fdt: introduce fdt_verify_alias_address() and fdt_get_base_address()

Introduce two functions, fdt_verify_alias_address() and
fdt_get_base_address(), which can be used to verify the physical address
of a device in a device tree.

fdt_get_base_address() returns the base address of an SOC or PCI node.

fdt_verify_alias_address() prints a message if the address of a node
specified by an alias does not match the given physical address.

Signed-off-by: Timur Tabi <timur@freescale.com>

2 files changed, 71 insertions, 0 deletions

diff --git a/common/fdt_support.c b/common/fdt_support.c
index 496040b54c..150a3c5a59 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -1223,3 +1223,70 @@ err_size:
 	return ret;
 }
 #endif
+
+/*
+ * Verify the physical address of device tree node for a given alias
+ *
+ * This function locates the device tree node of a given alias, and then
+ * verifies that the physical address of that device matches the given
+ * parameter.  It displays a message if there is a mismatch.
+ *
+ * Returns 1 on success, 0 on failure
+ */
+int fdt_verify_alias_address(void *fdt, int anode, const char *alias, u64 addr)
+{
+	const char *path;
+	const u32 *reg;
+	int node, len;
+	u64 dt_addr;
+
+	path = fdt_getprop(fdt, anode, alias, NULL);
+	if (!path) {
+		/* If there's no such alias, then it's not a failure */
+		return 1;
+	}
+
+	node = fdt_path_offset(fdt, path);
+	if (node < 0) {
+		printf("Warning: device tree alias '%s' points to invalid "
+		       "node %s.\n", alias, path);
+		return 0;
+	}
+
+	reg = fdt_getprop(fdt, node, "reg", &len);
+	if (!reg) {
+		printf("Warning: device tree node '%s' has no address.\n",
+		       path);
+		return 0;
+	}
+
+	dt_addr = fdt_translate_address(fdt, node, reg);
+	if (addr != dt_addr) {
+		printf("Warning: U-Boot configured device %s at address %llx,\n"
+		       " but the device tree has it address %llx.\n",
+		       alias, addr, dt_addr);
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Returns the base address of an SOC or PCI node
+ */
+u64 fdt_get_base_address(void *fdt, int node)
+{
+	int size;
+	u32 naddr;
+	const u32 *prop;
+
+	prop = fdt_getprop(fdt, node, "#address-cells", &size);
+	if (prop && size == 4)
+		naddr = *prop;
+	else
+		naddr = 2;
+
+	prop = fdt_getprop(fdt, node, "ranges", &size);
+
+	return prop ? fdt_translate_address(fdt, node, prop + naddr) : 0;
+}
diff --git a/include/fdt_support.h b/include/fdt_support.h
index ce6817b6d3..cefc990690 100644
--- a/include/fdt_support.h
+++ b/include/fdt_support.h
@@ -90,5 +90,9 @@ int fdt_node_offset_by_compat_reg(void *blob, const char *compat,
 int fdt_alloc_phandle(void *blob);
 int fdt_add_edid(void *blob, const char *compat, unsigned char *buf);
 
+int fdt_verify_alias_address(void *fdt, int anode, const char *alias,
+			      u64 addr);
+u64 fdt_get_base_address(void *fdt, int node);
+
 #endif /* ifdef CONFIG_OF_LIBFDT */
 #endif /* ifndef __FDT_SUPPORT_H */