Merge tag 'dt-dma-properties-for-arm' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone into devel-stable

DT support for 'dma-ranges'and 'dma-coherent' properties with ARM updates

- The 'dma-ranges' helps to take care of few DMAable system memory
        restrictions by use of dma_pfn_offset which is maintained per
        device. Arch code then uses it for dma address translations for such
        cases. We update the dma_pfn_offset accordingly during DT the device
        creation process.
- The 'dma-coherent' property is used to setup arch's coherent dma_ops.

1 files changed, 59 insertions, 6 deletions

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index bd47fbc53dc9..4e91583a3908 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -189,6 +189,64 @@ 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
  * @bus_id: name to assign device
@@ -213,12 +271,7 @@ 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;