dtoc: Warn of duplicate drivers

If drivers have the same name then we cannot distinguish them. This only
matters if the driver is actually used by dtoc, but in that case, issue
a warning.

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

tools/dtoc/src_scan.py

@@ -70,6 +70,10 @@ class Driver:
         phase (str): Which phase of U-Boot to use this driver
         headers (list): List of header files needed for this driver (each a str)
             e.g. ['<asm/cpu.h>']
+        dups (list): Driver objects with the same name as this one, that were
+            found after this one
+        warn_dups (bool): True if the duplicates are not distinguisble using
+            the phase
     """
     def __init__(self, name, fname):
         self.name = name
@@ -83,6 +87,8 @@ class Driver:
         self.used = False
         self.phase = ''
         self.headers = []
+        self.dups = []
+        self.warn_dups = False
 
     def __eq__(self, other):
         return (self.name == other.name and
@@ -531,7 +537,21 @@ class Scanner:
                     self._driver_aliases[m_alias[2]] = m_alias[1]
 
         # Make the updates based on what we found
-        self._drivers.update(drivers)
+        for driver in drivers.values():
+            if driver.name in self._drivers:
+                orig = self._drivers[driver.name]
+                if self._phase:
+                    # If the original driver matches our phase, use it
+                    if orig.phase == self._phase:
+                        orig.dups.append(driver)
+                        continue
+
+                    # Otherwise use the new driver, which is assumed to match
+                else:
+                    # We have no way of distinguishing them
+                    driver.warn_dups = True
+                driver.dups.append(orig)
+            self._drivers[driver.name] = driver
         self._of_match.update(of_match)
 
     def scan_driver(self, fname):
@@ -617,6 +637,8 @@ class Scanner:
         This takes a list of nodes, finds the driver for each one and marks it
         as used.
 
+        If two used drivers have the same name, issue a warning.
+
         Args:
             nodes (list of None): Nodes that are in use
         """
@@ -626,3 +648,7 @@ class Scanner:
             driver = self._drivers.get(struct_name)
             if driver:
                 driver.used = True
+                if driver.dups and driver.warn_dups:
+                    print("Warning: Duplicate driver name '%s' (orig=%s, dups=%s)" %
+                          (driver.name, driver.fname,
+                           ', '.join([drv.fname for drv in driver.dups])))

tools/dtoc/test_src_scan.py

@@ -371,3 +371,98 @@ struct another_struct {
         with test_util.capture_sys_output() as (stdout, _):
             scan.scan_header(output)
         self.assertIn('due to unicode error', stdout.getvalue())
+
+    def setup_dup_drivers(self, name, phase=''):
+        """Set up for a duplcate test
+
+        Returns:
+            tuple:
+                Scanner to use
+                Driver record for first driver
+                Text of second driver declaration
+                Node for driver 1
+        """
+        driver1 = '''
+static const struct udevice_id test_ids[] = {
+	{ .compatible = "nvidia,tegra114-i2c", .data = TYPE_114 },
+	{ }
+};
+
+U_BOOT_DRIVER(%s) = {
+	.name	= "testing",
+	.id	= UCLASS_I2C,
+	.of_match = test_ids,
+	%s
+};
+''' % (name, 'DM_PHASE(%s)' % phase if phase else '')
+        driver2 = '''
+static const struct udevice_id test_ids[] = {
+	{ .compatible = "nvidia,tegra114-dvc" },
+	{ }
+};
+
+U_BOOT_DRIVER(%s) = {
+	.name	= "testing",
+	.id	= UCLASS_RAM,
+	.of_match = test_ids,
+};
+''' % name
+        scan = src_scan.Scanner(None, False, None, phase)
+        scan._parse_driver('file1.c', driver1)
+        self.assertIn(name, scan._drivers)
+        drv1 = scan._drivers[name]
+
+        prop = FakeProp()
+        prop.name = 'compatible'
+        prop.value = 'nvidia,tegra114-i2c'
+        node = FakeNode()
+        node.name = 'testing'
+        node.props = {'compatible': prop}
+
+        return scan, drv1, driver2, node
+
+    def test_dup_drivers(self):
+        """Test handling of duplicate drivers"""
+        name = 'nvidia_tegra114_i2c'
+        scan, drv1, driver2, node = self.setup_dup_drivers(name)
+        self.assertEqual('', drv1.phase)
+
+        # The driver should not have a duplicate yet
+        self.assertEqual([], drv1.dups)
+
+        scan._parse_driver('file2.c', driver2)
+
+        # The first driver should now be a duplicate of the second
+        drv2 = scan._drivers[name]
+        self.assertEqual('', drv2.phase)
+        self.assertEqual(1, len(drv2.dups))
+        self.assertEqual([drv1], drv2.dups)
+
+        # There is no way to distinguish them, so we should expect a warning
+        self.assertTrue(drv2.warn_dups)
+
+        # We should see a warning
+        with test_util.capture_sys_output() as (stdout, _):
+            scan.mark_used([node])
+        self.assertEqual(
+            "Warning: Duplicate driver name 'nvidia_tegra114_i2c' (orig=file2.c, dups=file1.c)",
+            stdout.getvalue().strip())
+
+    def test_dup_drivers_phase(self):
+        """Test handling of duplicate drivers but with different phases"""
+        name = 'nvidia_tegra114_i2c'
+        scan, drv1, driver2, node = self.setup_dup_drivers(name, 'spl')
+        scan._parse_driver('file2.c', driver2)
+        self.assertEqual('spl', drv1.phase)
+
+        # The second driver should now be a duplicate of the second
+        self.assertEqual(1, len(drv1.dups))
+        drv2 = drv1.dups[0]
+
+        # The phase is different, so we should not warn of dups
+        self.assertFalse(drv1.warn_dups)
+
+        # We should not see a warning
+        with test_util.capture_sys_output() as (stdout, _):
+            scan.mark_used([node])
+        self.assertEqual('', stdout.getvalue().strip())