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 5A5CFCD98CE for ; Fri, 12 Jun 2026 22:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=HzeSy3OuMWqjXFm50tlFHc/ka5zNG1NXgfkNjH2Hvds=; b=DTp6ZPeszlkbkOUXhx6zie/Aoi UnoOu1XFQNFEyIzzpTYG8f19bHwyHeFt9tu7UxlENQEbxXYsq+u+RTgsBAidd0Mf+jCUG+ZJLkymM C2KV/aC+UUfDrnMUR2bWITUbZPxxCJa4bD0U6KuV5Nr+8gjjO5+vWBdlkis7yz9+Yqv4t834MfbMS mfB2ZMEJ0QvVuz7u8sAfWRKFshJTLqHbTIllb2ZpeYjKEcp02gP19eT2TIZM0jV0SwpwQQIeMpC1f 0BRmGJgfVIjwtDmJTm2Ahk2yqG3Pqje5v/IcZMKdCAyIjHkDtnvzcQDhMRa3nYiNAdW1aKxTjywWP AegZ5RDQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wYAYL-0000000Bhic-3ey2; Fri, 12 Jun 2026 22:40:41 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wYAYA-0000000BhT3-2WZV for linux-arm-kernel@lists.infradead.org; Fri, 12 Jun 2026 22:40:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D71DF4A09; Fri, 12 Jun 2026 15:40:24 -0700 (PDT) Received: from pluto.fritz.box (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B0B103FB7F; Fri, 12 Jun 2026 15:40:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1781304029; bh=GI0vwR1LEStmargetn1ql1v3LHVWj/3AFAUhwSQd72k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gPZUchLafmLmBTG6kU1XxPqRe5FZiTCIOutLUAYXpDRSVnwCv/siq+mk6Ghh0tIQq xzSi4vWou+YoRuAEGKyrrBAZYIOXRXqQO+8GZVsqPNnLqn22bE58SsPjlDmUW+UXh8 M0U/7Qqc9TeITAG3++SznwWKjEA1q9pcngEehzZY= From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org Cc: sudeep.holla@kernel.org, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, d-gole@ti.com, jic23@kernel.org, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, brauner@kernel.org, souvik.chakravarty@arm.com, leitao@kernel.org, kas@kernel.org, puranjay@kernel.org, usama.arif@linux.dev, kernel-team@meta.com, Cristian Marussi Subject: [PATCH v4 27/31] firmware: arm_scmi: stlmfs: Add generation file Date: Fri, 12 Jun 2026 23:37:57 +0100 Message-ID: <20260612223802.1337232-28-cristian.marussi@arm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260612223802.1337232-1-cristian.marussi@arm.com> References: <20260612223802.1337232-1-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260612_154030_734893_B329B8F8 X-CRM114-Status: GOOD ( 13.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Add a read-only generation file to be used for monitoring configuration changes across an instance: first read after the open returns the current value, then it blocks till next confiuration change is detected. Generation file supports also poll system call to monitor chamges. Signed-off-by: Cristian Marussi --- v3 --> v4 - added stlmfs tag in $SUBJECT --- .../firmware/arm_scmi/scmi_system_telemetry.c | 89 +++++++++++++++++++ 1 file changed, 89 insertions(+) diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c index c83d9763d479..df45fc212e13 100644 --- a/drivers/firmware/arm_scmi/scmi_system_telemetry.c +++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c @@ -19,12 +19,14 @@ #include #include #include +#include #include #include #include #include #include #include +#include #include @@ -1368,6 +1370,91 @@ static const struct file_operations available_interv_fops = { .release = scmi_tlm_priv_release, }; +struct scmi_tlm_gen_priv { + unsigned int last_seen; + struct wait_queue_head *wq; + struct scmi_tlm_buffer tb; +}; + +static int scmi_tlm_generation_open(struct inode *ino, struct file *filp) +{ + struct scmi_tlm_inode *tlmi = to_tlm_inode(ino); + struct scmi_tlm_setup *tsp = tlmi->tsp; + struct scmi_tlm_gen_priv *gen; + + gen = kzalloc_obj(*gen); + if (!gen) + return -ENOMEM; + + gen->wq = tsp->ops->event_wq_get(tsp->ph); + if (!gen->wq) { + kfree(gen); + return -ENOMEM; + } + + gen->last_seen = SCMI_TLM_GENERATION_INVALID; + filp->private_data = gen; + + return nonseekable_open(ino, filp); +} + +static ssize_t +scmi_tlm_generation_read(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct scmi_tlm_inode *tlmi = to_tlm_inode(file_inode(filp)); + struct scmi_tlm_gen_priv *gen = filp->private_data; + struct scmi_telemetry_info *info = (struct scmi_telemetry_info *)tlmi->priv; + unsigned int c; + + if (*ppos == gen->tb.used) + gen->tb.used = *ppos = 0; + + if (!gen->tb.used) { + int ret; + + ret = wait_event_interruptible(*gen->wq, + (c = atomic_read(&info->generation)) != + gen->last_seen); + if (ret) + return -ERESTARTSYS; + + gen->last_seen = c; + gen->tb.used = scnprintf(gen->tb.buf, SCMI_TLM_MAX_BUF_SZ, "%u\n", c); + } + + return simple_read_from_buffer(buf, count, ppos, gen->tb.buf, gen->tb.used); +} + +static __poll_t scmi_tlm_generation_poll(struct file *filp, poll_table *wait) +{ + struct scmi_tlm_inode *tlmi = to_tlm_inode(file_inode(filp)); + struct scmi_telemetry_info *info = (struct scmi_telemetry_info *)tlmi->priv; + struct scmi_tlm_gen_priv *gen = filp->private_data; + + poll_wait(filp, gen->wq, wait); + if (atomic_read(&info->generation) != gen->last_seen) + return EPOLLIN | EPOLLRDNORM; + + return 0; +} + +static int scmi_tlm_generation_release(struct inode *ino, struct file *filp) +{ + struct scmi_tlm_gen_priv *gen = filp->private_data; + + kfree(gen); + + return 0; +} + +static const struct file_operations generation_fops = { + .open = scmi_tlm_generation_open, + .read = scmi_tlm_generation_read, + .poll = scmi_tlm_generation_poll, + .release = scmi_tlm_generation_release, +}; + static const struct scmi_tlm_class tlm_tops[] = { TLM_ANON_CLASS("all_des_enable", TLM_IS_STATE, S_IFREG | 0666, &all_des_fops, NULL), @@ -1383,6 +1470,8 @@ static const struct scmi_tlm_class tlm_tops[] = { S_IFREG | 0444, &de_impl_vers_fops, NULL), TLM_ANON_CLASS("tlm_enable", 0, S_IFREG | 0666, &tlm_enable_fops, NULL), + TLM_ANON_CLASS("generation", 0, + S_IFREG | 0444, &generation_fops, NULL), TLM_ANON_CLASS(NULL, 0, 0, NULL, NULL), }; -- 2.54.0