[PATCH] bootstd: Replicate the dtb-filename quirks of distroboot

[Heinrich Schuchardt]

On 1/25/23 04:11, Simon Glass wrote:
> For EFI, the distro boot scripts search in three different directories
> for the .dtb file. The SOC-based filename fallback is supported only for
> 32-bit ARM.
> 
> Adjust the code to mirror this behaviour.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Suggested-by: Mark Kettenis <kettenis at openbsd.org>
> ---
> 
>   boot/bootmeth_efi.c | 63 ++++++++++++++++++++++++++++++++++++++-------
>   1 file changed, 54 insertions(+), 9 deletions(-)
> 
> diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c
> index 67c972e3fe4..f9544846e68 100644
> --- a/boot/bootmeth_efi.c
> +++ b/boot/bootmeth_efi.c
> @@ -147,25 +147,57 @@ 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)
> +/**
> + * distro_efi_get_fdt_name() - Get the filename for reading the .dtb file
> + *
> + * @fname: Place to put filename
> + * @size: Max size of filename
> + * @seq: Sequence number, to cycle through options (0=first)
> + * Returns: 0 on success, -ENOENT if the "fdtfile" env var does not exist,
> + * -EINVAL if there are no more options
> + */
> +static int distro_efi_get_fdt_name(char *fname, int size, int seq)
>   {
>   	const char *fdt_fname;
> +	const char *prefix;
> +
> +	/* select the prefix */
> +	switch (seq) {
> +	case 0:
> +		/* this is the default */
> +		prefix = "/dtb";
> +		break;
> +	case 1:
> +		prefix = "";
> +		break;
> +	case 2:
> +		prefix = "/dtb/current";
> +		break;
> +	default:
> +		return log_msg_ret("pref", -EINVAL);
> +	}
>   
>   	fdt_fname = env_get("fdtfile");
>   	if (fdt_fname) {
> -		snprintf(fname, size, "dtb/%s", fdt_fname);
> +		snprintf(fname, size, "%s/%s", prefix, fdt_fname);
>   		log_debug("Using device tree: %s\n", fname);
> -	} else {
> +
> +	/* Use this fallback only for 32-bit ARM */
> +	} else if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_ARM64)) {
>   		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",
> +		snprintf(fname, size, "%s/%s%s%s%s.dtb", prefix,
>   			 soc ? soc : "", soc ? "-" : "", board ? board : "",
>   			 boardver ? boardver : "");
>   		log_debug("Using default device tree: %s\n", fname);
> +	} else {
> +		return log_msg_ret("env", -ENOENT);
>   	}
> +
> +	return 0;
>   }
>   
>   static int distro_efi_read_bootflow_file(struct udevice *dev,
> @@ -174,7 +206,7 @@ static int distro_efi_read_bootflow_file(struct udevice *dev,
>   	struct blk_desc *desc = NULL;
>   	ulong fdt_addr, size;
>   	char fname[256];
> -	int ret;
> +	int ret, seq;
>   
>   	/* We require a partition table */
>   	if (!bflow->part)
> @@ -196,13 +228,22 @@ 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));
> +	fdt_addr = env_get_hex("fdt_addr_r", 0);
> +
> +	/* try the various available names */
> +	ret = -ENOENT;
> +	for (seq = 0; ret; seq++) 

There are boards that don't have a dtb file available and that is ok. 
Don't loop past seq = 2.

{
> +		ret = distro_efi_get_fdt_name(fname, sizeof(fname), seq);
> +		if (ret)
> +			return log_msg_ret("nam", ret);
> +		ret = bootmeth_common_read_file(dev, bflow, fname, fdt_addr,
> +						&size);
> +	}
> +
>   	bflow->fdt_fname = strdup(fname);
>   	if (!bflow->fdt_fname)
>   		return log_msg_ret("fil", -ENOMEM);

This should not be an error. The Distroboot fallback is the device-tree 
at $fdtcontroladdr.

Best regards

Heinrich

>   
> -	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;
> @@ -277,7 +318,11 @@ static int distro_efi_read_bootflow_net(struct bootflow *bflow)
>   	fdt_addr = hextoul(fdt_addr_str, NULL);
>   	sprintf(file_addr, "%lx", fdt_addr);
>   
> -	distro_efi_get_fdt_name(fname, sizeof(fname));
> +	/* We only allow the first prefix with PXE */
> +	ret = distro_efi_get_fdt_name(fname, sizeof(fname), 0);
> +	if (ret)
> +		return log_msg_ret("nam", ret);
> +
>   	bflow->fdt_fname = strdup(fname);
>   	if (!bflow->fdt_fname)
>   		return log_msg_ret("fil", -ENOMEM);