Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma

Pull slave-dmaengine updates from Vinod Koul:
 "This time we have dmatest improvements from Andy along with dw_dmac
  fixes.  He has also done support for acpi for dmanegine.

  Also we have bunch of fixes going in DT support for dmanegine for
  various folks.  Then Haswell and other ioat changes from Dave and
  SUDMAC support from Shimoda."

* 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (53 commits)
  dma: tegra: implement suspend/resume callbacks
  dma:of: Use a mutex to protect the of_dma_list
  dma: of: Fix of_node reference leak
  dmaengine: sirf: move driver init from module_init to subsys_initcall
  sudmac: add support for SUDMAC
  dma: sh: add Kconfig
  at_hdmac: move to generic DMA binding
  ioatdma: ioat3_alloc_sed can be static
  ioatdma: Adding write back descriptor error status support for ioatdma 3.3
  ioatdma: S1200 platforms ioatdma channel 2 and 3 falsely advertise RAID cap
  ioatdma: Adding support for 16 src PQ ops and super extended descriptors
  ioatdma: Removing hw bug workaround for CB3.x .2 and earlier
  dw_dmac: add ACPI support
  dmaengine: call acpi_dma_request_slave_channel as well
  dma: acpi-dma: introduce ACPI DMA helpers
  dma: of: Remove unnecessary list_empty check
  DMA: OF: Check properties value before running be32_to_cpup() on it
  DMA: of: Constant names
  ioatdma: skip silicon bug workaround for pq_align for cb3.3
  ioatdma: Removing PQ val disable for cb3.3
  ...

1 files changed, 30 insertions, 66 deletions

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 69d04d2..7aa0864 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -13,43 +13,31 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/module.h>
-#include <linux/rculist.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/of_dma.h>
 
 static LIST_HEAD(of_dma_list);
-static DEFINE_SPINLOCK(of_dma_lock);
+static DEFINE_MUTEX(of_dma_lock);
 
 /**
- * of_dma_get_controller - Get a DMA controller in DT DMA helpers list
+ * of_dma_find_controller - Get a DMA controller in DT DMA helpers list
  * @dma_spec:	pointer to DMA specifier as found in the device tree
  *
  * Finds a DMA controller with matching device node and number for dma cells
- * in a list of registered DMA controllers. If a match is found the use_count
- * variable is increased and a valid pointer to the DMA data stored is retuned.
- * A NULL pointer is returned if no match is found.
+ * in a list of registered DMA controllers. If a match is found a valid pointer
+ * to the DMA data stored is retuned. A NULL pointer is returned if no match is
+ * found.
  */
-static struct of_dma *of_dma_get_controller(struct of_phandle_args *dma_spec)
+static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec)
 {
 	struct of_dma *ofdma;
 
-	spin_lock(&of_dma_lock);
-
-	if (list_empty(&of_dma_list)) {
-		spin_unlock(&of_dma_lock);
-		return NULL;
-	}
-
 	list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
 		if ((ofdma->of_node == dma_spec->np) &&
-		    (ofdma->of_dma_nbcells == dma_spec->args_count)) {
-			ofdma->use_count++;
-			spin_unlock(&of_dma_lock);
+		    (ofdma->of_dma_nbcells == dma_spec->args_count))
 			return ofdma;
-		}
-
-	spin_unlock(&of_dma_lock);
 
 	pr_debug("%s: can't find DMA controller %s\n", __func__,
 		 dma_spec->np->full_name);
@@ -58,22 +46,6 @@ static struct of_dma *of_dma_get_controller(struct of_phandle_args *dma_spec)
 }
 
 /**
- * of_dma_put_controller - Decrement use count for a registered DMA controller
- * @of_dma:	pointer to DMA controller data
- *
- * Decrements the use_count variable in the DMA data structure. This function
- * should be called only when a valid pointer is returned from
- * of_dma_get_controller() and no further accesses to data referenced by that
- * pointer are needed.
- */
-static void of_dma_put_controller(struct of_dma *ofdma)
-{
-	spin_lock(&of_dma_lock);
-	ofdma->use_count--;
-	spin_unlock(&of_dma_lock);
-}
-
-/**
  * of_dma_controller_register - Register a DMA controller to DT DMA helpers
  * @np:			device node of DMA controller
  * @of_dma_xlate:	translation function which converts a phandle
@@ -93,6 +65,7 @@ int of_dma_controller_register(struct device_node *np,
 {
 	struct of_dma	*ofdma;
 	int		nbcells;
+	const __be32	*prop;
 
 	if (!np || !of_dma_xlate) {
 		pr_err("%s: not enough information provided\n", __func__);
@@ -103,8 +76,11 @@ int of_dma_controller_register(struct device_node *np,
 	if (!ofdma)
 		return -ENOMEM;
 
-	nbcells = be32_to_cpup(of_get_property(np, "#dma-cells", NULL));
-	if (!nbcells) {
+	prop = of_get_property(np, "#dma-cells", NULL);
+	if (prop)
+		nbcells = be32_to_cpup(prop);
+
+	if (!prop || !nbcells) {
 		pr_err("%s: #dma-cells property is missing or invalid\n",
 		       __func__);
 		kfree(ofdma);
@@ -115,12 +91,11 @@ int of_dma_controller_register(struct device_node *np,
 	ofdma->of_dma_nbcells = nbcells;
 	ofdma->of_dma_xlate = of_dma_xlate;
 	ofdma->of_dma_data = data;
-	ofdma->use_count = 0;
 
 	/* Now queue of_dma controller structure in list */
-	spin_lock(&of_dma_lock);
+	mutex_lock(&of_dma_lock);
 	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
-	spin_unlock(&of_dma_lock);
+	mutex_unlock(&of_dma_lock);
 
 	return 0;
 }
@@ -132,32 +107,20 @@ EXPORT_SYMBOL_GPL(of_dma_controller_register);
  *
  * Memory allocated by of_dma_controller_register() is freed here.
  */
-int of_dma_controller_free(struct device_node *np)
+void of_dma_controller_free(struct device_node *np)
 {
 	struct of_dma *ofdma;
 
-	spin_lock(&of_dma_lock);
-
-	if (list_empty(&of_dma_list)) {
-		spin_unlock(&of_dma_lock);
-		return -ENODEV;
-	}
+	mutex_lock(&of_dma_lock);
 
 	list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
 		if (ofdma->of_node == np) {
-			if (ofdma->use_count) {
-				spin_unlock(&of_dma_lock);
-				return -EBUSY;
-			}
-
 			list_del(&ofdma->of_dma_controllers);
-			spin_unlock(&of_dma_lock);
 			kfree(ofdma);
-			return 0;
+			break;
 		}
 
-	spin_unlock(&of_dma_lock);
-	return -ENODEV;
+	mutex_unlock(&of_dma_lock);
 }
 EXPORT_SYMBOL_GPL(of_dma_controller_free);
 
@@ -172,8 +135,8 @@ EXPORT_SYMBOL_GPL(of_dma_controller_free);
  * specifiers, matches the name provided. Returns 0 if the name matches and
  * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV.
  */
-static int of_dma_match_channel(struct device_node *np, char *name, int index,
-				struct of_phandle_args *dma_spec)
+static int of_dma_match_channel(struct device_node *np, const char *name,
+				int index, struct of_phandle_args *dma_spec)
 {
 	const char *s;
 
@@ -198,7 +161,7 @@ static int of_dma_match_channel(struct device_node *np, char *name, int index,
  * Returns pointer to appropriate dma channel on success or NULL on error.
  */
 struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
-					      char *name)
+					      const char *name)
 {
 	struct of_phandle_args	dma_spec;
 	struct of_dma		*ofdma;
@@ -220,14 +183,15 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 		if (of_dma_match_channel(np, name, i, &dma_spec))
 			continue;
 
-		ofdma = of_dma_get_controller(&dma_spec);
-
-		if (!ofdma)
-			continue;
+		mutex_lock(&of_dma_lock);
+		ofdma = of_dma_find_controller(&dma_spec);
 
-		chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
+		if (ofdma)
+			chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
+		else
+			chan = NULL;
 
-		of_dma_put_controller(ofdma);
+		mutex_unlock(&of_dma_lock);
 
 		of_node_put(dma_spec.np);