Merge tag 'tegra-for-3.14-dmas-resets-rework' into drm/for-next

ARM: tegra: implement common DMA and resets DT bindings

This series converts the Tegra DTs and drivers to use the common/
standard DMA and reset bindings, rather than custom bindings. It also
adds complete documentation for the Tegra clock bindings without
actually changing any binding definitions.

This conversion relies on a few sets of patches in branches from outside
the Tegra tree:

1) A patch to add an DMA channel request API which allows deferred probe
   to be implemented.

2) A patch to implement a common part of the of_xlate function for DMA
   controllers.

3) Some ASoC patches (which in turn rely on (1) above), which support
   deferred probe during DMA channel allocation.

4) The Tegra clock driver changes for 3.14.

Consequently, this branch is based on a merge of all of those external
branches.

In turn, this branch is or will be pulled into a few places that either
rely on features introduced here, or would otherwise conflict with the
patches:

a) Tegra's own for-3.14/powergate and for-4.14/dt branches, to avoid
   conflicts.

b) The DRM tree, which introduces new code that relies on the reset
   controller framework introduced in this branch, and to avoid
   conflicts.

4 files changed, 121 insertions, 39 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ea806bdc12ef..24095ff8a93b 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 8869500ab92b..c6a01ea8bc59 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 0b88dd3d05f4..e8fe9dc455f4 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 73654e33f13b..d11bb3620f27 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];