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=-15.8 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 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 F016BC07E94 for ; Fri, 4 Jun 2021 13:15:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2D0E613E7 for ; Fri, 4 Jun 2021 13:15:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230237AbhFDNRZ (ORCPT ); Fri, 4 Jun 2021 09:17:25 -0400 Received: from ssl.serverraum.org ([176.9.125.105]:41897 "EHLO ssl.serverraum.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230004AbhFDNRZ (ORCPT ); Fri, 4 Jun 2021 09:17:25 -0400 Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id BD23522236; Fri, 4 Jun 2021 15:15:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1622812537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bVEBT+g85dZ4P1pZoeBaCIbosbJPMLvVQTMmrkOydI4=; b=oKE40u5LSfcMcKVYaq157QYuDsgNkPozqL8++U6sBoEykZPxhpn9Rs4L3f1bvUjTCvPi6p puM/dfpeTxypDcFAoA5uFWBV2FHyyapbvk6VCOIoykM9zmVmKT6UuP2Y8mjD0aGpfF3YGo 0Fei8gyc046V0UgF3oTitI62I5xk5RE= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 04 Jun 2021 15:15:36 +0200 From: Michael Walle To: Tudor.Ambarus@microchip.com Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, p.yadav@ti.com, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com Subject: Re: [PATCH v5 3/5] mtd: spi-nor: otp: return -EROFS if region is read-only In-Reply-To: References: <20210604100252.9975-1-michael@walle.cc> <20210604100252.9975-4-michael@walle.cc> User-Agent: Roundcube Webmail/1.4.11 Message-ID: X-Sender: michael@walle.cc Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 2021-06-04 15:07, schrieb Tudor.Ambarus@microchip.com: > On 6/4/21 1:02 PM, Michael Walle wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know >> the content is safe >> >> 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; >> + > > You won't need this if you put patch 4/5 before this one. With this: This patch will get backported to the stable kernels. Patch 4 on the other hand does not. > > Reviewed-by: Tudor Ambarus > >> + /* >> + * 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 >>