From nobody Tue Apr 7 01:08:20 2026 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (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 5D0BB3AE6E8 for ; Tue, 17 Mar 2026 10:24:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773743092; cv=none; b=TxHT0i8F/aMg6VcWHDFpJ8lliasVEET153TuY9azLZvMccfHg1kR/eF5YlwqcAf5SRyzEKEC2dSKfa39DP3yZpjt/IPruHt05AFnD4zLe9W7Osh2KpLkd01oEOHggn2cmAuabOjG0Kq7p1oVW3gXmXatYHz3LTtgeDIc5XT7wGs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773743092; c=relaxed/simple; bh=TvmwqqzUjFXwsgjs9g4DkmvOJ12nKokPN5kUqwA0B18=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=eVSJL8dPrdwGLzgWJempu2cncnmnwkJF8LCLgsK9VwrvNeIkUDXWgT56zuF1PS8wrZpmCyqrCt0PZBRLo7dBwb7djpUOZU+mLOfncOcFJsm7bWlG7Zw8Ah+VfoVCqyyomEP+1w5uZ5aHC21oKa/tCTKN7N7X4+eL3Hcl6axvUik= 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=gDEDqNMl; arc=none smtp.client-ip=185.246.85.4 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="gDEDqNMl" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 18A274E42629; Tue, 17 Mar 2026 10:24:50 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id E2C695FC9A; Tue, 17 Mar 2026 10:24:49 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id D95EB10450451; Tue, 17 Mar 2026 11:24:47 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1773743089; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=7/ZShnKFDMohqlPS8rHFdEyfu+4BivJefw8T/oDlCwI=; b=gDEDqNMlUsolCHS1quv+HEvulyLizeJOQyEuOQB5JbEmouhDvxBkTouFH8pN1/ik3HGOj/ UGM5jghjoUKsHx/5dlrH9lVOXYQLjTY4cMXL/zFHloJVojteL01tcyAvXamOUKPdcdir1+ z2CjLdxtzm2VGpO/aBWLZvFVXAcCsFFkNxQbhfkBpo0OWJAJNv50RwbivNu0H5C0bGtXT6 SurouOuy4AobchJr+AaZmp6heXJENtlqfipytf4XsPQ8KwXHxy1wemPM+UiqppjtjgGrFF IOx/HukZKELS/bDRmhD3o0QdBFnMtjqNHDAqsX/mgsLZv9ykN1F3eO4aZWQxBA== From: Miquel Raynal Date: Tue, 17 Mar 2026 11:24:24 +0100 Subject: [PATCH v3 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: <20260317-winbond-v6-18-rc1-spi-nor-swp-v3-21-2ca9ea4e7b9b@bootlin.com> References: <20260317-winbond-v6-18-rc1-spi-nor-swp-v3-0-2ca9ea4e7b9b@bootlin.com> In-Reply-To: <20260317-winbond-v6-18-rc1-spi-nor-swp-v3-0-2ca9ea4e7b9b@bootlin.com> To: Pratyush Yadav , Michael Walle , Takahiro Kuwano , Richard Weinberger , Vignesh Raghavendra , Jonathan Corbet Cc: Tudor Ambarus , 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 2.51.1