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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS 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 F3771C04E53 for ; Wed, 15 May 2019 09:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE0B12084A for ; Wed, 15 May 2019 09:18:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726330AbfEOJSk (ORCPT ); Wed, 15 May 2019 05:18:40 -0400 Received: from twhmllg4.macronix.com ([122.147.135.202]:32813 "EHLO TWHMLLG4.macronix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725871AbfEOJSk (ORCPT ); Wed, 15 May 2019 05:18:40 -0400 Received: from twhfmnt1.mxic.com.tw (twhfm1p2.macronix.com [172.17.20.92]) by TWHMLLG4.macronix.com with ESMTP id x4F9IYq4083398; Wed, 15 May 2019 17:18:34 +0800 (GMT-8) (envelope-from masonccyang@mxic.com.tw) Received: from MXML06C.mxic.com.tw (mxml06c.macronix.com [172.17.14.55]) by Forcepoint Email with ESMTP id C9C318AF5007845D623E; Wed, 15 May 2019 17:18:34 +0800 (CST) In-Reply-To: References: <1555320234-15802-1-git-send-email-masonccyang@mxic.com.tw> <1555320234-15802-3-git-send-email-masonccyang@mxic.com.tw> <20190512151820.4f2dd9da@xps13> To: "Miquel Raynal" Cc: bbrezillon@kernel.org, broonie@kernel.org, christophe.kerello@st.com, computersforpeace@gmail.com, devicetree@vger.kernel.org, dwmw2@infradead.org, geert@linux-m68k.org, juliensu@mxic.com.tw, lee.jones@linaro.org, liang.yang@amlogic.com, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-spi@vger.kernel.org, marcel.ziswiler@toradex.com, marek.vasut@gmail.com, mark.rutland@arm.com, "Miquel Raynal" , paul.burton@mips.com, richard@nod.at, robh+dt@kernel.org, stefan@agner.ch, zhengxunli@mxic.com.tw Subject: Re: [PATCH v3 2/4] mtd: rawnand: Add Macronix MX25F0A NAND controller MIME-Version: 1.0 X-KeepSent: BFE3CB74:F4E01135-482583FB:00313C7E; type=4; name=$KeepSent X-Mailer: Lotus Notes Release 8.5.3FP4 SHF90 June 10, 2013 Message-ID: From: masonccyang@mxic.com.tw Date: Wed, 15 May 2019 17:18:35 +0800 X-MIMETrack: Serialize by Router on MXML06C/TAIWAN/MXIC(Release 9.0.1FP10 HF265|July 25, 2018) at 2019/05/15 PM 05:18:34, Serialize complete at 2019/05/15 PM 05:18:34 Content-Type: text/plain; charset="US-ASCII" X-MAIL: TWHMLLG4.macronix.com x4F9IYq4083398 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Miquel, Sorry, previous email missed this mxic_nand_data_xfer() reply. This Flash Memory Controller implemented the Buffer read-write data transfer for SPI mode and raw NAND mode. That is each time driver write to the transmit of the TXD port and the data is shifted out, new data is received in RXD port. By transmitting the entire buffer without reading any data, driver are losing the received data. Actually the mxic_nand_data_xfer() is a copy of mxic_spi_data_xfer(). https://github.com/torvalds/linux/blame/master/drivers/spi/spi-mxic.c therefore, I plan to patch this part to MFD as a common code for both raw NAND and SPI. i.e,. In driver/mfd/mxic-mfd.c, we have mxic_mfd_data_xfer() and here call mxic_mfd_data_xfer() for raw NAND data read-write. > > > +static int mxic_nand_data_xfer(struct mxic_nand_ctlr *mxic, const void *txbuf, > > > + void *rxbuf, unsigned int len) > > > +{ > > > > There is not so much code shared, why not separating this function for > > rx and tx cases? > > > > > + unsigned int pos = 0; > > > + > > > + while (pos < len) { > > > + unsigned int nbytes = len - pos; > > > + u32 data = 0xffffffff; > > > + u32 sts; > > > + int ret; > > > + > > > + if (nbytes > 4) > > > + nbytes = 4; > > > + > > > + if (txbuf) > > > + memcpy(&data, txbuf + pos, nbytes); > > > + > > > + ret = readl_poll_timeout(mxic->mfd->regs + INT_STS, sts, > > > + sts & INT_TX_EMPTY, 0, USEC_PER_SEC); > > > > Using USEC_PER_SEC for a delay is weird > > > > > + if (ret) > > > + return ret; > > > + > > > + writel(data, mxic->mfd->regs + TXD(nbytes % 4)); > > > + > > > + if (rxbuf) { > > > + ret = readl_poll_timeout(mxic->mfd->regs + INT_STS, sts, > > > + sts & INT_TX_EMPTY, 0, > > > + USEC_PER_SEC); > > > + if (ret) > > > + return ret; > > > + > > > + ret = readl_poll_timeout(mxic->mfd->regs + INT_STS, sts, > > > + sts & INT_RX_NOT_EMPTY, 0, > > > + USEC_PER_SEC); > > > + if (ret) > > > + return ret; > > > + > > > + data = readl(mxic->mfd->regs + RXD); > > > + data >>= (8 * (4 - nbytes)); > > > > What is this? Are you trying to handle some endianness issue? > > yes, > > > > > > + memcpy(rxbuf + pos, &data, nbytes); > > > + WARN_ON(readl(mxic->mfd->regs + INT_STS) & > > > + INT_RX_NOT_EMPTY); > > > + } else { > > > + readl(mxic->mfd->regs + RXD); > > > + } > > > + WARN_ON(readl(mxic->mfd->regs + INT_STS) & INT_RX_NOT_EMPTY); > > > + > > > + pos += nbytes; > > > + } > > > + > > > + return 0; > > > +} thanks for your review. best regards, Mason -- CONFIDENTIALITY NOTE: This e-mail and any attachments may contain confidential information and/or personal data, which is protected by applicable laws. Please be reminded that duplication, disclosure, distribution, or use of this e-mail (and/or its attachments) or any part thereof is prohibited. If you receive this e-mail in error, please notify us immediately and delete this mail as well as its attachment(s) from your system. 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