On Thursday 01 May 2014 08:49 PM, Rob Herring wrote:

On Thu, Apr 24, 2014 at 10:30 AM, Santosh Shilimkar
[off-list ref] wrote:

quoted

Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

[...]

quoted

+       /*
+        * if dma-ranges property doesn't exist - just return else
+        * setup the dma offset
+        */
+       ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
+       if ((ret == -ENODEV) || (ret < 0)) {

The 1st condition is redundant.

quoted

+               dev_dbg(dev, "no dma range information to setup\n");
+               return;
+       }
+
+       /* DMA ranges found. Calculate and set dma_pfn_offset */
+       dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+       dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
+}
+
+/**
  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
  * @np: pointer to node to create device for
  * @bus_id: name to assign device

@@ -214,9 +258,7 @@ static struct platform_device *of_platform_device_create_pdata(
 #if defined(CONFIG_MICROBLAZE)
        dev->archdata.dma_mask = 0xffffffffUL;
 #endif

This is also dma related setup. Please move *all* dma setup into the function.

Updated patch with above minor updates.

From 80a9f06a09a90801d8ee337d9b2d155c43da8f23 Mon Sep 17 00:00:00 2001

From: Santosh Shilimkar <redacted>
Date: Thu, 24 Apr 2014 11:30:04 -0400
Subject: [PATCH v3 4/7] of: configure the platform device dma parameters

Retrieve DMA configuration from DT and setup platform device's DMA
parameters. The DMA configuration in DT has to be specified using
"dma-ranges" and "dma-coherent" properties if supported.

We setup dma_pfn_offset using "dma-ranges" and dma_coherent_ops
using "dma-coherent" device tree properties.

The set_arch_dma_coherent_ops macro has to be defined by arch if
it supports coherent dma_ops. Otherwise, set_arch_dma_coherent_ops() is
declared as nop.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <redacted>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <redacted>
Cc: Grant Likely <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Walleij <redacted>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <redacted>
---
 drivers/of/platform.c       |   55 ++++++++++++++++++++++++++++++++++++++-----
 include/linux/dma-mapping.h |    7 ++++++
 2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1da..b71e089 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c

@@ -187,6 +187,54 @@ struct platform_device *of_device_alloc(struct device_node *np,
 EXPORT_SYMBOL(of_device_alloc);
 
 /**
+ * of_dma_configure - Setup DMA configuration
+ * @dev:	Device to apply DMA configuration
+ *
+ * Try to get devices's DMA configuration from DT and update it
+ * accordingly.
+ *
+ * In case if platform code need to use own special DMA configuration,it
+ * can use Platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE event
+ * to fix up DMA configuration.
+ */
+static void of_dma_configure(struct platform_device *pdev)
+{
+	u64 dma_addr, paddr, size;
+	int ret;
+	struct device *dev = &pdev->dev;
+
+#if defined(CONFIG_MICROBLAZE)
+	pdev->archdata.dma_mask = 0xffffffffUL;
+#endif
+	dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	if (!dev->dma_mask)
+		dev->dma_mask = &dev->coherent_dma_mask;
+
+	/*
+	 * if dma-coherent property exist, call arch hook to setup
+	 * dma coherent operations.
+	 */
+	if (of_dma_is_coherent(dev->of_node)) {
+		set_arch_dma_coherent_ops(dev);
+		dev_dbg(dev, "device is dma coherent\n");
+	}
+
+	/*
+	 * if dma-ranges property doesn't exist - just return else
+	 * setup the dma offset
+	 */
+	ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
+	if (ret < 0) {
+		dev_dbg(dev, "no dma range information to setup\n");
+		return;
+	}
+
+	/* DMA ranges found. Calculate and set dma_pfn_offset */
+	dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+	dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
+}
+
+/**
  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
  * @np: pointer to node to create device for
  * @bus_id: name to assign device

@@ -211,12 +259,7 @@ static struct platform_device *of_platform_device_create_pdata(
 	if (!dev)
 		return NULL;
 
-#if defined(CONFIG_MICROBLAZE)
-	dev->archdata.dma_mask = 0xffffffffUL;
-#endif
-	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
-	if (!dev->dev.dma_mask)
-		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+	of_dma_configure(dev);
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
 

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index fd4aee2..c7d9b1b 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h

@@ -123,6 +123,13 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
 
 extern u64 dma_get_required_mask(struct device *dev);
 
+#ifndef set_arch_dma_coherent_ops
+static inline int set_arch_dma_coherent_ops(struct device *dev)
+{
+	return 0;
+}
+#endif
+
 static inline unsigned int dma_get_max_seg_size(struct device *dev)
 {
 	return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536;

-- 
1.7.9.5