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 <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1da..91fa983 100644 (file)
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -186,6 +186,64 @@ 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
+
+       /*
+        * Set default dma-mask to 32 bit. Drivers are expected to setup
+        * the correct supported dma_mask.
+        */
+       dev->coherent_dma_mask = DMA_BIT_MASK(32);
+
+       /*
+        * Set it to coherent_dma_mask by default if the architecture
+        * code has not set it.
+        */
+       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
@@ -211,12 +269,7 @@ 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 (file)
--- 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;