Re: [PATCH 01/17] of: add dma-mask binding

On 21:55 Tue 13 Nov     , Rob Herring wrote:

On 11/12/2012 02:52 AM, Wenyou Yang wrote:

quoted

From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>

This will allow each device to specify its dma-mask for this we use the
coherent_dma_mask as pointer. By default the dma-mask will be set to
DMA_BIT_MASK(32).

Do you really have a use case this is not DMA_BIT_MASK(32)?

yes as exmample on 64bit platfrom it will be 64 on x86 it's also 24, on power
pc 40

quoted

The microblaze architecture hook is drop

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
Cc: grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org
Cc: rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
---
 drivers/of/platform.c |   23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b80891b..31ed405 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c

@@ -130,6 +130,21 @@ void of_device_make_bus_id(struct device *dev)
 	dev_set_name(dev, "%s.%d", node->name, magic - 1);
 }
 
+static void of_get_dma_mask(struct device *dev, struct device_node *np)
+{
+	const __be32 *prop;
+	int len;
+
+	prop = of_get_property(np, "dma-mask", &len);

dma-ranges may work for this purpose.

quoted

+
+	dev->dma_mask = &dev->coherent_dma_mask;

I don't really know, but I suspect this is wrong.

no this is correct was suggest by Russell
we already do so on other ARM or SH as example

the dma expect a pointer for dma_mask but the value is the same as coherent

quoted

+
+	if (!prop)
+		dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	else
+		dev->coherent_dma_mask = of_read_number(prop, len / 4);
+}
+
 /**
  * of_device_alloc - Allocate and initialize an of_device
  * @np: device node to assign to device

@@ -171,10 +186,8 @@ struct platform_device *of_device_alloc(struct device_node *np,
 		WARN_ON(of_irq_to_resource_table(np, res, num_irq) != num_irq);
 	}
 
+	of_get_dma_mask(&dev->dev, np);
 	dev->dev.of_node = of_node_get(np);
-#if defined(CONFIG_MICROBLAZE)
-	dev->dev.dma_mask = &dev->archdata.dma_mask;
-#endif
 	dev->dev.parent = parent;
 
 	if (bus_id)

@@ -211,10 +224,6 @@ 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);
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;