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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 577DDC636C8 for ; Thu, 15 Jul 2021 22:55:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4087C613D4 for ; Thu, 15 Jul 2021 22:55:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231163AbhGOW6u convert rfc822-to-8bit (ORCPT ); Thu, 15 Jul 2021 18:58:50 -0400 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:40943 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229624AbhGOW6s (ORCPT ); Thu, 15 Jul 2021 18:58:48 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id 23C041BF204; Thu, 15 Jul 2021 22:55:53 +0000 (UTC) Date: Fri, 16 Jul 2021 00:55:52 +0200 From: Miquel Raynal To: Clark Wang Cc: conor.culhane@silvaco.com, alexandre.belloni@bootlin.com, vitor.soares@synopsys.com, boris.brezillon@bootlin.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] i3c: master: svc: add support for slave to stop returning data Message-ID: <20210716005552.6078c7eb@xps13> In-Reply-To: <20210715082413.3042149-4-xiaoning.wang@nxp.com> References: <20210715082413.3042149-1-xiaoning.wang@nxp.com> <20210715082413.3042149-4-xiaoning.wang@nxp.com> Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Clark, Clark Wang wrote on Thu, 15 Jul 2021 16:24:12 +0800: > When i3c controller reads data from slave device, slave device can stop > returning data with an ACK after any byte. > Add this support for svc i3c controller. Otherwise, it will go TIMEOUT > error path when the slave device ends the read operation early. Is this part of the I3C specification? I am not aware about it. > Signed-off-by: Clark Wang > --- > drivers/i3c/master/svc-i3c-master.c | 28 ++++++++++++++++++++-------- > 1 file changed, 20 insertions(+), 8 deletions(-) > > diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c > index 9d80435638ea..892e57fec4b0 100644 > --- a/drivers/i3c/master/svc-i3c-master.c > +++ b/drivers/i3c/master/svc-i3c-master.c > @@ -865,7 +865,7 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > u8 *in, unsigned int len) > { > int offset = 0, i, ret; > - u32 mdctrl; > + u32 mdctrl, mstatus; > > while (offset < len) { > unsigned int count; > @@ -874,8 +874,15 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > mdctrl, > !(mdctrl & SVC_I3C_MDATACTRL_RXEMPTY), > 0, 1000); > - if (ret) > - return ret; > + if (ret) { > + ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, > + mstatus, SVC_I3C_MSTATUS_COMPLETE(mstatus), > + 0, 1000); > + if (ret) > + return ret; > + else > + return offset; > + } > > count = SVC_I3C_MDATACTRL_RXCOUNT(mdctrl); > for (i = 0; i < count; i++) > @@ -884,7 +891,7 @@ static int svc_i3c_master_read(struct svc_i3c_master *master, > offset += count; > } > > - return 0; > + return offset; > } > > static int svc_i3c_master_write(struct svc_i3c_master *master, > @@ -917,7 +924,7 @@ static int svc_i3c_master_write(struct svc_i3c_master *master, > static int svc_i3c_master_xfer(struct svc_i3c_master *master, > bool rnw, unsigned int xfer_type, u8 addr, > u8 *in, const u8 *out, unsigned int xfer_len, > - unsigned int read_len, bool continued) > + unsigned int *read_len, bool continued) > { > u32 reg; > int ret; > @@ -927,7 +934,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, > SVC_I3C_MCTRL_IBIRESP_NACK | > SVC_I3C_MCTRL_DIR(rnw) | > SVC_I3C_MCTRL_ADDR(addr) | > - SVC_I3C_MCTRL_RDTERM(read_len), > + SVC_I3C_MCTRL_RDTERM(*read_len), > master->regs + SVC_I3C_MCTRL); > > ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, > @@ -939,8 +946,10 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, > ret = svc_i3c_master_read(master, in, xfer_len); > else > ret = svc_i3c_master_write(master, out, xfer_len); > - if (ret) > + if (ret < 0) > goto emit_stop; > + if (rnw) > + *read_len = ret; > > ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg, > SVC_I3C_MSTATUS_COMPLETE(reg), 0, 1000); > @@ -1012,7 +1021,7 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master) > > ret = svc_i3c_master_xfer(master, cmd->rnw, xfer->type, > cmd->addr, cmd->in, cmd->out, > - cmd->len, cmd->read_len, > + cmd->len, &cmd->read_len, > cmd->continued); > if (ret) > break; > @@ -1141,6 +1150,9 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master, > if (!wait_for_completion_timeout(&xfer->comp, msecs_to_jiffies(1000))) > svc_i3c_master_dequeue_xfer(master, xfer); > > + if (cmd->read_len != xfer_len) > + ccc->dests[0].payload.len = cmd->read_len; > + > ret = xfer->ret; > svc_i3c_master_free_xfer(xfer); > Thanks, Miquèl