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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 0D0EDC2BA19 for ; Thu, 9 Apr 2020 22:42:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D836920730 for ; Thu, 9 Apr 2020 22:42:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726951AbgDIWmQ (ORCPT ); Thu, 9 Apr 2020 18:42:16 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:42684 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726734AbgDIWmP (ORCPT ); Thu, 9 Apr 2020 18:42:15 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id F0D1B28DA58 Subject: Re: [PATCH 1/2] platform/chrome: skip old cros_ec responses To: Mathew King , linux-kernel@vger.kernel.org Cc: Jett Rink , Benson Leung , Guenter Roeck References: <20200408181638.184559-1-mathewk@chromium.org> From: Enric Balletbo i Serra Message-ID: Date: Fri, 10 Apr 2020 00:42:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200408181638.184559-1-mathewk@chromium.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mathew, Thanks for your patch. On 8/4/20 20:16, Mathew King wrote: > From: Jett Rink > > The ISHTP layer can give us old responses that we already gave up on. We > do not want to interpret these old responses as the current response we > are waiting for. > Looking at the code and with the above explanation I am not sure I get what is doing this patch, could you explain a bit more, thanks. > Signed-off-by: Jett Rink > Signed-off-by: Mathew King > --- > drivers/platform/chrome/cros_ec_ishtp.c | 32 ++++++++++++++++++------- > 1 file changed, 23 insertions(+), 9 deletions(-) > > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c > index 93a71e93a2f1..6f90deb5cf55 100644 > --- a/drivers/platform/chrome/cros_ec_ishtp.c > +++ b/drivers/platform/chrome/cros_ec_ishtp.c > @@ -48,7 +48,8 @@ static const guid_t cros_ish_guid = > struct header { > u8 channel; > u8 status; > - u8 reserved[2]; > + u8 id; > + u8 reserved; > } __packed; > > struct cros_ish_out_msg { > @@ -90,6 +91,7 @@ static DECLARE_RWSEM(init_lock); > * data exceeds this value, we log an error. > * @size: Actual size of data received from firmware. > * @error: 0 for success, negative error code for a failure in process_recv(). > + * @expected_id: Expected id for response that we are waiting on. > * @received: Set to true on receiving a valid firmware response to host command > * @wait_queue: Wait queue for host to wait for firmware response. > */ > @@ -98,6 +100,7 @@ struct response_info { > size_t max_size; > size_t size; > int error; > + u8 expected_id; > bool received; > wait_queue_head_t wait_queue; > }; > @@ -162,6 +165,7 @@ static int ish_send(struct ishtp_cl_data *client_data, > u8 *out_msg, size_t out_size, > u8 *in_msg, size_t in_size) > { > + static u8 current_id; > int rv; > struct header *out_hdr = (struct header *)out_msg; > struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl; > @@ -174,8 +178,11 @@ static int ish_send(struct ishtp_cl_data *client_data, > client_data->response.data = in_msg; > client_data->response.max_size = in_size; > client_data->response.error = 0; > + client_data->response.expected_id = ++current_id; So on every ish_send call this variable is increased in a range 1 to 255 first, then overflows and goes from 0 to 255. Is this what you want to do? > client_data->response.received = false; > > + out_hdr->id = client_data->response.expected_id; > + > rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size); > if (rv) { > dev_err(cl_data_to_dev(client_data), > @@ -249,17 +256,23 @@ static void process_recv(struct ishtp_cl *cros_ish_cl, > > switch (in_msg->hdr.channel) { > case CROS_EC_COMMAND: > - /* Sanity check */ > - if (!client_data->response.data) { > + if (client_data->response.received) { > dev_err(dev, > - "Receiving buffer is null. Should be allocated by calling function\n"); > - client_data->response.error = -EINVAL; > - goto error_wake_up; > + "Previous firmware message not yet processed\n"); > + goto end_error; > } > > - if (client_data->response.received) { > + if (client_data->response.expected_id != in_msg->hdr.id) { And here you compare that the response received matches with the message id. I assume the ISH is sending a sequential id on every message? > dev_err(dev, > - "Previous firmware message not yet processed\n"); > + "Dropping old response id %d\n", > + in_msg->hdr.id); How often this message appears? > + goto end_error; > + } > + > + /* Sanity check */ > + if (!client_data->response.data) { > + dev_err(dev, > + "Receiving buffer is null. Should be allocated by calling function\n"); > client_data->response.error = -EINVAL; > goto error_wake_up; > } > @@ -289,9 +302,10 @@ static void process_recv(struct ishtp_cl *cros_ish_cl, > memcpy(client_data->response.data, > rb_in_proc->buffer.data, data_len); > > +error_wake_up: > /* Set flag before waking up the caller */ > client_data->response.received = true; > -error_wake_up: > + > /* Wake the calling thread */ > wake_up_interruptible(&client_data->response.wait_queue); > >