vbe: Add initial support for VBE

Create a new bootmeth for VBE along with a library to handle finding the
VBE methods.

Signed-off-by: Simon Glass <sjg@chromium.org>

boot/Kconfig

@@ -398,6 +398,16 @@ config BOOTMETH_EFILOADER
 
 	  This provides a way to try out standard boot on an existing boot flow.
 
+config BOOTMETH_VBE
+	bool "Bootdev support for Verified Boot for Embedded"
+	depends on FIT
+	default y
+	select BOOTMETH_GLOBAL
+	help
+	  Enables support for VBE boot. This is a standard boot method which
+	  supports selection of various firmware components, seleciton of an OS to
+	  boot as well as updating these using fwupd.
+
 config BOOTMETH_SANDBOX
 	def_bool y
 	depends on SANDBOX

boot/Makefile

@@ -46,3 +46,5 @@ obj-$(CONFIG_CMD_ADTIMG) += image-android-dt.o
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_LOAD_FIT) += common_fit.o
 endif
+
+obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_VBE) += vbe.o

boot/vbe.c

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Verified Boot for Embedded (VBE) access functions
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootmeth.h>
+#include <bootstd.h>
+#include <dm.h>
+#include <image.h>
+#include <vbe.h>
+#include <dm/uclass-internal.h>
+
+/**
+ * is_vbe() - Check if a device is a VBE method
+ *
+ * @dev: Device to check
+ * @return true if this is a VBE bootmth device, else false
+ */
+static bool is_vbe(struct udevice *dev)
+{
+	return !strncmp("vbe", dev->driver->name, 3);
+}
+
+int vbe_find_next_device(struct udevice **devp)
+{
+	for (uclass_find_next_device(devp);
+	     *devp;
+	     uclass_find_next_device(devp)) {
+		if (is_vbe(*devp))
+			return 0;
+	}
+
+	return 0;
+}
+
+int vbe_find_first_device(struct udevice **devp)
+{
+	uclass_find_first_device(UCLASS_BOOTMETH, devp);
+	if (*devp && is_vbe(*devp))
+		return 0;
+
+	return vbe_find_next_device(devp);
+}
+
+int vbe_list(void)
+{
+	struct bootstd_priv *std;
+	struct udevice *dev;
+	int ret;
+
+	ret = bootstd_get_priv(&std);
+	if (ret)
+		return ret;
+
+	printf("%3s  %-3s  %-15s  %-15s %s\n", "#", "Sel", "Device", "Driver",
+	       "Description");
+	printf("%3s  %-3s  %-15s  %-15s %s\n", "---", "---", "--------------",
+	       "--------------", "-----------");
+	for (ret = vbe_find_first_device(&dev); dev;
+	     ret = vbe_find_next_device(&dev)) {
+		const struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
+
+		printf("%3d  %-3s  %-15s  %-15s %s\n", dev_seq(dev),
+		       std->vbe_bootmeth == dev ? "*" : "", dev->name,
+		       dev->driver->name, plat->desc);
+	}
+	printf("%3s  %-3s  %-15s  %-15s %s\n", "---", "---", "--------------",
+	       "--------------", "-----------");
+
+	return 0;
+}
+
+int vbe_select(struct udevice *dev)
+{
+	struct bootstd_priv *std;
+	int ret;
+
+	ret = bootstd_get_priv(&std);
+	if (ret)
+		return ret;
+	std->vbe_bootmeth = dev;
+
+	return 0;
+}
+
+int vbe_find_by_any(const char *name, struct udevice **devp)
+{
+	struct udevice *dev;
+	int ret, seq;
+	char *endp;
+
+	seq = simple_strtol(name, &endp, 16);
+
+	/* Select by name */
+	if (*endp) {
+		ret = uclass_get_device_by_name(UCLASS_BOOTMETH, name, &dev);
+		if (ret) {
+			printf("Cannot probe VBE bootmeth '%s' (err=%d)\n", name,
+			       ret);
+			return ret;
+		}
+
+	/* select by number */
+	} else {
+		ret = uclass_get_device_by_seq(UCLASS_BOOTMETH, seq, &dev);
+		if (ret) {
+			printf("Cannot find '%s' (err=%d)\n", name, ret);
+			return ret;
+		}
+	}
+
+	*devp = dev;
+
+	return 0;
+}

include/bootstd.h

@@ -26,6 +26,7 @@ struct udevice;
  * @glob_head: Head for the global list of all bootflows across all bootdevs
  * @bootmeth_count: Number of bootmeth devices in @bootmeth_order
  * @bootmeth_order: List of bootmeth devices to use, in order, NULL-terminated
+ * @vbe_bootmeth: Currently selected VBE bootmeth, NULL if none
  */
 struct bootstd_priv {
 	const char **prefixes;
@@ -35,6 +36,7 @@ struct bootstd_priv {
 	struct list_head glob_head;
 	int bootmeth_count;
 	struct udevice **bootmeth_order;
+	struct udevice *vbe_bootmeth;
 };
 
 /**

include/vbe.h

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Verified Boot for Embedded (VBE) support
+ * See doc/develop/vbe.rst
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __VBE_H
+#define __VBE_H
+
+/**
+ * vbe_list() - List the VBE bootmeths
+ *
+ * This shows a list of the VBE bootmeth devices
+ *
+ * @return 0 (always)
+ */
+int vbe_list(void);
+
+/**
+ * vbe_find_by_any() - Find a VBE bootmeth by name or sequence
+ *
+ * @name: name (e.g. "vbe-simple"), or sequence ("2") to find
+ * @devp: returns the device found, on success
+ * Return: 0 if OK, -ve on error
+ */
+int vbe_find_by_any(const char *name, struct udevice **devp);
+
+/**
+ * vbe_find_first_device() - Find the first VBE bootmeth
+ *
+ * @devp: Returns first available VBE bootmeth, or NULL if none
+ * Returns: 0 (always)
+ */
+int vbe_find_first_device(struct udevice **devp);
+
+/**
+ * vbe_find_next_device() - Find the next available VBE bootmeth
+ *
+ * @devp: Previous device to start from. Returns next available VBE bootmeth,
+ * or NULL if none
+ * Returns: 0 (always)
+ */
+int vbe_find_next_device(struct udevice **devp);
+
+#endif