--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Verified Boot for Embedded (VBE) 'simple' method
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <log.h>
+#include <memalign.h>
+#include <part.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <dm.h>
+#include <mmc.h>
+#include <vbe.h>
+#include <version_string.h>
+#include <dm/device-internal.h>
+#include <dm/ofnode.h>
+#include <u-boot/crc.h>
+
+enum {
+ MAX_VERSION_LEN = 256,
+
+ NVD_HDR_VER_SHIFT = 0,
+ NVD_HDR_VER_MASK = 0xf,
+ NVD_HDR_SIZE_SHIFT = 4,
+ NVD_HDR_SIZE_MASK = 0xf << NVD_HDR_SIZE_SHIFT,
+
+ /* Firmware key-version is in the top 16 bits of fw_ver */
+ FWVER_KEY_SHIFT = 16,
+ FWVER_FW_MASK = 0xffff,
+
+ NVD_HDR_VER_CUR = 1, /* current version */
+};
+
+/** struct simple_priv - information read from the device tree */
+struct simple_priv {
+ u32 area_start;
+ u32 area_size;
+ u32 skip_offset;
+ u32 state_offset;
+ u32 state_size;
+ u32 version_offset;
+ u32 version_size;
+ const char *storage;
+};
+
+/** struct simple_state - state information read from media
+ *
+ * @fw_version: Firmware version string
+ * @fw_vernum: Firmware version number
+ */
+struct simple_state {
+ char fw_version[MAX_VERSION_LEN];
+ u32 fw_vernum;
+};
+
+/** struct simple_nvdata - storage format for non-volatile data */
+struct simple_nvdata {
+ u8 crc8;
+ u8 hdr;
+ u16 spare1;
+ u32 fw_vernum;
+ u8 spare2[0x38];
+};
+
+static int simple_read_version(struct udevice *dev, struct blk_desc *desc,
+ u8 *buf, struct simple_state *state)
+{
+ struct simple_priv *priv = dev_get_priv(dev);
+ int start;
+
+ if (priv->version_size > MMC_MAX_BLOCK_LEN)
+ return log_msg_ret("ver", -E2BIG);
+
+ start = priv->area_start + priv->version_offset;
+ if (start & (MMC_MAX_BLOCK_LEN - 1))
+ return log_msg_ret("get", -EBADF);
+ start /= MMC_MAX_BLOCK_LEN;
+
+ if (blk_dread(desc, start, 1, buf) != 1)
+ return log_msg_ret("read", -EIO);
+ strlcpy(state->fw_version, buf, MAX_VERSION_LEN);
+ log_debug("version=%s\n", state->fw_version);
+
+ return 0;
+}
+
+static int simple_read_nvdata(struct udevice *dev, struct blk_desc *desc,
+ u8 *buf, struct simple_state *state)
+{
+ struct simple_priv *priv = dev_get_priv(dev);
+ uint hdr_ver, hdr_size, size, crc;
+ const struct simple_nvdata *nvd;
+ int start;
+
+ if (priv->state_size > MMC_MAX_BLOCK_LEN)
+ return log_msg_ret("state", -E2BIG);
+
+ start = priv->area_start + priv->state_offset;
+ if (start & (MMC_MAX_BLOCK_LEN - 1))
+ return log_msg_ret("get", -EBADF);
+ start /= MMC_MAX_BLOCK_LEN;
+
+ if (blk_dread(desc, start, 1, buf) != 1)
+ return log_msg_ret("read", -EIO);
+ nvd = (struct simple_nvdata *)buf;
+ hdr_ver = (nvd->hdr & NVD_HDR_VER_MASK) >> NVD_HDR_VER_SHIFT;
+ hdr_size = (nvd->hdr & NVD_HDR_SIZE_MASK) >> NVD_HDR_SIZE_SHIFT;
+ if (hdr_ver != NVD_HDR_VER_CUR)
+ return log_msg_ret("hdr", -EPERM);
+ size = 1 << hdr_size;
+ if (size > sizeof(*nvd))
+ return log_msg_ret("sz", -ENOEXEC);
+
+ crc = crc8(0, buf + 1, size - 1);
+ if (crc != nvd->crc8)
+ return log_msg_ret("crc", -EPERM);
+ state->fw_vernum = nvd->fw_vernum;
+
+ log_debug("version=%s\n", state->fw_version);
+
+ return 0;
+}
+
+static int simple_read_state(struct udevice *dev, struct simple_state *state)
+{
+ ALLOC_CACHE_ALIGN_BUFFER(u8, buf, MMC_MAX_BLOCK_LEN);
+ struct simple_priv *priv = dev_get_priv(dev);
+ struct blk_desc *desc;
+ char devname[16];
+ const char *end;
+ int devnum;
+ int ret;
+
+ /* First figure out the block device */
+ log_debug("storage=%s\n", priv->storage);
+ devnum = trailing_strtoln_end(priv->storage, NULL, &end);
+ if (devnum == -1)
+ return log_msg_ret("num", -ENODEV);
+ if (end - priv->storage >= sizeof(devname))
+ return log_msg_ret("end", -E2BIG);
+ strlcpy(devname, priv->storage, end - priv->storage + 1);
+ log_debug("dev=%s, %x\n", devname, devnum);
+
+ desc = blk_get_dev(devname, devnum);
+ if (!desc)
+ return log_msg_ret("get", -ENXIO);
+
+ ret = simple_read_version(dev, desc, buf, state);
+ if (ret)
+ return log_msg_ret("ver", ret);
+
+ ret = simple_read_nvdata(dev, desc, buf, state);
+ if (ret)
+ return log_msg_ret("nvd", ret);
+
+ return 0;
+}
+
+static int vbe_simple_get_state_desc(struct udevice *dev, char *buf,
+ int maxsize)
+{
+ struct simple_state state;
+ int ret;
+
+ ret = simple_read_state(dev, &state);
+ if (ret)
+ return log_msg_ret("read", ret);
+
+ if (maxsize < 30)
+ return -ENOSPC;
+ snprintf(buf, maxsize, "Version: %s\nVernum: %x/%x", state.fw_version,
+ state.fw_vernum >> FWVER_KEY_SHIFT,
+ state.fw_vernum & FWVER_FW_MASK);
+
+ return 0;
+}
+
+static int vbe_simple_read_bootflow(struct udevice *dev, struct bootflow *bflow)
+{
+ /* To be implemented */
+
+ return -EINVAL;
+}
+
+static struct bootmeth_ops bootmeth_vbe_simple_ops = {
+ .get_state_desc = vbe_simple_get_state_desc,
+ .read_bootflow = vbe_simple_read_bootflow,
+ .read_file = bootmeth_common_read_file,
+};
+
+int vbe_simple_fixup_node(ofnode node, struct simple_state *state)
+{
+ char *version;
+ int ret;
+
+ version = strdup(state->fw_version);
+ if (!version)
+ return log_msg_ret("ver", -ENOMEM);
+
+ ret = ofnode_write_string(node, "cur-version", version);
+ if (ret)
+ return log_msg_ret("ver", ret);
+ ret = ofnode_write_u32(node, "cur-vernum", state->fw_vernum);
+ if (ret)
+ return log_msg_ret("ver", ret);
+ ret = ofnode_write_string(node, "bootloader-version", version_string);
+ if (ret)
+ return log_msg_ret("fix", ret);
+
+ return 0;
+}
+
+/**
+ * bootmeth_vbe_simple_ft_fixup() - Write out all VBE simple data to the DT
+ *
+ * @ctx: Context for event
+ * @event: Event to process
+ * @return 0 if OK, -ve on error
+ */
+static int bootmeth_vbe_simple_ft_fixup(void *ctx, struct event *event)
+{
+ oftree tree = event->data.ft_fixup.tree;
+ struct udevice *dev;
+ ofnode node;
+ int ret;
+
+ /*
+ * Ideally we would have driver model support for fixups, but that does
+ * not exist yet. It is a step too far to try to do this before VBE is
+ * in place.
+ */
+ for (ret = vbe_find_first_device(&dev); dev;
+ ret = vbe_find_next_device(&dev)) {
+ struct simple_state state;
+
+ if (strcmp("vbe_simple", dev->driver->name))
+ continue;
+
+ /* Check if there is a node to fix up */
+ node = ofnode_path_root(tree, "/chosen/fwupd");
+ if (!ofnode_valid(node))
+ continue;
+ node = ofnode_find_subnode(node, dev->name);
+ if (!ofnode_valid(node))
+ continue;
+
+ log_debug("Fixing up: %s\n", dev->name);
+ ret = device_probe(dev);
+ if (ret)
+ return log_msg_ret("probe", ret);
+ ret = simple_read_state(dev, &state);
+ if (ret)
+ return log_msg_ret("read", ret);
+
+ ret = vbe_simple_fixup_node(node, &state);
+ if (ret)
+ return log_msg_ret("fix", ret);
+ }
+
+ return 0;
+}
+EVENT_SPY(EVT_FT_FIXUP, bootmeth_vbe_simple_ft_fixup);
+
+static int bootmeth_vbe_simple_probe(struct udevice *dev)
+{
+ struct simple_priv *priv = dev_get_priv(dev);
+
+ memset(priv, '\0', sizeof(*priv));
+ if (dev_read_u32(dev, "area-start", &priv->area_start) ||
+ dev_read_u32(dev, "area-size", &priv->area_size) ||
+ dev_read_u32(dev, "version-offset", &priv->version_offset) ||
+ dev_read_u32(dev, "version-size", &priv->version_size) ||
+ dev_read_u32(dev, "state-offset", &priv->state_offset) ||
+ dev_read_u32(dev, "state-size", &priv->state_size))
+ return log_msg_ret("read", -EINVAL);
+ dev_read_u32(dev, "skip-offset", &priv->skip_offset);
+ priv->storage = strdup(dev_read_string(dev, "storage"));
+ if (!priv->storage)
+ return log_msg_ret("str", -EINVAL);
+
+ return 0;
+}
+
+static int bootmeth_vbe_simple_bind(struct udevice *dev)
+{
+ struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
+
+ plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
+ "VBE simple" : "vbe-simple";
+ plat->flags = BOOTMETHF_GLOBAL;
+
+ return 0;
+}
+
+#if CONFIG_IS_ENABLED(OF_REAL)
+static const struct udevice_id generic_simple_vbe_simple_ids[] = {
+ { .compatible = "fwupd,vbe-simple" },
+ { }
+};
+#endif
+
+U_BOOT_DRIVER(vbe_simple) = {
+ .name = "vbe_simple",
+ .id = UCLASS_BOOTMETH,
+ .of_match = of_match_ptr(generic_simple_vbe_simple_ids),
+ .ops = &bootmeth_vbe_simple_ops,
+ .bind = bootmeth_vbe_simple_bind,
+ .probe = bootmeth_vbe_simple_probe,
+ .flags = DM_FLAG_PRE_RELOC,
+ .priv_auto = sizeof(struct simple_priv),
+};
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