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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-05-22 18:11:07 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-05-23 12:30:52 +0100
commit6b74f61a471ad0f3a5e919e314d4f60cd3966f5e (patch)
tree9ab2c2ea8a78c499f1ce755737e5dc5003ca2a07 /drivers/of/platform.c
parent4b660a7f5c8099d88d1a43d8ae138965112592c7 (diff)
parent2161c2485d03520060f6094359b22f33913eefa2 (diff)
downloadlinux-6b74f61a471ad0f3a5e919e314d4f60cd3966f5e.tar.bz2
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.
Diffstat (limited to 'drivers/of/platform.c')
-rw-r--r--drivers/of/platform.c65
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;