Re: [PATCH v10 03/15] FWU: Add FWU metadata access driver for GPT partitioned block devices

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

Hi Sughosh

On Thu, Sep 15, 2022 at 01:44:39PM +0530, Sughosh Ganu wrote:
> In the FWU Multi Bank Update feature, the information about the
> updatable images is stored as part of the metadata, on a separate
> partition. Add a driver for reading from and writing to the metadata
> when the updatable images and the metadata are stored on a block
> device which is formatted with GPT based partition scheme.
> 
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
> Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
> ---
> Changes since V9:
> * s/formated/formatted in the commit message
> * Add a '\n' character in the log message
> 
>  drivers/fwu-mdata/Kconfig   |  16 ++
>  drivers/fwu-mdata/Makefile  |   8 +
>  drivers/fwu-mdata/gpt_blk.c | 378 ++++++++++++++++++++++++++++++++++++
>  include/fwu.h               |   4 +
>  4 files changed, 406 insertions(+)
>  create mode 100644 drivers/fwu-mdata/Kconfig
>  create mode 100644 drivers/fwu-mdata/Makefile
>  create mode 100644 drivers/fwu-mdata/gpt_blk.c
> 
> diff --git a/drivers/fwu-mdata/Kconfig b/drivers/fwu-mdata/Kconfig
> new file mode 100644
> index 0000000000..7322da48b1
> --- /dev/null
> +++ b/drivers/fwu-mdata/Kconfig
> @@ -0,0 +1,16 @@
> +config FWU_MDATA
> +	bool "Driver support for accessing FWU Metadata"
> +	depends on DM
> +	help
> +	  Enable support for accessing FWU Metadata partitions. The
> +	  FWU Metadata partitions reside on the same storage device
> +	  which contains the other FWU updatable firmware images.
> +
> +config FWU_MDATA_GPT_BLK
> +	bool "FWU Metadata access for GPT partitioned Block devices"
> +	select PARTITION_TYPE_GUID
> +	select PARTITION_UUIDS
> +	depends on DM && HAVE_BLOCK_DEVICE && EFI_PARTITION
> +	help
> +	  Enable support for accessing FWU Metadata on GPT partitioned
> +	  block devices.
> diff --git a/drivers/fwu-mdata/Makefile b/drivers/fwu-mdata/Makefile
> new file mode 100644
> index 0000000000..3fee64c10c
> --- /dev/null
> +++ b/drivers/fwu-mdata/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (c) 2022, Linaro Limited
> +#
> +
> +
> +obj-$(CONFIG_FWU_MDATA) += fwu-mdata-uclass.o
> +obj-$(CONFIG_FWU_MDATA_GPT_BLK) += gpt_blk.o
> diff --git a/drivers/fwu-mdata/gpt_blk.c b/drivers/fwu-mdata/gpt_blk.c
> new file mode 100644
> index 0000000000..df115575e0
> --- /dev/null
> +++ b/drivers/fwu-mdata/gpt_blk.c
> @@ -0,0 +1,378 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2022, Linaro Limited
> + */
> +
> +#define LOG_CATEGORY UCLASS_FWU_MDATA
> +
> +#include <blk.h>
> +#include <dm.h>
> +#include <efi_loader.h>
> +#include <fwu.h>
> +#include <fwu_mdata.h>
> +#include <log.h>
> +#include <memalign.h>
> +#include <part.h>
> +#include <part_efi.h>
> +
> +#include <dm/device-internal.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +
> +#define PRIMARY_PART		BIT(0)
> +#define SECONDARY_PART		BIT(1)
> +#define BOTH_PARTS		(PRIMARY_PART | SECONDARY_PART)
> +
> +#define MDATA_READ		BIT(0)
> +#define MDATA_WRITE		BIT(1)
> +
> +static int gpt_get_mdata_partitions(struct blk_desc *desc,
> +				    uint *primary_mpart,
> +				    uint *secondary_mpart)
> +{
> +	int i, ret;
> +	u32 mdata_parts;
> +	efi_guid_t part_type_guid;
> +	struct disk_partition info;
> +	const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
> +
> +	mdata_parts = 0;
> +	for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {
> +		if (part_get_info(desc, i, &info))
> +			continue;
> +		uuid_str_to_bin(info.type_guid, part_type_guid.b,
> +				UUID_STR_FORMAT_GUID);
> +
> +		if (!guidcmp(&fwu_mdata_guid, &part_type_guid)) {
> +			++mdata_parts;
> +			if (!*primary_mpart)
> +				*primary_mpart = i;
> +			else
> +				*secondary_mpart = i;
> +		}
> +	}
> +
> +	if (mdata_parts != 2) {
> +		log_debug("Expect two copies of the FWU metadata instead of %d\n",
> +			  mdata_parts);
> +		ret = -EINVAL;
> +	} else {
> +		ret = 0;
> +	}

Can we change that a bit?  There are are some assumptions in this code, e.g
the user must pass the values zero'ed out.  Can we instead get an array of
2 instead?  In that case you don't care if any of the values are zero and
you can just fill in the array.  Something like:

if (!guidcmp(&fwu_mdata_guid, &part_type_guid)) {
	array[mdata_parts] = i;
	mdata_parts++;
You can also move the check in that if and make the func a lot easier to
read.


> +
> +	return ret;
> +}
> +
> +static int gpt_get_mdata_disk_part(struct blk_desc *desc,
> +				   struct disk_partition *info,
> +				   u32 part_num)
> +{
> +	int ret;
> +	char *mdata_guid_str = "8a7a84a0-8387-40f6-ab41-a8b9a5a60d23";
> +
> +	ret = part_get_info(desc, part_num, info);
> +	if (ret < 0) {
> +		log_debug("Unable to get the partition info for the FWU metadata part %d\n",
> +			  part_num);
> +		return -ENOENT;
> +	}
> +
> +	/* Check that it is indeed the FWU metadata partition */
> +	if (!strncmp(info->type_guid, mdata_guid_str, UUID_STR_LEN)) {
> +		/* Found the FWU metadata partition */
> +		return 0;
> +	}
> +
> +	return -ENOENT;
> +}
> +
> +static int gpt_read_write_mdata(struct blk_desc *desc,
> +				struct fwu_mdata *mdata,
> +				u8 access, u32 part_num)
> +{
> +	int ret;
> +	u32 len, blk_start, blkcnt;
> +	struct disk_partition info;
> +
> +	ALLOC_CACHE_ALIGN_BUFFER_PAD(struct fwu_mdata, mdata_aligned, 1,
> +				     desc->blksz);
> +
> +	ret = gpt_get_mdata_disk_part(desc, &info, part_num);
> +	if (ret < 0) {
> +		printf("Unable to get the FWU metadata partition\n");
> +		return -ENOENT;
> +	}
> +
> +	len = sizeof(*mdata);
> +	blkcnt = BLOCK_CNT(len, desc);
> +	if (blkcnt > info.size) {
> +		log_debug("Block count exceeds FWU metadata partition size\n");
> +		return -ERANGE;
> +	}
> +
> +	blk_start = info.start;
> +	if (access == MDATA_READ) {
> +		if (blk_dread(desc, blk_start, blkcnt, mdata_aligned) != blkcnt) {
> +			log_debug("Error reading FWU metadata from the device\n");
> +			return -EIO;
> +		}
> +		memcpy(mdata, mdata_aligned, sizeof(struct fwu_mdata));
> +	} else {
> +		if (blk_dwrite(desc, blk_start, blkcnt, mdata) != blkcnt) {
> +			log_debug("Error writing FWU metadata to the device\n");
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int gpt_read_mdata(struct blk_desc *desc,
> +			  struct fwu_mdata *mdata, u32 part_num)
> +{
> +	return gpt_read_write_mdata(desc, mdata, MDATA_READ, part_num);
> +}
> +
> +static int gpt_write_mdata_partition(struct blk_desc *desc,
> +					struct fwu_mdata *mdata,
> +					u32 part_num)
> +{
> +	return gpt_read_write_mdata(desc, mdata, MDATA_WRITE, part_num);
> +}
> +
> +static int fwu_gpt_update_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> +	int ret;
> +	struct blk_desc *desc;
> +	uint primary_mpart = 0, secondary_mpart = 0;
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	desc = dev_get_uclass_plat(priv->blk_dev);
> +
> +	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
> +				       &secondary_mpart);
> +	if (ret < 0) {
> +		log_debug("Error getting the FWU metadata partitions\n");
> +		return -ENOENT;
> +	}
> +
> +	/* First write the primary partition */
> +	ret = gpt_write_mdata_partition(desc, mdata, primary_mpart);
> +	if (ret < 0) {
> +		log_debug("Updating primary FWU metadata partition failed\n");
> +		return ret;
> +	}
> +
> +	/* And now the replica */
> +	ret = gpt_write_mdata_partition(desc, mdata, secondary_mpart);
> +	if (ret < 0) {
> +		log_debug("Updating secondary FWU metadata partition failed\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int gpt_get_mdata(struct blk_desc *desc, struct fwu_mdata *mdata)
> +{
> +	int ret;
> +	uint primary_mpart = 0, secondary_mpart = 0;
> +
> +	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
> +				       &secondary_mpart);
> +
> +	if (ret < 0) {
> +		log_debug("Error getting the FWU metadata partitions\n");
> +		return -ENOENT;
> +	}
> +
> +	ret = gpt_read_mdata(desc, mdata, primary_mpart);
> +	if (ret < 0) {
> +		log_debug("Failed to read the FWU metadata from the device\n");
> +		return -EIO;
> +	}
> +
> +	ret = fwu_verify_mdata(mdata, 1);
> +	if (!ret)
> +		return 0;
> +
> +	/*
> +	 * Verification of the primary FWU metadata copy failed.
> +	 * Try to read the replica.
> +	 */
> +	memset(mdata, '\0', sizeof(struct fwu_mdata));
> +	ret = gpt_read_mdata(desc, mdata, secondary_mpart);
> +	if (ret < 0) {
> +		log_debug("Failed to read the FWU metadata from the device\n");
> +		return -EIO;
> +	}
> +
> +	ret = fwu_verify_mdata(mdata, 0);
> +	if (!ret)
> +		return 0;
> +
> +	/* Both the FWU metadata copies are corrupted. */
> +	return -EIO;
> +}
> +
> +static int gpt_check_mdata_validity(struct udevice *dev)
> +{
> +	int ret;
> +	struct blk_desc *desc;
> +	struct fwu_mdata pri_mdata;
> +	struct fwu_mdata secondary_mdata;
> +	uint primary_mpart = 0, secondary_mpart = 0;
> +	uint valid_partitions, invalid_partitions;
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	desc = dev_get_uclass_plat(priv->blk_dev);
> +
> +	/*
> +	 * Two FWU metadata partitions are expected.
> +	 * If we don't have two, user needs to create
> +	 * them first
> +	 */
> +	valid_partitions = 0;
> +	ret = gpt_get_mdata_partitions(desc, &primary_mpart,
> +				       &secondary_mpart);
> +
> +	if (ret < 0) {
> +		log_debug("Error getting the FWU metadata partitions\n");
> +		return -ENOENT;
> +	}
> +
> +	ret = gpt_read_mdata(desc, &pri_mdata, primary_mpart);
> +	if (ret < 0) {
> +		log_debug("Failed to read the FWU metadata from the device\n");
> +		goto secondary_read;

Can't we skip the goto here and just make the if above (if ret == 0)?
> +	}
> +
> +	ret = fwu_verify_mdata(&pri_mdata, 1);
> +	if (!ret)
> +		valid_partitions |= PRIMARY_PART;
> +
> +secondary_read:
> +	/* Now check the secondary partition */
> +	ret = gpt_read_mdata(desc, &secondary_mdata, secondary_mpart);
> +	if (ret < 0) {
> +		log_debug("Failed to read the FWU metadata from the device\n");

Same here

> +		goto mdata_restore;
> +	}
> +
> +	ret = fwu_verify_mdata(&secondary_mdata, 0);
> +	if (!ret)
> +		valid_partitions |= SECONDARY_PART;
> +
> +mdata_restore:
> +	if (valid_partitions == (PRIMARY_PART | SECONDARY_PART)) {
> +		ret = -1;
> +		/*
> +		 * Before returning, check that both the
> +		 * FWU metadata copies are the same. If not,
> +		 * the FWU metadata copies need to be
> +		 * re-populated.
> +		 */
> +		if (!memcmp(&pri_mdata, &secondary_mdata,
> +			    sizeof(struct fwu_mdata))) {
> +			ret = 0;
> +		} else {
> +			log_debug("Both FWU metadata copies are valid but do not match. Please check!\n");
> +		}
> +		goto out;
> +	}
> +
> +	ret = -1;
> +	if (!(valid_partitions & BOTH_PARTS))
> +		goto out;
> +
> +	invalid_partitions = valid_partitions ^ BOTH_PARTS;
> +	ret = gpt_write_mdata_partition(desc,
> +					(invalid_partitions == PRIMARY_PART) ?
> +					&secondary_mdata : &pri_mdata,
> +					(invalid_partitions == PRIMARY_PART) ?
> +					primary_mpart : secondary_mpart);
> +
> +	if (ret < 0)
> +		log_debug("Restoring %s FWU metadata partition failed\n",
> +			  (invalid_partitions == PRIMARY_PART) ?
> +			  "primary" : "secondary");
> +
> +out:
> +	return ret;
> +}
> +
> +static int fwu_gpt_mdata_check(struct udevice *dev)
> +{
> +	/*
> +	 * Check if both the copies of the FWU
> +	 * metadata are valid. If one has gone
> +	 * bad, restore it from the other good
> +	 * copy.
> +	 */
> +	return gpt_check_mdata_validity(dev);
> +}
> +
> +static int fwu_gpt_get_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return gpt_get_mdata(dev_get_uclass_plat(priv->blk_dev), mdata);
> +}
> +
> +static int fwu_get_mdata_device(struct udevice *dev, struct udevice **mdata_dev)
> +{
> +	u32 phandle;
> +	int ret, size;
> +	struct udevice *parent;
> +	const fdt32_t *phandle_p = NULL;
> +
> +	phandle_p = dev_read_prop(dev, "fwu-mdata-store", &size);
> +	if (!phandle_p) {
> +		log_debug("fwu-mdata-store property not found\n");
> +		return -ENOENT;
> +	}
> +
> +	phandle = fdt32_to_cpu(*phandle_p);
> +
> +	ret = device_get_global_by_ofnode(ofnode_get_by_phandle(phandle),
> +					  &parent);
> +	if (ret)
> +		return ret;
> +
> +	return blk_get_from_parent(parent, mdata_dev);
> +}
> +
> +static int fwu_mdata_gpt_blk_probe(struct udevice *dev)
> +{
> +	int ret;
> +	struct udevice *mdata_dev = NULL;
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	ret = fwu_get_mdata_device(dev, &mdata_dev);
> +	if (ret)
> +		return ret;
> +
> +	priv->blk_dev = mdata_dev;
> +
> +	return 0;
> +}
> +
> +static const struct fwu_mdata_ops fwu_gpt_blk_ops = {
> +	.mdata_check = fwu_gpt_mdata_check,
> +	.get_mdata = fwu_gpt_get_mdata,
> +	.update_mdata = fwu_gpt_update_mdata,
> +};
> +
> +static const struct udevice_id fwu_mdata_ids[] = {
> +	{ .compatible = "u-boot,fwu-mdata-gpt" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(fwu_mdata_gpt_blk) = {
> +	.name		= "fwu-mdata-gpt-blk",
> +	.id		= UCLASS_FWU_MDATA,
> +	.of_match	= fwu_mdata_ids,
> +	.ops		= &fwu_gpt_blk_ops,
> +	.probe		= fwu_mdata_gpt_blk_probe,
> +	.priv_auto	= sizeof(struct fwu_mdata_gpt_blk_priv),
> +};
> diff --git a/include/fwu.h b/include/fwu.h
> index 745f6225d0..1e16253f69 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -14,6 +14,10 @@
>  struct fwu_mdata;
>  struct udevice;
>  
> +struct fwu_mdata_gpt_blk_priv {
> +	struct udevice *blk_dev;
> +};
> +
>  /**
>   * @mdata_check: check the validity of the FWU metadata partitions
>   * @get_mdata() - Get a FWU metadata copy
> -- 
> 2.34.1
> 


Cheers
/Ilias