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

1 files changed, 139 insertions, 0 deletions

diff --git a/boot/bootmeth_script.c b/boot/bootmeth_script.c
new file mode 100644
index 00000000000..d1c3f940037
--- /dev/null
+++ b/boot/bootmeth_script.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootmethod for booting via a U-Boot script
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <[email protected]>
+ */
+
+#define LOG_CATEGORY UCLASS_BOOTSTD
+
+#include <common.h>
+#include <blk.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <bootstd.h>
+#include <dm.h>
+#include <env.h>
+#include <fs.h>
+#include <image.h>
+#include <malloc.h>
+#include <mapmem.h>
+
+#define SCRIPT_FNAME1	"boot.scr.uimg"
+#define SCRIPT_FNAME2	"boot.scr"
+
+static int script_check(struct udevice *dev, struct bootflow_iter *iter)
+{
+	int ret;
+
+	/* This only works on block devices */
+	ret = bootflow_iter_uses_blk_dev(iter);
+	if (ret)
+		return log_msg_ret("blk", ret);
+
+	return 0;
+}
+
+static int script_read_bootflow(struct udevice *dev, struct bootflow *bflow)
+{
+	struct blk_desc *desc = NULL;
+	const char *const *prefixes;
+	struct udevice *bootstd;
+	const char *prefix;
+	int ret, i;
+
+	ret = uclass_first_device_err(UCLASS_BOOTSTD, &bootstd);
+	if (ret)
+		return log_msg_ret("std", ret);
+
+	/* We require a partition table */
+	if (!bflow->part)
+		return -ENOENT;
+
+	if (bflow->blk)
+		 desc = dev_get_uclass_plat(bflow->blk);
+
+	prefixes = bootstd_get_prefixes(bootstd);
+	i = 0;
+	do {
+		prefix = prefixes ? prefixes[i] : NULL;
+
+		ret = bootmeth_try_file(bflow, desc, prefix, SCRIPT_FNAME1);
+		if (ret)
+			ret = bootmeth_try_file(bflow, desc, prefix,
+						SCRIPT_FNAME2);
+	} while (ret && prefixes && prefixes[++i]);
+	if (ret)
+		return log_msg_ret("try", ret);
+
+	bflow->subdir = strdup(prefix ? prefix : "");
+	if (!bflow->subdir)
+		return log_msg_ret("prefix", -ENOMEM);
+
+	ret = bootmeth_alloc_file(bflow, 0x10000, 1);
+	if (ret)
+		return log_msg_ret("read", ret);
+
+	return 0;
+}
+
+static int script_boot(struct udevice *dev, struct bootflow *bflow)
+{
+	struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
+	ulong addr;
+	int ret;
+
+	ret = env_set("devtype", blk_get_devtype(bflow->blk));
+	if (!ret)
+		ret = env_set_hex("devnum", desc->devnum);
+	if (!ret)
+		ret = env_set("prefix", bflow->subdir);
+	if (!ret && IS_ENABLED(CONFIG_ARCH_SUNXI) &&
+	    !strcmp("mmc", blk_get_devtype(bflow->blk)))
+		ret = env_set_hex("mmc_bootdev", desc->devnum);
+	if (ret)
+		return log_msg_ret("env", ret);
+
+	log_debug("devtype: %s\n", env_get("devtype"));
+	log_debug("devnum: %s\n", env_get("devnum"));
+	log_debug("prefix: %s\n", env_get("prefix"));
+	log_debug("mmc_bootdev: %s\n", env_get("mmc_bootdev"));
+
+	addr = map_to_sysmem(bflow->buf);
+	ret = image_source_script(addr, NULL);
+	if (ret)
+		return log_msg_ret("boot", ret);
+
+	return 0;
+}
+
+static int script_bootmeth_bind(struct udevice *dev)
+{
+	struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
+
+	plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
+		"Script boot from a block device" : "script";
+
+	return 0;
+}
+
+static struct bootmeth_ops script_bootmeth_ops = {
+	.check		= script_check,
+	.read_bootflow	= script_read_bootflow,
+	.read_file	= bootmeth_common_read_file,
+	.boot		= script_boot,
+};
+
+static const struct udevice_id script_bootmeth_ids[] = {
+	{ .compatible = "u-boot,script" },
+	{ }
+};
+
+U_BOOT_DRIVER(bootmeth_script) = {
+	.name		= "bootmeth_script",
+	.id		= UCLASS_BOOTMETH,
+	.of_match	= script_bootmeth_ids,
+	.ops		= &script_bootmeth_ops,
+	.bind		= script_bootmeth_bind,
+};