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[PATCH v5 05/24] 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 7c2fe527e53b..d82fceda13a3 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);
 
-- 
2.6.1

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Thread

[PATCH v5 00/24] dmaengine/ARM: Merge the edma drivers into one Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 22/24] dmaengine: edma: Read channel mapping support only once from HW Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 19/24] dmaengine: edma: Simplify the interrupt handling Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 05/24] ARM/dmaengine: edma: Move of_dma_controller_register to the dmaengine driver Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 15/24] dmaengine: edma: Use dev_dbg instead pr_debug Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 21/24] dmaengine: edma: Simplify and optimize ccerr interrupt handler Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 13/24] dmaengine: edma: Use devm_kcalloc when possible Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 24/24] dmaengine: edma: Dynamic paRAM slot handling if HW supports it Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 13:50 +0200
  [PATCH v5 10/24] ARM: davinci: Add dma_mask to eDMA devices Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 14:00 +0200
  [PATCH v5 08/24] ARM/dmaengine: edma: Remove limitation on the number of eDMA controllers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 14:00 +0200
  [PATCH v5 07/24] ARM/dmaengine: edma: Public API to use private struct pointer Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 14:00 +0200
  [PATCH v5 02/24] ARM: common: edma: Remove unused functions Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 14:00 +0200
  [PATCH v5 12/24] dmaengine: edma: Allocate memory dynamically for bitmaps and structures Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-14 14:00 +0200
  Re: [PATCH v5 00/24] dmaengine/ARM: Merge the edma drivers into one Vinod Koul <vinod.koul@intel.com> - 2015-10-14 16:30 +0200
    Re: [PATCH v5 00/24] dmaengine/ARM: Merge the edma drivers into one Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-15 09:20 +0200

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