[PATCH v4 3/3] dma: Add Freescale eDMA engine driver support

On Thu, Aug 29, 2013 at 03:32:04AM +0000, Lu Jingchang-B35083 wrote:

Please use a right MUA and wrap your lines at 80chars...

quoted

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+			return -EINVAL;
+		}
+		return 0;
+
+	default:
+		return -ENXIO;
+	}
+}
+
+static enum dma_status fsl_edma_tx_status(struct dma_chan *chan,
+		dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
+
+	if (fsl_chan->status == DMA_ERROR)
+		return DMA_ERROR;
+
+	return dma_cookie_status(chan, cookie, txstate);

this will tell if the DMA is completed or not only.
You also need to calculate residue for the pending dma

Since you support cyclic this should be done properly...

also you cna take more help from vchan support to make your life
simpler...

[Lu Jingchang]

No need to put your name :)
 

Ok, if it is needed, I will add residue calculation in the next version. 

Yes this is needed

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+static bool fsl_edma_filter_fn(struct dma_chan *chan, void *fn_param)
+{
+	struct fsl_edma_filter_param *fparam = fn_param;
+	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
+
+	if (fsl_chan->edmamux->mux_id != fparam->mux_id)
+		return false;
+
+	fsl_chan->slot_id = fparam->slot_id;
+	chan->private = fn_param;

why do you need to use chan->private?

[Lu Jingchang] 
The private used here is to store the slot_id information, which must be used
by the DMAMUX in alloc_chan_resources function. Thanks.

Why dont you pass this in struct dma_slave_config memeber slave_id for this.

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+	return true;
+}
+
+static struct dma_chan *fsl_edma_xlate(struct of_phandle_args

*dma_spec,

quoted

+		struct of_dma *ofdma)
+{
+	dma_cap_mask_t mask;
+	struct fsl_edma_filter_param fparam;
+
+	if (dma_spec->args_count != 2)
+		return NULL;
+
+	fparam.mux_id = dma_spec->args[0];
+	fparam.slot_id = dma_spec->args[1];
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	dma_cap_set(DMA_CYCLIC, mask);
+	return dma_request_channel(mask, fsl_edma_filter_fn, (void

*)&fparam);

quoted

+}
+
+static int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
+	struct fsl_edma_filter_param *data = chan->private;
+	unsigned char val;
+
+	val = EDMAMUX_CHCFG_ENBL | EDMAMUX_CHCFG_SOURCE(data->slot_id);

okay, so what does the slot_id mean?

[Lu Jingchang] 
slot_id is the request source id, a peripheral device ID. Each peripheral
using DMA has a ID that can be identified by the DMA engine. the peripheral ID
must be written to the DMAMUX configuration register to route the peripheral
to DMA engine channel. Thanks.

And thanks makes me belive you dont need this way, slave_id is the thing for
you...

~Vinod

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