Hi Sughosh,

On Wed, 17 Aug 2022 at 06:44, Sughosh Ganu <sughosh.g...@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 formated with GPT based partition scheme.
>
> Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
> Reviewed-by: Patrick Delaunay <patrick.delau...@foss.st.com>
> ---
> Changes since V7: None
>
>  drivers/fwu-mdata/Kconfig             |   9 +
>  drivers/fwu-mdata/Makefile            |   1 +
>  drivers/fwu-mdata/fwu_mdata_gpt_blk.c | 410 ++++++++++++++++++++++++++
>  include/fwu.h                         |   5 +
>  4 files changed, 425 insertions(+)
>  create mode 100644 drivers/fwu-mdata/fwu_mdata_gpt_blk.c
>
> diff --git a/drivers/fwu-mdata/Kconfig b/drivers/fwu-mdata/Kconfig
> index d6a21c8e19..d5edef19d6 100644
> --- a/drivers/fwu-mdata/Kconfig
> +++ b/drivers/fwu-mdata/Kconfig
> @@ -5,3 +5,12 @@ config DM_FWU_MDATA
>           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.

Can we link to the docs here, or will it be easy for people to find in
the U-Boot docs?

> +
> +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.

GPT-partitioned (I think)

> diff --git a/drivers/fwu-mdata/Makefile b/drivers/fwu-mdata/Makefile
> index e53a8c9983..313049f67a 100644
> --- a/drivers/fwu-mdata/Makefile
> +++ b/drivers/fwu-mdata/Makefile
> @@ -4,3 +4,4 @@
>  #
>
>  obj-$(CONFIG_DM_FWU_MDATA) += fwu-mdata-uclass.o
> +obj-$(CONFIG_FWU_MDATA_GPT_BLK) += fwu_mdata_gpt_blk.o
> diff --git a/drivers/fwu-mdata/fwu_mdata_gpt_blk.c 
> b/drivers/fwu-mdata/fwu_mdata_gpt_blk.c

Perhaps just call it gpt_blk.c since it is in this directory

> new file mode 100644
> index 0000000000..f694c4369b
> --- /dev/null
> +++ b/drivers/fwu-mdata/fwu_mdata_gpt_blk.c
> @@ -0,0 +1,410 @@
> +// 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 <malloc.h>
> +#include <memalign.h>
> +#include <part.h>
> +#include <part_efi.h>
> +
> +#include <dm/device-internal.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +#include <u-boot/crc.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)
> +

comment?

> +static int gpt_get_mdata_partitions(struct blk_desc *desc,
> +                                   u16 *primary_mpart,
> +                                   u16 *secondary_mpart)

Should use uint, no need to select a 16-bit var so far as I can get

> +{
> +       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_err("Expect two copies of the FWU metadata instead of 
> %d\n",
> +                       mdata_parts);
> +               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";

This is fine, but I wonder if it should that go in a header with all
the other GUIDs? Or does it go hear because it is a string?

> +
> +       ret = part_get_info(desc, part_num, info);
> +       if (ret < 0) {
> +               log_err("Unable to get the partition info for the FWU 
> metadata part %d",
> +                       part_num);
> +               return -1;
> +       }
> +
> +       /* 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 -1;
> +}
> +
> +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 -ENODEV;

How about -ENOENT ?

There is a device, so we cannot use -ENODEV

Please fix below too

> +       }
> +
> +       len = sizeof(*mdata);
> +       blkcnt = BLOCK_CNT(len, desc);
> +       if (blkcnt > info.size) {
> +               log_err("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_err("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_err("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;
> +       u16 primary_mpart = 0, secondary_mpart = 0;

uint

> +       struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +       desc = dev_get_uclass_plat(priv->blk_dev);
> +       if (!desc) {
> +               log_err("Block device not found\n");
> +               return -ENODEV;

This cannot happen, drop this if()

> +       }
> +
> +       ret = gpt_get_mdata_partitions(desc, &primary_mpart,
> +                                      &secondary_mpart);
> +

drop blank line so the error check is next to the thing that reads it

> +       if (ret < 0) {
> +               log_err("Error getting the FWU metadata partitions\n");
> +               return -ENODEV;
> +       }
> +
> +       /* First write the primary partition*/

space before */

> +       ret = gpt_write_mdata_partition(desc, mdata, primary_mpart);
> +       if (ret < 0) {
> +               log_err("Updating primary FWU metadata partition failed\n");

This is very error-heavy. The log_err() things produce a string in the
code so this ends up being very large. Is that what you want? If these
things can happen in the real world and users need to debug them, then
I suppose it is OK. But normally with driver model we report errors in
the command code, or the logic, not in drivers themselves. Otherwise
when you write tests you get lots of confusing error output that needs
to be ignored.

> +               return ret;
> +       }
> +
> +       /* And now the replica */
> +       ret = gpt_write_mdata_partition(desc, mdata, secondary_mpart);
> +       if (ret < 0) {
> +               log_err("Updating secondary FWU metadata partition failed\n");
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int gpt_get_mdata(struct blk_desc *desc, struct fwu_mdata **mdata)

mdatap

> +{
> +       int ret;
> +       u16 primary_mpart = 0, secondary_mpart = 0;

uint

Also do you need to set them to 0

Declare a locate mdata and use that here instead of *mdata, which is a pain.

> +
> +       ret = gpt_get_mdata_partitions(desc, &primary_mpart,
> +                                      &secondary_mpart);
> +
> +       if (ret < 0) {
> +               log_err("Error getting the FWU metadata partitions\n");
> +               return -ENODEV;
> +       }
> +
> +       *mdata = malloc(sizeof(struct fwu_mdata));
> +       if (!*mdata) {
> +               log_err("Unable to allocate memory for reading FWU 
> metadata\n");
> +               return -ENOMEM;
> +       }
> +
> +       ret = gpt_read_mdata(desc, *mdata, primary_mpart);
> +       if (ret < 0) {
> +               log_err("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));

'\0'

> +       ret = gpt_read_mdata(desc, *mdata, secondary_mpart);
> +       if (ret < 0) {
> +               log_err("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 -1;

This is -EPERM

Perhaps choose something else?

> +}
> +
> +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;
> +       u16 primary_mpart = 0, secondary_mpart = 0;
> +       u16 valid_partitions, invalid_partitions;
> +       struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +       desc = dev_get_uclass_plat(priv->blk_dev);
> +       if (!desc) {
> +               log_err("Block device not found\n");
> +               return -ENODEV;
> +       }
> +
> +       /*
> +        * 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_err("Error getting the FWU metadata partitions\n");
> +               return -ENODEV;
> +       }
> +
> +       ret = gpt_read_mdata(desc, &pri_mdata, primary_mpart);
> +       if (ret < 0) {
> +               log_err("Failed to read the FWU metadata from the device\n");
> +               goto secondary_read;
> +       }
> +
> +       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_err("Failed to read the FWU metadata from the device\n");
> +               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_err("Both FWU metadata copies are valid but do 
> not match. Please check!\n");

Honestly the error handling needs a rethink IMO. You should try to
return error codes that indicate what went wrong (you mostly do in
this file) and then have the top-level code decode those errors and
produce an error message.

> +               }
> +               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_err("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.

word wrap wider

> +        */
> +       return gpt_check_mdata_validity(dev);
> +}
> +
> +static int fwu_gpt_get_mdata(struct udevice *dev, struct fwu_mdata **mdata)
> +{
> +       struct blk_desc *desc;
> +       struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +       desc = dev_get_uclass_plat(priv->blk_dev);
> +       if (!desc) {
> +               log_err("Block device not found\n");
> +               return -ENODEV;

Again this cannot happen

> +       }
> +
> +       return gpt_get_mdata(desc, mdata);
> +}
> +
> +static int fwu_get_mdata_device(struct udevice *dev, struct udevice 
> **mdata_dev)
> +{
> +       u32 phandle;
> +       int ret, size;
> +       struct udevice *parent, *child;
> +       const fdt32_t *phandle_p = NULL;
> +
> +       phandle_p = dev_read_prop(dev, "fwu-mdata-store", &size);
> +       if (!phandle_p) {
> +               log_err("fwu-mdata-store property not found\n");
> +               return -ENOENT;
> +       }
> +
> +       phandle = fdt32_to_cpu(*phandle_p);

Can you use dev_read_u32() ?

> +
> +       ret = device_get_global_by_ofnode(ofnode_get_by_phandle(phandle),
> +                                         &parent);
> +       if (ret)
> +               return ret;
> +
> +       ret = -ENODEV;

Here it is correct to return -ENODEV I think

> +       for (device_find_first_child(parent, &child); child;
> +            device_find_next_child(&child)) {
> +               if (device_get_uclass_id(child) == UCLASS_BLK) {
> +                       *mdata_dev = child;
> +                       ret = 0;

See blk_get_from_parent()

> +               }
> +       }
> +
> +       return ret;
> +}
> +
> +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 e03cfff800..8259c75d12 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
> @@ -39,6 +43,7 @@ int fwu_get_active_index(u32 *active_idx);
>  int fwu_update_active_index(u32 active_idx);
>  int fwu_get_image_alt_num(efi_guid_t *image_type_id, u32 update_bank,
>                           int *alt_num);
> +int fwu_verify_mdata(struct fwu_mdata *mdata, bool pri_part);

comments again

>  int fwu_mdata_check(void);
>  int fwu_revert_boot_index(void);
>  int fwu_accept_image(efi_guid_t *img_type_id, u32 bank);
> --
> 2.34.1
>

Regards,
Simon

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