diff mbox series

[PATCHv2,2/4] fwu: move meta-data management in core

Message ID 20221203031702.579790-1-jassisinghbrar@gmail.com
State Superseded
Headers show
Series FWU: Handle meta-data in common code | expand

Commit Message

Jassi Brar Dec. 3, 2022, 3:17 a.m. UTC
From: Jassi Brar <jaswinder.singh@linaro.org>

Instead of each i/f having to implement their own meta-data verification
and storage, move the logic in common code. This simplifies the i/f code
much simpler and compact.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 drivers/fwu-mdata/fwu-mdata-uclass.c |  34 +++++++
 include/fwu.h                        |  41 ++++++++
 lib/fwu_updates/fwu.c                | 143 ++++++++++++++++++++++++++-
 3 files changed, 214 insertions(+), 4 deletions(-)

Comments

Etienne Carriere Dec. 13, 2022, 2:59 p.m. UTC | #1
Hello Jassi,

On Sat, 3 Dec 2022 at 04:17, <jassisinghbrar@gmail.com> wrote:
>
> From: Jassi Brar <jaswinder.singh@linaro.org>
>
> Instead of each i/f having to implement their own meta-data verification
> and storage, move the logic in common code. This simplifies the i/f code
> much simpler and compact.
>
> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
> ---
>  drivers/fwu-mdata/fwu-mdata-uclass.c |  34 +++++++
>  include/fwu.h                        |  41 ++++++++
>  lib/fwu_updates/fwu.c                | 143 ++++++++++++++++++++++++++-
>  3 files changed, 214 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c b/drivers/fwu-mdata/fwu-mdata-uclass.c
> index b477e9603f..e03773c584 100644
> --- a/drivers/fwu-mdata/fwu-mdata-uclass.c
> +++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
> @@ -16,6 +16,40 @@
>  #include <linux/types.h>
>  #include <u-boot/crc.h>
>
> +/**
> + * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
> + *
> + * Return: 0 if OK, -ve on error
> + */
> +int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
> +{
> +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->read_mdata) {
> +               log_debug("read_mdata() method not defined\n");
> +               return -ENOSYS;
> +       }
> +
> +       return ops->read_mdata(dev, mdata, primary);
> +}
> +
> +/**
> + * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
> + *
> + * Return: 0 if OK, -ve on error
> + */
> +int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
> +{
> +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> +
> +       if (!ops->write_mdata) {
> +               log_debug("write_mdata() method not defined\n");
> +               return -ENOSYS;
> +       }
> +
> +       return ops->write_mdata(dev, mdata, primary);
> +}
> +
>  /**
>   * fwu_get_mdata_part_num() - Get the FWU metadata partition numbers
>   * @dev: FWU metadata device
> diff --git a/include/fwu.h b/include/fwu.h
> index 0919ced812..1a700c9e6a 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -24,6 +24,26 @@ struct fwu_mdata_gpt_blk_priv {
>   * @update_mdata() - Update the FWU metadata copy
>   */
>  struct fwu_mdata_ops {
> +       /**
> +        * read_mdata() - Populate the asked FWU metadata copy
> +        * @dev: FWU metadata device
> +        * @mdata: Copy of the FWU metadata
> +        * @primary: If primary or secondary copy of meta-data is to be read
> +        *
> +        * Return: 0 if OK, -ve on error
> +        */
> +       int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> +
> +       /**
> +        * write_mdata() - Write the given FWU metadata copy
> +        * @dev: FWU metadata device
> +        * @mdata: Copy of the FWU metadata
> +        * @primary: If primary or secondary copy of meta-data is to be written
> +        *
> +        * Return: 0 if OK, -ve on error
> +        */
> +       int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> +
>         /**
>          * check_mdata() - Check if the FWU metadata is valid
>          * @dev:        FWU device
> @@ -126,6 +146,27 @@ struct fwu_mdata_ops {
>         EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
>                  0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
>
> +/**
> + * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
> + */
> +int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> +
> +/**
> + * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
> + */
> +int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> +
> +/**
> + * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
> + *
> + * Read both the metadata copies from the storage media, verify their checksum,
> + * and ascertain that both copies match. If one of the copies has gone bad,
> + * restore it from the good copy.
> + *
> + * Return: 0 if OK, -ve on error
> +*/
> +int fwu_get_verified_mdata(struct fwu_mdata *mdata);
> +
>  /**
>   * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
>   *
> diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> index 5313d07302..f17bd8ea63 100644
> --- a/lib/fwu_updates/fwu.c
> +++ b/lib/fwu_updates/fwu.c
> @@ -15,13 +15,13 @@
>  #include <linux/errno.h>
>  #include <linux/types.h>
>
> +#include <u-boot/crc.h>
> +
> +static struct fwu_mdata g_mdata; /* = {0} makes uninit crc32 always invalid */
> +static struct udevice *g_dev;
>  static u8 in_trial;
>  static u8 boottime_check;
>
> -#include <linux/errno.h>
> -#include <linux/types.h>
> -#include <u-boot/crc.h>
> -
>  enum {
>         IMAGE_ACCEPT_SET = 1,
>         IMAGE_ACCEPT_CLEAR,
> @@ -161,6 +161,141 @@ static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
>         return -ENOENT;
>  }
>
> +/**
> + * fwu_sync_mdata() - Update given meta-data partition(s) with the copy provided
> + * @mdata: FWU metadata structure
> + * @part: Bitmask of FWU metadata partitions to be written to
> + *
> + * Return: 0 if OK, -ve on error
> + */
> +static int fwu_sync_mdata(struct fwu_mdata *mdata, int part)
> +{
> +       void *buf = &mdata->version;
> +       int err = 0;
> +
> +       /*
> +        * Calculate the crc32 for the updated FWU metadata
> +        * and put the updated value in the FWU metadata crc32
> +        * field
> +        */
> +       mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
> +
> +       if (part & PRIMARY_PART)
> +               err = fwu_write_mdata(g_dev, mdata, true);
> +
> +       if (err) {
> +               log_err("Unable to write primary mdata\n");
> +               return err;
> +       }
> +
> +       if (part & SECONDARY_PART)
> +               err = fwu_write_mdata(g_dev, mdata, false);
> +
> +       if (err) {
> +               log_err("Unable to write secondary mdata\n");
> +               return err;
> +       }
> +
> +       /* update the cached copy of meta-data */
> +       memcpy(&g_mdata, mdata, sizeof(struct fwu_mdata));
> +
> +       return 0;
> +}
> +
> +static inline int mdata_crc_check(struct fwu_mdata *mdata)
> +{
> +       void *buf = &mdata->version;
> +       u32 calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
> +
> +       return calc_crc32 == mdata->crc32 ? 0 : -EINVAL;
> +}
> +
> +/**
> + * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
> + *
> + * Read both the metadata copies from the storage media, verify their checksum,
> + * and ascertain that both copies match. If one of the copies has gone bad,
> + * restore it from the good copy.
> + *
> + * Return: 0 if OK, -ve on error
> + */
> +int fwu_get_verified_mdata(struct fwu_mdata *mdata)
> +{
> +       int err;
> +       bool pri_ok, sec_ok;
> +       struct fwu_mdata s, *p_mdata, *s_mdata;
> +
> +       p_mdata = &g_mdata;
> +       s_mdata = &s;
> +
> +       /* if mdata already read and ready */
> +       err = mdata_crc_check(p_mdata);
> +       if (!err) {
> +               if (mdata)
> +                       memcpy(mdata, p_mdata, sizeof(struct fwu_mdata));
> +               return 0;
> +       }
> +       /* else read, verify and, if needed, fix mdata */
> +
> +       pri_ok = false;
> +       err = fwu_read_mdata(g_dev, p_mdata, true);
> +       if (!err) {
> +               err = mdata_crc_check(p_mdata);
> +               if (!err)
> +                       pri_ok = true;
> +               else
> +                       log_debug("primary mdata: crc32 failed\n");
> +       }
> +
> +       sec_ok = false;
> +       err = fwu_read_mdata(g_dev, s_mdata, false);
> +       if (!err) {
> +               err = mdata_crc_check(s_mdata);
> +               if (!err)
> +                       sec_ok = true;
> +               else
> +                       log_debug("secondary mdata: crc32 failed\n");
> +       }
> +
> +       if (pri_ok && sec_ok) {
> +               /*
> +                * Before returning, check that both the
> +                * FWU metadata copies are the same.
> +                */
> +               err = memcmp(p_mdata, s_mdata, sizeof(struct fwu_mdata));
> +               if (!err)
> +                       return 0;

Copy of the metadata to @mdata is missing here and in success path
before exit_fix branch label.

regards,
etienne

> +
> +               /*
> +                * If not, populate the secondary partition from the
> +                * primary partition copy.
> +                */
> +               log_info("Both FWU metadata copies are valid but do not match.");
> +               log_info(" Restoring the secondary partition from the primary\n");
> +               sec_ok = false;
> +       }
> +
> +       if (!pri_ok) {
> +               memcpy(p_mdata, s_mdata, sizeof(struct fwu_mdata));
> +               err = fwu_sync_mdata(p_mdata, PRIMARY_PART);
> +               if (err)
> +                       goto exit_fix;
> +       }
> +
> +       if (!sec_ok) {
> +               memcpy(s_mdata, p_mdata, sizeof(struct fwu_mdata));
> +               err = fwu_sync_mdata(s_mdata, SECONDARY_PART);
> +               if (err)
> +                       goto exit_fix;
> +       }
> +
> +exit_fix:
> +       if (err)
> +               log_debug("mdata saving : crc32 failed\n");
> +
> +       return err;
> +}
> +
>  /**
>   * fwu_verify_mdata() - Verify the FWU metadata
>   * @mdata: FWU metadata structure
> --
> 2.34.1
>
Jassi Brar Jan. 2, 2023, 4:05 p.m. UTC | #2
On Tue, 13 Dec 2022 at 09:00, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Hello Jassi,
>
> On Sat, 3 Dec 2022 at 04:17, <jassisinghbrar@gmail.com> wrote:
> >
> > From: Jassi Brar <jaswinder.singh@linaro.org>
> >
> > Instead of each i/f having to implement their own meta-data verification
> > and storage, move the logic in common code. This simplifies the i/f code
> > much simpler and compact.
> >
> > Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
> > ---
> >  drivers/fwu-mdata/fwu-mdata-uclass.c |  34 +++++++
> >  include/fwu.h                        |  41 ++++++++
> >  lib/fwu_updates/fwu.c                | 143 ++++++++++++++++++++++++++-
> >  3 files changed, 214 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c b/drivers/fwu-mdata/fwu-mdata-uclass.c
> > index b477e9603f..e03773c584 100644
> > --- a/drivers/fwu-mdata/fwu-mdata-uclass.c
> > +++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
> > @@ -16,6 +16,40 @@
> >  #include <linux/types.h>
> >  #include <u-boot/crc.h>
> >
> > +/**
> > + * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
> > + *
> > + * Return: 0 if OK, -ve on error
> > + */
> > +int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
> > +{
> > +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> > +
> > +       if (!ops->read_mdata) {
> > +               log_debug("read_mdata() method not defined\n");
> > +               return -ENOSYS;
> > +       }
> > +
> > +       return ops->read_mdata(dev, mdata, primary);
> > +}
> > +
> > +/**
> > + * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
> > + *
> > + * Return: 0 if OK, -ve on error
> > + */
> > +int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
> > +{
> > +       const struct fwu_mdata_ops *ops = device_get_ops(dev);
> > +
> > +       if (!ops->write_mdata) {
> > +               log_debug("write_mdata() method not defined\n");
> > +               return -ENOSYS;
> > +       }
> > +
> > +       return ops->write_mdata(dev, mdata, primary);
> > +}
> > +
> >  /**
> >   * fwu_get_mdata_part_num() - Get the FWU metadata partition numbers
> >   * @dev: FWU metadata device
> > diff --git a/include/fwu.h b/include/fwu.h
> > index 0919ced812..1a700c9e6a 100644
> > --- a/include/fwu.h
> > +++ b/include/fwu.h
> > @@ -24,6 +24,26 @@ struct fwu_mdata_gpt_blk_priv {
> >   * @update_mdata() - Update the FWU metadata copy
> >   */
> >  struct fwu_mdata_ops {
> > +       /**
> > +        * read_mdata() - Populate the asked FWU metadata copy
> > +        * @dev: FWU metadata device
> > +        * @mdata: Copy of the FWU metadata
> > +        * @primary: If primary or secondary copy of meta-data is to be read
> > +        *
> > +        * Return: 0 if OK, -ve on error
> > +        */
> > +       int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> > +
> > +       /**
> > +        * write_mdata() - Write the given FWU metadata copy
> > +        * @dev: FWU metadata device
> > +        * @mdata: Copy of the FWU metadata
> > +        * @primary: If primary or secondary copy of meta-data is to be written
> > +        *
> > +        * Return: 0 if OK, -ve on error
> > +        */
> > +       int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> > +
> >         /**
> >          * check_mdata() - Check if the FWU metadata is valid
> >          * @dev:        FWU device
> > @@ -126,6 +146,27 @@ struct fwu_mdata_ops {
> >         EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
> >                  0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
> >
> > +/**
> > + * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
> > + */
> > +int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> > +
> > +/**
> > + * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
> > + */
> > +int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
> > +
> > +/**
> > + * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
> > + *
> > + * Read both the metadata copies from the storage media, verify their checksum,
> > + * and ascertain that both copies match. If one of the copies has gone bad,
> > + * restore it from the good copy.
> > + *
> > + * Return: 0 if OK, -ve on error
> > +*/
> > +int fwu_get_verified_mdata(struct fwu_mdata *mdata);
> > +
> >  /**
> >   * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
> >   *
> > diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> > index 5313d07302..f17bd8ea63 100644
> > --- a/lib/fwu_updates/fwu.c
> > +++ b/lib/fwu_updates/fwu.c
> > @@ -15,13 +15,13 @@
> >  #include <linux/errno.h>
> >  #include <linux/types.h>
> >
> > +#include <u-boot/crc.h>
> > +
> > +static struct fwu_mdata g_mdata; /* = {0} makes uninit crc32 always invalid */
> > +static struct udevice *g_dev;
> >  static u8 in_trial;
> >  static u8 boottime_check;
> >
> > -#include <linux/errno.h>
> > -#include <linux/types.h>
> > -#include <u-boot/crc.h>
> > -
> >  enum {
> >         IMAGE_ACCEPT_SET = 1,
> >         IMAGE_ACCEPT_CLEAR,
> > @@ -161,6 +161,141 @@ static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
> >         return -ENOENT;
> >  }
> >
> > +/**
> > + * fwu_sync_mdata() - Update given meta-data partition(s) with the copy provided
> > + * @mdata: FWU metadata structure
> > + * @part: Bitmask of FWU metadata partitions to be written to
> > + *
> > + * Return: 0 if OK, -ve on error
> > + */
> > +static int fwu_sync_mdata(struct fwu_mdata *mdata, int part)
> > +{
> > +       void *buf = &mdata->version;
> > +       int err = 0;
> > +
> > +       /*
> > +        * Calculate the crc32 for the updated FWU metadata
> > +        * and put the updated value in the FWU metadata crc32
> > +        * field
> > +        */
> > +       mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
> > +
> > +       if (part & PRIMARY_PART)
> > +               err = fwu_write_mdata(g_dev, mdata, true);
> > +
> > +       if (err) {
> > +               log_err("Unable to write primary mdata\n");
> > +               return err;
> > +       }
> > +
> > +       if (part & SECONDARY_PART)
> > +               err = fwu_write_mdata(g_dev, mdata, false);
> > +
> > +       if (err) {
> > +               log_err("Unable to write secondary mdata\n");
> > +               return err;
> > +       }
> > +
> > +       /* update the cached copy of meta-data */
> > +       memcpy(&g_mdata, mdata, sizeof(struct fwu_mdata));
> > +
> > +       return 0;
> > +}
> > +
> > +static inline int mdata_crc_check(struct fwu_mdata *mdata)
> > +{
> > +       void *buf = &mdata->version;
> > +       u32 calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
> > +
> > +       return calc_crc32 == mdata->crc32 ? 0 : -EINVAL;
> > +}
> > +
> > +/**
> > + * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
> > + *
> > + * Read both the metadata copies from the storage media, verify their checksum,
> > + * and ascertain that both copies match. If one of the copies has gone bad,
> > + * restore it from the good copy.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + */
> > +int fwu_get_verified_mdata(struct fwu_mdata *mdata)
> > +{
> > +       int err;
> > +       bool pri_ok, sec_ok;
> > +       struct fwu_mdata s, *p_mdata, *s_mdata;
> > +
> > +       p_mdata = &g_mdata;
> > +       s_mdata = &s;
> > +
> > +       /* if mdata already read and ready */
> > +       err = mdata_crc_check(p_mdata);
> > +       if (!err) {
> > +               if (mdata)
> > +                       memcpy(mdata, p_mdata, sizeof(struct fwu_mdata));
> > +               return 0;
> > +       }
> > +       /* else read, verify and, if needed, fix mdata */
> > +
> > +       pri_ok = false;
> > +       err = fwu_read_mdata(g_dev, p_mdata, true);
> > +       if (!err) {
> > +               err = mdata_crc_check(p_mdata);
> > +               if (!err)
> > +                       pri_ok = true;
> > +               else
> > +                       log_debug("primary mdata: crc32 failed\n");
> > +       }
> > +
> > +       sec_ok = false;
> > +       err = fwu_read_mdata(g_dev, s_mdata, false);
> > +       if (!err) {
> > +               err = mdata_crc_check(s_mdata);
> > +               if (!err)
> > +                       sec_ok = true;
> > +               else
> > +                       log_debug("secondary mdata: crc32 failed\n");
> > +       }
> > +
> > +       if (pri_ok && sec_ok) {
> > +               /*
> > +                * Before returning, check that both the
> > +                * FWU metadata copies are the same.
> > +                */
> > +               err = memcmp(p_mdata, s_mdata, sizeof(struct fwu_mdata));
> > +               if (!err)
> > +                       return 0;
>
> Copy of the metadata to @mdata is missing here and in success path
> before exit_fix branch label.
>
Thanks for locating the omission.

Cheers.
diff mbox series

Patch

diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c b/drivers/fwu-mdata/fwu-mdata-uclass.c
index b477e9603f..e03773c584 100644
--- a/drivers/fwu-mdata/fwu-mdata-uclass.c
+++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
@@ -16,6 +16,40 @@ 
 #include <linux/types.h>
 #include <u-boot/crc.h>
 
+/**
+ * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+{
+	const struct fwu_mdata_ops *ops = device_get_ops(dev);
+
+	if (!ops->read_mdata) {
+		log_debug("read_mdata() method not defined\n");
+		return -ENOSYS;
+	}
+
+	return ops->read_mdata(dev, mdata, primary);
+}
+
+/**
+ * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+{
+	const struct fwu_mdata_ops *ops = device_get_ops(dev);
+
+	if (!ops->write_mdata) {
+		log_debug("write_mdata() method not defined\n");
+		return -ENOSYS;
+	}
+
+	return ops->write_mdata(dev, mdata, primary);
+}
+
 /**
  * fwu_get_mdata_part_num() - Get the FWU metadata partition numbers
  * @dev: FWU metadata device
diff --git a/include/fwu.h b/include/fwu.h
index 0919ced812..1a700c9e6a 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -24,6 +24,26 @@  struct fwu_mdata_gpt_blk_priv {
  * @update_mdata() - Update the FWU metadata copy
  */
 struct fwu_mdata_ops {
+	/**
+	 * read_mdata() - Populate the asked FWU metadata copy
+	 * @dev: FWU metadata device
+	 * @mdata: Copy of the FWU metadata
+	 * @primary: If primary or secondary copy of meta-data is to be read
+	 *
+	 * Return: 0 if OK, -ve on error
+	 */
+	int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+	/**
+	 * write_mdata() - Write the given FWU metadata copy
+	 * @dev: FWU metadata device
+	 * @mdata: Copy of the FWU metadata
+	 * @primary: If primary or secondary copy of meta-data is to be written
+	 *
+	 * Return: 0 if OK, -ve on error
+	 */
+	int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
 	/**
 	 * check_mdata() - Check if the FWU metadata is valid
 	 * @dev:	FWU device
@@ -126,6 +146,27 @@  struct fwu_mdata_ops {
 	EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
 		 0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
 
+/**
+ * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
+ */
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+/**
+ * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
+ */
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+
+/**
+ * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
+ *
+ * Read both the metadata copies from the storage media, verify their checksum,
+ * and ascertain that both copies match. If one of the copies has gone bad,
+ * restore it from the good copy.
+ *
+ * Return: 0 if OK, -ve on error
+*/
+int fwu_get_verified_mdata(struct fwu_mdata *mdata);
+
 /**
  * fwu_check_mdata_validity() - Check for validity of the FWU metadata copies
  *
diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
index 5313d07302..f17bd8ea63 100644
--- a/lib/fwu_updates/fwu.c
+++ b/lib/fwu_updates/fwu.c
@@ -15,13 +15,13 @@ 
 #include <linux/errno.h>
 #include <linux/types.h>
 
+#include <u-boot/crc.h>
+
+static struct fwu_mdata g_mdata; /* = {0} makes uninit crc32 always invalid */
+static struct udevice *g_dev;
 static u8 in_trial;
 static u8 boottime_check;
 
-#include <linux/errno.h>
-#include <linux/types.h>
-#include <u-boot/crc.h>
-
 enum {
 	IMAGE_ACCEPT_SET = 1,
 	IMAGE_ACCEPT_CLEAR,
@@ -161,6 +161,141 @@  static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
 	return -ENOENT;
 }
 
+/**
+ * fwu_sync_mdata() - Update given meta-data partition(s) with the copy provided
+ * @mdata: FWU metadata structure
+ * @part: Bitmask of FWU metadata partitions to be written to
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static int fwu_sync_mdata(struct fwu_mdata *mdata, int part)
+{
+	void *buf = &mdata->version;
+	int err = 0;
+
+	/*
+	 * Calculate the crc32 for the updated FWU metadata
+	 * and put the updated value in the FWU metadata crc32
+	 * field
+	 */
+	mdata->crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	if (part & PRIMARY_PART)
+		err = fwu_write_mdata(g_dev, mdata, true);
+
+	if (err) {
+		log_err("Unable to write primary mdata\n");
+		return err;
+	}
+
+	if (part & SECONDARY_PART)
+		err = fwu_write_mdata(g_dev, mdata, false);
+
+	if (err) {
+		log_err("Unable to write secondary mdata\n");
+		return err;
+	}
+
+	/* update the cached copy of meta-data */
+	memcpy(&g_mdata, mdata, sizeof(struct fwu_mdata));
+
+	return 0;
+}
+
+static inline int mdata_crc_check(struct fwu_mdata *mdata)
+{
+	void *buf = &mdata->version;
+	u32 calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
+
+	return calc_crc32 == mdata->crc32 ? 0 : -EINVAL;
+}
+
+/**
+ * fwu_get_verified_mdata() - Read, verify and return the FWU metadata
+ *
+ * Read both the metadata copies from the storage media, verify their checksum,
+ * and ascertain that both copies match. If one of the copies has gone bad,
+ * restore it from the good copy.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int fwu_get_verified_mdata(struct fwu_mdata *mdata)
+{
+	int err;
+	bool pri_ok, sec_ok;
+	struct fwu_mdata s, *p_mdata, *s_mdata;
+
+	p_mdata = &g_mdata;
+	s_mdata = &s;
+
+	/* if mdata already read and ready */
+	err = mdata_crc_check(p_mdata);
+	if (!err) {
+		if (mdata)
+			memcpy(mdata, p_mdata, sizeof(struct fwu_mdata));
+		return 0;
+	}
+	/* else read, verify and, if needed, fix mdata */
+
+	pri_ok = false;
+	err = fwu_read_mdata(g_dev, p_mdata, true);
+	if (!err) {
+		err = mdata_crc_check(p_mdata);
+		if (!err)
+			pri_ok = true;
+		else
+			log_debug("primary mdata: crc32 failed\n");
+	}
+
+	sec_ok = false;
+	err = fwu_read_mdata(g_dev, s_mdata, false);
+	if (!err) {
+		err = mdata_crc_check(s_mdata);
+		if (!err)
+			sec_ok = true;
+		else
+			log_debug("secondary mdata: crc32 failed\n");
+	}
+
+	if (pri_ok && sec_ok) {
+		/*
+		 * Before returning, check that both the
+		 * FWU metadata copies are the same.
+		 */
+		err = memcmp(p_mdata, s_mdata, sizeof(struct fwu_mdata));
+		if (!err)
+			return 0;
+
+		/*
+		 * If not, populate the secondary partition from the
+		 * primary partition copy.
+		 */
+		log_info("Both FWU metadata copies are valid but do not match.");
+		log_info(" Restoring the secondary partition from the primary\n");
+		sec_ok = false;
+	}
+
+	if (!pri_ok) {
+		memcpy(p_mdata, s_mdata, sizeof(struct fwu_mdata));
+		err = fwu_sync_mdata(p_mdata, PRIMARY_PART);
+		if (err)
+			goto exit_fix;
+	}
+
+	if (!sec_ok) {
+		memcpy(s_mdata, p_mdata, sizeof(struct fwu_mdata));
+		err = fwu_sync_mdata(s_mdata, SECONDARY_PART);
+		if (err)
+			goto exit_fix;
+	}
+
+exit_fix:
+	if (err)
+		log_debug("mdata saving : crc32 failed\n");
+
+	return err;
+}
+
 /**
  * fwu_verify_mdata() - Verify the FWU metadata
  * @mdata: FWU metadata structure