Merge branch '2022-04-25-initial-implementation-of-stdboot'

To quote the author:
The bootflow feature provide a built-in way for U-Boot to automatically
boot an Operating System without custom scripting and other customisation.
This is called 'standard boot' since it provides a standard way for
U-Boot to boot a distro, without scripting.

It introduces the following concepts:

   - bootdev - a device which can hold a distro
   - bootmeth - a method to scan a bootdev to find bootflows (owned by
                U-Boot)
   - bootflow - a description of how to boot (owned by the distro)

This series provides an implementation of these, enabled to scan for
bootflows from MMC, USB and Ethernet. It supports the existing distro
boot as well as the EFI loader flow (bootefi/bootmgr). It works
similiarly to the existing script-based approach, but is native to
U-Boot.

With this we can boot on a Raspberry Pi 3 with just one command:

   bootflow scan -lb

which means to scan, listing (-l) each bootflow and trying to boot each
one (-b). The final patch shows this.

With a standard way to identify boot devices, booting become easier. It
also should be possible to support U-Boot scripts, for backwards
compatibility only.

...

The design is described in these two documents:

https://drive.google.com/file/d/1ggW0KJpUOR__vBkj3l61L2dav4ZkNC12/view?usp=sharing

https://drive.google.com/file/d/1kTrflO9vvGlKp-ZH_jlgb9TY3WYG6FF9/view?usp=sharing

5 files changed, 66 insertions, 0 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index cda9f66cc93..aa13d4faa77 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -16,6 +16,8 @@ source "fs/fat/Kconfig"
 
 source "fs/jffs2/Kconfig"
 
+source "fs/sandbox/Kconfig"
+
 source "fs/ubifs/Kconfig"
 
 source "fs/cramfs/Kconfig"
diff --git a/fs/fs.c b/fs/fs.c
index b812597ced9..6de1a3eb6d5 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -36,6 +36,11 @@ static int fs_dev_part;
 static struct disk_partition fs_partition;
 static int fs_type = FS_TYPE_ANY;
 
+void fs_set_type(int type)
+{
+	fs_type = type;
+}
+
 static inline int fs_probe_unsupported(struct blk_desc *fs_dev_desc,
 				      struct disk_partition *fs_partition)
 {
diff --git a/fs/sandbox/Kconfig b/fs/sandbox/Kconfig
new file mode 100644
index 00000000000..b2af8482428
--- /dev/null
+++ b/fs/sandbox/Kconfig
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
diff --git a/fs/sandbox/Makefile b/fs/sandbox/Makefile
index 06090519bf4..880d59dd693 100644
--- a/fs/sandbox/Makefile
+++ b/fs/sandbox/Makefile
@@ -9,3 +9,4 @@
 # Pavel Bartusek, Sysgo Real-Time Solutions AG, pba@sysgo.de
 
 obj-y := sandboxfs.o
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += host_bootdev.o
diff --git a/fs/sandbox/host_bootdev.c b/fs/sandbox/host_bootdev.c
new file mode 100644
index 00000000000..0d12ee4ef74
--- /dev/null
+++ b/fs/sandbox/host_bootdev.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootdevice for MMC
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootdev.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <dm.h>
+#include <fs.h>
+
+static int host_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			     struct bootflow *bflow)
+{
+	int ret;
+
+	if (iter->part)
+		return log_msg_ret("max", -ESHUTDOWN);
+
+	bflow->name = strdup(dev->name);
+	if (!bflow->name)
+		return log_msg_ret("name", -ENOMEM);
+
+	ret = bootmeth_check(bflow->method, iter);
+	if (ret)
+		return log_msg_ret("check", ret);
+
+	bflow->state = BOOTFLOWST_MEDIA;
+	bflow->fs_type = FS_TYPE_SANDBOX;
+
+	ret = bootmeth_read_bootflow(bflow->method, bflow);
+	if (ret)
+		return log_msg_ret("method", ret);
+
+	return 0;
+}
+
+struct bootdev_ops host_bootdev_ops = {
+	.get_bootflow	= host_get_bootflow,
+};
+
+static const struct udevice_id host_bootdev_ids[] = {
+	{ .compatible = "sandbox,bootdev-host" },
+	{ }
+};
+
+U_BOOT_DRIVER(host_bootdev) = {
+	.name		= "host_bootdev",
+	.id		= UCLASS_BOOTDEV,
+	.ops		= &host_bootdev_ops,
+	.of_match	= host_bootdev_ids,
+};