[PATCH] fwu: Mark failed bank as invalid during rollback

[Kory Maincent]

When boot_idx differs from active_idx at boot time, it indicates a
rollback scenario where the firmware update failed and the system
reverted to the previous working bank. In this case, mark the failed
bank (active_idx) as invalid to prevent future boot attempts from that
bank.

This change adds a new fwu_invalid_bank() function that sets the bank
state to FWU_BANK_INVALID and syncs the metadata. This is only
supported in FWU metadata version 2; version 1 provides a no-op stub.

Without this change, a failed bank would remain in a valid state and
could potentially be selected for boot again, leading to repeated
boot failures.

Signed-off-by: Kory Maincent <kory.maincent at bootlin.com>
---
 include/fwu.h            |  8 ++++++++
 lib/fwu_updates/fwu.c    |  1 +
 lib/fwu_updates/fwu_v1.c | 10 ++++++++++
 lib/fwu_updates/fwu_v2.c | 19 +++++++++++++++++++
 4 files changed, 38 insertions(+)

diff --git a/include/fwu.h b/include/fwu.h
index e7bd1d492af..e4f3a062e36 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -415,6 +415,14 @@ int fwu_get_mdata_size(uint32_t *mdata_size);
  */
 int fwu_state_machine_updates(bool trial_state, uint32_t update_index);
 
+/**
+ * fwu_invalid_bank() - Invalid bank state of a specific bank
+ * @index: Index of the bank
+ *
+ * Only supported in version 2 of FWU metadata.
+ */
+void fwu_invalid_bank(uint32_t index);
+
 /**
  * fwu_init() - FWU specific initialisations
  *
diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
index 0f5ef2ba515..e54c19b0c64 100644
--- a/lib/fwu_updates/fwu.c
+++ b/lib/fwu_updates/fwu.c
@@ -766,6 +766,7 @@ static int fwu_boottime_checks(void)
 	if (boot_idx != active_idx) {
 		log_info("Boot idx %u is not matching active idx %u, changing active_idx\n",
 			 boot_idx, active_idx);
+		fwu_invalid_bank(active_idx);
 		ret = fwu_set_active_index(boot_idx);
 		if (!ret)
 			boottime_check = 1;
diff --git a/lib/fwu_updates/fwu_v1.c b/lib/fwu_updates/fwu_v1.c
index 974abf216f6..c9ac1ec244d 100644
--- a/lib/fwu_updates/fwu_v1.c
+++ b/lib/fwu_updates/fwu_v1.c
@@ -136,6 +136,16 @@ int fwu_get_mdata_size(uint32_t *mdata_size)
 	return 0;
 }
 
+/**
+ * fwu_invalid_bank() - Invalid bank state of a specific bank
+ * @index: Index of the bank
+ *
+ * Not supported.
+ */
+void fwu_invalid_bank(uint32_t index)
+{
+}
+
 /**
  * fwu_init() - FWU specific initialisations
  *
diff --git a/lib/fwu_updates/fwu_v2.c b/lib/fwu_updates/fwu_v2.c
index 159315b45b9..3c07adfd4e0 100644
--- a/lib/fwu_updates/fwu_v2.c
+++ b/lib/fwu_updates/fwu_v2.c
@@ -194,6 +194,25 @@ int fwu_state_machine_updates(bool trial_state, uint32_t update_index)
 		fwu_bank_state_update(0, update_index);
 }
 
+/**
+ * fwu_invalid_bank() - Invalid bank state of a specific bank
+ * @index: Index of the bank
+ */
+void fwu_invalid_bank(uint32_t index)
+{
+	struct fwu_data *data = fwu_get_data();
+	struct fwu_mdata *mdata;
+	int ret;
+
+	mdata = data->fwu_mdata;
+	data->bank_state[index] = FWU_BANK_INVALID;
+	mdata->bank_state[index] = FWU_BANK_INVALID;
+
+	ret = fwu_sync_mdata(mdata, BOTH_PARTS);
+	if (ret)
+		log_err("Unable to invalid bank %u\n", index);
+}
+
 /**
  * fwu_get_mdata_size() - Get the FWU metadata size
  * @mdata_size: Size of the metadata structure
-- 
2.43.0