of: Introduce of_translate_dma_region()

This function is similar to of_translate_dma_address() but also reads a
length in addition to an address from a device tree property.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230120174251.4004100-2-thierry.reding@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/of/address.c b/drivers/of/address.c
index c34ac33b7338a991051e75adec81770fe8a35292..14f137a21b0c165caaa2cf6366ff6b4282b65ee3 100644 (file)
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -626,6 +626,47 @@ u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
 }
 EXPORT_SYMBOL(of_translate_dma_address);
 
+/**
+ * of_translate_dma_region - Translate device tree address and size tuple
+ * @dev: device tree node for which to translate
+ * @prop: pointer into array of cells
+ * @start: return value for the start of the DMA range
+ * @length: return value for the length of the DMA range
+ *
+ * Returns a pointer to the cell immediately following the translated DMA region.
+ */
+const __be32 *of_translate_dma_region(struct device_node *dev, const __be32 *prop,
+                                     phys_addr_t *start, size_t *length)
+{
+       struct device_node *parent;
+       u64 address, size;
+       int na, ns;
+
+       parent = __of_get_dma_parent(dev);
+       if (!parent)
+               return NULL;
+
+       na = of_bus_n_addr_cells(parent);
+       ns = of_bus_n_size_cells(parent);
+
+       of_node_put(parent);
+
+       address = of_translate_dma_address(dev, prop);
+       if (address == OF_BAD_ADDR)
+               return NULL;
+
+       size = of_read_number(prop + na, ns);
+
+       if (start)
+               *start = address;
+
+       if (length)
+               *length = size;
+
+       return prop + na + ns;
+}
+EXPORT_SYMBOL(of_translate_dma_region);
+
 const __be32 *__of_get_address(struct device_node *dev, int index, int bar_no,
                               u64 *size, unsigned int *flags)
 {

diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 265f26eeaf6b6a63692e5e4ae93047d3f12653c1..376671594746b22261abc5c885dd324aa2698f66 100644 (file)
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -38,6 +38,8 @@ struct of_pci_range {
 /* Translate a DMA address from device space to CPU space */
 extern u64 of_translate_dma_address(struct device_node *dev,
                                    const __be32 *in_addr);
+extern const __be32 *of_translate_dma_region(struct device_node *dev, const __be32 *addr,
+                                            phys_addr_t *start, size_t *length);
 
 #ifdef CONFIG_OF_ADDRESS
 extern u64 of_translate_address(struct device_node *np, const __be32 *addr);