libfdt: fdt_rw: Introduce fdt_downgrade_version()
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Current code perform a version downgrade at one place only, the end of
fdt_rw_probe_().

In order to offer a finer grain and choose to downgrade or not depending
on the exact writes done, introduce fdt_downgrade_version() to perform
the downgrade operation.

The modification doesn't introduce any functional changes.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Message-ID: <20260210173349.636766-5-herve.codina@bootlin.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Herve Codina 2026-02-10 18:33:32 +01:00 committed by David Gibson
parent 5bb5bedd34
commit 5976c4a660

View file

@ -22,6 +22,12 @@ static int fdt_blocks_misordered_(const void *fdt,
(fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt)));
}
static void fdt_downgrade_version(void *fdt)
{
if (!can_assume(LATEST) && fdt_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
}
static int fdt_rw_probe_(void *fdt)
{
if (can_assume(VALID_DTB))
@ -33,9 +39,8 @@ static int fdt_rw_probe_(void *fdt)
if (fdt_blocks_misordered_(fdt, sizeof(struct fdt_reserve_entry),
fdt_size_dt_struct(fdt)))
return -FDT_ERR_BADLAYOUT;
if (!can_assume(LATEST) && fdt_version(fdt) > 17)
fdt_set_version(fdt, 17);
fdt_downgrade_version(fdt);
return 0;
}