binman: Support adding a U-Boot environment

In some cases it is useful to include a U-Boot environment region in an
image. This allows the board to start up with an environment ready to go.

Add a new entry type for this. The input is a text file containing the
environment entries, one per line, in the format:

   var=value

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

tools/binman/etype/u_boot_env.py

@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2018 Google, Inc
+# Written by Simon Glass <sjg@chromium.org>
+#
+
+import struct
+import zlib
+
+from binman.etype.blob import Entry_blob
+from dtoc import fdt_util
+from patman import tools
+
+class Entry_u_boot_env(Entry_blob):
+    """An entry which contains a U-Boot environment
+
+    Properties / Entry arguments:
+        - filename: File containing the environment text, with each line in the
+            form var=value
+    """
+    def __init__(self, section, etype, node):
+        super().__init__(section, etype, node)
+
+    def ReadNode(self):
+        super().ReadNode()
+        if self.size is None:
+            self.Raise("'u-boot-env' entry must have a size property")
+        self.fill_value = fdt_util.GetByte(self._node, 'fill-byte', 0)
+
+    def ReadBlobContents(self):
+        indata = tools.ReadFile(self._pathname)
+        data = b''
+        for line in indata.splitlines():
+            data += line + b'\0'
+        data += b'\0';
+        pad = self.size - len(data) - 5
+        if pad < 0:
+            self.Raise("'u-boot-env' entry too small to hold data (need %#x more bytes)" % -pad)
+        data += tools.GetBytes(self.fill_value, pad)
+        crc = zlib.crc32(data)
+        buf = struct.pack('<I', crc) + b'\x01' + data
+        self.SetContents(buf)
+        return True

tools/binman/ftest.py

@@ -77,6 +77,7 @@ FSP_T_DATA            = b'fsp_t'
 ATF_BL31_DATA         = b'bl31'
 TEST_FDT1_DATA        = b'fdt1'
 TEST_FDT2_DATA        = b'test-fdt2'
+ENV_DATA              = b'var1=1\nvar2="2"'
 
 # Subdirectory of the input dir to use to put test FDTs
 TEST_FDT_SUBDIR       = 'fdts'
@@ -181,6 +182,8 @@ class TestFunctional(unittest.TestCase):
         TestFunctional._MakeInputFile('%s/test-fdt2.dtb' % TEST_FDT_SUBDIR,
                                       TEST_FDT2_DATA)
 
+        TestFunctional._MakeInputFile('env.txt', ENV_DATA)
+
         # Travis-CI may have an old lz4
         cls.have_lz4 = True
         try:
@@ -3715,5 +3718,33 @@ class TestFunctional(unittest.TestCase):
         self.assertIn("Filename 'missing' not found in input path",
                       str(e.exception))
 
+    def testEnvironment(self):
+        """Test adding a U-Boot environment"""
+        data = self._DoReadFile('174_env.dts')
+        self.assertEqual(U_BOOT_DATA, data[:len(U_BOOT_DATA)])
+        self.assertEqual(U_BOOT_NODTB_DATA, data[-len(U_BOOT_NODTB_DATA):])
+        env = data[len(U_BOOT_DATA):-len(U_BOOT_NODTB_DATA)]
+        self.assertEqual(b'\x1b\x97\x22\x7c\x01var1=1\0var2="2"\0\0\xff\xff',
+                         env)
+
+    def testEnvironmentNoSize(self):
+        """Test that a missing 'size' property is detected"""
+        with self.assertRaises(ValueError) as e:
+            data = self._DoTestFile('175_env_no_size.dts')
+        self.assertIn("'u-boot-env' entry must have a size property",
+                      str(e.exception))
+
+    def testEnvironmentTooSmall(self):
+        """Test handling of an environment that does not fit"""
+        with self.assertRaises(ValueError) as e:
+            data = self._DoTestFile('176_env_too_small.dts')
+
+        # checksum, start byte, environment with \0 terminator, final \0
+        need = 4 + 1 + len(ENV_DATA) + 1 + 1
+        short = need - 0x8
+        self.assertIn("too small to hold data (need %#x more bytes)" % short,
+                      str(e.exception))
+
+
 if __name__ == "__main__":
     unittest.main()

tools/binman/test/174_env.dts

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		u-boot {
+		};
+		u-boot-env {
+			filename = "env.txt";
+			size = <0x18>;
+			fill-byte = [ff];
+		};
+		u-boot-nodtb {
+		};
+	};
+};

tools/binman/test/175_env_no_size.dts

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		u-boot {
+		};
+		u-boot-env {
+			filename = "env.txt";
+			fill-byte = [ff];
+		};
+		u-boot-nodtb {
+		};
+	};
+};

tools/binman/test/176_env_too_small.dts

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		u-boot {
+		};
+		u-boot-env {
+			filename = "env.txt";
+			size = <0x8>;
+			fill-byte = [ff];
+		};
+		u-boot-nodtb {
+		};
+	};
+};