dm: Support address translation for simple-bus

The 'ranges' property can be used to specify a translation from the system
address to the bus address. Add support for this using the dev_get_addr()
function, which devices should use to find their address.

Signed-off-by: Simon Glass <sjg@chromium.org>

3 files changed, 53 insertions, 6 deletions

diff --git a/drivers/core/device.c b/drivers/core/device.c
index 51b1b44e5b0..d65717ddc7e 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -552,17 +552,22 @@ const char *dev_get_uclass_name(struct udevice *dev)
 	return dev->uclass->uc_drv->name;
 }
 
-#ifdef CONFIG_OF_CONTROL
 fdt_addr_t dev_get_addr(struct udevice *dev)
 {
-	return fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
-}
+#ifdef CONFIG_OF_CONTROL
+	fdt_addr_t addr;
+
+	addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
+	if (addr != FDT_ADDR_T_NONE) {
+		if (device_get_uclass_id(dev->parent) == UCLASS_SIMPLE_BUS)
+			addr = simple_bus_translate(dev->parent, addr);
+	}
+
+	return addr;
 #else
-fdt_addr_t dev_get_addr(struct udevice *dev)
-{
 	return FDT_ADDR_T_NONE;
-}
 #endif
+}
 
 bool device_has_children(struct udevice *dev)
 {
diff --git a/drivers/core/simple-bus.c b/drivers/core/simple-bus.c
index 3ea4d8230bd..913c3ccc70b 100644
--- a/drivers/core/simple-bus.c
+++ b/drivers/core/simple-bus.c
@@ -10,8 +10,37 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+struct simple_bus_plat {
+	u32 base;
+	u32 size;
+	u32 target;
+};
+
+fdt_addr_t simple_bus_translate(struct udevice *dev, fdt_addr_t addr)
+{
+	struct simple_bus_plat *plat = dev_get_uclass_platdata(dev);
+
+	if (addr >= plat->base && addr < plat->base + plat->size)
+		addr = (addr - plat->base) + plat->target;
+
+	return addr;
+}
+
 static int simple_bus_post_bind(struct udevice *dev)
 {
+	u32 cell[3];
+	int ret;
+
+	ret = fdtdec_get_int_array(gd->fdt_blob, dev->of_offset, "ranges",
+				   cell, ARRAY_SIZE(cell));
+	if (!ret) {
+		struct simple_bus_plat *plat = dev_get_uclass_platdata(dev);
+
+		plat->base = cell[0];
+		plat->target = cell[1];
+		plat->size = cell[2];
+	}
+
 	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
 }
 
@@ -19,6 +48,7 @@ UCLASS_DRIVER(simple_bus) = {
 	.id		= UCLASS_SIMPLE_BUS,
 	.name		= "simple_bus",
 	.post_bind	= simple_bus_post_bind,
+	.per_device_platdata_auto_alloc_size = sizeof(struct simple_bus_plat),
 };
 
 static const struct udevice_id generic_simple_bus_ids[] = {
diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
index 402304f19ef..1a9ba01b3b8 100644
--- a/include/dm/device-internal.h
+++ b/include/dm/device-internal.h
@@ -139,6 +139,18 @@ void device_free(struct udevice *dev);
 static inline void device_free(struct udevice *dev) {}
 #endif
 
+/**
+ * simple_bus_translate() - translate a bus address to a system address
+ *
+ * This handles the 'ranges' property in a simple bus. It translates the
+ * device address @addr to a system address using this property.
+ *
+ * @dev:	Simple bus device (parent of target device)
+ * @addr:	Address to translate
+ * @return new address
+ */
+fdt_addr_t simple_bus_translate(struct udevice *dev, fdt_addr_t addr);
+
 /* Cast away any volatile pointer */
 #define DM_ROOT_NON_CONST		(((gd_t *)gd)->dm_root)
 #define DM_UCLASS_ROOT_NON_CONST	(((gd_t *)gd)->uclass_root)