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[PATCH 05/21] ARM/dmaengine: edma: Move of_dma_controller_register to the dmaengine driver

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If the of_dma_controller is registered in the non dmaengine driver we could
have race condition:
the of_dma_controller has been registered, but the dmaengine driver is not
yet probed. Drivers requesting DMA channels during this window will fail
since we do not yet have dmaengine drivers registered.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 arch/arm/common/edma.c | 10 ----------
 drivers/dma/edma.c     | 16 ++++++++++++++++
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
index 72fce68a959f..dc960de1a95f 100644
--- a/arch/arm/common/edma.c
+++ b/arch/arm/common/edma.c
@@ -29,7 +29,6 @@
 #include <linux/dma-mapping.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
-#include <linux/of_dma.h>
 #include <linux/of_irq.h>
 #include <linux/pm_runtime.h>
 
@@ -1191,10 +1190,6 @@ static int edma_of_parse_dt(struct device *dev,
 	return ret;
 }
 
-static struct of_dma_filter_info edma_filter_info = {
-	.filter_fn = edma_filter_fn,
-};
-
 static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
 						      struct device_node *node)
 {
@@ -1209,11 +1204,6 @@ static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
 	if (ret)
 		return ERR_PTR(ret);
 
-	dma_cap_set(DMA_SLAVE, edma_filter_info.dma_cap);
-	dma_cap_set(DMA_CYCLIC, edma_filter_info.dma_cap);
-	of_dma_controller_register(dev->of_node, of_dma_simple_xlate,
-				   &edma_filter_info);
-
 	return info;
 }
 #else
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 19fa49d6f555..fcb4680efed7 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/of.h>
+#include <linux/of_dma.h>
 
 #include <linux/platform_data/edma.h>
 
@@ -987,9 +988,14 @@ static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
 	INIT_LIST_HEAD(&dma->channels);
 }
 
+static struct of_dma_filter_info edma_filter_info = {
+	.filter_fn = edma_filter_fn,
+};
+
 static int edma_probe(struct platform_device *pdev)
 {
 	struct edma_cc *ecc;
+	struct device_node *parent_node = pdev->dev.parent->of_node;
 	int ret;
 
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
@@ -1024,6 +1030,13 @@ static int edma_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, ecc);
 
+	if (parent_node) {
+		dma_cap_set(DMA_SLAVE, edma_filter_info.dma_cap);
+		dma_cap_set(DMA_CYCLIC, edma_filter_info.dma_cap);
+		of_dma_controller_register(parent_node, of_dma_simple_xlate,
+					   &edma_filter_info);
+	}
+
 	dev_info(&pdev->dev, "TI EDMA DMA engine driver\n");
 
 	return 0;
@@ -1037,7 +1050,10 @@ static int edma_remove(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct edma_cc *ecc = dev_get_drvdata(dev);
+	struct device_node *parent_node = pdev->dev.parent->of_node;
 
+	if (parent_node)
+		of_dma_controller_free(parent_node);
 	dma_async_device_unregister(&ecc->dma_slave);
 	edma_free_slot(ecc->dummy_slot);
 
-- 
2.5.1

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Thread

[PATCH 00/21] dmaengine/ARM: Merge the edma drivers into one Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:40 +0200
  Re: [PATCH 00/21] dmaengine/ARM: Merge the edma drivers into one Arnd Bergmann <arnd@arndb.de> - 2015-09-10 10:50 +0200
  [PATCH 05/21] ARM/dmaengine: edma: Move of_dma_controller_register to the dmaengine driver Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 13/21] dmaengine: edma: Use devm_kcalloc when possible Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  Re: [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the number of eDMA controllers Arnd Bergmann <arnd@arndb.de> - 2015-09-10 10:50 +0200
    Re: [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the  number of eDMA controllers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 11:20 +0200
  [PATCH 02/21] ARM: common: edma: Remove unused functions Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 14/21] dmaengine: edma: Cleanup regarding the use of dev around the code Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 03/21] dmaengine: edma: Simplify and optimize the edma_execute path Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 04/21] ARM: davinci/common: Convert edma driver to handle one eDMA instance per driver Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the number of eDMA controllers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 21/21] dmaengine: edma: Simplify and optimize ccerr interrupt handler Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 16/21] dmaengine: edma: Use the edma_write_slot instead open coded memcpy_toio Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 19/21] dmaengine: edma: Simplify the interrupt handling Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 18/21] dmaengine: edma: Consolidate the comments for functions Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 12/21] dmaengine: edma: Parameter alignment and long line fixes Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 07/21] ARM/dmaengine: edma: Public API to use private struct pointer Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 15/21] dmaengine: edma: Use dev_dbg instead pr_debug Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 20/21] dmaengine: edma: Move the pending error check into helper function Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200

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