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=-16.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 9784EC433E1 for ; Fri, 24 Jul 2020 05:42:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70D0B20767 for ; Fri, 24 Jul 2020 05:42:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="dro2IQ3g" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726642AbgGXFmR (ORCPT ); Fri, 24 Jul 2020 01:42:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726277AbgGXFmQ (ORCPT ); Fri, 24 Jul 2020 01:42:16 -0400 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EB02C0619D3 for ; Thu, 23 Jul 2020 22:42:15 -0700 (PDT) Received: by mail-pf1-x443.google.com with SMTP id s26so4480994pfm.4 for ; Thu, 23 Jul 2020 22:42:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=/7h13uK3yaCmC6CvwntDrcPq/x8aDHrW9fKg5HxHfJ8=; b=dro2IQ3giApo6ftru/j+SRlfgGyyq/joz+CqXpj+SkXiFG3KqSiPG5xEf84M0adWtQ DQFwEcqs5o/AojmOxk2loupywrh4gZ7jVgS7M8uXJTixBZpsr0TPa3lSFDRV9eQbfk85 3NJf37XuXYMHx6zLiRbFwRZbnFIzVAxyKQdkwFcVS+vcuDR/8zNMWwaEo9Zx3R7MfBsx llbxS8G1Hipp9VKkcmrw2eWaqp9ZXY8TuDjW+4EsWt+lf+91noSc35V+3MmeIHWRLC9b ew0tpQExMvxfRadSlQG5p/Pk2uvg1M9BUS6QcPNmZpNPNYi2sIkn+MlI9Sn5uKb7ZXhV k/Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=/7h13uK3yaCmC6CvwntDrcPq/x8aDHrW9fKg5HxHfJ8=; b=XDH4zYN5LSHr3Abay733hr/UydoKYX9Gv+3v5hWIY86WpvZYZugUzQ6QRZ3+T6AJLs 0Wqj1VxO0DW0xpfjyCdUiyaJrFkrAhjrBVScA6/JD9U6dNDl+U/VX2HLoKZs+oO7PlV+ h4yd61SQH/htMUn+N5P+XyGTkK1YA1kChRI+Hbh3tAILfvTHQIh6Df+fkpeSXWjnQtSu UeXjUuB/08dbfhClnEyXmM/FyjF8UNn5HV6rSVgbkCEdk01qntNgrf+5QhDF7itxD4Ro ErgKyfMaUlpbMZNNkZq4Q6cxk2Yb4IONtd9WFBDHJPLXdgugd9IDL2bpaJwjhjhg8qNs EhqA== X-Gm-Message-State: AOAM5338jUvIBTH5I1PwgsLlVcQmtn2z6zADR6xYf9BSfFxX6Vi3Yjmn 4zYMPIqDBc466tzd9gp0uZeu X-Google-Smtp-Source: ABdhPJxlVphFfTC0uNq8+LW41fK8sJCI/GPQ8wSRCRSNL4eEQMMHcVxK25DtuSSiYx9Yw9Eesr2yUA== X-Received: by 2002:a63:8c5c:: with SMTP id q28mr7157006pgn.111.1595569334629; Thu, 23 Jul 2020 22:42:14 -0700 (PDT) Received: from Mani-XPS-13-9360 ([2409:4072:6c9b:7816:d54:f58c:a790:e57b]) by smtp.gmail.com with ESMTPSA id ml8sm4462138pjb.47.2020.07.23.22.42.10 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 23 Jul 2020 22:42:14 -0700 (PDT) Date: Fri, 24 Jul 2020 11:12:06 +0530 From: Manivannan Sadhasivam To: Bhaumik Bhatt Cc: linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org, jhugo@codeaurora.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 10/10] bus: mhi: core: Introduce sysfs entries for MHI Message-ID: <20200724054206.GC17957@Mani-XPS-13-9360> References: <1595543802-17859-1-git-send-email-bbhatt@codeaurora.org> <1595543802-17859-11-git-send-email-bbhatt@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1595543802-17859-11-git-send-email-bbhatt@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Jul 23, 2020 at 03:36:42PM -0700, Bhaumik Bhatt wrote: > Introduce sysfs entries to enable userspace clients the ability to read > the serial number and the OEM PK Hash values obtained from BHI. OEMs > need to read these device-specific hardware information values through > userspace for factory testing purposes and cannot be exposed via degbufs > as it may remain disabled for performance reasons. Also, update the > documentation for ABI to include these entries. > > Signed-off-by: Bhaumik Bhatt > --- > Documentation/ABI/stable/sysfs-bus-mhi | 25 ++++++++++++++++ > MAINTAINERS | 1 + > drivers/bus/mhi/core/init.c | 53 ++++++++++++++++++++++++++++++++++ > 3 files changed, 79 insertions(+) > create mode 100644 Documentation/ABI/stable/sysfs-bus-mhi > > diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi > new file mode 100644 > index 0000000..a4e4bd2 > --- /dev/null > +++ b/Documentation/ABI/stable/sysfs-bus-mhi > @@ -0,0 +1,25 @@ > +What: /sys/bus/mhi/devices/.../serialnumber > +Date: July 2020 > +KernelVersion: 5.8 > +Contact: Bhaumik Bhatt > +Description: > + The file holds the serial number of the client device obtained > + using a BHI (Boot Host Interface) register read after at least > + one attempt to power up the device has been done. If read > + without having the device power on at least once, the file will > + read all 0's. > +Users: Any userspace application or clients interested in the device > + hardware information. Please align all the fields onto a single starting point. Have a look at other ABI documentation like, Documentation/ABI/stable/sysfs-bus-vmbus. > + > +What: /sys/bus/mhi/devices/.../oem_pk_hash > +Date: July 2020 > +KernelVersion: 5.8 > +Contact: Bhaumik Bhatt > +Description: > + The file holds the OEM PK Hash value of the endpoint device > + obtained using a BHI (Boot Host Interface) register read after > + at least one attempt to power up the device has been done. If > + read without having the device power on at least once, the file > + will read all 0's. > +Users: Any userspace application or clients interested in the device > + hardware information. > diff --git a/MAINTAINERS b/MAINTAINERS > index e64e5db..5e49316 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -11018,6 +11018,7 @@ M: Hemant Kumar > L: linux-arm-msm@vger.kernel.org > S: Maintained > T: git git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git > +F: Documentation/ABI/stable/sysfs-bus-mhi > F: Documentation/mhi/ > F: drivers/bus/mhi/ > F: include/linux/mhi.h > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > index d2c0f6e..a7b0d76 100644 > --- a/drivers/bus/mhi/core/init.c > +++ b/drivers/bus/mhi/core/init.c > @@ -76,6 +76,56 @@ const char *to_mhi_pm_state_str(enum mhi_pm_state state) > return mhi_pm_state_str[index]; > } > > +static ssize_t serial_number_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) We haven't followed this before but it is good to align the function parameters with respect to '('. > +{ > + struct mhi_device *mhi_dev = to_mhi_device(dev); > + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; > + > + return snprintf(buf, PAGE_SIZE, "Serial Number: %u\n", > + mhi_cntrl->serial_number); We need to think about what happens if the mhi_cntrl structure is not zero initialized by the controller driver. All throughout the stack we assume that the mhi_cntrl struct is zero initialized but things can go awry if it was not the case! There was one API in the downstream (mhi_alloc_controller()) for this purpose but I removed it since we ended up with just a kzalloc(). Does it make sense to introduce it now? Thanks, Mani > +} > +static DEVICE_ATTR_RO(serial_number); > + > +static ssize_t oem_pk_hash_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct mhi_device *mhi_dev = to_mhi_device(dev); > + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; > + int i, cnt = 0; > + > + for (i = 0; i < ARRAY_SIZE(mhi_cntrl->oem_pk_hash); i++) > + cnt += snprintf(buf + cnt, PAGE_SIZE - cnt, > + "OEMPKHASH[%d]: 0x%x\n", i, > + mhi_cntrl->oem_pk_hash[i]); > + > + return cnt; > +} > +static DEVICE_ATTR_RO(oem_pk_hash); > + > +static struct attribute *mhi_sysfs_attrs[] = { > + &dev_attr_serial_number.attr, > + &dev_attr_oem_pk_hash.attr, > + NULL, > +}; > + > +static const struct attribute_group mhi_sysfs_group = { > + .attrs = mhi_sysfs_attrs, > +}; > + > +static int mhi_create_sysfs(struct mhi_controller *mhi_cntrl) > +{ > + return sysfs_create_group(&mhi_cntrl->mhi_dev->dev.kobj, > + &mhi_sysfs_group); > +} > + > +static void mhi_destroy_sysfs(struct mhi_controller *mhi_cntrl) > +{ > + sysfs_remove_group(&mhi_cntrl->mhi_dev->dev.kobj, &mhi_sysfs_group); > +} > + > /* MHI protocol requires the transfer ring to be aligned with ring length */ > static int mhi_alloc_aligned_ring(struct mhi_controller *mhi_cntrl, > struct mhi_ring *ring, > @@ -917,6 +967,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, > mhi_cntrl->mhi_dev = mhi_dev; > > mhi_create_debugfs(mhi_cntrl); > + if (mhi_create_sysfs(mhi_cntrl)) > + dev_err(mhi_cntrl->cntrl_dev, "Failed to create sysfs entries\n"); > > return 0; > > @@ -940,6 +992,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl) > struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan; > unsigned int i; > > + mhi_destroy_sysfs(mhi_cntrl); > mhi_destroy_debugfs(mhi_cntrl); > > kfree(mhi_cntrl->mhi_cmd); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >