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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4750FC6FA99 for ; Mon, 6 Mar 2023 14:39:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230110AbjCFOjo (ORCPT ); Mon, 6 Mar 2023 09:39:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229997AbjCFOjm (ORCPT ); Mon, 6 Mar 2023 09:39:42 -0500 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B803E234D3; Mon, 6 Mar 2023 06:39:17 -0800 (PST) Received: (Authenticated sender: miquel.raynal@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 24CE820010; Mon, 6 Mar 2023 14:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1678113535; 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=7CihFIQuO8EkmKbOqb/odYY87aF0bfbQPJr+dXyqKWM=; b=imwyQChFmKzT+FDHfXvNHpYEw+0cNlqq2MzSIf0Y6kQRaRnympSOGcJyCF6oa+u0s++p1f z0TZhBtyQLY3G4mMI2RJcpXyltBnvfqIRMmpCk/QB2jt1ItcexfiduaTzQHjv7dCHyT+Ew fg6wrc11NJX8dsfzZ/4AlqToIGTn5U+35lJ8Z4GQAiLBy/OH/HH/EFfE2xQ2XXcxinDmTE bi8an4Vs5CU+ULHj85iPNr/Vv9D8pPQwOFl6ugxdO2aOz3EYXuDOAfsmabOrOZimj4LV1b ZJq50BHsr/xVg9cHoEb7RR/WgqiM9jwk9lWFotMS6aOIPc22YDwZFiPRPZzArg== Date: Mon, 6 Mar 2023 15:38:51 +0100 From: Miquel Raynal To: Md Sadre Alam Cc: Boris Brezillon , , , , , , , , , , , , Subject: Re: [PATCH 2/5] mtd: rawnand: qcom: Add initial support for qspi nand Message-ID: <20230306153851.0dcdda27@xps-13> In-Reply-To: References: <1602307902-16761-1-git-send-email-mdalam@codeaurora.org> <1602307902-16761-3-git-send-email-mdalam@codeaurora.org> <20201029100751.713e27df@collabora.com> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hello, quic_mdalam@quicinc.com wrote on Mon, 6 Mar 2023 19:45:58 +0530: > On 10/29/2020 2:37 PM, Boris Brezillon wrote: > > Hello, > > > > On Sat, 10 Oct 2020 11:01:39 +0530 > > Md Sadre Alam wrote: > > =20 > >> This change will add initial support for qspi (serial nand). > >> > >> QPIC Version v.2.0 onwards supports serial nand as well so this > >> change will initialize all required register to enable qspi (serial > >> nand). > >> > >> This change is supporting very basic functionality of qspi nand flash. > >> > >> 1. Reset device (Reset QSPI NAND device). > >> > >> 2. Device detection (Read id QSPI NAND device). =20 > > Unfortunately, that's not going to work in the long term. You're > > basically hacking the raw NAND framework to make SPI NANDs fit. I do > > understand the rationale behind this decision (re-using the code for > > ECC and probably other things), but that's not going to work. So I'd > > recommend doing the following instead: > > > > 1/ implement a SPI-mem controller driver > > 2/ implement an ECC engine driver so the ECC logic can be shared > > between the SPI controller and raw NAND controller drivers > > 3/ convert the raw NAND driver to the exec_op() interface (none of > > this hack would have been possible if the driver was using the new > > API) > > > > Regards, > > > > Boris > > =20 > =C2=A0=C2=A0 Sorry for late reply, again started working on this feature= support.=C2=A0 The QPIC v2 on wards there is serial nand support got added= , its not a standard SPI controller >=20 > =C2=A0=C2=A0 its QPIC controller having support for serial nand. All SPI= related configuration done by QPIC hardware and its not exposed as SPI bus= to the external world. Only based on >=20 > =C2=A0=C2=A0 QPIC_SPI_CFG =3D 1, serial functionality will get selected.= So that no need to implement as SPI-mem controller driver, since its not a= SPI controller. >=20 > =C2=A0 Please check the below diagram for top view of QPIC controller. One of the hard things in the Linux kernel is to make devices fit frameworks. This feature does not fit the raw NAND framework. It does not follow any of the conventions taken there. It is not gonna be accepted there. You need to expose spi-mem functionalities, even if the spi-proper features are not available. I believe your situation still fits the spi-mem abstraction. Thanks, Miqu=C3=A8l 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BE1F4C6FA99 for ; Mon, 6 Mar 2023 14:51:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pJxlMc9grDQIM2owziKd7dSdvGI+I9qUqulnBm3geck=; b=evhQRJkNQGqXmr go+9kdA3t37rE83uWYjoBdpsNptKPXvluAUkxxEohT152Csis78qTWXE1463XUPD+m/E0h3hb/eBm a7SDq5BykC7GrTYP9qlGDGiIHzNDrgJfA8SIY+yQH3177gwiEVAFdmk9DJIeVAjOrV/b+4Mh9Z3Wh 0gVN18lSHl7djVL47WiXy7epZNrtxXAzrRdCfDzDUq5G3leCuNQvKxL2XDy/LuMe3QvX2/MOtj1VW kW25Ss/1hOlw3zoVb4syXtURmk+p427Im6hhK7avsSgXvZNbv5EY8C3XO8fAZoFqjvbwIRIS8CKZR PyDb3frDU23gHGjPvcFg==; 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