Merge patch series "Fix device removal order for Apple dart iommu"

Janne Grunau <j@jannau.net> says:

Starting with v2024.10 dev_iommu_dma_unmap calls during device removal
trigger a NULL pointer dereference in the Apple dart iommu driver. The
iommu device is removed before its user. The sparsely used DM_FLAG_VITAL
flag is intended to describe this dependency. Add it to the driver.

Adding this flag is unfortunately not enough since the boot routines
except the arm one simply remove all drivers. Add and use a new function
which calls
    dm_remove_devioce_flags(DM_REMOVE_ACTIVE_ALL | DM_REMOVE_NON_VITAL);
    dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
to ensure this order dependency is head consistently.

Link: https://lore.kernel.org/r/20241123-iommu_apple_dart_ordering-v2-0-cc2ade6dde97@jannau.net

1 files changed, 50 insertions, 0 deletions

diff --git a/test/dm/core.c b/test/dm/core.c
index 7371d3ff426..c59ffc6f611 100644
--- a/test/dm/core.c
+++ b/test/dm/core.c
@@ -999,6 +999,56 @@ static int dm_test_remove_vital(struct unit_test_state *uts)
 }
 DM_TEST(dm_test_remove_vital, 0);
 
+/* Test removal of 'active' devices */
+static int dm_test_remove_active(struct unit_test_state *uts)
+{
+	struct udevice *normal, *dma, *vital, *dma_vital;
+
+	/* Skip the behaviour in test_post_probe() */
+	uts->skip_post_probe = 1;
+
+	ut_assertok(device_bind_by_name(uts->root, false, &driver_info_manual,
+					&normal));
+	ut_assertnonnull(normal);
+
+	ut_assertok(device_bind_by_name(uts->root, false, &driver_info_act_dma,
+					&dma));
+	ut_assertnonnull(dma);
+
+	ut_assertok(device_bind_by_name(uts->root, false,
+					&driver_info_vital_clk, &vital));
+	ut_assertnonnull(vital);
+
+	ut_assertok(device_bind_by_name(uts->root, false,
+					&driver_info_act_dma_vital_clk,
+					&dma_vital));
+	ut_assertnonnull(dma_vital);
+
+	/* Probe the devices */
+	ut_assertok(device_probe(normal));
+	ut_assertok(device_probe(dma));
+	ut_assertok(device_probe(vital));
+	ut_assertok(device_probe(dma_vital));
+
+	/* Check that devices are active right now */
+	ut_asserteq(true, device_active(normal));
+	ut_asserteq(true, device_active(dma));
+	ut_asserteq(true, device_active(vital));
+	ut_asserteq(true, device_active(dma_vital));
+
+	/* Remove active devices in an ordered way */
+	dm_remove_devices_active();
+
+	/* Check that all devices are inactive right now */
+	ut_asserteq(true, device_active(normal));
+	ut_asserteq(false, device_active(dma));
+	ut_asserteq(true, device_active(vital));
+	ut_asserteq(false, device_active(dma_vital));
+
+	return 0;
+}
+DM_TEST(dm_test_remove_active, 0);
+
 static int dm_test_uclass_before_ready(struct unit_test_state *uts)
 {
 	struct uclass *uc;