[PATCH v2 48/71] bootstd: Support reading the device tree with EFI

[Mark Kettenis]

> From: Simon Glass <sjg at chromium.org>
> Date: Sat,  7 Jan 2023 19:50:24 -0700
> 
> With EFI booting the device tree is required but is not actually specified
> in any way. The normal method is to use a fdtfile environment variable to
> get the filename, then look for that file on the media.
> 
> Implement this in the bootmeth.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---

Hi Simon,

The distroboot scripts also reads dtb files from the root directory of
the ESP (so without the "dtb/" prefix).  This code needs to do that as
well otherwise some folks will run with a different device tree after
switching to bootstd.

The construction of a fallback dtb filename based on soc, board and
boardver is only done for (32-bit) arm and not for arm64.  It isn't
done for riscv either.  That feels to me like someone recognized that
was a bit of a mistake and shouldn't be done for modern targets.  So I
think that code should be under the same

   #if defined(CONFIG_ARM) && !defined(CONFIG_ARM64)

as it is now in config_distro_bootcmd.h.

Cheers,

Mark

> (no changes since v1)
> 
>  boot/bootmeth_efi.c | 105 +++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 99 insertions(+), 6 deletions(-)
> 
> diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c
> index 77b4ba22470..53a0489b93c 100644
> --- a/boot/bootmeth_efi.c
> +++ b/boot/bootmeth_efi.c
> @@ -143,10 +143,32 @@ static int distro_efi_check(struct udevice *dev, struct bootflow_iter *iter)
>  	return 0;
>  }
>  
> +static void distro_efi_get_fdt_name(char *fname, int size)
> +{
> +	const char *fdt_fname;
> +
> +	fdt_fname = env_get("fdtfile");
> +	if (fdt_fname) {
> +		snprintf(fname, size, "dtb/%s", fdt_fname);
> +		log_debug("Using device tree: %s\n", fname);
> +	} else {
> +		const char *soc = env_get("soc");
> +		const char *board = env_get("board");
> +		const char *boardver = env_get("boardver");
> +
> +		/* cf the code in label_boot() which seems very complex */
> +		snprintf(fname, size, "dtb/%s%s%s%s.dtb",
> +			 soc ? soc : "", soc ? "-" : "", board ? board : "",
> +			 boardver ? boardver : "");
> +		log_debug("Using default device tree: %s\n", fname);
> +	}
> +}
> +
>  static int distro_efi_read_bootflow_file(struct udevice *dev,
>  					 struct bootflow *bflow)
>  {
>  	struct blk_desc *desc = NULL;
> +	ulong fdt_addr, size;
>  	char fname[256];
>  	int ret;
>  
> @@ -170,15 +192,43 @@ static int distro_efi_read_bootflow_file(struct udevice *dev,
>  	if (ret)
>  		return log_msg_ret("read", -EINVAL);
>  
> +	distro_efi_get_fdt_name(fname, sizeof(fname));
> +	bflow->fdt_fname = strdup(fname);
> +	if (!bflow->fdt_fname)
> +		return log_msg_ret("fil", -ENOMEM);
> +
> +	fdt_addr = env_get_hex("fdt_addr_r", 0);
> +	ret = bootmeth_common_read_file(dev, bflow, fname, fdt_addr, &size);
> +	if (!ret) {
> +		bflow->fdt_size = size;
> +		bflow->fdt_addr = fdt_addr;
> +
> +		/*
> +		 * TODO: Apply extension overlay
> +		 *
> +		 * Here we need to load and apply the extension overlay. This is
> +		 * not implemented. See do_extension_apply(). The extension
> +		 * stuff needs an implementation in boot/extension.c so it is
> +		 * separate from the command code. Really the extension stuff
> +		 * should use the device tree and a uclass / driver interface
> +		 * rather than implementing its own list
> +		 */
> +	} else {
> +		log_debug("No device tree available\n");
> +	}
> +
>  	return 0;
>  }
>  
>  static int distro_efi_read_bootflow_net(struct bootflow *bflow)
>  {
> -	const char *addr_str;
> +	char file_addr[17], fname[256];
> +	char *tftp_argv[] = {"tftp", file_addr, fname, NULL};
> +	struct cmd_tbl cmdtp = {};	/* dummy */
> +	const char *addr_str, *fdt_addr_str;
>  	int ret, arch, size;
> +	ulong addr, fdt_addr;
>  	char str[36];
> -	ulong addr;
>  
>  	ret = get_efi_pxe_vci(str, sizeof(str));
>  	if (ret)
> @@ -216,6 +266,25 @@ static int distro_efi_read_bootflow_net(struct bootflow *bflow)
>  	efi_set_bootdev("Net", "", bflow->fname, map_sysmem(addr, 0),
>  			bflow->size);
>  
> +	/* read the DT file also */
> +	fdt_addr_str = env_get("fdt_addr_r");
> +	if (!fdt_addr_str)
> +		return log_msg_ret("fdt", -EINVAL);
> +	fdt_addr = hextoul(fdt_addr_str, NULL);
> +	sprintf(file_addr, "%lx", fdt_addr);
> +
> +	distro_efi_get_fdt_name(fname, sizeof(fname));
> +	bflow->fdt_fname = strdup(fname);
> +	if (!bflow->fdt_fname)
> +		return log_msg_ret("fil", -ENOMEM);
> +
> +	if (!do_tftpb(&cmdtp, 0, 3, tftp_argv)) {
> +		bflow->fdt_size = env_get_hex("filesize", 0);
> +		bflow->fdt_addr = fdt_addr;
> +	} else {
> +		log_debug("No device tree available\n");
> +	}
> +
>  	bflow->state = BOOTFLOWST_READY;
>  
>  	return 0;
> @@ -243,15 +312,39 @@ static int distro_efi_read_bootflow(struct udevice *dev, struct bootflow *bflow)
>  
>  int distro_efi_boot(struct udevice *dev, struct bootflow *bflow)
>  {
> +	ulong kernel, fdt;
>  	char cmd[50];
>  
> +	/* A non-zero buffer indicates the kernel is there */
> +	if (bflow->buf) {
> +		kernel = (ulong)map_to_sysmem(bflow->buf);
> +
> +		/*
> +		 * use the provided device tree if available, else fall back to
> +		 * the control FDT
> +		 */
> +		if (bflow->fdt_fname)
> +			fdt = bflow->fdt_addr;
> +		else
> +			fdt = (ulong)map_to_sysmem(gd->fdt_blob);
> +	} else {
> +		/*
> +		 * This doesn't actually work for network devices:
> +		 *
> +		 * do_bootefi_image() No UEFI binary known at 0x02080000
> +		 *
> +		 * But this is the same behaviour for distro boot, so it can be
> +		 * fixed here.
> +		 */
> +		kernel = env_get_hex("kernel_addr_r", 0);
> +		fdt = env_get_hex("fdt_addr_r", 0);
> +	}
> +
>  	/*
>  	 * 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.
> +	 * 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));
> +	snprintf(cmd, sizeof(cmd), "bootefi %lx %lx", kernel, fdt);
>  	if (run_command(cmd, 0))
>  		return log_msg_ret("run", -EINVAL);
>  
> -- 
> 2.39.0.314.g84b9a713c41-goog
> 
>