iommu: Add DMA mapping operations

In order to support IOMMUs in non-bypass mode we need device ops
to map and unmap DMA memory.  The map operation enters a mapping
for a region specified by CPU address and size into the translation
table of the IOMMU and returns a DMA address suitable for
programming the device to do DMA.  The unmap operation removes
this mapping from the translation table of the IOMMU.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>

diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
index ed917b3..f6b1457 100644 (file)
--- a/drivers/iommu/iommu-uclass.c
+++ b/drivers/iommu/iommu-uclass.c
@@ -7,6 +7,9 @@
 
 #include <common.h>
 #include <dm.h>
+#include <iommu.h>
+#include <phys2bus.h>
+#include <asm/io.h>
 
 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
 int dev_iommu_enable(struct udevice *dev)
@@ -33,12 +36,37 @@ int dev_iommu_enable(struct udevice *dev)
                              __func__, ret);
                        return ret;
                }
+               dev->iommu = dev_iommu;
        }
 
        return 0;
 }
 #endif
 
+dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size)
+{
+       const struct iommu_ops *ops;
+
+       if (dev->iommu) {
+               ops = device_get_ops(dev->iommu);
+               if (ops && ops->map)
+                       return ops->map(dev->iommu, addr, size);
+       }
+
+       return dev_phys_to_bus(dev, virt_to_phys(addr));
+}
+
+void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size)
+{
+       const struct iommu_ops *ops;
+
+       if (dev->iommu) {
+               ops = device_get_ops(dev->iommu);
+               if (ops && ops->unmap)
+                       ops->unmap(dev->iommu, addr, size);
+       }
+}
+
 UCLASS_DRIVER(iommu) = {
        .id             = UCLASS_IOMMU,
        .name           = "iommu",

diff --git a/include/dm/device.h b/include/dm/device.h
index f3f953c..e946038 100644 (file)
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -165,6 +165,7 @@ enum {
  *             automatically when the device is removed / unbound
  * @dma_offset: Offset between the physical address space (CPU's) and the
  *             device's bus address space
+ * @iommu: IOMMU device associated with this device
  */
 struct udevice {
        const struct driver *driver;
@@ -194,6 +195,9 @@ struct udevice {
 #if CONFIG_IS_ENABLED(DM_DMA)
        ulong dma_offset;
 #endif
+#if CONFIG_IS_ENABLED(IOMMU)
+       struct udevice *iommu;
+#endif
 };
 
 static inline int dm_udevice_size(void)

diff --git a/include/iommu.h b/include/iommu.h
index 6c46adf..cf9719c 100644 (file)
--- a/include/iommu.h
+++ b/include/iommu.h
@@ -3,6 +3,27 @@
 
 struct udevice;
 
+struct iommu_ops {
+       /**
+        * map() - map DMA memory
+        *
+        * @dev:        device for which to map DMA memory
+        * @addr:       CPU address of the memory
+        * @size:       size of the memory
+        * @return DMA address for the device
+        */
+       dma_addr_t (*map)(struct udevice *dev, void *addr, size_t size);
+
+       /**
+        * unmap() - unmap DMA memory
+        *
+        * @dev:        device for which to unmap DMA memory
+        * @addr:       DMA address of the memory
+        * @size:       size of the memory
+        */
+       void (*unmap)(struct udevice *dev, dma_addr_t addr, size_t size);
+};
+
 #if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
        CONFIG_IS_ENABLED(IOMMU)
 int dev_iommu_enable(struct udevice *dev);
@@ -13,4 +34,7 @@ static inline int dev_iommu_enable(struct udevice *dev)
 }
 #endif
 
+dma_addr_t dev_iommu_dma_map(struct udevice *dev, void *addr, size_t size);
+void dev_iommu_dma_unmap(struct udevice *dev, dma_addr_t addr, size_t size);
+
 #endif