4 files changed, 121 insertions, 39 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ea806bdc12e..24095ff8a93 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -535,11 +535,41 @@ struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
 }
 EXPORT_SYMBOL_GPL(dma_get_slave_channel);
 
+struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
+{
+	dma_cap_mask_t mask;
+	struct dma_chan *chan;
+	int err;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	/* lock against __dma_request_channel */
+	mutex_lock(&dma_list_mutex);
+
+	chan = private_candidate(&mask, device, NULL, NULL);
+	if (chan) {
+		err = dma_chan_get(chan);
+		if (err) {
+			pr_debug("%s: failed to get %s: (%d)\n",
+				__func__, dma_chan_name(chan), err);
+			chan = NULL;
+		}
+	}
+
+	mutex_unlock(&dma_list_mutex);
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
+
 /**
  * __dma_request_channel - try to allocate an exclusive channel
  * @mask: capabilities that the channel must satisfy
  * @fn: optional callback to disposition available channels
  * @fn_param: opaque parameter to pass to dma_filter_fn
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
  */
 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 				       dma_filter_fn fn, void *fn_param)
@@ -591,18 +621,43 @@ EXPORT_SYMBOL_GPL(__dma_request_channel);
  * dma_request_slave_channel - try to allocate an exclusive slave channel
  * @dev:	pointer to client device structure
  * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
  */
-struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name)
+struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
+						  const char *name)
 {
+	struct dma_chan *chan;
+
 	/* If device-tree is present get slave info from here */
 	if (dev->of_node)
 		return of_dma_request_slave_channel(dev->of_node, name);
 
 	/* If device was enumerated by ACPI get slave info from here */
-	if (ACPI_HANDLE(dev))
-		return acpi_dma_request_slave_chan_by_name(dev, name);
+	if (ACPI_HANDLE(dev)) {
+		chan = acpi_dma_request_slave_chan_by_name(dev, name);
+		if (chan)
+			return chan;
+	}
 
-	return NULL;
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
+
+/**
+ * dma_request_slave_channel - try to allocate an exclusive slave channel
+ * @dev:	pointer to client device structure
+ * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
+ */
+struct dma_chan *dma_request_slave_channel(struct device *dev,
+					   const char *name)
+{
+	struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
+	if (IS_ERR(ch))
+		return NULL;
+	return ch;
 }
 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
 
diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
index dcb1e05149a..2998f1bffac 100644
--- a/drivers/dma/mmp_pdma.c
+++ b/drivers/dma/mmp_pdma.c
@@ -893,33 +893,17 @@ 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;
+	struct dma_chan *chan;
+	struct mmp_pdma_chan *c;
 
-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)
+	chan = dma_get_any_slave_channel(&d->device);
+	if (!chan)
 		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;
-	}
+	c = to_mmp_pdma_chan(chan);
+	c->drcmr = dma_spec->args[0];
 
-	goto retry;
+	return chan;
 }
 
 static int mmp_pdma_probe(struct platform_device *op)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 0b88dd3d05f..e8fe9dc455f 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -143,7 +143,7 @@ static int of_dma_match_channel(struct device_node *np, const char *name,
  * @np:		device node to get DMA request from
  * @name:	name of desired channel
  *
- * Returns pointer to appropriate dma channel on success or NULL on error.
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
  */
 struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 					      const char *name)
@@ -152,17 +152,18 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 	struct of_dma		*ofdma;
 	struct dma_chan		*chan;
 	int			count, i;
+	int			ret_no_channel = -ENODEV;
 
 	if (!np || !name) {
 		pr_err("%s: not enough information provided\n", __func__);
-		return NULL;
+		return ERR_PTR(-ENODEV);
 	}
 
 	count = of_property_count_strings(np, "dma-names");
 	if (count < 0) {
 		pr_err("%s: dma-names property of node '%s' missing or empty\n",
 			__func__, np->full_name);
-		return NULL;
+		return ERR_PTR(-ENODEV);
 	}
 
 	for (i = 0; i < count; i++) {
@@ -172,10 +173,12 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 		mutex_lock(&of_dma_lock);
 		ofdma = of_dma_find_controller(&dma_spec);
 
-		if (ofdma)
+		if (ofdma) {
 			chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
-		else
+		} else {
+			ret_no_channel = -EPROBE_DEFER;
 			chan = NULL;
+		}
 
 		mutex_unlock(&of_dma_lock);
 
@@ -185,7 +188,7 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 			return chan;
 	}
 
-	return NULL;
+	return ERR_PTR(ret_no_channel);
 }
 
 /**
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 73654e33f13..d11bb3620f2 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1,7 +1,7 @@
 /*
  * DMA driver for Nvidia's Tegra20 APB DMA controller.
  *
- * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2012-2013, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -29,11 +29,12 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
-#include <linux/clk/tegra.h>
 
 #include "dmaengine.h"
 
@@ -199,6 +200,7 @@ struct tegra_dma_channel {
 	void			*callback_param;
 
 	/* Channel-slave specific configuration */
+	unsigned int slave_id;
 	struct dma_slave_config dma_sconfig;
 	struct tegra_dma_channel_regs	channel_reg;
 };
@@ -208,6 +210,7 @@ struct tegra_dma {
 	struct dma_device		dma_dev;
 	struct device			*dev;
 	struct clk			*dma_clk;
+	struct reset_control		*rst;
 	spinlock_t			global_lock;
 	void __iomem			*base_addr;
 	const struct tegra_dma_chip_data *chip_data;
@@ -339,6 +342,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
 	}
 
 	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
+	if (!tdc->slave_id)
+		tdc->slave_id = sconfig->slave_id;
 	tdc->config_init = true;
 	return 0;
 }
@@ -941,7 +946,7 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
 
 	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
-	csr |= tdc->dma_sconfig.slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
 	if (flags & DMA_PREP_INTERRUPT)
 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
 
@@ -1085,7 +1090,7 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
 	csr |= TEGRA_APBDMA_CSR_FLOW;
 	if (flags & DMA_PREP_INTERRUPT)
 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
-	csr |= tdc->dma_sconfig.slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
 
 	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
 
@@ -1205,6 +1210,25 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 		kfree(sg_req);
 	}
 	clk_disable_unprepare(tdma->dma_clk);
+
+	tdc->slave_id = 0;
+}
+
+static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct tegra_dma *tdma = ofdma->of_dma_data;
+	struct dma_chan *chan;
+	struct tegra_dma_channel *tdc;
+
+	chan = dma_get_any_slave_channel(&tdma->dma_dev);
+	if (!chan)
+		return NULL;
+
+	tdc = to_tegra_dma_chan(chan);
+	tdc->slave_id = dma_spec->args[0];
+
+	return chan;
 }
 
 /* Tegra20 specific DMA controller information */
@@ -1282,6 +1306,12 @@ static int tegra_dma_probe(struct platform_device *pdev)
 		return PTR_ERR(tdma->dma_clk);
 	}
 
+	tdma->rst = devm_reset_control_get(&pdev->dev, "dma");
+	if (IS_ERR(tdma->rst)) {
+		dev_err(&pdev->dev, "Error: Missing reset\n");
+		return PTR_ERR(tdma->rst);
+	}
+
 	spin_lock_init(&tdma->global_lock);
 
 	pm_runtime_enable(&pdev->dev);
@@ -1302,9 +1332,9 @@ static int tegra_dma_probe(struct platform_device *pdev)
 	}
 
 	/* Reset DMA controller */
-	tegra_periph_reset_assert(tdma->dma_clk);
+	reset_control_assert(tdma->rst);
 	udelay(2);
-	tegra_periph_reset_deassert(tdma->dma_clk);
+	reset_control_deassert(tdma->rst);
 
 	/* Enable global DMA registers */
 	tdma_write(tdma, TEGRA_APBDMA_GENERAL, TEGRA_APBDMA_GENERAL_ENABLE);
@@ -1376,10 +1406,20 @@ static int tegra_dma_probe(struct platform_device *pdev)
 		goto err_irq;
 	}
 
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 tegra_dma_of_xlate, tdma);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"Tegra20 APB DMA OF registration failed %d\n", ret);
+		goto err_unregister_dma_dev;
+	}
+
 	dev_info(&pdev->dev, "Tegra20 APB DMA driver register %d channels\n",
 			cdata->nr_channels);
 	return 0;
 
+err_unregister_dma_dev:
+	dma_async_device_unregister(&tdma->dma_dev);
 err_irq:
 	while (--i >= 0) {
 		struct tegra_dma_channel *tdc = &tdma->channels[i];