dmaengine: dw_dmac: Enhance device tree support

dw_dmac driver already supports device tree but it used to have its platform
data passed the non-DT way.

This patch does following changes:
- pass platform data via DT, non-DT way still takes precedence if both are used.
- create generic filter routine
- Earlier slave information was made available by slave specific filter routines
  in chan->private field. Now, this information would be passed from within dmac
  DT node. Slave drivers would now be required to pass bus_id (a string) as
  parameter to this generic filter(), which would be compared against the slave
  data passed from DT, by the generic filter routine.
- Update binding document

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[Fixed __devinit usage]
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

2 files changed, 138 insertions, 0 deletions

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 8f0b111af4de..27b8e1d1845e 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1179,6 +1179,50 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
 	dev_vdbg(chan2dev(chan), "%s: done\n", __func__);
 }
 
+bool dw_dma_generic_filter(struct dma_chan *chan, void *param)
+{
+	struct dw_dma *dw = to_dw_dma(chan->device);
+	static struct dw_dma *last_dw;
+	static char *last_bus_id;
+	int i = -1;
+
+	/*
+	 * dmaengine framework calls this routine for all channels of all dma
+	 * controller, until true is returned. If 'param' bus_id is not
+	 * registered with a dma controller (dw), then there is no need of
+	 * running below function for all channels of dw.
+	 *
+	 * This block of code does this by saving the parameters of last
+	 * failure. If dw and param are same, i.e. trying on same dw with
+	 * different channel, return false.
+	 */
+	if ((last_dw == dw) && (last_bus_id == param))
+		return false;
+	/*
+	 * Return true:
+	 * - If dw_dma's platform data is not filled with slave info, then all
+	 *   dma controllers are fine for transfer.
+	 * - Or if param is NULL
+	 */
+	if (!dw->sd || !param)
+		return true;
+
+	while (++i < dw->sd_count) {
+		if (!strcmp(dw->sd[i].bus_id, param)) {
+			chan->private = &dw->sd[i];
+			last_dw = NULL;
+			last_bus_id = NULL;
+
+			return true;
+		}
+	}
+
+	last_dw = dw;
+	last_bus_id = param;
+	return false;
+}
+EXPORT_SYMBOL(dw_dma_generic_filter);
+
 /* --------------------- Cyclic DMA API extensions -------------------- */
 
 /**
@@ -1462,6 +1506,91 @@ static void dw_dma_off(struct dw_dma *dw)
 		dw->chan[i].initialized = false;
 }
 
+#ifdef CONFIG_OF
+static struct dw_dma_platform_data *
+dw_dma_parse_dt(struct platform_device *pdev)
+{
+	struct device_node *sn, *cn, *np = pdev->dev.of_node;
+	struct dw_dma_platform_data *pdata;
+	struct dw_dma_slave *sd;
+	u32 tmp, arr[4];
+
+	if (!np) {
+		dev_err(&pdev->dev, "Missing DT data\n");
+		return NULL;
+	}
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return NULL;
+
+	if (of_property_read_u32(np, "nr_channels", &pdata->nr_channels))
+		return NULL;
+
+	if (of_property_read_bool(np, "is_private"))
+		pdata->is_private = true;
+
+	if (!of_property_read_u32(np, "chan_allocation_order", &tmp))
+		pdata->chan_allocation_order = (unsigned char)tmp;
+
+	if (!of_property_read_u32(np, "chan_priority", &tmp))
+		pdata->chan_priority = tmp;
+
+	if (!of_property_read_u32(np, "block_size", &tmp))
+		pdata->block_size = tmp;
+
+	if (!of_property_read_u32(np, "nr_masters", &tmp)) {
+		if (tmp > 4)
+			return NULL;
+
+		pdata->nr_masters = tmp;
+	}
+
+	if (!of_property_read_u32_array(np, "data_width", arr,
+				pdata->nr_masters))
+		for (tmp = 0; tmp < pdata->nr_masters; tmp++)
+			pdata->data_width[tmp] = arr[tmp];
+
+	/* parse slave data */
+	sn = of_find_node_by_name(np, "slave_info");
+	if (!sn)
+		return pdata;
+
+	/* calculate number of slaves */
+	tmp = of_get_child_count(sn);
+	if (!tmp)
+		return NULL;
+
+	sd = devm_kzalloc(&pdev->dev, sizeof(*sd) * tmp, GFP_KERNEL);
+	if (!sd)
+		return NULL;
+
+	pdata->sd = sd;
+	pdata->sd_count = tmp;
+
+	for_each_child_of_node(sn, cn) {
+		sd->dma_dev = &pdev->dev;
+		of_property_read_string(cn, "bus_id", &sd->bus_id);
+		of_property_read_u32(cn, "cfg_hi", &sd->cfg_hi);
+		of_property_read_u32(cn, "cfg_lo", &sd->cfg_lo);
+		if (!of_property_read_u32(cn, "src_master", &tmp))
+			sd->src_master = tmp;
+
+		if (!of_property_read_u32(cn, "dst_master", &tmp))
+			sd->dst_master = tmp;
+		sd++;
+	}
+
+	return pdata;
+}
+#else
+static inline struct dw_dma_platform_data *
+dw_dma_parse_dt(struct platform_device *pdev)
+{
+	return NULL;
+}
+#endif
+
 static int dw_probe(struct platform_device *pdev)
 {
 	struct dw_dma_platform_data *pdata;
@@ -1478,6 +1607,9 @@ static int dw_probe(struct platform_device *pdev)
 	int			i;
 
 	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata)
+		pdata = dw_dma_parse_dt(pdev);
+
 	if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
 		return -EINVAL;
 
@@ -1512,6 +1644,8 @@ static int dw_probe(struct platform_device *pdev)
 	clk_prepare_enable(dw->clk);
 
 	dw->regs = regs;
+	dw->sd = pdata->sd;
+	dw->sd_count = pdata->sd_count;
 
 	/* get hardware configuration parameters */
 	if (autocfg) {
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 88965597b7d0..88a069f66b89 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -239,6 +239,10 @@ struct dw_dma {
 	struct tasklet_struct	tasklet;
 	struct clk		*clk;
 
+	/* slave information */
+	struct dw_dma_slave	*sd;
+	unsigned int		sd_count;
+
 	u8			all_chan_mask;
 
 	/* hardware configuration */