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path: root/drivers/of/device.c
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Diffstat (limited to 'drivers/of/device.c')
-rw-r--r--drivers/of/device.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 46d6c75c1404..20c1332a0018 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -2,6 +2,9 @@
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/of_iommu.h>
+#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
@@ -66,6 +69,87 @@ int of_device_add(struct platform_device *ofdev)
return device_add(&ofdev->dev);
}
+/**
+ * of_dma_configure - Setup DMA configuration
+ * @dev: Device to apply DMA configuration
+ * @np: Pointer to OF node having DMA configuration
+ *
+ * Try to get devices's DMA configuration from DT and update it
+ * accordingly.
+ *
+ * If platform code needs to use its own special DMA configuration, it
+ * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
+ * to fix up DMA configuration.
+ */
+void of_dma_configure(struct device *dev, struct device_node *np)
+{
+ u64 dma_addr, paddr, size;
+ int ret;
+ bool coherent;
+ unsigned long offset;
+ struct iommu_ops *iommu;
+
+ /*
+ * Set default coherent_dma_mask to 32 bit. Drivers are expected to
+ * setup the correct supported mask.
+ */
+ if (!dev->coherent_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;
+
+ ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
+ if (ret < 0) {
+ dma_addr = offset = 0;
+ size = dev->coherent_dma_mask + 1;
+ } else {
+ offset = PFN_DOWN(paddr - dma_addr);
+
+ /*
+ * Add a work around to treat the size as mask + 1 in case
+ * it is defined in DT as a mask.
+ */
+ if (size & 1) {
+ dev_warn(dev, "Invalid size 0x%llx for dma-range\n",
+ size);
+ size = size + 1;
+ }
+
+ if (!size) {
+ dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
+ return;
+ }
+ dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
+ }
+
+ dev->dma_pfn_offset = offset;
+
+ /*
+ * Limit coherent and dma mask based on size and default mask
+ * set by the driver.
+ */
+ dev->coherent_dma_mask = min(dev->coherent_dma_mask,
+ DMA_BIT_MASK(ilog2(dma_addr + size)));
+ *dev->dma_mask = min((*dev->dma_mask),
+ DMA_BIT_MASK(ilog2(dma_addr + size)));
+
+ coherent = of_dma_is_coherent(np);
+ dev_dbg(dev, "device is%sdma coherent\n",
+ coherent ? " " : " not ");
+
+ iommu = of_iommu_configure(dev, np);
+ dev_dbg(dev, "device is%sbehind an iommu\n",
+ iommu ? " " : " not ");
+
+ arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
+}
+EXPORT_SYMBOL_GPL(of_dma_configure);
+
int of_device_register(struct platform_device *pdev)
{
device_initialize(&pdev->dev);