Re: [PATCH v11 03/15] FWU: Add FWU metadata access driver for GPT partitioned block devices

Etienne Carriere
2022-09-30T06:11:01Z

Hi Sughosh,

My R-b tag still applies, with the 2 below comments addressed or not.

Br,
etienne

On Wed, 28 Sept 2022 at 11:30, Sughosh Ganu <sughosh.ganu@linaro.org> 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 V10:
> * Use array for storing the metadata partition numbers as suggested by
> Ilias
> * Skip a couple of goto's in gpt_check_mdata_validity() as suggested
> by Ilias
> * Have the FWU_MDATA_GPT_BLK config symbol depend on FWU_MDATA and BLK
> * Remove the comment in fwu_gpt_mdata_check() as it is already
> mentioned in the corresponding API comment
>
> drivers/fwu-mdata/Kconfig | 16 ++
> drivers/fwu-mdata/Makefile | 8 +
> drivers/fwu-mdata/gpt_blk.c | 356 ++++++++++++++++++++++++++++++++++++
> include/fwu.h | 4 +
> 4 files changed, 384 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..36c4479a59
> --- /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 FWU_MDATA && BLK && 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..d20bb19d52
> --- /dev/null
> +++ b/drivers/fwu-mdata/gpt_blk.c
> @@ -0,0 +1,356 @@
> +// 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 *mdata_parts)

Maybe nitpicking but I think this should better explicit declare a 2
cell array argument:
static int gpt_get_mdata_partitions(struct blk_desc *desc, uint mdata_parts[2])

> +{
> + int i, ret;
> + u32 nparts;
> + efi_guid_t part_type_guid;
> + struct disk_partition info;
> + const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
> +
> + nparts = 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 (nparts < 2 && !guidcmp(&fwu_mdata_guid, &part_type_guid)) {
> + mdata_parts[nparts] = i;
> + ++nparts;
> + }
> + }
> +
> + if (nparts != 2) {
> + log_debug("Expect two copies of the FWU metadata instead of %d\n",
> + nparts);
> + ret = -EINVAL;
> + } else {
> + ret = 0;
> + }
> +
> + 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 mdata_parts[2];
> + 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, mdata_parts);
> + 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, mdata_parts[0]);
> + 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, mdata_parts[1]);
> + 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 mdata_parts[2];
> +
> + ret = gpt_get_mdata_partitions(desc, mdata_parts);
> +
> + if (ret < 0) {
> + log_debug("Error getting the FWU metadata partitions\n");
> + return -ENOENT;
> + }
> +
> + ret = gpt_read_mdata(desc, mdata, mdata_parts[0]);
> + 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, mdata_parts[1]);
> + 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 mdata_parts[2];
> + 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, mdata_parts);
> + if (ret < 0) {
> + log_debug("Error getting the FWU metadata partitions\n");
> + return -ENOENT;
> + }
> +
> + ret = gpt_read_mdata(desc, &pri_mdata, mdata_parts[0]);
> + if (!ret) {
> + ret = fwu_verify_mdata(&pri_mdata, 1);
> + if (!ret)
> + valid_partitions |= PRIMARY_PART;
> + }
> +
> + /* Now check the secondary partition */
> + ret = gpt_read_mdata(desc, &secondary_mdata, mdata_parts[1]);
> + if (!ret) {
> + ret = fwu_verify_mdata(&secondary_mdata, 0);
> + if (!ret)
> + valid_partitions |= SECONDARY_PART;
> + }
> +
> + 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;

The 3 above preload of @ret are a bit misplaced (yet no functional
issue) i think.
Better a classic way:

if (valid_partitions == (PRIMARY_PART | SECONDARY_PART)) {
- ret = -1;
(...)
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");
+ ret = -1;
}
goto out;
}

- ret = -1;
if (!(valid_partitions & BOTH_PARTS)) {
+ ret = -1;
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) ?
> + mdata_parts[0] : mdata_parts[1]);
> +
> + 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)
> +{
> + 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 = {
> + .check_mdata = 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 a4d2d35d9a..167f91388e 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
>