linux-kernel - [RFC PATCH 3/9] drivers: dma: omap-dma: Add a seperate xlate function to get router data

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Date:	Fri, 7 Mar 2014 17:46:10 +0530
From:	Sricharan R <r.sricharan@...com>
To:	<r.sricharan@...com>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-omap@...r.kernel.org>, <dmaengine@...r.kernel.org>
CC:	<santosh.shilimkar@...com>, <rnayak@...com>, <nsekhar@...com>,
	<tony@...mide.com>, <linux@....linux.org.uk>,
	<vinod.koul@...el.com>, <dan.j.williams@...el.com>, <nm@...com>
Subject: [RFC PATCH 3/9] drivers: dma: omap-dma: Add a seperate xlate function to get router data

Each dma-request channel can be connected to the dma-controller either
directly or through a crossbar router. In such cases request lines
should be routed to the dma-controller. Adding a xlate function
which would retrieve and store the router data associated with a particular
channel in the dma-channel specific structure. This is used to map/unmap
the dma request lines.

Signed-off-by: Sricharan R <r.sricharan@...com>
---
 drivers/dma/omap-dma.c |   47 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index a0d6639..38407f9 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -44,6 +44,8 @@ struct omap_chan {
 	uint32_t ccr;
 
 	struct dma_slave_config	cfg;
+	struct dma_xbar_device *router;
+
 	unsigned dma_sig;
 	bool cyclic;
 	bool paused;
@@ -75,6 +77,11 @@ struct omap_desc {
 	struct omap_sg sg[0];
 };
 
+struct omap_dma_filter_args {
+	void *router_data;
+	unsigned chan;
+};
+
 enum {
 	CCR_FS			= BIT(5),
 	CCR_READ_PRIORITY	= BIT(6),
@@ -586,6 +593,7 @@ static void omap_dma_free_chan_resources(struct dma_chan *chan)
 	c->channel_base = NULL;
 	od->lch_map[c->dma_ch] = NULL;
 	vchan_free_chan_resources(&c->vc);
+
 	omap_free_dma(c->dma_ch);
 
 	dev_dbg(od->ddev.dev, "freeing channel for %u\n", c->dma_sig);
@@ -1088,6 +1096,34 @@ static void omap_dma_free(struct omap_dmadev *od)
 	}
 }
 
+static struct dma_chan *of_omap_dma_xlate(struct of_phandle_args *dma_spec,
+						 struct of_dma *ofdma)
+{
+	int count = dma_spec->args_count;
+	struct of_dma_filter_info *info = ofdma->of_dma_data;
+	struct omap_dma_filter_args args;
+	struct dma_xbar_device *c = NULL;
+
+	if (!info || !info->filter_fn)
+		return NULL;
+
+	if ((count != 1) && (count != 2))
+		return NULL;
+
+	args.chan = dma_spec->args[0];
+	args.router_data = NULL;
+
+	if (count == 2) {
+		c = of_dma_get_router_data(dma_spec->args[1]);
+
+		if (c && c->ops && c->ops->map && c->ops->unmap)
+			args.router_data = c;
+	}
+
+	return dma_request_channel(info->dma_cap, info->filter_fn,
+			&args);
+}
+
 static int omap_dma_probe(struct platform_device *pdev)
 {
 	struct omap_dmadev *od;
@@ -1167,7 +1203,7 @@ static int omap_dma_probe(struct platform_device *pdev)
 
 		/* Device-tree DMA controller registration */
 		rc = of_dma_controller_register(pdev->dev.of_node,
-				of_dma_simple_xlate, &omap_dma_info);
+				of_omap_dma_xlate, &omap_dma_info);
 		if (rc) {
 			pr_warn("OMAP-DMA: failed to register DMA controller\n");
 			dma_async_device_unregister(&od->ddev);
@@ -1221,11 +1257,16 @@ static struct platform_driver omap_dma_driver = {
 
 bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
 {
+	struct omap_dma_filter_args *args = param;
+
 	if (chan->device->dev->driver == &omap_dma_driver.driver) {
 		struct omap_chan *c = to_omap_dma_chan(chan);
-		unsigned req = *(unsigned *)param;
+		unsigned req = args->chan;
 
-		return req == c->dma_sig;
+		if (req == c->dma_sig) {
+			c->router = args->router_data;
+			return true;
+		}
 	}
 	return false;
 }
-- 
1.7.9.5

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