dtoc: Set up the uclasses that are used

We only care about uclasses that are actually used. This is determined by
the drivers that use them. Check all the used drivers and build a list of
'valid' uclasses.

Also add references to the uclasses so we can generate C code that uses
them. Attach a uclass to each valid driver.

For the tests, now that we have uclasses we must create an explicit test
for the case where a node does not have one. This should only happen if
the source code does not build, or the source-code scanning fails to find
it.

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

4 files changed, 119 insertions, 18 deletions

diff --git a/tools/dtoc/dtb_platdata.py b/tools/dtoc/dtb_platdata.py
index 9e99c63ae70..af21156659b 100644
--- a/tools/dtoc/dtb_platdata.py
+++ b/tools/dtoc/dtb_platdata.py
@@ -151,6 +151,8 @@ class DtbPlatdata():
                         key (str): Field name
                         value: Prop object with field information
         _basedir (str): Base directory of source tree
+        _valid_uclasses (list of src_scan.Uclass): List of uclasses needed for
+            the selected devices (see _valid_node), in alphabetical order
     """
     def __init__(self, scan, dtb_fname, include_disabled):
         self._scan = scan
@@ -164,6 +166,7 @@ class DtbPlatdata():
         self._dirnames = [None] * len(Ftype)
         self._struct_data = collections.OrderedDict()
         self._basedir = None
+        self._valid_uclasses = None
 
     def setup_output_dirs(self, output_dirs):
         """Set up the output directories
@@ -677,23 +680,12 @@ class DtbPlatdata():
             elif result is False:
                 print("Could not find uclass for alias '%s'" % prop.name)
 
-    def assign_seq(self):
+    def assign_seqs(self):
         """Assign a sequence number to each node"""
         for node in self._valid_nodes_unsorted:
-            if node.driver and node.seq == -1 and node.uclass:
-                uclass = node.uclass
-                num = uclass.alias_path_to_num.get(node.path)
-                if num is not None:
-                    node.seq = num
-                else:
-                    # Dynamically allocate the next available value after all
-                    # existing ones
-                    for seq in range(1000):
-                        if seq not in uclass.alias_num_to_node:
-                            break
-                    node.seq = seq
-                    uclass.alias_path_to_num[node.path] = seq
-                    uclass.alias_num_to_node[seq] = node
+            seq = self._scan.assign_seq(node)
+            if seq is not None:
+                node.seq = seq
 
     def process_nodes(self, need_drivers):
         nodes_to_output = list(self._valid_nodes)
@@ -710,6 +702,16 @@ class DtbPlatdata():
                 raise ValueError("Cannot parse/find driver for '%s'" %
                                  node.struct_name)
             node.driver = driver
+            uclass = self._scan._uclass.get(driver.uclass_id)
+            if not uclass:
+                raise ValueError("Cannot parse/find uclass '%s' for driver '%s'" %
+                                (driver.uclass_id, node.struct_name))
+            node.uclass = uclass
+            node.uclass_seq = len(node.uclass.devs)
+            node.uclass.devs.append(node)
+            uclass.node_refs[node.uclass_seq] = \
+                '&%s->uclass_node' % node.dev_ref
+
             parent_driver = None
             if node.parent in self._valid_nodes:
                 parent_driver = self._scan.get_driver(node.parent.struct_name)
@@ -730,6 +732,18 @@ class DtbPlatdata():
             node.child_refs[-1] = ref
             node.child_refs[len(node.child_devs)] = ref
 
+        uclass_set = set()
+        for driver in self._scan._drivers.values():
+            if driver.used and driver.uclass:
+                uclass_set.add(driver.uclass)
+        self._valid_uclasses = sorted(list(uclass_set),
+                                      key=lambda uc: uc.uclass_id)
+
+        for seq, uclass in enumerate(uclass_set):
+            ref = '&DM_UCLASS_REF(%s)->dev_head' % uclass.name
+            uclass.node_refs[-1] = ref
+            uclass.node_refs[len(uclass.devs)] = ref
+
     def output_node(self, node):
         """Output the C code for a node
 
@@ -833,7 +847,7 @@ def run_steps(args, dtb_file, include_disabled, output, output_dirs, phase,
     plat.scan_phandles()
     plat.process_nodes(False)
     plat.read_aliases()
-    plat.assign_seq()
+    plat.assign_seqs()
 
     cmds = args[0].split(',')
     if 'all' in cmds:
diff --git a/tools/dtoc/src_scan.py b/tools/dtoc/src_scan.py
index bb22b0b64ff..8619206a8d4 100644
--- a/tools/dtoc/src_scan.py
+++ b/tools/dtoc/src_scan.py
@@ -74,6 +74,7 @@ class Driver:
             found after this one
         warn_dups (bool): True if the duplicates are not distinguisble using
             the phase
+        uclass (Uclass): uclass for this driver
     """
     def __init__(self, name, fname):
         self.name = name
@@ -89,6 +90,7 @@ class Driver:
         self.headers = []
         self.dups = []
         self.warn_dups = False
+        self.uclass = None
 
     def __eq__(self, other):
         return (self.name == other.name and
@@ -123,6 +125,10 @@ class UclassDriver:
         alias_path_to_num (dict): Convert a path to an alias number
             key (str): Full path to node (e.g. '/soc/pci')
             seq (int): Alias number, e.g. 2 for "pci2"
+        devs (list): List of devices in this uclass, each a Node
+        node_refs (dict): References in the linked list of devices:
+            key (int): Sequence number (0=first, n-1=last, -1=head, n=tail)
+            value (str): Reference to the device at that position
     """
     def __init__(self, name):
         self.name = name
@@ -134,6 +140,8 @@ class UclassDriver:
         self.per_child_plat = ''
         self.alias_num_to_node = {}
         self.alias_path_to_num = {}
+        self.devs = []
+        self.node_refs = {}
 
     def __eq__(self, other):
         return (self.name == other.name and
@@ -639,6 +647,12 @@ class Scanner:
             else:
                 self.scan_driver(self._basedir + '/' + fname)
 
+        # Get the uclass for each driver
+        # TODO: Can we just get the uclass for the ones we use, e.g. in
+        # mark_used()?
+        for driver in self._drivers.values():
+            driver.uclass = self._uclass.get(driver.uclass_id)
+
     def mark_used(self, nodes):
         """Mark the drivers associated with a list of nodes as 'used'
 
@@ -682,3 +696,34 @@ class Scanner:
                 uclass.alias_path_to_num[node.path] = int(num)
                 return True
         return False
+
+    def assign_seq(self, node):
+        """Figure out the sequence number for a node
+
+        This looks in the node's uclass and assigns a sequence number if needed,
+        based on the aliases and other nodes in that uclass.
+
+        It updates the uclass alias_path_to_num and alias_num_to_node
+
+        Args:
+            node (Node): Node object to look up
+        """
+        if node.driver and node.seq == -1 and node.uclass:
+            uclass = node.uclass
+            num = uclass.alias_path_to_num.get(node.path)
+            if num is not None:
+                return num
+            else:
+                # Dynamically allocate the next available value after all
+                # existing ones
+                if uclass.alias_num_to_node:
+                    start = max(uclass.alias_num_to_node.keys())
+                else:
+                    start = -1
+                for seq in range(start + 1, 1000):
+                    if seq not in uclass.alias_num_to_node:
+                        break
+                uclass.alias_path_to_num[node.path] = seq
+                uclass.alias_num_to_node[seq] = node
+                return seq
+        return None
diff --git a/tools/dtoc/test_dtoc.py b/tools/dtoc/test_dtoc.py
index b4c0a042a9f..b077cf0e76d 100755
--- a/tools/dtoc/test_dtoc.py
+++ b/tools/dtoc/test_dtoc.py
@@ -141,6 +141,8 @@ class TestDtoc(unittest.TestCase):
         Returns:
             DtbPlatdata object
         """
+        # Make a copy of the 'scan' object, since it includes uclasses and
+        # drivers, which get updated during execution.
         return dtb_platdata.run_steps(args, dtb_file, False, output, [], None,
                                       warning_disabled=True, scan=copy_scan())
 
@@ -1033,6 +1035,16 @@ U_BOOT_DRVINFO(spl_test2) = {
         self.assertIn("Cannot parse/find driver for 'sandbox_pmic",
                       str(exc.exception))
 
+    def test_process_nodes_bad_uclass(self):
+        plat, scan = self.setup_process_test()
+
+        self.assertIn('UCLASS_I2C', scan._uclass)
+        del scan._uclass['UCLASS_I2C']
+        with self.assertRaises(ValueError) as exc:
+            plat.process_nodes(True)
+        self.assertIn("Cannot parse/find uclass 'UCLASS_I2C' for driver 'sandbox_i2c'",
+                      str(exc.exception))
+
     def test_process_nodes_used(self):
         """Test processing nodes to add various info"""
         plat, scan = self.setup_process_test()
@@ -1052,10 +1064,13 @@ U_BOOT_DRVINFO(spl_test2) = {
 
         scan = plat._scan
         testfdt_node = plat._fdt.GetNode('/some-bus/test')
+        test0_node = plat._fdt.GetNode('/some-bus/test0')
         self.assertIn('UCLASS_TEST_FDT', scan._uclass)
         uc = scan._uclass['UCLASS_TEST_FDT']
-        self.assertEqual({1: testfdt_node}, uc.alias_num_to_node)
-        self.assertEqual({'/some-bus/test': 1}, uc.alias_path_to_num)
+        self.assertEqual({1: testfdt_node, 2: test0_node},
+                         uc.alias_num_to_node)
+        self.assertEqual({'/some-bus/test': 1, '/some-bus/test0': 2},
+                         uc.alias_path_to_num)
 
         # Try adding an alias that doesn't exist
         self.assertFalse(scan.add_uclass_alias('fred', 3, None))
@@ -1098,3 +1113,13 @@ U_BOOT_DRVINFO(spl_test2) = {
         dtb_file = get_dtb_file('dtoc_test_inst.dts')
         output = tools.GetOutputFilename('output')
         plat = self.run_test(['struct'], dtb_file, output)
+
+        scan = plat._scan
+        testfdt = plat._fdt.GetNode('/some-bus/test')
+        self.assertEqual(1, testfdt.seq)
+        i2c = plat._fdt.GetNode('/i2c')
+
+        # For now this uclass is not compiled in, so no sequence is assigned
+        self.assertEqual(4, i2c.seq)
+        spl = plat._fdt.GetNode('/spl-test')
+        self.assertEqual(0, spl.seq)
diff --git a/tools/dtoc/test_src_scan.py b/tools/dtoc/test_src_scan.py
index 598ff256a60..d32aa58400f 100644
--- a/tools/dtoc/test_src_scan.py
+++ b/tools/dtoc/test_src_scan.py
@@ -466,3 +466,20 @@ U_BOOT_DRIVER(%s) = {
         with test_util.capture_sys_output() as (stdout, _):
             scan.mark_used([node])
         self.assertEqual('', stdout.getvalue().strip())
+
+    def test_sequence(self):
+        """Test assignment of sequence numnbers"""
+        scan = src_scan.Scanner(None, False, None, '')
+        node = FakeNode()
+        uc = src_scan.UclassDriver('UCLASS_I2C')
+        node.uclass = uc
+        node.driver = True
+        node.seq = -1
+        node.path = 'mypath'
+        uc.alias_num_to_node[2] = node
+
+        # This should assign 3 (after the 2 that exists)
+        seq = scan.assign_seq(node)
+        self.assertEqual(3, seq)
+        self.assertEqual({'mypath': 3}, uc.alias_path_to_num)
+        self.assertEqual({2: node, 3: node}, uc.alias_num_to_node)