From nobody Tue Apr 7 01:36:55 2026 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 297A53D9049 for ; Fri, 3 Apr 2026 16:10:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775232629; cv=none; b=GeB5JAvGsa7YubmXbjhMHqqHr98kPuRPzIGYJPiwC0U+l/praaYndK0ifrXz3EcuIBP7SkndmOuvGCdp+BAfhhkKAQIBZByxeWVhNXX1+oQVVWjtSBoRnuiSvrq2Ivgd0n0WG9uhj5xNJEUGCHck2e1A0jxQ38AU6TRx3ij45Ug= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775232629; c=relaxed/simple; bh=gnzj7GWcp98ZnLLkgndMyN+X9yfr8XWTdmY+32KVcqc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=M0Ix+Hvr0+xkJV2biyl9rD9Q3cgf1ecFQLGN5yBnb9Agzyvvk5rx7rew92SDn09K6Pd43fghkBdcXCqOkYmg3VZea+cPhBVZWZ7I3zyOhH/vPhvKlBW7AjGMUIRCU0jQjwzXnh05c/FejETzNjxiB8RpXYiHGu5/m5xW0v47bFI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=0JRh3nd7; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="0JRh3nd7" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 104FA1A312E for ; Fri, 3 Apr 2026 16:10:27 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id DAF21603C1; Fri, 3 Apr 2026 16:10:26 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 4FA44104500F6; Fri, 3 Apr 2026 18:10:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1775232626; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=3IYxtkzdeu6bnBo9MR5hdgZZXX41AGqFyUgLNr5QV1k=; b=0JRh3nd7uPxKBQjr0gpuMTv+uGoVpzl/OUHmv+NgwRBOaQgZ5jaETyEddbJfKTMamPPG8g kTEWoBYiMLLrxigSWWfHxTLD/V6IDDf0isVqztHjtkuDNIZ/cafXTLkevGhK+LVhkB9tQY kQd/dv88B34HM+du4N8Geh+3zS6OhEaoj7mibc1Kkq1r8aadPavB5LQ/nqiWjBJdai761H 6bCwHr7gCJq7ROek8qettAe3OPt1zqzOPqVtzyrhQIH68yDeIzyHjFxayEYkwZiRrZ+pSJ tSLbsLFNjBp+lWz80aqj6pbOjsllVmF21R1LJL5nXer/SSE7TtulLj1Z19ChIA== From: Miquel Raynal Date: Fri, 03 Apr 2026 18:09:39 +0200 Subject: [PATCH v4 21/27] mtd: spi-nor: Add steps for testing locking with CMP Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260403-winbond-v6-18-rc1-spi-nor-swp-v4-21-833dab5e7288@bootlin.com> References: <20260403-winbond-v6-18-rc1-spi-nor-swp-v4-0-833dab5e7288@bootlin.com> In-Reply-To: <20260403-winbond-v6-18-rc1-spi-nor-swp-v4-0-833dab5e7288@bootlin.com> To: Pratyush Yadav , Michael Walle , Takahiro Kuwano , Richard Weinberger , Vignesh Raghavendra , Jonathan Corbet Cc: Sean Anderson , Thomas Petazzoni , Steam Lin , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Miquel Raynal X-Mailer: b4 0.14.3 X-Last-TLS-Session-Version: TLSv1.3 Extend the test coverage by giving guidelines to verify the CMP bit acts according to our expectations. Signed-off-by: Miquel Raynal --- The instructions listed in this file target people adding support for new chips, however here are below extra steps that I also ran with the same W25H512NWxxAM chip. They are here to prove core correctness. $ flash_lock -u /dev/mtd0 $ flash_lock -l /dev/mtd0 0 1008 $ show_sectors software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03efffff | locked | 1008 03f00000-03ffffff | unlocked | 16 $ flash_lock -l /dev/mtd0 0 1009 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03efffff | locked | 1008 03f00000-03ffffff | unlocked | 16 $ flash_lock -l /dev/mtd0 0 1015 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03efffff | locked | 1008 03f00000-03ffffff | unlocked | 16 $ flash_lock -l /dev/mtd0 0 1016 $ show_sectors # should cover more software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03f7ffff | locked | 1016 03f80000-03ffffff | unlocked | 8 $ flash_lock -u /dev/mtd0 $((1015 * $bs)) 1 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03f7ffff | locked | 1016 03f80000-03ffffff | unlocked | 8 $ flash_lock -u /dev/mtd0 $((1009 * $bs)) 7 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03f7ffff | locked | 1016 03f80000-03ffffff | unlocked | 8 $ flash_lock -u /dev/mtd0 $((1008 * $bs)) 8 $ show_sectors # range should reduce down to initial value software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-03efffff | locked | 1008 03f00000-03ffffff | unlocked | 16 [Similar situations, on the other side of the device] $ flash_lock -u /dev/mtd0 $ flash_lock -l /dev/mtd0 $((16 * $bs)) 1008 $ show_sectors software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-000fffff | unlocked | 16 00100000-03ffffff | locked | 1008 $ flash_lock -l /dev/mtd0 $((15 * $bs)) 1009 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-000fffff | unlocked | 16 00100000-03ffffff | locked | 1008 $ flash_lock -l /dev/mtd0 $((9 * $bs)) 1015 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-000fffff | unlocked | 16 00100000-03ffffff | locked | 1008 $ flash_lock -l /dev/mtd0 $((8 * $bs)) 1016 $ show_sectors # should cover more software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-0007ffff | unlocked | 8 00080000-03ffffff | locked | 1016 $ flash_lock -u /dev/mtd0 $((8 * $bs)) 1 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-0007ffff | unlocked | 8 00080000-03ffffff | locked | 1016 $ flash_lock -u /dev/mtd0 $((8 * $bs)) 7 $ show_sectors # should not change software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-0007ffff | unlocked | 8 00080000-03ffffff | locked | 1016 $ flash_lock -u /dev/mtd0 $((8 * $bs)) 8 $ show_sectors # range should reduce down to initial value software locked sectors region (in hex) | status | #blocks ------------------+----------+-------- 00000000-000fffff | unlocked | 16 00100000-03ffffff | locked | 1008 --- Documentation/driver-api/mtd/spi-nor.rst | 36 ++++++++++++++++++++++++++++= ++++ 1 file changed, 36 insertions(+) diff --git a/Documentation/driver-api/mtd/spi-nor.rst b/Documentation/drive= r-api/mtd/spi-nor.rst index 4755eb75fe5e..ec46bba8297a 100644 --- a/Documentation/driver-api/mtd/spi-nor.rst +++ b/Documentation/driver-api/mtd/spi-nor.rst @@ -331,3 +331,39 @@ section, after the ``---`` marker. ------------------+----------+-------- 00000000-0000ffff | locked | 1 00010000-03ffffff | unlocked | 1023 + + If the flash features a Complement (CMP) bit, we can protect with + more granularity above half of the capacity. Let's lock all but one + block, then unlock one more block:: + + root@1:~# all_but_one=3D$((($size / $bs) - 1)) + root@1:~# flash_lock -u /dev/mtd0 + root@1:~# flash_lock -l /dev/mtd0 $bs $all_but_one # all but the first + root@1:~# show_sectors + software locked sectors + region (in hex) | status | #blocks + ------------------+----------+-------- + 00000000-0000ffff | unlocked | 1 + 00010000-03ffffff | locked | 1023 + root@1:~# flash_lock -u /dev/mtd0 $bs 1 # all but the two first + root@1:~# show_sectors + software locked sectors + region (in hex) | status | #blocks + ------------------+----------+-------- + 00000000-0001ffff | unlocked | 2 + 00020000-03ffffff | locked | 1022 + root@1:~# flash_lock -u /dev/mtd0 + root@1:~# flash_lock -l /dev/mtd0 0 $all_but_one # same from the other= side + root@1:~# show_sectors + software locked sectors + region (in hex) | status | #blocks + ------------------+----------+-------- + 00000000-03feffff | locked | 1023 + 03ff0000-03ffffff | unlocked | 1 + root@1:~# flash_lock -u /dev/mtd0 $(($size - (2 * $bs))) 1 # all but t= wo + root@1:~# show_sectors + software locked sectors + region (in hex) | status | #blocks + ------------------+----------+-------- + 00000000-03fdffff | locked | 1022 + 03fe0000-03ffffff | unlocked | 2 --=20 2.53.0