[PATCH 2/2] efi_loader: support FMP versioning for FWU multi bank update

[Masahisa Kojima]

Current FMP versioning uses the FMPStateXXXX UEFI variables
that XXXX indicates image_index. When CONFIG_FWU_MULTI_BANK_UPDATE
is enabled, U-Boot instances installed in different banks
read the same FMPStateXXXX variable and it ends up with reading
wrong fw_version.

This commit includes the bank_index in the FMPStateXXYY variable.
XX indicates a bank_index, YY indicates an image_index.
With this, it keeps backward compatibility for the case that
CONFIG_FWU_MULTI_BANK_UPDATE is not enabled, bank_index is
always 0 for this case.

The bank index size is defined 4 bytes in FWU-PSA-A_DEN0118_1.0ALP3.pdf,
but 1-255 range is practically enough big. This commit adds the range
for FWU_NUM_BANKS since above XX(bank_index) has 1 byte.

Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
---
 lib/efi_loader/efi_firmware.c | 63 ++++++++++++++++++++++++++---------
 lib/fwu_updates/Kconfig       |  1 +
 2 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
index 9c1a273926..6d3620a649 100644
--- a/lib/efi_loader/efi_firmware.c
+++ b/lib/efi_loader/efi_firmware.c
@@ -205,13 +205,33 @@ static
 void efi_firmware_fill_version_info(struct efi_firmware_image_descriptor *image_info,
 				    struct efi_fw_image *fw_array)
 {
-	u16 varname[13]; /* u"FmpStateXXXX" */
+	int err;
+	u16 varname[13]; /* u"FmpStateXXYY" */
 	efi_status_t ret;
 	efi_uintn_t size;
+	uint active_bank = 0, var_index;
 	struct fmp_state var_state = { 0 };
 
+	efi_firmware_get_lsv_from_dtb(fw_array->image_index,
+				      &fw_array->image_type_id,
+				      &image_info->lowest_supported_image_version);
+
+	image_info->version_name = NULL; /* not supported */
+	image_info->last_attempt_version = 0;
+	image_info->last_attempt_status = LAST_ATTEMPT_STATUS_SUCCESS;
+
+	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
+		err = fwu_get_active_index(&active_bank);
+		if (err) {
+			log_debug("Unable to get active index\n");
+			image_info->version = 0;
+			return;
+		}
+	}
+
+	var_index = ((active_bank & 0xFF) << 8 | (fw_array->image_index & 0xFF));
 	efi_create_indexed_name(varname, sizeof(varname), "FmpState",
-				fw_array->image_index);
+				var_index);
 	size = sizeof(var_state);
 	ret = efi_get_variable_int(varname, &fw_array->image_type_id,
 				   NULL, &size, &var_state, NULL);
@@ -219,14 +239,6 @@ void efi_firmware_fill_version_info(struct efi_firmware_image_descriptor *image_
 		image_info->version = var_state.fw_version;
 	else
 		image_info->version = 0;
-
-	efi_firmware_get_lsv_from_dtb(fw_array->image_index,
-				      &fw_array->image_type_id,
-				      &image_info->lowest_supported_image_version);
-
-	image_info->version_name = NULL; /* not supported */
-	image_info->last_attempt_version = 0;
-	image_info->last_attempt_status = LAST_ATTEMPT_STATUS_SUCCESS;
 }
 
 /**
@@ -353,15 +365,20 @@ efi_status_t efi_firmware_capsule_authenticate(const void **p_image,
  * @state:		Pointer to fmp state
  * @image_index:	image index
  *
- * Update the FmpStateXXXX variable with the firmware update state.
+ * Update the FmpStateXXYY variable with the firmware update state.
+ * XX is a bank index, YY is an image_index
+ * When CONFIG_FWU_MULTI_BANK_UPDATE is not enabled, update_bank is always 0.
  *
  * Return:		status code
  */
 static
 efi_status_t efi_firmware_set_fmp_state_var(struct fmp_state *state, u8 image_index)
 {
-	u16 varname[13]; /* u"FmpStateXXXX" */
+	int err;
+	u16 varname[13]; /* u"FmpStateXXYY" */
 	efi_status_t ret;
+	uint update_bank = 0;
+	unsigned int var_index;
 	efi_guid_t *image_type_id;
 	struct fmp_state var_state = { 0 };
 
@@ -369,9 +386,15 @@ efi_status_t efi_firmware_set_fmp_state_var(struct fmp_state *state, u8 image_in
 	if (!image_type_id)
 		return EFI_INVALID_PARAMETER;
 
-	efi_create_indexed_name(varname, sizeof(varname), "FmpState",
-				image_index);
+	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
+		err = fwu_plat_get_update_index(&update_bank);
+		if (err)
+			return EFI_INVALID_PARAMETER;
+	}
 
+	var_index = ((update_bank & 0xFF) << 8 | (image_index & 0xFF));
+	efi_create_indexed_name(varname, sizeof(varname), "FmpState",
+				var_index);
 	/*
 	 * Only the fw_version is set here.
 	 * lowest_supported_version in FmpState variable is ignored since
@@ -563,7 +586,11 @@ efi_status_t EFIAPI efi_firmware_fit_set_image(
 	if (fit_update(image))
 		return EFI_EXIT(EFI_DEVICE_ERROR);
 
-	efi_firmware_set_fmp_state_var(&state, image_index);
+	status = efi_firmware_set_fmp_state_var(&state, image_index);
+	if (status != EFI_SUCCESS) {
+		log_err("Set FmpState variable failed\n");
+		return EFI_EXIT(status);
+	}
 
 	return EFI_EXIT(EFI_SUCCESS);
 }
@@ -643,7 +670,11 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
 			     NULL, NULL))
 		return EFI_EXIT(EFI_DEVICE_ERROR);
 
-	efi_firmware_set_fmp_state_var(&state, original_image_index);
+	status = efi_firmware_set_fmp_state_var(&state, original_image_index);
+	if (status != EFI_SUCCESS) {
+		log_err("Set FmpState variable failed\n");
+		return EFI_EXIT(status);
+	}
 
 	return EFI_EXIT(EFI_SUCCESS);
 }
diff --git a/lib/fwu_updates/Kconfig b/lib/fwu_updates/Kconfig
index d35247d0e5..eb42f25fc0 100644
--- a/lib/fwu_updates/Kconfig
+++ b/lib/fwu_updates/Kconfig
@@ -14,6 +14,7 @@ if FWU_MULTI_BANK_UPDATE
 
 config FWU_NUM_BANKS
 	int "Number of Banks defined by the platform"
+	range 1 255
 	help
 	  Define the number of banks of firmware images on a platform
 
-- 
2.34.1