dtoc: Support ACPI paths in of-platdata

The start of an ACPI path typically has backslashes in it. These are not
preserved during the translation from device tree to C code, since dtc
(correctly) uses the first backslash as an escape character, and dtoc
therefore leaves it out of the C string.

Fix this with special-case handling.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/dtoc/dtb_platdata.py b/tools/dtoc/dtb_platdata.py
index c148c49..8ba8f16 100644
--- a/tools/dtoc/dtb_platdata.py
+++ b/tools/dtoc/dtb_platdata.py
@@ -104,7 +104,9 @@
     elif ftype == fdt.TYPE_BYTE:
         return '%#x' % tools.ToByte(value[0])
     elif ftype == fdt.TYPE_STRING:
-        return '"%s"' % value
+        # Handle evil ACPI backslashes by adding another backslash before them.
+        # So "\\_SB.GPO0" in the device tree effectively stays like that in C
+        return '"%s"' % value.replace('\\', '\\\\')
     elif ftype == fdt.TYPE_BOOL:
         return 'true'
     elif ftype == fdt.TYPE_INT64:
diff --git a/tools/dtoc/dtoc_test_simple.dts b/tools/dtoc/dtoc_test_simple.dts
index 165680b..11bfc4c 100644
--- a/tools/dtoc/dtoc_test_simple.dts
+++ b/tools/dtoc/dtoc_test_simple.dts
@@ -34,6 +34,7 @@
 		longbytearray = [09 0a 0b 0c];
 		stringval = "message2";
 		stringarray = "another", "multi-word", "message";
+		acpi-name =  "\\_SB.GPO0";
 	};
 
 	spl-test3 {
diff --git a/tools/dtoc/test_dtoc.py b/tools/dtoc/test_dtoc.py
index 3c8e343..08b02d4 100755
--- a/tools/dtoc/test_dtoc.py
+++ b/tools/dtoc/test_dtoc.py
@@ -72,6 +72,7 @@
     @classmethod
     def setUpClass(cls):
         tools.PrepareOutputDir(None)
+        cls.maxDiff = None
 
     @classmethod
     def tearDownClass(cls):
@@ -188,6 +189,7 @@
 \tfdt64_t\t\treg[2];
 };
 struct dtd_sandbox_spl_test {
+\tconst char *	acpi_name;
 \tbool\t\tboolval;
 \tunsigned char\tbytearray[3];
 \tunsigned char\tbyteval;
@@ -225,6 +227,7 @@
 };
 
 static struct dtd_sandbox_spl_test dtv_spl_test2 = {
+\t.acpi_name\t\t= "\\\\_SB.GPO0",
 \t.bytearray\t\t= {0x1, 0x23, 0x34},
 \t.byteval\t\t= 0x8,
 \t.intarray\t\t= {0x5, 0x0, 0x0, 0x0},