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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 41045CA9EB5 for ; Mon, 21 Oct 2019 08:56:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11BEE206C2 for ; Mon, 21 Oct 2019 08:56:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727495AbfJUI4i (ORCPT ); Mon, 21 Oct 2019 04:56:38 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:60544 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727461AbfJUI4h (ORCPT ); Mon, 21 Oct 2019 04:56:37 -0400 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 5AEE828A1AA; Mon, 21 Oct 2019 09:56:35 +0100 (BST) Date: Mon, 21 Oct 2019 10:56:32 +0200 From: Boris Brezillon To: masonccyang@mxic.com.tw Cc: bbrezillon@kernel.org, computersforpeace@gmail.com, dwmw2@infradead.org, frieder.schrempf@kontron.de, gregkh@linuxfoundation.org, juliensu@mxic.com.tw, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, marcel.ziswiler@toradex.com, marek.vasut@gmail.com, "Miquel Raynal" , richard@nod.at, tglx@linutronix.de, vigneshr@ti.com Subject: Re: [PATCH RFC 2/3] mtd: rawnand: Add support Macronix Block Protection function Message-ID: <20191021105632.3fa7b3ce@collabora.com> In-Reply-To: References: <1568793387-25199-1-git-send-email-masonccyang@mxic.com.tw> <1568793387-25199-2-git-send-email-masonccyang@mxic.com.tw> <20191007104511.5aa7b8f2@xps13> <20191007112442.783e4fbe@xps13> <20191008170249.06bd45ce@xps13> <20191021094435.78f4b16e@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Oct 2019 16:40:57 +0800 masonccyang@mxic.com.tw wrote: > Hi Boris, > > > > > > > > > Then fill-in these two hooks from the manufacturer code, > without > > > the > > > > > > > postponed init. > > > > > > > > > > > > > > > > > > > But in the final of nand_scan_tail(), mtd->_lock/_unlock will be > > > > > > filled by NULL, right ? > > > > > > > > > > The NAND core should set mtd->_lock/_unlock() to NAND specific > hooks > > > so > > > > > that the MTD layer is abstracted and and drivers do not see it. > Then, > > > > > in the NAND helper, either there is no specific hook defined by a > > > > > manufacturer driver and you return -ENOTSUPP, or you execute the > > > > > defined hook. > > > > > > > > okay, patch specific manufacturer _lock/_unlock driver > > > > in nand_manufacturer_init(); > > > > > > > > and in the final of nand_scan_tail() > > > > if (!mtd->_lock) > > > > mtd->_lock = NULL; > > > > if (!mtd->_unlock) > > > > mtd->_unlock = NULL; > > > > > > > > > I'm still considering of post_init() in nand_scan_tail() for > > > MTD layer default call-back function replacement because > > > there would be more call-back functions need it. > > > i.e., > > > MTD->_lock/_unlokc > > > MTD->_suspend/_resume > > > > Again, that's something that needs to be abstracted so that both the > > NAND manufacturer driver and the NAND controller driver can take > > appropriate actions on suspend/resume operations. > > > > > NTD->_point/_unpoint > > > > ->_point/_unpoint() are irrelevant for a NAND chip. > > > > > ... > > > > > > > > > actually, my patch series are including MTD->_locl/_unlock and > > > MTD->_suspend/_resume. how do you think ? > > > > Miquel was suggesting to add nand_chip->{lock,unlock,is_locked}() > > methods that would be implemented by the NAND manufacturer drivers, and > > have generic wrappers implemented in nand_base.c: > > > > static int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len) > > { > > struct nand_chip *chip = mtd_to_nand(mtd); > > > > if (!chip->lock) > > return -ENOTSUPP; > > > > return chip->lock(chip, ofs, len); > > } > > > > ... > > > > If you do that, you won't need this post_init() hook. > > got it, but ... > user space program flash_lock/flash_unlock are calling > mtd_lock() & mtd_unlock(). > i.e., > int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len) > { > if (!mtd->_lock) > return -EOPNOTSUPP; > if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs) > return -EINVAL; > if (!len) > return 0; > return mtd->_lock(mtd, ofs, len); > } > Assign mtd lock/unlock/is_locked hooks to the generic wrappers in nand_scan_tail(): mtd->_lock = nand_lock; mtd->_unlock = nand_unlock; mtd->_is_locked = nand_is_locked; Seriously, we've almost implemented the thing for you with all the details we've given. At some point you have to look more closely at how things are done/designed in the NAND framework if you want to contribute core changes. I'm fine giving hints but we're far beyond that point here.