[v15,10/15] FWU: Add support for the FWU Multi Bank Update feature

The FWU Multi Bank Update feature supports updating firmware images
to one of multiple sets(also called banks) of images. The firmware
images are clubbed together in banks, with the system booting images
from the active bank. Information on the images such as which bank
they belong to is stored as part of the metadata structure, which is
stored on the same storage media as the firmware images on a dedicated
partition.

At the time of update, the metadata is read to identify the bank to
which the images need to be flashed(update bank). On a successful
update, the metadata is modified to set the updated bank as active
bank to subsequently boot from.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
---
Changes since V14:
* Initialise the return value to EFI_INVALID_PARAMETER in
  fwu_empty_capsule_process() and get rid of the else part as
  suggested by Ilias
* Remove the superfluous assignment of EFI_SUCCESS in
  fwu_post_update_process() as suggested by Ilias
* Add a check for fwu_empty_capsule_checks_pass() to allow application
  of empty capsules only in trial state

 drivers/Kconfig               |   2 +
 drivers/Makefile              |   1 +
 include/fwu.h                 |  30 +++++
 lib/Kconfig                   |   6 +
 lib/Makefile                  |   1 +
 lib/efi_loader/efi_capsule.c  | 210 +++++++++++++++++++++++++++++++++-
 lib/efi_loader/efi_firmware.c |  14 +++
 lib/fwu_updates/Kconfig       |  33 ++++++
 lib/fwu_updates/Makefile      |   7 ++
 lib/fwu_updates/fwu.c         |  22 ++++
 10 files changed, 324 insertions(+), 2 deletions(-)
 create mode 100644 lib/fwu_updates/Kconfig
 create mode 100644 lib/fwu_updates/Makefile

Hi Sughosh, 

Ideally this would be better of as a different FMP, but I understand we are
missing some information (the capsule header) on the FMP level.

I think we can include it as is for now and have another look when we add
support for more boards

On Fri, Oct 21, 2022 at 06:16:03PM +0530, Sughosh Ganu wrote:
> The FWU Multi Bank Update feature supports updating firmware images
> to one of multiple sets(also called banks) of images. The firmware
> images are clubbed together in banks, with the system booting images
> from the active bank. Information on the images such as which bank
> they belong to is stored as part of the metadata structure, which is
> stored on the same storage media as the firmware images on a dedicated
> partition.
> 
> At the time of update, the metadata is read to identify the bank to
> which the images need to be flashed(update bank). On a successful
> update, the metadata is modified to set the updated bank as active
> bank to subsequently boot from.
> 
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> ---
> Changes since V14:
> * Initialise the return value to EFI_INVALID_PARAMETER in
>   fwu_empty_capsule_process() and get rid of the else part as
>   suggested by Ilias
> * Remove the superfluous assignment of EFI_SUCCESS in
>   fwu_post_update_process() as suggested by Ilias
> * Add a check for fwu_empty_capsule_checks_pass() to allow application
>   of empty capsules only in trial state
> 
>  drivers/Kconfig               |   2 +
>  drivers/Makefile              |   1 +
>  include/fwu.h                 |  30 +++++
>  lib/Kconfig                   |   6 +
>  lib/Makefile                  |   1 +
>  lib/efi_loader/efi_capsule.c  | 210 +++++++++++++++++++++++++++++++++-
>  lib/efi_loader/efi_firmware.c |  14 +++
>  lib/fwu_updates/Kconfig       |  33 ++++++
>  lib/fwu_updates/Makefile      |   7 ++
>  lib/fwu_updates/fwu.c         |  22 ++++
>  10 files changed, 324 insertions(+), 2 deletions(-)
>  create mode 100644 lib/fwu_updates/Kconfig
>  create mode 100644 lib/fwu_updates/Makefile
> 
> diff --git a/drivers/Kconfig b/drivers/Kconfig
> index 8b6fead351..75ac149d31 100644
> --- a/drivers/Kconfig
> +++ b/drivers/Kconfig
> @@ -44,6 +44,8 @@ source "drivers/fuzz/Kconfig"
>  
>  source "drivers/fpga/Kconfig"
>  
> +source "drivers/fwu-mdata/Kconfig"
> +
>  source "drivers/gpio/Kconfig"
>  
>  source "drivers/hwspinlock/Kconfig"
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 9d9f69a3c9..253cbfb71d 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -85,6 +85,7 @@ obj-y += cache/
>  obj-$(CONFIG_CPU) += cpu/
>  obj-y += crypto/
>  obj-$(CONFIG_FASTBOOT) += fastboot/
> +obj-$(CONFIG_FWU_MDATA) += fwu-mdata/
>  obj-y += misc/
>  obj-$(CONFIG_MMC) += mmc/
>  obj-$(CONFIG_NVME) += nvme/
> diff --git a/include/fwu.h b/include/fwu.h
> index a8ed67b0e0..0919ced812 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -98,6 +98,7 @@ struct fwu_mdata_ops {
>  };
>  
>  #define FWU_MDATA_VERSION	0x1
> +#define FWU_IMAGE_ACCEPTED	0x1
>  
>  /*
>  * GUID value defined in the FWU specification for identification
> @@ -107,6 +108,24 @@ struct fwu_mdata_ops {
>  	EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
>  		 0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
>  
> +/*
> +* GUID value defined in the Dependable Boot specification for
> +* identification of the revert capsule, used for reverting
> +* any image in the updated bank.
> +*/
> +#define FWU_OS_REQUEST_FW_REVERT_GUID \
> +	EFI_GUID(0xacd58b4b, 0xc0e8, 0x475f, 0x99, 0xb5, \
> +		 0x6b, 0x3f, 0x7e, 0x07, 0xaa, 0xf0)
> +
> +/*
> +* GUID value defined in the Dependable Boot specification for
> +* identification of the accept capsule, used for accepting
> +* an image in the updated bank.
> +*/
> +#define FWU_OS_REQUEST_FW_ACCEPT_GUID \
> +	EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
> +		 0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
> +
>  /**
>   * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
>   *
> @@ -379,4 +398,15 @@ u8 fwu_update_checks_pass(void);
>   */
>  u8 fwu_empty_capsule_checks_pass(void);
>  
> +/**
> + * fwu_trial_state_ctr_start() - Start the Trial State counter
> + *
> + * Start the counter to identify the platform booting in the
> + * Trial State. The counter is implemented as an EFI variable.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_trial_state_ctr_start(void);
> +
>  #endif /* _FWU_H_ */
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 6121c80dc8..6abe1d0a86 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -978,3 +978,9 @@ config LMB_RESERVED_REGIONS
>  	  memory blocks.
>  
>  endmenu
> +
> +menu "FWU Multi Bank Updates"
> +
> +source lib/fwu_updates/Kconfig
> +
> +endmenu
> diff --git a/lib/Makefile b/lib/Makefile
> index e3deb15287..f2cfd1e428 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_EFI) += efi/
>  obj-$(CONFIG_EFI_LOADER) += efi_driver/
>  obj-$(CONFIG_EFI_LOADER) += efi_loader/
>  obj-$(CONFIG_CMD_BOOTEFI_SELFTEST) += efi_selftest/
> +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu_updates/
>  obj-$(CONFIG_LZMA) += lzma/
>  obj-$(CONFIG_BZIP2) += bzip2/
>  obj-$(CONFIG_FIT) += libfdt/
> diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> index 397e393a18..1163a2ee30 100644
> --- a/lib/efi_loader/efi_capsule.c
> +++ b/lib/efi_loader/efi_capsule.c
> @@ -14,6 +14,7 @@
>  #include <env.h>
>  #include <fdtdec.h>
>  #include <fs.h>
> +#include <fwu.h>
>  #include <hang.h>
>  #include <malloc.h>
>  #include <mapmem.h>
> @@ -32,6 +33,12 @@ static const efi_guid_t efi_guid_firmware_management_capsule_id =
>  		EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
>  const efi_guid_t efi_guid_firmware_management_protocol =
>  		EFI_FIRMWARE_MANAGEMENT_PROTOCOL_GUID;
> +const efi_guid_t fwu_guid_os_request_fw_revert =
> +		FWU_OS_REQUEST_FW_REVERT_GUID;
> +const efi_guid_t fwu_guid_os_request_fw_accept =
> +		FWU_OS_REQUEST_FW_ACCEPT_GUID;
> +
> +#define FW_ACCEPT_OS	(u32)0x8000
>  
>  #ifdef CONFIG_EFI_CAPSULE_ON_DISK
>  /* for file system access */
> @@ -386,6 +393,132 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
>  }
>  #endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
>  
> +static __maybe_unused bool fwu_empty_capsule(struct efi_capsule_header *capsule)
> +{
> +	return !guidcmp(&capsule->capsule_guid,
> +			&fwu_guid_os_request_fw_revert) ||
> +		!guidcmp(&capsule->capsule_guid,
> +			 &fwu_guid_os_request_fw_accept);
> +}
> +
> +static __maybe_unused efi_status_t fwu_to_efi_error(int err)
> +{
> +	efi_status_t ret;
> +
> +	switch(err) {
> +	case 0:
> +		ret = EFI_SUCCESS;
> +		break;
> +	case -ERANGE:
> +	case -EIO:
> +		ret = EFI_DEVICE_ERROR;
> +		break;
> +	case -EINVAL:
> +		ret = EFI_INVALID_PARAMETER;
> +		break;
> +	case -ENODEV:
> +		ret = EFI_NOT_FOUND;
> +		break;
> +	default:
> +		ret = EFI_OUT_OF_RESOURCES;
> +	}
> +
> +	return ret;
> +}
> +
> +static __maybe_unused efi_status_t fwu_empty_capsule_process(
> +	struct efi_capsule_header *capsule)
> +{
> +	int status;
> +	u32 active_idx;
> +	efi_guid_t *image_guid;
> +	efi_status_t ret = EFI_INVALID_PARAMETER;
> +
> +	if (!guidcmp(&capsule->capsule_guid,
> +		     &fwu_guid_os_request_fw_revert)) {
> +		/*
> +		 * One of the previously updated image has
> +		 * failed the OS acceptance test. OS has
> +		 * requested to revert back to the earlier
> +		 * boot index
> +		 */
> +		status = fwu_revert_boot_index();
> +		ret = fwu_to_efi_error(status);
> +		if (ret == EFI_SUCCESS)
> +			log_debug("Reverted the FWU active_index. Recommend rebooting the system\n");
> +		else
> +			log_err("Failed to revert the FWU boot index\n");
> +	} else if (!guidcmp(&capsule->capsule_guid,
> +			    &fwu_guid_os_request_fw_accept)) {
> +		/*
> +		 * Image accepted by the OS. Set the acceptance
> +		 * status for the image.
> +		 */
> +		image_guid = (void *)(char *)capsule +
> +			capsule->header_size;
> +
> +		status = fwu_get_active_index(&active_idx);
> +		ret = fwu_to_efi_error(status);
> +		if (ret != EFI_SUCCESS) {
> +			log_err("Unable to get the active_index from the FWU metadata\n");
> +			return ret;
> +		}
> +
> +		status = fwu_accept_image(image_guid, active_idx);
> +		ret = fwu_to_efi_error(status);
> +		if (ret != EFI_SUCCESS)
> +			log_err("Unable to set the Accept bit for the image %pUs\n",
> +				image_guid);
> +	}
> +
> +	return ret;
> +}
> +
> +static __maybe_unused void fwu_post_update_checks(
> +	struct efi_capsule_header *capsule,
> +	bool *fw_accept_os, bool *capsule_update)
> +{
> +	if (fwu_empty_capsule(capsule))
> +		*capsule_update = false;
> +	else
> +		if (!*fw_accept_os)
> +			*fw_accept_os =
> +				capsule->flags & FW_ACCEPT_OS ? true : false;
> +}
> +
> +static __maybe_unused efi_status_t fwu_post_update_process(bool fw_accept_os)
> +{
> +	int status;
> +	uint update_index;
> +	efi_status_t ret;
> +
> +	status = fwu_plat_get_update_index(&update_index);
> +	if (status < 0) {
> +		log_err("Failed to get the FWU update_index value\n");
> +		return EFI_DEVICE_ERROR;
> +	}
> +
> +	/*
> +	 * All the capsules have been updated successfully,
> +	 * update the FWU metadata.
> +	 */
> +	log_debug("Update Complete. Now updating active_index to %u\n",
> +		  update_index);
> +	status = fwu_set_active_index(update_index);
> +	ret = fwu_to_efi_error(status);
> +	if (ret != EFI_SUCCESS) {
> +		log_err("Failed to update FWU metadata index values\n");
> +	} else {
> +		log_debug("Successfully updated the active_index\n");
> +		if (fw_accept_os) {
> +			status = fwu_trial_state_ctr_start();
> +			if (status < 0)
> +				ret = EFI_DEVICE_ERROR;
> +		}
> +	}
> +
> +	return ret;
> +}
>  
>  /**
>   * efi_capsule_update_firmware - update firmware from capsule
> @@ -408,7 +541,32 @@ static efi_status_t efi_capsule_update_firmware(
>  	int item;
>  	struct efi_firmware_management_protocol *fmp;
>  	u16 *abort_reason;
> +	efi_guid_t *image_type_id;
>  	efi_status_t ret = EFI_SUCCESS;
> +	int status;
> +	uint update_index;
> +	bool fw_accept_os;
> +
> +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> +		if (fwu_empty_capsule_checks_pass() &&
> +		    fwu_empty_capsule(capsule_data))
> +			return fwu_empty_capsule_process(capsule_data);
> +
> +		if (!fwu_update_checks_pass()) {
> +			log_err("FWU checks failed. Cannot start update\n");
> +			return EFI_INVALID_PARAMETER;
> +		}
> +
> +
> +		/* Obtain the update_index from the platform */
> +		status = fwu_plat_get_update_index(&update_index);
> +		if (status < 0) {
> +			log_err("Failed to get the FWU update_index value\n");
> +			return EFI_DEVICE_ERROR;
> +		}
> +
> +		fw_accept_os = capsule_data->flags & FW_ACCEPT_OS ? 0x1 : 0x0;
> +	}
>  
>  	/* sanity check */
>  	if (capsule_data->header_size < sizeof(*capsule) ||
> @@ -495,6 +653,34 @@ static efi_status_t efi_capsule_update_firmware(
>  			efi_free_pool(abort_reason);
>  			goto out;
>  		}
> +
> +		if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> +			image_type_id = &image->update_image_type_id;
> +			if (!fw_accept_os) {
> +				/*
> +				 * The OS will not be accepting the firmware
> +				 * images. Set the accept bit of all the
> +				 * images contained in this capsule.
> +				 */
> +				status = fwu_accept_image(image_type_id,
> +							  update_index);
> +			} else {
> +				status = fwu_clear_accept_image(image_type_id,
> +								update_index);
> +			}
> +			ret = fwu_to_efi_error(status);
> +			if (ret != EFI_SUCCESS) {
> +				log_err("Unable to %s the accept bit for the image %pUs\n",
> +					fw_accept_os ? "clear" : "set",
> +					image_type_id);
> +				goto out;
> +			}
> +
> +			log_debug("%s the accepted bit for Image %pUs\n",
> +				  fw_accept_os ? "Cleared" : "Set",
> +				  image_type_id);
> +		}
> +
>  	}
>  
>  out:
> @@ -1103,6 +1289,9 @@ efi_status_t efi_launch_capsules(void)
>  	u16 **files;
>  	unsigned int nfiles, index, i;
>  	efi_status_t ret;
> +	bool capsule_update = true;
> +	bool update_status = true;
> +	bool fw_accept_os = false;
>  
>  	if (check_run_capsules() != EFI_SUCCESS)
>  		return EFI_SUCCESS;
> @@ -1130,12 +1319,19 @@ efi_status_t efi_launch_capsules(void)
>  		ret = efi_capsule_read_file(files[i], &capsule);
>  		if (ret == EFI_SUCCESS) {
>  			ret = efi_capsule_update_firmware(capsule);
> -			if (ret != EFI_SUCCESS)
> +			if (ret != EFI_SUCCESS) {
>  				log_err("Applying capsule %ls failed.\n",
>  					files[i]);
> -			else
> +				update_status = false;
> +			} else {
>  				log_info("Applying capsule %ls succeeded.\n",
>  					 files[i]);
> +				if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> +					fwu_post_update_checks(capsule,
> +							       &fw_accept_os,
> +							       &capsule_update);
> +				}
> +			}
>  
>  			/* create CapsuleXXXX */
>  			set_capsule_result(index, capsule, ret);
> @@ -1143,6 +1339,7 @@ efi_status_t efi_launch_capsules(void)
>  			free(capsule);
>  		} else {
>  			log_err("Reading capsule %ls failed\n", files[i]);
> +			update_status = false;
>  		}
>  		/* delete a capsule either in case of success or failure */
>  		ret = efi_capsule_delete_file(files[i]);
> @@ -1150,8 +1347,17 @@ efi_status_t efi_launch_capsules(void)
>  			log_err("Deleting capsule %ls failed\n",
>  				files[i]);
>  	}
> +
>  	efi_capsule_scan_done();
>  
> +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> +		if (capsule_update == true && update_status == true) {
> +			ret = fwu_post_update_process(fw_accept_os);
> +		} else if (capsule_update == true && update_status == false) {
> +			log_err("All capsules were not updated. Not updating FWU metadata\n");
> +		}
> +	}
> +
>  	for (i = 0; i < nfiles; i++)
>  		free(files[i]);
>  	free(files);
> diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> index 30cafd15ca..93e2b01c07 100644
> --- a/lib/efi_loader/efi_firmware.c
> +++ b/lib/efi_loader/efi_firmware.c
> @@ -10,6 +10,7 @@
>  #include <charset.h>
>  #include <dfu.h>
>  #include <efi_loader.h>
> +#include <fwu.h>
>  #include <image.h>
>  #include <signatures.h>
>  
> @@ -389,6 +390,7 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
>  	efi_status_t (*progress)(efi_uintn_t completion),
>  	u16 **abort_reason)
>  {
> +	int ret;
>  	efi_status_t status;
>  
>  	EFI_ENTRY("%p %d %p %zu %p %p %p\n", this, image_index, image,
> @@ -401,6 +403,18 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
>  	if (status != EFI_SUCCESS)
>  		return EFI_EXIT(status);
>  
> +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> +		/*
> +		 * Based on the value of update bank, derive the
> +		 * image index value.
> +		 */
> +		ret = fwu_get_image_index(&image_index);
> +		if (ret) {
> +			log_debug("Unable to get FWU image_index\n");
> +			return EFI_EXIT(EFI_DEVICE_ERROR);
> +		}
> +	}
> +
>  	if (dfu_write_by_alt(image_index - 1, (void *)image, image_size,
>  			     NULL, NULL))
>  		return EFI_EXIT(EFI_DEVICE_ERROR);
> diff --git a/lib/fwu_updates/Kconfig b/lib/fwu_updates/Kconfig
> new file mode 100644
> index 0000000000..78759e6618
> --- /dev/null
> +++ b/lib/fwu_updates/Kconfig
> @@ -0,0 +1,33 @@
> +config FWU_MULTI_BANK_UPDATE
> +	bool "Enable FWU Multi Bank Update Feature"
> +	depends on EFI_CAPSULE_ON_DISK
> +	select PARTITION_TYPE_GUID
> +	select EFI_SETUP_EARLY
> +	imply EFI_CAPSULE_ON_DISK_EARLY
> +	select EVENT
> +	help
> +	  Feature for updating firmware images on platforms having
> +	  multiple banks(copies) of the firmware images. One of the
> +	  bank is selected for updating all the firmware components
> +
> +config FWU_NUM_BANKS
> +	int "Number of Banks defined by the platform"
> +	depends on FWU_MULTI_BANK_UPDATE
> +	help
> +	  Define the number of banks of firmware images on a platform
> +
> +config FWU_NUM_IMAGES_PER_BANK
> +	int "Number of firmware images per bank"
> +	depends on FWU_MULTI_BANK_UPDATE
> +	help
> +	  Define the number of firmware images per bank. This value
> +	  should be the same for all the banks.
> +
> +config FWU_TRIAL_STATE_CNT
> +	int "Number of times system boots in Trial State"
> +	depends on FWU_MULTI_BANK_UPDATE
> +	default 3
> +	help
> +	  With FWU Multi Bank Update feature enabled, number of times
> +	  the platform is allowed to boot in Trial State after an
> +	  update.
> diff --git a/lib/fwu_updates/Makefile b/lib/fwu_updates/Makefile
> new file mode 100644
> index 0000000000..1993088e5b
> --- /dev/null
> +++ b/lib/fwu_updates/Makefile
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (c) 2022, Linaro Limited
> +#
> +
> +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu.o
> +obj-$(CONFIG_FWU_MDATA_GPT_BLK) += fwu_gpt.o
> diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> index c9a9022a59..6e159c050c 100644
> --- a/lib/fwu_updates/fwu.c
> +++ b/lib/fwu_updates/fwu.c
> @@ -630,6 +630,28 @@ u8 fwu_empty_capsule_checks_pass(void)
>  	return in_trial && boottime_check;
>  }
>  
> +/**
> + * fwu_trial_state_ctr_start() - Start the Trial State counter
> + *
> + * Start the counter to identify the platform booting in the
> + * Trial State. The counter is implemented as an EFI variable.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_trial_state_ctr_start(void)
> +{
> +	int ret;
> +	u16 trial_state_ctr;
> +
> +	trial_state_ctr = 0;
> +	ret = trial_counter_update(&trial_state_ctr);
> +	if (ret)
> +		log_err("Unable to initialise TrialStateCtr\n");
> +
> +	return ret;
> +}
> +
>  static int fwu_boottime_checks(void *ctx, struct event *event)
>  {
>  	int ret;
> -- 
> 2.34.1
> 

Heinrich pls shout if you think otherwise

Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

On Mon, Oct 31, 2022 at 07:59:42PM +0200, Ilias Apalodimas wrote:
> Hi Sughosh, 
> 
> Ideally this would be better of as a different FMP, but I understand we are
> missing some information (the capsule header) on the FMP level.
> 
> I think we can include it as is for now and have another look when we add
> support for more boards
> 
> On Fri, Oct 21, 2022 at 06:16:03PM +0530, Sughosh Ganu wrote:
> > The FWU Multi Bank Update feature supports updating firmware images
> > to one of multiple sets(also called banks) of images. The firmware
> > images are clubbed together in banks, with the system booting images
> > from the active bank. Information on the images such as which bank
> > they belong to is stored as part of the metadata structure, which is
> > stored on the same storage media as the firmware images on a dedicated
> > partition.
> > 
> > At the time of update, the metadata is read to identify the bank to
> > which the images need to be flashed(update bank). On a successful
> > update, the metadata is modified to set the updated bank as active
> > bank to subsequently boot from.
> > 
> > Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> > ---
> > Changes since V14:
> > * Initialise the return value to EFI_INVALID_PARAMETER in
> >   fwu_empty_capsule_process() and get rid of the else part as
> >   suggested by Ilias
> > * Remove the superfluous assignment of EFI_SUCCESS in
> >   fwu_post_update_process() as suggested by Ilias
> > * Add a check for fwu_empty_capsule_checks_pass() to allow application
> >   of empty capsules only in trial state
> > 
> >  drivers/Kconfig               |   2 +
> >  drivers/Makefile              |   1 +
> >  include/fwu.h                 |  30 +++++
> >  lib/Kconfig                   |   6 +
> >  lib/Makefile                  |   1 +
> >  lib/efi_loader/efi_capsule.c  | 210 +++++++++++++++++++++++++++++++++-
> >  lib/efi_loader/efi_firmware.c |  14 +++
> >  lib/fwu_updates/Kconfig       |  33 ++++++
> >  lib/fwu_updates/Makefile      |   7 ++
> >  lib/fwu_updates/fwu.c         |  22 ++++
> >  10 files changed, 324 insertions(+), 2 deletions(-)
> >  create mode 100644 lib/fwu_updates/Kconfig
> >  create mode 100644 lib/fwu_updates/Makefile
> > 
> > diff --git a/drivers/Kconfig b/drivers/Kconfig
> > index 8b6fead351..75ac149d31 100644
> > --- a/drivers/Kconfig
> > +++ b/drivers/Kconfig
> > @@ -44,6 +44,8 @@ source "drivers/fuzz/Kconfig"
> >  
> >  source "drivers/fpga/Kconfig"
> >  
> > +source "drivers/fwu-mdata/Kconfig"
> > +
> >  source "drivers/gpio/Kconfig"
> >  
> >  source "drivers/hwspinlock/Kconfig"
> > diff --git a/drivers/Makefile b/drivers/Makefile
> > index 9d9f69a3c9..253cbfb71d 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -85,6 +85,7 @@ obj-y += cache/
> >  obj-$(CONFIG_CPU) += cpu/
> >  obj-y += crypto/
> >  obj-$(CONFIG_FASTBOOT) += fastboot/
> > +obj-$(CONFIG_FWU_MDATA) += fwu-mdata/
> >  obj-y += misc/
> >  obj-$(CONFIG_MMC) += mmc/
> >  obj-$(CONFIG_NVME) += nvme/
> > diff --git a/include/fwu.h b/include/fwu.h
> > index a8ed67b0e0..0919ced812 100644
> > --- a/include/fwu.h
> > +++ b/include/fwu.h
> > @@ -98,6 +98,7 @@ struct fwu_mdata_ops {
> >  };
> >  
> >  #define FWU_MDATA_VERSION	0x1
> > +#define FWU_IMAGE_ACCEPTED	0x1
> >  
> >  /*
> >  * GUID value defined in the FWU specification for identification
> > @@ -107,6 +108,24 @@ struct fwu_mdata_ops {
> >  	EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
> >  		 0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
> >  
> > +/*
> > +* GUID value defined in the Dependable Boot specification for
> > +* identification of the revert capsule, used for reverting
> > +* any image in the updated bank.
> > +*/
> > +#define FWU_OS_REQUEST_FW_REVERT_GUID \
> > +	EFI_GUID(0xacd58b4b, 0xc0e8, 0x475f, 0x99, 0xb5, \
> > +		 0x6b, 0x3f, 0x7e, 0x07, 0xaa, 0xf0)
> > +
> > +/*
> > +* GUID value defined in the Dependable Boot specification for
> > +* identification of the accept capsule, used for accepting
> > +* an image in the updated bank.
> > +*/
> > +#define FWU_OS_REQUEST_FW_ACCEPT_GUID \
> > +	EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
> > +		 0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
> > +
> >  /**
> >   * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
> >   *
> > @@ -379,4 +398,15 @@ u8 fwu_update_checks_pass(void);
> >   */
> >  u8 fwu_empty_capsule_checks_pass(void);
> >  
> > +/**
> > + * fwu_trial_state_ctr_start() - Start the Trial State counter
> > + *
> > + * Start the counter to identify the platform booting in the
> > + * Trial State. The counter is implemented as an EFI variable.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_trial_state_ctr_start(void);
> > +
> >  #endif /* _FWU_H_ */
> > diff --git a/lib/Kconfig b/lib/Kconfig
> > index 6121c80dc8..6abe1d0a86 100644
> > --- a/lib/Kconfig
> > +++ b/lib/Kconfig
> > @@ -978,3 +978,9 @@ config LMB_RESERVED_REGIONS
> >  	  memory blocks.
> >  
> >  endmenu
> > +
> > +menu "FWU Multi Bank Updates"
> > +
> > +source lib/fwu_updates/Kconfig
> > +
> > +endmenu
> > diff --git a/lib/Makefile b/lib/Makefile
> > index e3deb15287..f2cfd1e428 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -9,6 +9,7 @@ obj-$(CONFIG_EFI) += efi/
> >  obj-$(CONFIG_EFI_LOADER) += efi_driver/
> >  obj-$(CONFIG_EFI_LOADER) += efi_loader/
> >  obj-$(CONFIG_CMD_BOOTEFI_SELFTEST) += efi_selftest/
> > +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu_updates/
> >  obj-$(CONFIG_LZMA) += lzma/
> >  obj-$(CONFIG_BZIP2) += bzip2/
> >  obj-$(CONFIG_FIT) += libfdt/
> > diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> > index 397e393a18..1163a2ee30 100644
> > --- a/lib/efi_loader/efi_capsule.c
> > +++ b/lib/efi_loader/efi_capsule.c
> > @@ -14,6 +14,7 @@
> >  #include <env.h>
> >  #include <fdtdec.h>
> >  #include <fs.h>
> > +#include <fwu.h>
> >  #include <hang.h>
> >  #include <malloc.h>
> >  #include <mapmem.h>
> > @@ -32,6 +33,12 @@ static const efi_guid_t efi_guid_firmware_management_capsule_id =
> >  		EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
> >  const efi_guid_t efi_guid_firmware_management_protocol =
> >  		EFI_FIRMWARE_MANAGEMENT_PROTOCOL_GUID;
> > +const efi_guid_t fwu_guid_os_request_fw_revert =
> > +		FWU_OS_REQUEST_FW_REVERT_GUID;
> > +const efi_guid_t fwu_guid_os_request_fw_accept =
> > +		FWU_OS_REQUEST_FW_ACCEPT_GUID;
> > +
> > +#define FW_ACCEPT_OS	(u32)0x8000
> >  
> >  #ifdef CONFIG_EFI_CAPSULE_ON_DISK
> >  /* for file system access */
> > @@ -386,6 +393,132 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
> >  }
> >  #endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
> >  
> > +static __maybe_unused bool fwu_empty_capsule(struct efi_capsule_header *capsule)
> > +{
> > +	return !guidcmp(&capsule->capsule_guid,
> > +			&fwu_guid_os_request_fw_revert) ||
> > +		!guidcmp(&capsule->capsule_guid,
> > +			 &fwu_guid_os_request_fw_accept);
> > +}
> > +
> > +static __maybe_unused efi_status_t fwu_to_efi_error(int err)
> > +{
> > +	efi_status_t ret;
> > +
> > +	switch(err) {
> > +	case 0:
> > +		ret = EFI_SUCCESS;
> > +		break;
> > +	case -ERANGE:
> > +	case -EIO:
> > +		ret = EFI_DEVICE_ERROR;
> > +		break;
> > +	case -EINVAL:
> > +		ret = EFI_INVALID_PARAMETER;
> > +		break;
> > +	case -ENODEV:
> > +		ret = EFI_NOT_FOUND;
> > +		break;
> > +	default:
> > +		ret = EFI_OUT_OF_RESOURCES;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static __maybe_unused efi_status_t fwu_empty_capsule_process(
> > +	struct efi_capsule_header *capsule)
> > +{
> > +	int status;
> > +	u32 active_idx;
> > +	efi_guid_t *image_guid;
> > +	efi_status_t ret = EFI_INVALID_PARAMETER;
> > +
> > +	if (!guidcmp(&capsule->capsule_guid,
> > +		     &fwu_guid_os_request_fw_revert)) {
> > +		/*
> > +		 * One of the previously updated image has
> > +		 * failed the OS acceptance test. OS has
> > +		 * requested to revert back to the earlier
> > +		 * boot index
> > +		 */
> > +		status = fwu_revert_boot_index();
> > +		ret = fwu_to_efi_error(status);
> > +		if (ret == EFI_SUCCESS)
> > +			log_debug("Reverted the FWU active_index. Recommend rebooting the system\n");
> > +		else
> > +			log_err("Failed to revert the FWU boot index\n");
> > +	} else if (!guidcmp(&capsule->capsule_guid,
> > +			    &fwu_guid_os_request_fw_accept)) {
> > +		/*
> > +		 * Image accepted by the OS. Set the acceptance
> > +		 * status for the image.
> > +		 */
> > +		image_guid = (void *)(char *)capsule +
> > +			capsule->header_size;
> > +
> > +		status = fwu_get_active_index(&active_idx);
> > +		ret = fwu_to_efi_error(status);
> > +		if (ret != EFI_SUCCESS) {
> > +			log_err("Unable to get the active_index from the FWU metadata\n");
> > +			return ret;
> > +		}
> > +
> > +		status = fwu_accept_image(image_guid, active_idx);
> > +		ret = fwu_to_efi_error(status);
> > +		if (ret != EFI_SUCCESS)
> > +			log_err("Unable to set the Accept bit for the image %pUs\n",
> > +				image_guid);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static __maybe_unused void fwu_post_update_checks(
> > +	struct efi_capsule_header *capsule,
> > +	bool *fw_accept_os, bool *capsule_update)
> > +{
> > +	if (fwu_empty_capsule(capsule))
> > +		*capsule_update = false;
> > +	else
> > +		if (!*fw_accept_os)
> > +			*fw_accept_os =
> > +				capsule->flags & FW_ACCEPT_OS ? true : false;
> > +}
> > +
> > +static __maybe_unused efi_status_t fwu_post_update_process(bool fw_accept_os)
> > +{
> > +	int status;
> > +	uint update_index;
> > +	efi_status_t ret;
> > +
> > +	status = fwu_plat_get_update_index(&update_index);
> > +	if (status < 0) {
> > +		log_err("Failed to get the FWU update_index value\n");
> > +		return EFI_DEVICE_ERROR;
> > +	}
> > +
> > +	/*
> > +	 * All the capsules have been updated successfully,
> > +	 * update the FWU metadata.
> > +	 */
> > +	log_debug("Update Complete. Now updating active_index to %u\n",
> > +		  update_index);
> > +	status = fwu_set_active_index(update_index);
> > +	ret = fwu_to_efi_error(status);
> > +	if (ret != EFI_SUCCESS) {
> > +		log_err("Failed to update FWU metadata index values\n");
> > +	} else {
> > +		log_debug("Successfully updated the active_index\n");
> > +		if (fw_accept_os) {
> > +			status = fwu_trial_state_ctr_start();
> > +			if (status < 0)
> > +				ret = EFI_DEVICE_ERROR;
> > +		}
> > +	}
> > +
> > +	return ret;
> > +}
> >  
> >  /**
> >   * efi_capsule_update_firmware - update firmware from capsule
> > @@ -408,7 +541,32 @@ static efi_status_t efi_capsule_update_firmware(
> >  	int item;
> >  	struct efi_firmware_management_protocol *fmp;
> >  	u16 *abort_reason;
> > +	efi_guid_t *image_type_id;
> >  	efi_status_t ret = EFI_SUCCESS;
> > +	int status;
> > +	uint update_index;
> > +	bool fw_accept_os;
> > +
> > +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > +		if (fwu_empty_capsule_checks_pass() &&
> > +		    fwu_empty_capsule(capsule_data))
> > +			return fwu_empty_capsule_process(capsule_data);
> > +
> > +		if (!fwu_update_checks_pass()) {
> > +			log_err("FWU checks failed. Cannot start update\n");
> > +			return EFI_INVALID_PARAMETER;
> > +		}
> > +
> > +
> > +		/* Obtain the update_index from the platform */
> > +		status = fwu_plat_get_update_index(&update_index);
> > +		if (status < 0) {
> > +			log_err("Failed to get the FWU update_index value\n");
> > +			return EFI_DEVICE_ERROR;
> > +		}
> > +
> > +		fw_accept_os = capsule_data->flags & FW_ACCEPT_OS ? 0x1 : 0x0;
> > +	}
> >  
> >  	/* sanity check */
> >  	if (capsule_data->header_size < sizeof(*capsule) ||
> > @@ -495,6 +653,34 @@ static efi_status_t efi_capsule_update_firmware(
> >  			efi_free_pool(abort_reason);
> >  			goto out;
> >  		}
> > +
> > +		if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > +			image_type_id = &image->update_image_type_id;
> > +			if (!fw_accept_os) {
> > +				/*
> > +				 * The OS will not be accepting the firmware
> > +				 * images. Set the accept bit of all the
> > +				 * images contained in this capsule.
> > +				 */
> > +				status = fwu_accept_image(image_type_id,
> > +							  update_index);
> > +			} else {
> > +				status = fwu_clear_accept_image(image_type_id,
> > +								update_index);
> > +			}
> > +			ret = fwu_to_efi_error(status);
> > +			if (ret != EFI_SUCCESS) {
> > +				log_err("Unable to %s the accept bit for the image %pUs\n",
> > +					fw_accept_os ? "clear" : "set",
> > +					image_type_id);
> > +				goto out;
> > +			}
> > +
> > +			log_debug("%s the accepted bit for Image %pUs\n",
> > +				  fw_accept_os ? "Cleared" : "Set",
> > +				  image_type_id);
> > +		}
> > +
> >  	}
> >  
> >  out:
> > @@ -1103,6 +1289,9 @@ efi_status_t efi_launch_capsules(void)
> >  	u16 **files;
> >  	unsigned int nfiles, index, i;
> >  	efi_status_t ret;
> > +	bool capsule_update = true;
> > +	bool update_status = true;
> > +	bool fw_accept_os = false;
> >  
> >  	if (check_run_capsules() != EFI_SUCCESS)
> >  		return EFI_SUCCESS;
> > @@ -1130,12 +1319,19 @@ efi_status_t efi_launch_capsules(void)
> >  		ret = efi_capsule_read_file(files[i], &capsule);
> >  		if (ret == EFI_SUCCESS) {
> >  			ret = efi_capsule_update_firmware(capsule);
> > -			if (ret != EFI_SUCCESS)
> > +			if (ret != EFI_SUCCESS) {
> >  				log_err("Applying capsule %ls failed.\n",
> >  					files[i]);
> > -			else
> > +				update_status = false;
> > +			} else {
> >  				log_info("Applying capsule %ls succeeded.\n",
> >  					 files[i]);
> > +				if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > +					fwu_post_update_checks(capsule,
> > +							       &fw_accept_os,
> > +							       &capsule_update);
> > +				}
> > +			}
> >  
> >  			/* create CapsuleXXXX */
> >  			set_capsule_result(index, capsule, ret);
> > @@ -1143,6 +1339,7 @@ efi_status_t efi_launch_capsules(void)
> >  			free(capsule);
> >  		} else {
> >  			log_err("Reading capsule %ls failed\n", files[i]);
> > +			update_status = false;
> >  		}
> >  		/* delete a capsule either in case of success or failure */
> >  		ret = efi_capsule_delete_file(files[i]);
> > @@ -1150,8 +1347,17 @@ efi_status_t efi_launch_capsules(void)
> >  			log_err("Deleting capsule %ls failed\n",
> >  				files[i]);
> >  	}
> > +
> >  	efi_capsule_scan_done();
> >  
> > +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > +		if (capsule_update == true && update_status == true) {
> > +			ret = fwu_post_update_process(fw_accept_os);
> > +		} else if (capsule_update == true && update_status == false) {
> > +			log_err("All capsules were not updated. Not updating FWU metadata\n");
> > +		}
> > +	}
> > +
> >  	for (i = 0; i < nfiles; i++)
> >  		free(files[i]);
> >  	free(files);
> > diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> > index 30cafd15ca..93e2b01c07 100644
> > --- a/lib/efi_loader/efi_firmware.c
> > +++ b/lib/efi_loader/efi_firmware.c
> > @@ -10,6 +10,7 @@
> >  #include <charset.h>
> >  #include <dfu.h>
> >  #include <efi_loader.h>
> > +#include <fwu.h>
> >  #include <image.h>
> >  #include <signatures.h>
> >  
> > @@ -389,6 +390,7 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> >  	efi_status_t (*progress)(efi_uintn_t completion),
> >  	u16 **abort_reason)
> >  {
> > +	int ret;
> >  	efi_status_t status;
> >  
> >  	EFI_ENTRY("%p %d %p %zu %p %p %p\n", this, image_index, image,
> > @@ -401,6 +403,18 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> >  	if (status != EFI_SUCCESS)
> >  		return EFI_EXIT(status);
> >  
> > +	if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > +		/*
> > +		 * Based on the value of update bank, derive the
> > +		 * image index value.
> > +		 */
> > +		ret = fwu_get_image_index(&image_index);
> > +		if (ret) {
> > +			log_debug("Unable to get FWU image_index\n");
> > +			return EFI_EXIT(EFI_DEVICE_ERROR);
> > +		}
> > +	}
> > +
> >  	if (dfu_write_by_alt(image_index - 1, (void *)image, image_size,
> >  			     NULL, NULL))
> >  		return EFI_EXIT(EFI_DEVICE_ERROR);
> > diff --git a/lib/fwu_updates/Kconfig b/lib/fwu_updates/Kconfig
> > new file mode 100644
> > index 0000000000..78759e6618
> > --- /dev/null
> > +++ b/lib/fwu_updates/Kconfig
> > @@ -0,0 +1,33 @@
> > +config FWU_MULTI_BANK_UPDATE
> > +	bool "Enable FWU Multi Bank Update Feature"
> > +	depends on EFI_CAPSULE_ON_DISK
> > +	select PARTITION_TYPE_GUID
> > +	select EFI_SETUP_EARLY
> > +	imply EFI_CAPSULE_ON_DISK_EARLY
> > +	select EVENT
> > +	help
> > +	  Feature for updating firmware images on platforms having
> > +	  multiple banks(copies) of the firmware images. One of the
> > +	  bank is selected for updating all the firmware components
> > +
> > +config FWU_NUM_BANKS
> > +	int "Number of Banks defined by the platform"
> > +	depends on FWU_MULTI_BANK_UPDATE
> > +	help
> > +	  Define the number of banks of firmware images on a platform
> > +
> > +config FWU_NUM_IMAGES_PER_BANK
> > +	int "Number of firmware images per bank"
> > +	depends on FWU_MULTI_BANK_UPDATE
> > +	help
> > +	  Define the number of firmware images per bank. This value
> > +	  should be the same for all the banks.
> > +
> > +config FWU_TRIAL_STATE_CNT
> > +	int "Number of times system boots in Trial State"
> > +	depends on FWU_MULTI_BANK_UPDATE
> > +	default 3
> > +	help
> > +	  With FWU Multi Bank Update feature enabled, number of times
> > +	  the platform is allowed to boot in Trial State after an
> > +	  update.
> > diff --git a/lib/fwu_updates/Makefile b/lib/fwu_updates/Makefile
> > new file mode 100644
> > index 0000000000..1993088e5b
> > --- /dev/null
> > +++ b/lib/fwu_updates/Makefile
> > @@ -0,0 +1,7 @@
> > +# SPDX-License-Identifier: GPL-2.0-or-later
> > +#
> > +# Copyright (c) 2022, Linaro Limited
> > +#
> > +
> > +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu.o
> > +obj-$(CONFIG_FWU_MDATA_GPT_BLK) += fwu_gpt.o
> > diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> > index c9a9022a59..6e159c050c 100644
> > --- a/lib/fwu_updates/fwu.c
> > +++ b/lib/fwu_updates/fwu.c
> > @@ -630,6 +630,28 @@ u8 fwu_empty_capsule_checks_pass(void)
> >  	return in_trial && boottime_check;
> >  }
> >  
> > +/**
> > + * fwu_trial_state_ctr_start() - Start the Trial State counter
> > + *
> > + * Start the counter to identify the platform booting in the
> > + * Trial State. The counter is implemented as an EFI variable.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_trial_state_ctr_start(void)
> > +{
> > +	int ret;
> > +	u16 trial_state_ctr;
> > +
> > +	trial_state_ctr = 0;
> > +	ret = trial_counter_update(&trial_state_ctr);
> > +	if (ret)
> > +		log_err("Unable to initialise TrialStateCtr\n");
> > +
> > +	return ret;
> > +}
> > +
> >  static int fwu_boottime_checks(void *ctx, struct event *event)
> >  {
> >  	int ret;
> > -- 
> > 2.34.1
> > 
> 
> Heinrich pls shout if you think otherwise
> 
> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

I wanted to pick this up yesterday, but I'm going to pick this up today
as I don't think there's fundamental disagreement here but just a bit
more cleanup / refactoring to do, which can happen after merging.

Hi Tom,

On Tue, 1 Nov 2022 at 07:31, Tom Rini <trini@konsulko.com> wrote:
>
> On Mon, Oct 31, 2022 at 07:59:42PM +0200, Ilias Apalodimas wrote:
> > Hi Sughosh,
> >
> > Ideally this would be better of as a different FMP, but I understand we are
> > missing some information (the capsule header) on the FMP level.
> >
> > I think we can include it as is for now and have another look when we add
> > support for more boards
> >
> > On Fri, Oct 21, 2022 at 06:16:03PM +0530, Sughosh Ganu wrote:
> > > The FWU Multi Bank Update feature supports updating firmware images
> > > to one of multiple sets(also called banks) of images. The firmware
> > > images are clubbed together in banks, with the system booting images
> > > from the active bank. Information on the images such as which bank
> > > they belong to is stored as part of the metadata structure, which is
> > > stored on the same storage media as the firmware images on a dedicated
> > > partition.
> > >
> > > At the time of update, the metadata is read to identify the bank to
> > > which the images need to be flashed(update bank). On a successful
> > > update, the metadata is modified to set the updated bank as active
> > > bank to subsequently boot from.
> > >
> > > Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> > > ---
> > > Changes since V14:
> > > * Initialise the return value to EFI_INVALID_PARAMETER in
> > >   fwu_empty_capsule_process() and get rid of the else part as
> > >   suggested by Ilias
> > > * Remove the superfluous assignment of EFI_SUCCESS in
> > >   fwu_post_update_process() as suggested by Ilias
> > > * Add a check for fwu_empty_capsule_checks_pass() to allow application
> > >   of empty capsules only in trial state
> > >
> > >  drivers/Kconfig               |   2 +
> > >  drivers/Makefile              |   1 +
> > >  include/fwu.h                 |  30 +++++
> > >  lib/Kconfig                   |   6 +
> > >  lib/Makefile                  |   1 +
> > >  lib/efi_loader/efi_capsule.c  | 210 +++++++++++++++++++++++++++++++++-
> > >  lib/efi_loader/efi_firmware.c |  14 +++
> > >  lib/fwu_updates/Kconfig       |  33 ++++++
> > >  lib/fwu_updates/Makefile      |   7 ++
> > >  lib/fwu_updates/fwu.c         |  22 ++++
> > >  10 files changed, 324 insertions(+), 2 deletions(-)
> > >  create mode 100644 lib/fwu_updates/Kconfig
> > >  create mode 100644 lib/fwu_updates/Makefile
> > >
> > > diff --git a/drivers/Kconfig b/drivers/Kconfig
> > > index 8b6fead351..75ac149d31 100644
> > > --- a/drivers/Kconfig
> > > +++ b/drivers/Kconfig
> > > @@ -44,6 +44,8 @@ source "drivers/fuzz/Kconfig"
> > >
> > >  source "drivers/fpga/Kconfig"
> > >
> > > +source "drivers/fwu-mdata/Kconfig"
> > > +
> > >  source "drivers/gpio/Kconfig"
> > >
> > >  source "drivers/hwspinlock/Kconfig"
> > > diff --git a/drivers/Makefile b/drivers/Makefile
> > > index 9d9f69a3c9..253cbfb71d 100644
> > > --- a/drivers/Makefile
> > > +++ b/drivers/Makefile
> > > @@ -85,6 +85,7 @@ obj-y += cache/
> > >  obj-$(CONFIG_CPU) += cpu/
> > >  obj-y += crypto/
> > >  obj-$(CONFIG_FASTBOOT) += fastboot/
> > > +obj-$(CONFIG_FWU_MDATA) += fwu-mdata/
> > >  obj-y += misc/
> > >  obj-$(CONFIG_MMC) += mmc/
> > >  obj-$(CONFIG_NVME) += nvme/
> > > diff --git a/include/fwu.h b/include/fwu.h
> > > index a8ed67b0e0..0919ced812 100644
> > > --- a/include/fwu.h
> > > +++ b/include/fwu.h
> > > @@ -98,6 +98,7 @@ struct fwu_mdata_ops {
> > >  };
> > >
> > >  #define FWU_MDATA_VERSION  0x1
> > > +#define FWU_IMAGE_ACCEPTED 0x1
> > >
> > >  /*
> > >  * GUID value defined in the FWU specification for identification
> > > @@ -107,6 +108,24 @@ struct fwu_mdata_ops {
> > >     EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
> > >              0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
> > >
> > > +/*
> > > +* GUID value defined in the Dependable Boot specification for
> > > +* identification of the revert capsule, used for reverting
> > > +* any image in the updated bank.
> > > +*/
> > > +#define FWU_OS_REQUEST_FW_REVERT_GUID \
> > > +   EFI_GUID(0xacd58b4b, 0xc0e8, 0x475f, 0x99, 0xb5, \
> > > +            0x6b, 0x3f, 0x7e, 0x07, 0xaa, 0xf0)
> > > +
> > > +/*
> > > +* GUID value defined in the Dependable Boot specification for
> > > +* identification of the accept capsule, used for accepting
> > > +* an image in the updated bank.
> > > +*/
> > > +#define FWU_OS_REQUEST_FW_ACCEPT_GUID \
> > > +   EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
> > > +            0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
> > > +
> > >  /**
> > >   * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
> > >   *
> > > @@ -379,4 +398,15 @@ u8 fwu_update_checks_pass(void);
> > >   */
> > >  u8 fwu_empty_capsule_checks_pass(void);
> > >
> > > +/**
> > > + * fwu_trial_state_ctr_start() - Start the Trial State counter
> > > + *
> > > + * Start the counter to identify the platform booting in the
> > > + * Trial State. The counter is implemented as an EFI variable.
> > > + *
> > > + * Return: 0 if OK, -ve on error
> > > + *
> > > + */
> > > +int fwu_trial_state_ctr_start(void);
> > > +
> > >  #endif /* _FWU_H_ */
> > > diff --git a/lib/Kconfig b/lib/Kconfig
> > > index 6121c80dc8..6abe1d0a86 100644
> > > --- a/lib/Kconfig
> > > +++ b/lib/Kconfig
> > > @@ -978,3 +978,9 @@ config LMB_RESERVED_REGIONS
> > >       memory blocks.
> > >
> > >  endmenu
> > > +
> > > +menu "FWU Multi Bank Updates"
> > > +
> > > +source lib/fwu_updates/Kconfig
> > > +
> > > +endmenu
> > > diff --git a/lib/Makefile b/lib/Makefile
> > > index e3deb15287..f2cfd1e428 100644
> > > --- a/lib/Makefile
> > > +++ b/lib/Makefile
> > > @@ -9,6 +9,7 @@ obj-$(CONFIG_EFI) += efi/
> > >  obj-$(CONFIG_EFI_LOADER) += efi_driver/
> > >  obj-$(CONFIG_EFI_LOADER) += efi_loader/
> > >  obj-$(CONFIG_CMD_BOOTEFI_SELFTEST) += efi_selftest/
> > > +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu_updates/
> > >  obj-$(CONFIG_LZMA) += lzma/
> > >  obj-$(CONFIG_BZIP2) += bzip2/
> > >  obj-$(CONFIG_FIT) += libfdt/
> > > diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> > > index 397e393a18..1163a2ee30 100644
> > > --- a/lib/efi_loader/efi_capsule.c
> > > +++ b/lib/efi_loader/efi_capsule.c
> > > @@ -14,6 +14,7 @@
> > >  #include <env.h>
> > >  #include <fdtdec.h>
> > >  #include <fs.h>
> > > +#include <fwu.h>
> > >  #include <hang.h>
> > >  #include <malloc.h>
> > >  #include <mapmem.h>
> > > @@ -32,6 +33,12 @@ static const efi_guid_t efi_guid_firmware_management_capsule_id =
> > >             EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
> > >  const efi_guid_t efi_guid_firmware_management_protocol =
> > >             EFI_FIRMWARE_MANAGEMENT_PROTOCOL_GUID;
> > > +const efi_guid_t fwu_guid_os_request_fw_revert =
> > > +           FWU_OS_REQUEST_FW_REVERT_GUID;
> > > +const efi_guid_t fwu_guid_os_request_fw_accept =
> > > +           FWU_OS_REQUEST_FW_ACCEPT_GUID;
> > > +
> > > +#define FW_ACCEPT_OS       (u32)0x8000
> > >
> > >  #ifdef CONFIG_EFI_CAPSULE_ON_DISK
> > >  /* for file system access */
> > > @@ -386,6 +393,132 @@ efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_s
> > >  }
> > >  #endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
> > >
> > > +static __maybe_unused bool fwu_empty_capsule(struct efi_capsule_header *capsule)
> > > +{
> > > +   return !guidcmp(&capsule->capsule_guid,
> > > +                   &fwu_guid_os_request_fw_revert) ||
> > > +           !guidcmp(&capsule->capsule_guid,
> > > +                    &fwu_guid_os_request_fw_accept);
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_to_efi_error(int err)
> > > +{
> > > +   efi_status_t ret;
> > > +
> > > +   switch(err) {
> > > +   case 0:
> > > +           ret = EFI_SUCCESS;
> > > +           break;
> > > +   case -ERANGE:
> > > +   case -EIO:
> > > +           ret = EFI_DEVICE_ERROR;
> > > +           break;
> > > +   case -EINVAL:
> > > +           ret = EFI_INVALID_PARAMETER;
> > > +           break;
> > > +   case -ENODEV:
> > > +           ret = EFI_NOT_FOUND;
> > > +           break;
> > > +   default:
> > > +           ret = EFI_OUT_OF_RESOURCES;
> > > +   }
> > > +
> > > +   return ret;
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_empty_capsule_process(
> > > +   struct efi_capsule_header *capsule)
> > > +{
> > > +   int status;
> > > +   u32 active_idx;
> > > +   efi_guid_t *image_guid;
> > > +   efi_status_t ret = EFI_INVALID_PARAMETER;
> > > +
> > > +   if (!guidcmp(&capsule->capsule_guid,
> > > +                &fwu_guid_os_request_fw_revert)) {
> > > +           /*
> > > +            * One of the previously updated image has
> > > +            * failed the OS acceptance test. OS has
> > > +            * requested to revert back to the earlier
> > > +            * boot index
> > > +            */
> > > +           status = fwu_revert_boot_index();
> > > +           ret = fwu_to_efi_error(status);
> > > +           if (ret == EFI_SUCCESS)
> > > +                   log_debug("Reverted the FWU active_index. Recommend rebooting the system\n");
> > > +           else
> > > +                   log_err("Failed to revert the FWU boot index\n");
> > > +   } else if (!guidcmp(&capsule->capsule_guid,
> > > +                       &fwu_guid_os_request_fw_accept)) {
> > > +           /*
> > > +            * Image accepted by the OS. Set the acceptance
> > > +            * status for the image.
> > > +            */
> > > +           image_guid = (void *)(char *)capsule +
> > > +                   capsule->header_size;
> > > +
> > > +           status = fwu_get_active_index(&active_idx);
> > > +           ret = fwu_to_efi_error(status);
> > > +           if (ret != EFI_SUCCESS) {
> > > +                   log_err("Unable to get the active_index from the FWU metadata\n");
> > > +                   return ret;
> > > +           }
> > > +
> > > +           status = fwu_accept_image(image_guid, active_idx);
> > > +           ret = fwu_to_efi_error(status);
> > > +           if (ret != EFI_SUCCESS)
> > > +                   log_err("Unable to set the Accept bit for the image %pUs\n",
> > > +                           image_guid);
> > > +   }
> > > +
> > > +   return ret;
> > > +}
> > > +
> > > +static __maybe_unused void fwu_post_update_checks(
> > > +   struct efi_capsule_header *capsule,
> > > +   bool *fw_accept_os, bool *capsule_update)
> > > +{
> > > +   if (fwu_empty_capsule(capsule))
> > > +           *capsule_update = false;
> > > +   else
> > > +           if (!*fw_accept_os)
> > > +                   *fw_accept_os =
> > > +                           capsule->flags & FW_ACCEPT_OS ? true : false;
> > > +}
> > > +
> > > +static __maybe_unused efi_status_t fwu_post_update_process(bool fw_accept_os)
> > > +{
> > > +   int status;
> > > +   uint update_index;
> > > +   efi_status_t ret;
> > > +
> > > +   status = fwu_plat_get_update_index(&update_index);
> > > +   if (status < 0) {
> > > +           log_err("Failed to get the FWU update_index value\n");
> > > +           return EFI_DEVICE_ERROR;
> > > +   }
> > > +
> > > +   /*
> > > +    * All the capsules have been updated successfully,
> > > +    * update the FWU metadata.
> > > +    */
> > > +   log_debug("Update Complete. Now updating active_index to %u\n",
> > > +             update_index);
> > > +   status = fwu_set_active_index(update_index);
> > > +   ret = fwu_to_efi_error(status);
> > > +   if (ret != EFI_SUCCESS) {
> > > +           log_err("Failed to update FWU metadata index values\n");
> > > +   } else {
> > > +           log_debug("Successfully updated the active_index\n");
> > > +           if (fw_accept_os) {
> > > +                   status = fwu_trial_state_ctr_start();
> > > +                   if (status < 0)
> > > +                           ret = EFI_DEVICE_ERROR;
> > > +           }
> > > +   }
> > > +
> > > +   return ret;
> > > +}
> > >
> > >  /**
> > >   * efi_capsule_update_firmware - update firmware from capsule
> > > @@ -408,7 +541,32 @@ static efi_status_t efi_capsule_update_firmware(
> > >     int item;
> > >     struct efi_firmware_management_protocol *fmp;
> > >     u16 *abort_reason;
> > > +   efi_guid_t *image_type_id;
> > >     efi_status_t ret = EFI_SUCCESS;
> > > +   int status;
> > > +   uint update_index;
> > > +   bool fw_accept_os;
> > > +
> > > +   if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > > +           if (fwu_empty_capsule_checks_pass() &&
> > > +               fwu_empty_capsule(capsule_data))
> > > +                   return fwu_empty_capsule_process(capsule_data);
> > > +
> > > +           if (!fwu_update_checks_pass()) {
> > > +                   log_err("FWU checks failed. Cannot start update\n");
> > > +                   return EFI_INVALID_PARAMETER;
> > > +           }
> > > +
> > > +
> > > +           /* Obtain the update_index from the platform */
> > > +           status = fwu_plat_get_update_index(&update_index);
> > > +           if (status < 0) {
> > > +                   log_err("Failed to get the FWU update_index value\n");
> > > +                   return EFI_DEVICE_ERROR;
> > > +           }
> > > +
> > > +           fw_accept_os = capsule_data->flags & FW_ACCEPT_OS ? 0x1 : 0x0;
> > > +   }
> > >
> > >     /* sanity check */
> > >     if (capsule_data->header_size < sizeof(*capsule) ||
> > > @@ -495,6 +653,34 @@ static efi_status_t efi_capsule_update_firmware(
> > >                     efi_free_pool(abort_reason);
> > >                     goto out;
> > >             }
> > > +
> > > +           if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > > +                   image_type_id = &image->update_image_type_id;
> > > +                   if (!fw_accept_os) {
> > > +                           /*
> > > +                            * The OS will not be accepting the firmware
> > > +                            * images. Set the accept bit of all the
> > > +                            * images contained in this capsule.
> > > +                            */
> > > +                           status = fwu_accept_image(image_type_id,
> > > +                                                     update_index);
> > > +                   } else {
> > > +                           status = fwu_clear_accept_image(image_type_id,
> > > +                                                           update_index);
> > > +                   }
> > > +                   ret = fwu_to_efi_error(status);
> > > +                   if (ret != EFI_SUCCESS) {
> > > +                           log_err("Unable to %s the accept bit for the image %pUs\n",
> > > +                                   fw_accept_os ? "clear" : "set",
> > > +                                   image_type_id);
> > > +                           goto out;
> > > +                   }
> > > +
> > > +                   log_debug("%s the accepted bit for Image %pUs\n",
> > > +                             fw_accept_os ? "Cleared" : "Set",
> > > +                             image_type_id);
> > > +           }
> > > +
> > >     }
> > >
> > >  out:
> > > @@ -1103,6 +1289,9 @@ efi_status_t efi_launch_capsules(void)
> > >     u16 **files;
> > >     unsigned int nfiles, index, i;
> > >     efi_status_t ret;
> > > +   bool capsule_update = true;
> > > +   bool update_status = true;
> > > +   bool fw_accept_os = false;
> > >
> > >     if (check_run_capsules() != EFI_SUCCESS)
> > >             return EFI_SUCCESS;
> > > @@ -1130,12 +1319,19 @@ efi_status_t efi_launch_capsules(void)
> > >             ret = efi_capsule_read_file(files[i], &capsule);
> > >             if (ret == EFI_SUCCESS) {
> > >                     ret = efi_capsule_update_firmware(capsule);
> > > -                   if (ret != EFI_SUCCESS)
> > > +                   if (ret != EFI_SUCCESS) {
> > >                             log_err("Applying capsule %ls failed.\n",
> > >                                     files[i]);
> > > -                   else
> > > +                           update_status = false;
> > > +                   } else {
> > >                             log_info("Applying capsule %ls succeeded.\n",
> > >                                      files[i]);
> > > +                           if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > > +                                   fwu_post_update_checks(capsule,
> > > +                                                          &fw_accept_os,
> > > +                                                          &capsule_update);
> > > +                           }
> > > +                   }
> > >
> > >                     /* create CapsuleXXXX */
> > >                     set_capsule_result(index, capsule, ret);
> > > @@ -1143,6 +1339,7 @@ efi_status_t efi_launch_capsules(void)
> > >                     free(capsule);
> > >             } else {
> > >                     log_err("Reading capsule %ls failed\n", files[i]);
> > > +                   update_status = false;
> > >             }
> > >             /* delete a capsule either in case of success or failure */
> > >             ret = efi_capsule_delete_file(files[i]);
> > > @@ -1150,8 +1347,17 @@ efi_status_t efi_launch_capsules(void)
> > >                     log_err("Deleting capsule %ls failed\n",
> > >                             files[i]);
> > >     }
> > > +
> > >     efi_capsule_scan_done();
> > >
> > > +   if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > > +           if (capsule_update == true && update_status == true) {
> > > +                   ret = fwu_post_update_process(fw_accept_os);
> > > +           } else if (capsule_update == true && update_status == false) {
> > > +                   log_err("All capsules were not updated. Not updating FWU metadata\n");
> > > +           }
> > > +   }
> > > +
> > >     for (i = 0; i < nfiles; i++)
> > >             free(files[i]);
> > >     free(files);
> > > diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> > > index 30cafd15ca..93e2b01c07 100644
> > > --- a/lib/efi_loader/efi_firmware.c
> > > +++ b/lib/efi_loader/efi_firmware.c
> > > @@ -10,6 +10,7 @@
> > >  #include <charset.h>
> > >  #include <dfu.h>
> > >  #include <efi_loader.h>
> > > +#include <fwu.h>
> > >  #include <image.h>
> > >  #include <signatures.h>
> > >
> > > @@ -389,6 +390,7 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> > >     efi_status_t (*progress)(efi_uintn_t completion),
> > >     u16 **abort_reason)
> > >  {
> > > +   int ret;
> > >     efi_status_t status;
> > >
> > >     EFI_ENTRY("%p %d %p %zu %p %p %p\n", this, image_index, image,
> > > @@ -401,6 +403,18 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> > >     if (status != EFI_SUCCESS)
> > >             return EFI_EXIT(status);
> > >
> > > +   if (IS_ENABLED(CONFIG_FWU_MULTI_BANK_UPDATE)) {
> > > +           /*
> > > +            * Based on the value of update bank, derive the
> > > +            * image index value.
> > > +            */
> > > +           ret = fwu_get_image_index(&image_index);
> > > +           if (ret) {
> > > +                   log_debug("Unable to get FWU image_index\n");
> > > +                   return EFI_EXIT(EFI_DEVICE_ERROR);
> > > +           }
> > > +   }
> > > +
> > >     if (dfu_write_by_alt(image_index - 1, (void *)image, image_size,
> > >                          NULL, NULL))
> > >             return EFI_EXIT(EFI_DEVICE_ERROR);
> > > diff --git a/lib/fwu_updates/Kconfig b/lib/fwu_updates/Kconfig
> > > new file mode 100644
> > > index 0000000000..78759e6618
> > > --- /dev/null
> > > +++ b/lib/fwu_updates/Kconfig
> > > @@ -0,0 +1,33 @@
> > > +config FWU_MULTI_BANK_UPDATE
> > > +   bool "Enable FWU Multi Bank Update Feature"
> > > +   depends on EFI_CAPSULE_ON_DISK
> > > +   select PARTITION_TYPE_GUID
> > > +   select EFI_SETUP_EARLY
> > > +   imply EFI_CAPSULE_ON_DISK_EARLY
> > > +   select EVENT
> > > +   help
> > > +     Feature for updating firmware images on platforms having
> > > +     multiple banks(copies) of the firmware images. One of the
> > > +     bank is selected for updating all the firmware components
> > > +
> > > +config FWU_NUM_BANKS
> > > +   int "Number of Banks defined by the platform"
> > > +   depends on FWU_MULTI_BANK_UPDATE
> > > +   help
> > > +     Define the number of banks of firmware images on a platform
> > > +
> > > +config FWU_NUM_IMAGES_PER_BANK
> > > +   int "Number of firmware images per bank"
> > > +   depends on FWU_MULTI_BANK_UPDATE
> > > +   help
> > > +     Define the number of firmware images per bank. This value
> > > +     should be the same for all the banks.
> > > +
> > > +config FWU_TRIAL_STATE_CNT
> > > +   int "Number of times system boots in Trial State"
> > > +   depends on FWU_MULTI_BANK_UPDATE
> > > +   default 3
> > > +   help
> > > +     With FWU Multi Bank Update feature enabled, number of times
> > > +     the platform is allowed to boot in Trial State after an
> > > +     update.
> > > diff --git a/lib/fwu_updates/Makefile b/lib/fwu_updates/Makefile
> > > new file mode 100644
> > > index 0000000000..1993088e5b
> > > --- /dev/null
> > > +++ b/lib/fwu_updates/Makefile
> > > @@ -0,0 +1,7 @@
> > > +# SPDX-License-Identifier: GPL-2.0-or-later
> > > +#
> > > +# Copyright (c) 2022, Linaro Limited
> > > +#
> > > +
> > > +obj-$(CONFIG_FWU_MULTI_BANK_UPDATE) += fwu.o
> > > +obj-$(CONFIG_FWU_MDATA_GPT_BLK) += fwu_gpt.o
> > > diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> > > index c9a9022a59..6e159c050c 100644
> > > --- a/lib/fwu_updates/fwu.c
> > > +++ b/lib/fwu_updates/fwu.c
> > > @@ -630,6 +630,28 @@ u8 fwu_empty_capsule_checks_pass(void)
> > >     return in_trial && boottime_check;
> > >  }
> > >
> > > +/**
> > > + * fwu_trial_state_ctr_start() - Start the Trial State counter
> > > + *
> > > + * Start the counter to identify the platform booting in the
> > > + * Trial State. The counter is implemented as an EFI variable.
> > > + *
> > > + * Return: 0 if OK, -ve on error
> > > + *
> > > + */
> > > +int fwu_trial_state_ctr_start(void)
> > > +{
> > > +   int ret;
> > > +   u16 trial_state_ctr;
> > > +
> > > +   trial_state_ctr = 0;
> > > +   ret = trial_counter_update(&trial_state_ctr);
> > > +   if (ret)
> > > +           log_err("Unable to initialise TrialStateCtr\n");
> > > +
> > > +   return ret;
> > > +}
> > > +
> > >  static int fwu_boottime_checks(void *ctx, struct event *event)
> > >  {
> > >     int ret;
> > > --
> > > 2.34.1
> > >
> >
> > Heinrich pls shout if you think otherwise
> >
> > Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
>
> I wanted to pick this up yesterday, but I'm going to pick this up today
> as I don't think there's fundamental disagreement here but just a bit
> more cleanup / refactoring to do, which can happen after merging.

Sounds right. From my side, the biggest priority is for Sughosh to do
a unit test as discussed a few times on this series.

Regards,
Simon


>
> --
> Tom