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

[Tom Rini]

On Wed, Jan 25, 2023 at 06:04:56PM +0100, Heinrich Schuchardt wrote:
> On 1/25/23 17:15, Tom Rini wrote:
> > On Wed, Jan 25, 2023 at 04:38:53PM +0100, Heinrich Schuchardt wrote:
> > > 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.
> > 
> > But it should note that it's using that because that's still quite often
> > an unexpected feature to people.
> > 
> 
> On QEMU it is just what is needed. Other boards supply the device-tree via
> TF-A or OpenSBI. We should not start breaking boards.
> 
> A message "fil: returning err= -12" signals not caring about users.

Yes, I'm saying we need a positive message when using the in memory
device tree.

-- 
Tom
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