From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF96FC07E94 for ; Fri, 4 Jun 2021 10:03:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2A2361369 for ; Fri, 4 Jun 2021 10:03:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230341AbhFDKE4 (ORCPT ); Fri, 4 Jun 2021 06:04:56 -0400 Received: from ssl.serverraum.org ([176.9.125.105]:45893 "EHLO ssl.serverraum.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230008AbhFDKEv (ORCPT ); Fri, 4 Jun 2021 06:04:51 -0400 Received: from mwalle01.fritz.box (ip4d17858c.dynamic.kabel-deutschland.de [77.23.133.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id DDBE12224F; Fri, 4 Jun 2021 12:03:03 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1622800984; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Kt4yiaInnmJeaGkE/MPYgei4muQd1jn/4Uq7TKm1ceo=; b=s5gDsHN1cHhYbtdUp1fJxvZ6xKbFmmUlz6nIoBpG4a4LuzOuUUFWfJZB1SbXpzs+R//nsw uyejZ+Du9Z9x7sNLZzznvCJiPV3QFPo+3e6Bt232XIz3uMCqkwd+ZLRO5/13VcLZ/vGbYp sY5Va3n618gKwABX/PxjX8KVzHOOfDk= From: Michael Walle To: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Tudor Ambarus , Michael Walle , Pratyush Yadav , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Subject: [PATCH v5 3/5] mtd: spi-nor: otp: return -EROFS if region is read-only Date: Fri, 4 Jun 2021 12:02:50 +0200 Message-Id: <20210604100252.9975-4-michael@walle.cc> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210604100252.9975-1-michael@walle.cc> References: <20210604100252.9975-1-michael@walle.cc> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. From what I can tell, chips/cfi_cmdset_0001.c also return this error code. One could optimize spi_nor_mtd_otp_range_is_locked() to read the status register only once and not for every OTP region, but for that we would need some more invasive changes. Given that this is one-time-programmable memory and the normal access mode is reading, we just live with the small overhead. Fixes: 069089acf88b ("mtd: spi-nor: add OTP support") Signed-off-by: Michael Walle Reviewed-by: Pratyush Yadav --- drivers/mtd/spi-nor/otp.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c index 3898ed67ba1c..063f8fb68649 100644 --- a/drivers/mtd/spi-nor/otp.c +++ b/drivers/mtd/spi-nor/otp.c @@ -249,6 +249,32 @@ static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len, return ret; } +static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs, + size_t len) +{ + const struct spi_nor_otp_ops *ops = nor->params->otp.ops; + unsigned int region; + int locked; + + if (!len) + return 0; + + /* + * If any of the affected OTP regions are locked the entire range is + * considered locked. + */ + for (region = spi_nor_otp_offset_to_region(nor, ofs); + region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1); + region++) { + locked = ops->is_locked(nor, region); + /* take the branch it is locked or in case of an error */ + if (locked) + return locked; + } + + return 0; +} + static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, size_t total_len, size_t *retlen, const u8 *buf, bool is_write) @@ -271,6 +297,16 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, /* don't access beyond the end */ total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + if (is_write) { + ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len); + if (ret < 0) { + goto out; + } else if (ret) { + ret = -EROFS; + goto out; + } + } + *retlen = 0; while (total_len) { /* -- 2.20.1