Re: [PATCH v5 13/23] FWU: Add FWU metadata access driver for non-GPT MTD devices

Etienne Carriere
2022-06-21T10:57:17Z

On Thu, 9 Jun 2022 at 14:31, Sughosh Ganu <sughosh.ganu@linaro.org> wrote:
>
> From: Masami Hiramatsu <masami.hiramatsu@linaro.org>
>
> For the platform which doesn't have GPT partitions for the firmware
> but on MTD devices, the FWU metadata is stored on MTD device as raw
> image at specific offset. This driver gives the access methods
> for the FWU metadata information on such MTD devices.
>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> ---
> drivers/fwu-mdata/Kconfig | 8 +
> drivers/fwu-mdata/Makefile | 1 +
> drivers/fwu-mdata/fwu_mdata_mtd.c | 308 ++++++++++++++++++++++++++++++
> 3 files changed, 317 insertions(+)
> create mode 100644 drivers/fwu-mdata/fwu_mdata_mtd.c
>
> diff --git a/drivers/fwu-mdata/Kconfig b/drivers/fwu-mdata/Kconfig
> index d5edef19d6..a8fa9ad783 100644
> --- a/drivers/fwu-mdata/Kconfig
> +++ b/drivers/fwu-mdata/Kconfig
> @@ -14,3 +14,11 @@ config FWU_MDATA_GPT_BLK
> help
> Enable support for accessing FWU Metadata on GPT partitioned
> block devices.
> +
> +config FWU_MDATA_MTD
> + bool "FWU Metadata access for non-GPT MTD devices"
> + depends on DM_FWU_MDATA && MTD
> + help
> + Enable support for accessing FWU Metadata on non-partitioned
> + (or non-GPT partitioned, e.g. partition nodes in devicetree)
> + MTD devices.
> diff --git a/drivers/fwu-mdata/Makefile b/drivers/fwu-mdata/Makefile
> index 12a5b4fe04..c574c59be2 100644
> --- a/drivers/fwu-mdata/Makefile
> +++ b/drivers/fwu-mdata/Makefile
> @@ -5,3 +5,4 @@
>
> obj-$(CONFIG_DM_FWU_MDATA) += fwu-mdata-uclass.o
> obj-$(CONFIG_FWU_MDATA_GPT_BLK) += fwu_mdata_gpt_blk.o
> +obj-$(CONFIG_FWU_MDATA_MTD) += fwu_mdata_mtd.o
> diff --git a/drivers/fwu-mdata/fwu_mdata_mtd.c b/drivers/fwu-mdata/fwu_mdata_mtd.c
> new file mode 100644
> index 0000000000..9eb471e73e
> --- /dev/null
> +++ b/drivers/fwu-mdata/fwu_mdata_mtd.c
> @@ -0,0 +1,308 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2022, Linaro Limited
> + */
> +
> +#include <efi_loader.h>
> +#include <fwu.h>
> +#include <fwu_mdata.h>
> +#include <malloc.h>
> +#include <memalign.h>
> +#include <spi.h>
> +#include <spi_flash.h>
> +#include <flash.h>
> +
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +#include <u-boot/crc.h>
> +
> +struct fwu_mdata_mtd_priv {
> + struct mtd_info *mtd;
> + u32 pri_offset;
> + u32 sec_offset;
> +};

Add an inline description of the fields.

> +
> +enum fwu_mtd_op {
> + FWU_MTD_READ,
> + FWU_MTD_WRITE,
> +};
> +
> +static bool mtd_is_aligned_with_block_size(struct mtd_info *mtd, u64 size)
> +{
> + return !do_div(size, mtd->erasesize);
> +}
> +
> +static int mtd_io_data(struct mtd_info *mtd, u32 offs, u32 size, void *data,
> + enum fwu_mtd_op op)
> +{
> + struct mtd_oob_ops io_op ={};
> + u64 lock_offs, lock_len;
> + size_t len;
> + void *buf;
> + int ret;
> +
> + if (!mtd_is_aligned_with_block_size(mtd, offs))
> + return -EINVAL;
> + lock_offs = offs;
> + lock_len = round_up(size, mtd->erasesize);
> +
> + ret = mtd_unlock(mtd, lock_offs, lock_len);
> + if (ret && ret != -EOPNOTSUPP)
> + return ret;
> +
> + if (op == FWU_MTD_WRITE) {
> + struct erase_info erase_op = {};
> +
> + /* This will expand erase size to align with the block size */
> + erase_op.mtd = mtd;
> + erase_op.addr = lock_offs;
> + erase_op.len = lock_len;
> + erase_op.scrub = 0;
> +
> + ret = mtd_erase(mtd, &erase_op);
> + if (ret)
> + goto lock_out;
> + }
> +
> + /* Also, expand the write size to align with the write size */
> + len = round_up(size, mtd->writesize);
> +
> + buf = memalign(ARCH_DMA_MINALIGN, len);
> + if (!buf) {
> + ret = -ENOMEM;
> + goto lock_out;
> + }
> + io_op.mode = MTD_OPS_AUTO_OOB;
> + io_op.len = len;
> + io_op.ooblen = 0;
> + io_op.datbuf = buf;
> + io_op.oobbuf = NULL;
> +
> + if (op == FWU_MTD_WRITE) {
> + memcpy(buf, data, size);
> + ret = mtd_write_oob(mtd, offs, &io_op);
> + } else {
> + ret = mtd_read_oob(mtd, offs, &io_op);
> + if (!ret)
> + memcpy(data, buf, size);
> + }
> + free(buf);
> +
> +lock_out:
> + mtd_lock(mtd, lock_offs, lock_len);
> +
> + return ret;
> +}
> +
> +static int fwu_mtd_load_mdata(struct mtd_info *mtd, struct fwu_mdata **mdata,
> + u32 offs, bool primary)
> +{
> + size_t size = sizeof(struct fwu_mdata);
> + int ret;
> +
> + *mdata = malloc(size);
> + if (!*mdata)
> + return -ENOMEM;
> +
> + ret = mtd_io_data(mtd, offs, size, (void *)*mdata, FWU_MTD_READ);
> + if (ret >= 0) {
> + ret = fwu_verify_mdata(*mdata, primary);
> + if (ret < 0) {
> + free(*mdata);
> + *mdata = NULL;
> + }
> + }
> +
> + return ret;
> +}
> +
> +static int fwu_mtd_load_primary_mdata(struct fwu_mdata_mtd_priv *mtd_priv,
> + struct fwu_mdata **mdata)
> +{
> + return fwu_mtd_load_mdata(mtd_priv->mtd, mdata, mtd_priv->pri_offset, true);
> +}
> +
> +static int fwu_mtd_load_secondary_mdata(struct fwu_mdata_mtd_priv *mtd_priv,
> + struct fwu_mdata **mdata)
> +{
> + return fwu_mtd_load_mdata(mtd_priv->mtd, mdata, mtd_priv->sec_offset, false);
> +}
> +
> +static int fwu_mtd_save_primary_mdata(struct fwu_mdata_mtd_priv *mtd_priv,
> + struct fwu_mdata *mdata)
> +{
> + return mtd_io_data(mtd_priv->mtd, mtd_priv->pri_offset,
> + sizeof(struct fwu_mdata), mdata, FWU_MTD_WRITE);
> +}
> +
> +static int fwu_mtd_save_secondary_mdata(struct fwu_mdata_mtd_priv *mtd_priv,
> + struct fwu_mdata *mdata)
> +{
> + return mtd_io_data(mtd_priv->mtd, mtd_priv->sec_offset,
> + sizeof(struct fwu_mdata), mdata, FWU_MTD_WRITE);
> +}
> +
> +static int fwu_mtd_get_valid_mdata(struct fwu_mdata_mtd_priv *mtd_priv,
> + struct fwu_mdata **mdata)
> +{
> + if (fwu_mtd_load_primary_mdata(mtd_priv, mdata) == 0)
> + return 0;

Is it possible this can fail knowing that content of both images were
checked at probe time?
If it can fail, then, as for the GPT case, i think this function
should ensure the primary and secondary images, in the boot media, are
valid and consistent (sae data).
For example calling back fwu_mtd_mdata_check() for that purpose.
Otherwise, if fwu_mtd_update_mdata() is interrupted (e.g. power loss),
it would leave no valid fwu_mdata in the storage, preventing the
system from rebooting.

> +
> + log_err("Failed to load/verify primary mdata. Try secondary.\n");
> +
> + if (fwu_mtd_load_secondary_mdata(mtd_priv, mdata) == 0)
> + return 0;
> +
> + log_err("Failed to load/verify secondary mdata.\n");
> +
> + return -1;
> +}
> +
> +static int fwu_mtd_update_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> + struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
> + int ret;
> +
> + /* Update mdata crc32 field */
> + mdata->crc32 = crc32(0, (void *)&mdata->version,
> + sizeof(*mdata) - sizeof(u32));
> +
> + /* First write the primary mdata */
> + ret = fwu_mtd_save_primary_mdata(mtd_priv, mdata);
> + if (ret < 0) {
> + log_err("Failed to update the primary mdata.\n");
> + return ret;
> + }
> +
> + /* And now the replica */
> + ret = fwu_mtd_save_secondary_mdata(mtd_priv, mdata);
> + if (ret < 0) {
> + log_err("Failed to update the secondary mdata.\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int fwu_mtd_mdata_check(struct udevice *dev)
> +{
> + struct fwu_mdata *primary = NULL, *secondary = NULL;
> + struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
> + int ret;
> +
> + ret = fwu_mtd_load_primary_mdata(mtd_priv, &primary);
> + if (ret < 0)
> + log_err("Failed to read the primary mdata: %d\n", ret);
> +
> + ret = fwu_mtd_load_secondary_mdata(mtd_priv, &secondary);
> + if (ret < 0)
> + log_err("Failed to read the secondary mdata: %d\n", ret);
> +
> + if (primary && secondary) {
> + if (memcmp(primary, secondary, sizeof(struct fwu_mdata))) {
> + log_err("The primary and the secondary mdata are different\n");
> + ret = -1;
> + }
> + } else if (primary) {
> + ret = fwu_mtd_save_secondary_mdata(mtd_priv, primary);
> + if (ret < 0)
> + log_err("Restoring secondary mdata partition failed\n");
> + } else if (secondary) {
> + ret = fwu_mtd_save_primary_mdata(mtd_priv, secondary);
> + if (ret < 0)
> + log_err("Restoring primary mdata partition failed\n");
> + }
> +
> + free(primary);
> + free(secondary);
> + return ret;
> +}
> +
> +static int fwu_mtd_get_mdata(struct udevice *dev, struct fwu_mdata **mdata)
> +{
> + struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
> +
> + return fwu_mtd_get_valid_mdata(mtd_priv, mdata);
> +}
> +
> +/**
> + * fwu_mdata_mtd_of_to_plat() - Translate from DT to fwu mdata device
> + */
> +static int fwu_mdata_mtd_of_to_plat(struct udevice *dev)
> +{
> + struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
> + const fdt32_t *phandle_p = NULL;
> + struct udevice *mtd_dev;
> + struct mtd_info *mtd;
> + int ret, size;
> + u32 phandle;
> +
> + /* Find the FWU mdata storage device */
> + phandle_p = ofnode_get_property(dev_ofnode(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);
> +
> + ret = device_get_global_by_ofnode(
> + ofnode_get_by_phandle(phandle),
> + &mtd_dev);
> + if (ret)
> + return ret;
> +
> + mtd_probe_devices();
> +
> + mtd_for_each_device(mtd) {
> + if (mtd->dev == mtd_dev) {
> + mtd_priv->mtd = mtd;
> + log_debug("Found the FWU mdata mtd device %s\n", mtd->name);
> + break;
> + }
> + }
> + if (!mtd_priv->mtd) {
> + log_err("Failed to find mtd device by fwu-mdata-store\n");
> + return -ENOENT;
> + }
> +
> + /* Get the offset of primary and seconday mdata */
> + ret = ofnode_read_u32_index(dev_ofnode(dev), "mdata-offsets", 0,
> + &mtd_priv->pri_offset);
> + if (ret)
> + return ret;
> + ret = ofnode_read_u32_index(dev_ofnode(dev), "mdata-offsets", 1,
> + &mtd_priv->sec_offset);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int fwu_mdata_mtd_probe(struct udevice *dev)
> +{
> + /* Ensure the metadata can be read. */
> + return fwu_mtd_mdata_check(dev);
> +}
> +
> +static struct fwu_mdata_ops fwu_mtd_ops = {
> + .mdata_check = fwu_mtd_mdata_check,
> + .get_mdata = fwu_mtd_get_mdata,
> + .update_mdata = fwu_mtd_update_mdata,
> +};
> +
> +static const struct udevice_id fwu_mdata_ids[] = {
> + { .compatible = "u-boot,fwu-mdata-mtd" },
> + { }
> +};
> +
> +U_BOOT_DRIVER(fwu_mdata_mtd) = {
> + .name = "fwu-mdata-mtd",
> + .id = UCLASS_FWU_MDATA,
> + .of_match = fwu_mdata_ids,
> + .ops = &fwu_mtd_ops,
> + .probe = fwu_mdata_mtd_probe,
> + .of_to_plat = fwu_mdata_mtd_of_to_plat,
> + .priv_auto = sizeof(struct fwu_mdata_mtd_priv),
> +};
> --
> 2.25.1
>