Re: [PATCH v11 02/15] FWU: Add FWU metadata structure and driver for accessing metadata

[Sughosh Ganu <sughosh.ganu@linaro.org>]

hi Etienne,

On Fri, 30 Sept 2022 at 11:24, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Hello Sughosh,
>
> 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, which is stored on
> > a dedicated partition. Add the metadata structure, and a driver model
> > uclass which provides functions to access the metadata. These are
> > generic API's, and implementations can be added based on parameters
> > like how the metadata partition is accessed and what type of storage
> > device houses the metadata.
> >
> > 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:
> > * s/fwu_update_active_index/fwu_set_active_index as per comment from
> >   Jassi
> > * Change the argument type of fwu_set_active_index() to uint from u32
> >   as per comment from Jassi
> > * s/mdata_check/check_mdata as per comment from Jassi
> > * Fix the typo in the function comment of fwu_mdata_check()
> >
> >  drivers/fwu-mdata/fwu-mdata-uclass.c | 107 ++++++++
> >  include/dm/uclass-id.h               |   1 +
> >  include/fwu.h                        | 211 ++++++++++++++++
> >  include/fwu_mdata.h                  |  67 +++++
> >  lib/fwu_updates/fwu.c                | 363 +++++++++++++++++++++++++++
> >  5 files changed, 749 insertions(+)
> >  create mode 100644 drivers/fwu-mdata/fwu-mdata-uclass.c
> >  create mode 100644 include/fwu.h
> >  create mode 100644 include/fwu_mdata.h
> >  create mode 100644 lib/fwu_updates/fwu.c

<snip>

> > diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
> > new file mode 100644
> > index 0000000000..fe8058bc37
> > --- /dev/null
> > +++ b/lib/fwu_updates/fwu.c
> > @@ -0,0 +1,363 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright (c) 2022, Linaro Limited
> > + */
> > +
> > +#include <dm.h>
> > +#include <efi_loader.h>
> > +#include <fwu.h>
> > +#include <fwu_mdata.h>
> > +#include <log.h>
> > +
> > +#include <linux/errno.h>
> > +#include <linux/types.h>
> > +#include <u-boot/crc.h>
> > +
> > +#define IMAGE_ACCEPT_SET       BIT(0)
> > +#define IMAGE_ACCEPT_CLEAR     BIT(1)
>
> Nitpicking: i think an enumerated type would be better here.
> (not a strong opinion)

Okay

>
> > +
> > +static int fwu_get_dev_mdata(struct udevice **dev, struct fwu_mdata *mdata)
> > +
>
> Remove this empty line.

Will do

>
> > +{
> > +       int ret;
> > +
> > +       ret = uclass_first_device(UCLASS_FWU_MDATA, dev);
> > +       if (ret) {
> > +               log_debug("Cannot find fwu device\n");
> > +               return ret;
> > +       }
>
> `uclass_first_device()` returns 0 when node is not found but no issue
> reported while parsing the FDT (learned by experience :(. In that
> case, *dev is set to NULL and next instruction segfaults.
> Proposal:
>
>      ret = uclass_first_device(UCLASS_FWU_MDATA, dev);
> -    if (ret) {
> +    if (ret || !*dev) {
>          log_debug("Cannot find fwu device\n");
> +        if (!ret)
> +            ret = -ENOENT;
>          return ret;
>      }

I think I can instead use uclass_first_device_err(). I think that is
doing what you are proposing above.

>
>
>
> > +
> > +       ret = fwu_get_mdata(*dev, mdata);
> > +       if (ret < 0)
> > +               log_debug("Unable to get valid FWU metadata\n");
> > +
> > +       return ret;
> > +}
> > +
> > +static int fwu_get_image_type_id(u8 *image_index, efi_guid_t *image_type_id)
> > +{
> > +       u8 index;
> > +       int i;
> > +       struct efi_fw_image *image;
> > +
> > +       index = *image_index;
> > +       image = update_info.images;
> > +       for (i = 0; i < num_image_type_guids; i++) {
> > +               if (index == image[i].image_index) {
> > +                       guidcpy(image_type_id, &image[i].image_type_id);
> > +                       return 0;
> > +               }
> > +       }
> > +
> > +       return -ENOENT;
> > +}
> > +
> > +/**
> > + * fwu_verify_mdata() - Verify the FWU metadata
> > + * @mdata: FWU metadata structure
> > + * @pri_part: FWU metadata partition is primary or secondary
> > + *
> > + * Verify the FWU metadata by computing the CRC32 for the metadata
> > + * structure and comparing it against the CRC32 value stored as part
> > + * of the structure.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_verify_mdata(struct fwu_mdata *mdata, bool pri_part)
> > +{
> > +       u32 calc_crc32;
> > +       void *buf;
> > +
> > +       buf = &mdata->version;
> > +       calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));
> > +
> > +       if (calc_crc32 != mdata->crc32) {
> > +               log_debug("crc32 check failed for %s FWU metadata partition\n",
> > +                         pri_part ? "primary" : "secondary");
> > +               return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +/**
> > + * fwu_get_active_index() - Get active_index from the FWU metadata
> > + * @active_idx: active_index value to be read
> > + *
> > + * Read the active_index field from the FWU metadata and place it in
> > + * the variable pointed to be the function argument.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_get_active_index(uint *active_idx)
> > +{
> > +       int ret;
> > +       struct udevice *dev;
> > +       struct fwu_mdata mdata = { 0 };
> > +
> > +       ret = fwu_get_dev_mdata(&dev, &mdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * Found the FWU metadata partition, now read the active_index
> > +        * value
> > +        */
> > +       *active_idx = mdata.active_index;
> > +       if (*active_idx >= CONFIG_FWU_NUM_BANKS) {
> > +               log_debug("Active index value read is incorrect\n");
> > +               ret = -EINVAL;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +/**
> > + * fwu_set_active_index() - Set active_index in the FWU metadata
> > + * @active_idx: active_index value to be set
> > + *
> > + * Update the active_index field in the FWU metadata
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_set_active_index(uint active_idx)
> > +{
> > +       int ret;
> > +       struct udevice *dev;
> > +       struct fwu_mdata mdata = { 0 };
> > +
> > +       if (active_idx >= CONFIG_FWU_NUM_BANKS) {
> > +               log_debug("Invalid active index value\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       ret = fwu_get_dev_mdata(&dev, &mdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * Update the active index and previous_active_index fields
> > +        * in the FWU metadata
> > +        */
> > +       mdata.previous_active_index = mdata.active_index;
> > +       mdata.active_index = active_idx;
> > +
> > +       /*
> > +        * Now write this updated FWU metadata to both the
> > +        * FWU metadata partitions
> > +        */
> > +       ret = fwu_update_mdata(dev, &mdata);
> > +       if (ret < 0) {
>
> Function description says it returns 0 on success so prefer here 'if (ret)'.

Okay

>
> > +               log_debug("Failed to update FWU metadata partitions\n");
> > +               ret = -EIO;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +/**
> > + * fwu_get_image_index() - Get the Image Index to be used for capsule update
> > + * @image_index: The Image Index for the image
> > + *
> > + * The FWU multi bank update feature computes the value of image_index at
> > + * runtime, based on the bank to which the image needs to be written to.
> > + * Derive the image_index value for the image.
> > + *
> > + * Currently, the capsule update driver uses the DFU framework for
> > + * the updates. This function gets the DFU alt number which is to
> > + * be used as the Image Index
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_get_image_index(u8 *image_index)
> > +{
> > +       int ret, i;
> > +       u8 alt_num;
> > +       u32 update_bank;
> > +       efi_guid_t *image_guid, image_type_id;
> > +       struct udevice *dev;
> > +       struct fwu_mdata mdata = { 0 };
> > +       struct fwu_image_entry *img_entry;
> > +       struct fwu_image_bank_info *img_bank_info;
> > +
> > +       ret = fwu_get_dev_mdata(&dev, &mdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = fwu_plat_get_update_index(&update_bank);
> > +       if (ret) {
> > +               log_debug("Failed to get the FWU update bank\n");
> > +               goto out;
> > +       }
> > +
> > +       ret = fwu_get_image_type_id(image_index, &image_type_id);
> > +       if (ret) {
> > +               log_debug("Unable to get image_type_id for image_index %u\n",
> > +                         *image_index);
> > +               goto out;
> > +       }
> > +
> > +       ret = -EINVAL;
> > +       /*
> > +        * The FWU metadata has been read. Now get the image_uuid for the
> > +        * image with the update_bank.
> > +        */
> > +       for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; i++) {
> > +               if (!guidcmp(&image_type_id,
> > +                            &mdata.img_entry[i].image_type_uuid)) {
> > +                       img_entry = &mdata.img_entry[i];
> > +                       img_bank_info = &img_entry->img_bank_info[update_bank];
> > +                       image_guid = &img_bank_info->image_uuid;
> > +                       ret = fwu_plat_get_alt_num(dev, image_guid, &alt_num);
> > +                       if (ret) {
> > +                               log_debug("alt_num not found for partition with GUID %pUs\n",
> > +                                         image_guid);
> > +                       } else {
> > +                               log_debug("alt_num %d for partition %pUs\n",
> > +                                         alt_num, image_guid);
> > +                               *image_index = alt_num + 1;
> > +                       }
> > +
> > +                       goto out;
> > +               }
> > +       }
> > +
> > +       log_debug("Partition with the image type %pUs not found\n",
> > +                 &image_type_id);
> > +
> > +out:
> > +       return ret;
> > +}
> > +
> > +/**
> > + * fwu_revert_boot_index() - Revert the active index in the FWU metadata
> > + *
> > + * Revert the active_index value in the FWU metadata, by swapping the values
> > + * of active_index and previous_active_index in both copies of the
> > + * FWU metadata.
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_revert_boot_index(void)
> > +{
> > +       int ret;
> > +       u32 cur_active_index;
> > +       struct udevice *dev;
> > +       struct fwu_mdata mdata = { 0 };
> > +
> > +       ret = fwu_get_dev_mdata(&dev, &mdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * Swap the active index and previous_active_index fields
> > +        * in the FWU metadata
> > +        */
> > +       cur_active_index = mdata.active_index;
> > +       mdata.active_index = mdata.previous_active_index;
> > +       mdata.previous_active_index = cur_active_index;
> > +
> > +       /*
> > +        * Now write this updated FWU metadata to both the
> > +        * FWU metadata partitions
> > +        */
> > +       ret = fwu_update_mdata(dev, &mdata);
> > +       if (ret < 0) {
>
> Same comment here: error case should be trapped with 'if (ret)'.

Okay

-sughosh

>
> br,
> etienne
>
> > +               log_debug("Failed to update FWU metadata partitions\n");
> > +               ret = -EIO;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +/**
> > + * fwu_clrset_image_accept() - Set or Clear the Acceptance bit for the image
> > + * @img_type_id: GUID of the image type for which the accepted bit is to be
> > + *               set or cleared
> > + * @bank: Bank of which the image's Accept bit is to be set or cleared
> > + * @action: Action which specifies whether image's Accept bit is to be set or
> > + *          cleared
> > + *
> > + * Set/Clear the accepted bit for the image specified by the img_guid parameter.
> > + * This indicates acceptance or rejection of image for subsequent boots by some
> > + * governing component like OS(or firmware).
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +static int fwu_clrset_image_accept(efi_guid_t *img_type_id, u32 bank, u8 action)
> > +{
> > +       int ret, i;
> > +       struct udevice *dev;
> > +       struct fwu_mdata mdata = { 0 };
> > +       struct fwu_image_entry *img_entry;
> > +       struct fwu_image_bank_info *img_bank_info;
> > +
> > +       ret = fwu_get_dev_mdata(&dev, &mdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       img_entry = &mdata.img_entry[0];
> > +       for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; i++) {
> > +               if (!guidcmp(&img_entry[i].image_type_uuid, img_type_id)) {
> > +                       img_bank_info = &img_entry[i].img_bank_info[bank];
> > +                       if (action == IMAGE_ACCEPT_SET)
> > +                               img_bank_info->accepted |= FWU_IMAGE_ACCEPTED;
> > +                       else
> > +                               img_bank_info->accepted = 0;
> > +
> > +                       ret = fwu_update_mdata(dev, &mdata);
> > +                       goto out;
> > +               }
> > +       }
> > +
> > +       /* Image not found */
> > +       ret = -ENOENT;
> > +
> > +out:
> > +       return ret;
> > +}
> > +
> > +/**
> > + * fwu_accept_image() - Set the Acceptance bit for the image
> > + * @img_type_id: GUID of the image type for which the accepted bit is to be
> > + *               cleared
> > + * @bank: Bank of which the image's Accept bit is to be set
> > + *
> > + * Set the accepted bit for the image specified by the img_guid parameter. This
> > + * indicates acceptance of image for subsequent boots by some governing component
> > + * like OS(or firmware).
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_accept_image(efi_guid_t *img_type_id, u32 bank)
> > +{
> > +       return fwu_clrset_image_accept(img_type_id, bank,
> > +                                      IMAGE_ACCEPT_SET);
> > +}
> > +
> > +/**
> > + * fwu_clear_accept_image() - Clear the Acceptance bit for the image
> > + * @img_type_id: GUID of the image type for which the accepted bit is to be
> > + *               cleared
> > + * @bank: Bank of which the image's Accept bit is to be cleared
> > + *
> > + * Clear the accepted bit for the image type specified by the img_type_id parameter.
> > + * This function is called after the image has been updated. The accepted bit is
> > + * cleared to be set subsequently after passing the image acceptance criteria, by
> > + * either the OS(or firmware)
> > + *
> > + * Return: 0 if OK, -ve on error
> > + *
> > + */
> > +int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
> > +{
> > +       return fwu_clrset_image_accept(img_type_id, bank,
> > +                                      IMAGE_ACCEPT_CLEAR);
> > +}
> > --
> > 2.34.1
> >