_cb)
@@ -2303,16 +2299,6 @@ static void dma_pl330_rqcb(void *token, enum pl330_op_err err)
 	tasklet_schedule(&pch->task);
 }
 
-static bool pl330_dt_filter(struct dma_chan *chan, void *param)
-{
-	struct dma_pl330_filter_args *fargs = param;
-
-	if (chan->device != &fargs->pdmac->ddma)
-		return false;
-
-	return (chan->chan_id == fargs->chan_id);
-}
-
 bool pl330_filter(struct dma_chan *chan, void *param)
 {
 	u8 *peri_id;
@@ -2330,23 +2316,16 @@ static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
 {
 	int count = dma_spec->args_count;
 	struct dma_pl330_dmac *pdmac = ofdma->of_dma_data;
-	struct dma_pl330_filter_args fargs;
-	dma_cap_mask_t cap;
-
-	if (!pdmac)
-		return NULL;
+	unsigned int chan_id;
 
 	if (count != 1)
 		return NULL;
 
-	fargs.pdmac = pdmac;
-	fargs.chan_id = dma_spec->args[0];
+	chan_id = dma_spec->args[0];
+	if (chan_id >= pdmac->num_peripherals)
+		return NULL;
 
-	dma_cap_zero(cap);
-	dma_cap_set(DMA_SLAVE, cap);
-	dma_cap_set(DMA_CYCLIC, cap);
-
-	return dma_request_channel(cap, pl330_dt_filter, &fargs);
+	return dma_get_slave_channel(&pdmac->peripherals[chan_id].chan);
 }
 
 static int pl330_alloc_chan_resources(struct dma_chan *chan)
@@ -2980,6 +2959,8 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
 	else
 		num_chan = max_t(int, pi->pcfg.num_peri, pi->pcfg.num_chan);
 
+	pdmac->num_peripherals = num_chan;
+
 	pdmac->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);
 	if (!pdmac->peripherals) {
 		ret = -ENOMEM;