bootstd: Add an implementation of EFI boot

Add a bootmeth driver which handles EFI boot, using EFI_LOADER.

In effect, this provides the same functionality as the 'bootefi' command
and shares the same code. But the interface into it is via a bootmeth,
so it does not require any special scripts, etc.

For now this requires the 'bootefi' command be enabled. Future work may
tidy this up so that it can be used without CONFIG_CMDLINE being enabled.

There was much discussion about whether this is needed, but it seems
that it is, at least for now.

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

3 files changed, 210 insertions, 0 deletions

diff --git a/boot/Kconfig b/boot/Kconfig
index 9e02a75..0bfea27 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -349,6 +349,27 @@ config BOOTMETH_DISTRO_PXE
 
 	  This provides a way to try out standard boot on an existing boot flow.
 
+config BOOTMETH_EFILOADER
+	bool "Bootdev support for EFI boot"
+	depends on CMD_BOOTEFI
+	default y
+	help
+	  Enables support for EFI boot using bootdevs. This makes the
+	  bootdevs look for a 'boot<arch>.efi' on each filesystem
+	  they scan. The resulting file is booted after enabling U-Boot's
+	  EFI loader support.
+
+	  The <arch> depends on the architecture of the board:
+
+	     aa64      - aarch64 (ARM 64-bit)
+	     arm       - ARM 32-bit
+	     ia32      - x86 32-bit
+	     x64       - x86 64-bit
+	     riscv32   - RISC-V 32-bit
+	     riscv64   - RISC-V 64-bit
+
+	  This provides a way to try out standard boot on an existing boot flow.
+
 endif
 
 config LEGACY_IMAGE_FORMAT
diff --git a/boot/Makefile b/boot/Makefile
index 9c9613d..4f92676 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootstd-uclass.o
 
 obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO) += bootmeth_distro.o
 obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO_PXE) += bootmeth_pxe.o
+obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_EFILOADER) += bootmeth_efi.o
 
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += fdt_region.o
diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c
new file mode 100644
index 0000000..d5438eb
--- /dev/null
+++ b/boot/bootmeth_efi.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootmethod for distro boot via EFI
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY UCLASS_BOOTSTD
+
+#include <common.h>
+#include <bootdev.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <command.h>
+#include <dm.h>
+#include <efi_loader.h>
+#include <fs.h>
+#include <malloc.h>
+#include <mapmem.h>
+#include <mmc.h>
+#include <pxe_utils.h>
+
+#define EFI_DIRNAME	"efi/boot/"
+
+/**
+ * get_efi_leafname() - Get the leaf name for the EFI file we expect
+ *
+ * @str: Place to put leaf name for this architecture, e.g. "bootaa64.efi".
+ *	Must have at least 16 bytes of space
+ * @max_len: Length of @str, must be >=16
+ */
+static int get_efi_leafname(char *str, int max_len)
+{
+	const char *base;
+
+	if (max_len < 16)
+		return log_msg_ret("spc", -ENOSPC);
+	if (IS_ENABLED(CONFIG_ARM64))
+		base = "bootaa64";
+	else if (IS_ENABLED(CONFIG_ARM))
+		base = "bootarm";
+	else if (IS_ENABLED(CONFIG_X86_RUN_32BIT))
+		base = "bootia32";
+	else if (IS_ENABLED(CONFIG_X86_RUN_64BIT))
+		base = "bootx64";
+	else if (IS_ENABLED(CONFIG_ARCH_RV32I))
+		base = "bootriscv32";
+	else if (IS_ENABLED(CONFIG_ARCH_RV64I))
+		base = "bootriscv64";
+	else if (IS_ENABLED(CONFIG_SANDBOX))
+		base = "bootsbox";
+	else
+		return -EINVAL;
+
+	strcpy(str, base);
+	strcat(str, ".efi");
+
+	return 0;
+}
+
+static int efiload_read_file(struct blk_desc *desc, struct bootflow *bflow)
+{
+	const struct udevice *media_dev;
+	int size = bflow->size;
+	const char *dev_name;
+	char devnum_str[9];
+	char dirname[200];
+	char *last_slash;
+	int ret;
+
+	ret = bootmeth_alloc_file(bflow, 0x2000000, 0x10000);
+	if (ret)
+		return log_msg_ret("read", ret);
+
+	/*
+	 * This is a horrible hack to tell EFI about this boot device. Once we
+	 * unify EFI with the rest of U-Boot we can clean this up. The same hack
+	 * exists in multiple places, e.g. in the fs, tftp and load commands.
+	 *
+	 * Once we can clean up the EFI code to make proper use of driver model,
+	 * this can go away.
+	 */
+	media_dev = dev_get_parent(bflow->dev);
+	snprintf(devnum_str, sizeof(devnum_str), "%x", dev_seq(media_dev));
+
+	strlcpy(dirname, bflow->fname, sizeof(dirname));
+	last_slash = strrchr(dirname, '/');
+	if (last_slash)
+		*last_slash = '\0';
+
+	log_debug("setting bootdev %s, %s, %s, %p, %x\n",
+		  dev_get_uclass_name(media_dev), devnum_str, bflow->fname,
+		  bflow->buf, size);
+	dev_name = device_get_uclass_id(media_dev) == UCLASS_MASS_STORAGE ?
+		 "usb" : dev_get_uclass_name(media_dev);
+	efi_set_bootdev(dev_name, devnum_str, bflow->fname, bflow->buf, size);
+
+	return 0;
+}
+
+static int distro_efi_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 distro_efi_read_bootflow(struct udevice *dev, struct bootflow *bflow)
+{
+	struct blk_desc *desc = NULL;
+	char fname[sizeof(EFI_DIRNAME) + 16];
+	int ret;
+
+	/* We require a partition table */
+	if (!bflow->part)
+		return -ENOENT;
+
+	strcpy(fname, EFI_DIRNAME);
+	ret = get_efi_leafname(fname + strlen(fname),
+			       sizeof(fname) - strlen(fname));
+	if (ret)
+		return log_msg_ret("leaf", ret);
+
+	if (bflow->blk)
+		 desc = dev_get_uclass_plat(bflow->blk);
+	ret = bootmeth_try_file(bflow, desc, NULL, fname);
+	if (ret)
+		return log_msg_ret("try", ret);
+
+	ret = efiload_read_file(desc, bflow);
+	if (ret)
+		return log_msg_ret("read", -EINVAL);
+
+	return 0;
+}
+
+int distro_efi_boot(struct udevice *dev, struct bootflow *bflow)
+{
+	char cmd[50];
+
+	/*
+	 * At some point we can add a real interface to bootefi so we can call
+	 * this directly. For now, go through the CLI like distro boot.
+	 */
+	snprintf(cmd, sizeof(cmd), "bootefi %lx %lx",
+		 (ulong)map_to_sysmem(bflow->buf),
+		 (ulong)map_to_sysmem(gd->fdt_blob));
+	if (run_command(cmd, 0))
+		return log_msg_ret("run", -EINVAL);
+
+	return 0;
+}
+
+static int distro_bootmeth_efi_bind(struct udevice *dev)
+{
+	struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
+
+	plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
+		"EFI boot from an .efi file" : "EFI";
+
+	return 0;
+}
+
+static struct bootmeth_ops distro_efi_bootmeth_ops = {
+	.check		= distro_efi_check,
+	.read_bootflow	= distro_efi_read_bootflow,
+	.read_file	= bootmeth_common_read_file,
+	.boot		= distro_efi_boot,
+};
+
+static const struct udevice_id distro_efi_bootmeth_ids[] = {
+	{ .compatible = "u-boot,distro-efi" },
+	{ }
+};
+
+U_BOOT_DRIVER(bootmeth_efi) = {
+	.name		= "bootmeth_efi",
+	.id		= UCLASS_BOOTMETH,
+	.of_match	= distro_efi_bootmeth_ids,
+	.ops		= &distro_efi_bootmeth_ops,
+	.bind		= distro_bootmeth_efi_bind,
+};