diff options
Diffstat (limited to 'drivers/of/device.c')
| -rw-r--r-- | drivers/of/device.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/of/device.c b/drivers/of/device.c index 46d6c75c1404..31a7875b34a4 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 +69,62 @@ 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 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; + + ret = of_dma_get_range(np, &dma_addr, &paddr, &size); + if (ret < 0) { + dma_addr = offset = 0; + size = dev->coherent_dma_mask; + } else { + offset = PFN_DOWN(paddr - dma_addr); + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); + } + + dev->dma_pfn_offset = offset; + + 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); |