From patchwork Thu Jun 3 23:45:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298423 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B1397C47096 for ; Thu, 3 Jun 2021 23:46:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 94D59613E7 for ; Thu, 3 Jun 2021 23:46:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229864AbhFCXsl (ORCPT ); Thu, 3 Jun 2021 19:48:41 -0400 Received: from mail-wm1-f46.google.com ([209.85.128.46]:45624 "EHLO mail-wm1-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229576AbhFCXsk (ORCPT ); Thu, 3 Jun 2021 19:48:40 -0400 Received: by mail-wm1-f46.google.com with SMTP id v206-20020a1cded70000b02901a586d3fa23so336940wmg.4; Thu, 03 Jun 2021 16:46:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zEhd2JIVnEi/+Epm1rky2qOq6YPm+V27d0RLFZVEOBU=; b=ZxmyOK9uEmovmY4Za5mXppXj/tTIovO45GVAOhjsfq1ywnEJ9F+TVy4xaaaOi6/KrJ KAmPqUbSXTwdcAPdikjgXGB3v7sJqcvRhVVEov3kUJBxsqn/OWLgWgSr+R9xD72TlBfm /d3X0M+9fmwpXG3lFeTU4X3C/cLf1zqSuF3WxRWGoVdtp9n0KHp2mbbsZqmP8Y2xFyZj 0iiV0Cs0bBaLn+y5vMRClEDvmH2NnK4n8PVwhgzTXyv2wL4W1q+bLYftByycRPillKAx 8kyoQJkhKowO+FUkZZ+CuMaXCRzrojtpzRcqDv75uU/L+07KrIdXnoSsQUEfbZPE5pTA 8LmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=zEhd2JIVnEi/+Epm1rky2qOq6YPm+V27d0RLFZVEOBU=; b=tFdZLLvR/VAOvk7RM7q5Sqsnigl6HWIsS/X7dyPQ9y8f+RlETjrXyUma70GOXDuvhF a2EHXJO80ctrx/k+UeP8fxAY3MxNi5C+Y0KTu4mf9rDJeHpb6OHugGcIF9vCxrvSoFLd 0apYC/o1nJpKX25e7nYxH4w/WLXRxBedsNF8jDkXoLKJOgrsU9CBzEAzLLYxNS5Lhp3R Snaibzv0s3/IF0r2cZNorxA5TMqY2koFWH1nyqwV2Mve5vDTyOYYcF/OWIqwzlqL1YE7 xXGlgyAlFwDmNPgCH0zYrT6APcztPt+PVbUmgMmNIBs/je/6NhchIEvvDWy04OIPWp4e 50SQ== X-Gm-Message-State: AOAM533PAggtg2Lj29uOYXavYHiLfqyuR68oNDDrw12jA5D22pBt4BeT RN6862txv4BM1Ths44t1REU= X-Google-Smtp-Source: ABdhPJxU7MILRLV2PZGkn5S6pcw2NeGK92Ystc6GanPBphMv1oUP9iGPyHcLdRQx3GsM6BZMUH4w2g== X-Received: by 2002:a1c:2155:: with SMTP id h82mr768841wmh.115.1622763943815; Thu, 03 Jun 2021 16:45:43 -0700 (PDT) Received: from xws.localdomain ([37.58.58.229]) by smtp.gmail.com with ESMTPSA id a11sm4743386wrr.48.2021.06.03.16.45.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jun 2021 16:45:43 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/7] platform/surface: aggregator: Allow registering notifiers without enabling events Date: Fri, 4 Jun 2021 01:45:20 +0200 Message-Id: <20210603234526.2503590-2-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Currently, each SSAM event notifier is directly tied to one group of events. This makes sense as registering a notifier will automatically take care of enabling the corresponding event group and normally drivers only need notifications for a very limited number of events, associated with different callbacks for each group. However, there are rare cases, especially for debugging, when we want to get notifications for a whole event target category instead of just a single group of events in that category. Registering multiple notifiers, i.e. one per group, may be infeasible due to two issues: a) we might not know every event enable/disable specification as some events are auto-enabled by the EC and b) forwarding this to the same callback will lead to duplicate events as we might not know the full event specification to perform the appropriate filtering. This commit introduces observer-notifiers, which are notifiers that are not tied to a specific event group and do not attempt to manage any events. In other words, they can be registered without enabling any event group or incrementing the corresponding reference count and just act as silent observers, listening to all currently/previously enabled events based on their match-specification. Essentially, this allows us to register one single notifier for a full event target category, meaning that we can process all events of that target category in a single callback without duplication. Specifically, this will be used in the cdev debug interface to forward events to user-space via a device file from which the events can be read. Signed-off-by: Maximilian Luz --- .../platform/surface/aggregator/controller.c | 69 +++++++++++-------- include/linux/surface_aggregator/controller.h | 17 +++++ 2 files changed, 58 insertions(+), 28 deletions(-) diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c index a06964aa96e7..cd3a6b77f48d 100644 --- a/drivers/platform/surface/aggregator/controller.c +++ b/drivers/platform/surface/aggregator/controller.c @@ -2127,9 +2127,15 @@ int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl) * @ctrl: The controller to register the notifier on. * @n: The event notifier to register. * - * Register an event notifier and increment the usage counter of the - * associated SAM event. If the event was previously not enabled, it will be - * enabled during this call. + * Register an event notifier. Increment the usage counter of the associated + * SAM event if the notifier is not marked as an observer. If the event is not + * marked as an observer and is currently not enabled, it will be enabled + * during this call. If the notifier is marked as an observer, no attempt will + * be made at enabling any event and no reference count will be modified. + * + * Notifiers marked as observers do not need to be associated with one specific + * event, i.e. as long as no event matching is performed, only the event target + * category needs to be set. * * Return: Returns zero on success, %-ENOSPC if there have already been * %INT_MAX notifiers for the event ID/type associated with the notifier block @@ -2138,11 +2144,10 @@ int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl) * for the specific associated event, returns the status of the event-enable * EC-command. */ -int ssam_notifier_register(struct ssam_controller *ctrl, - struct ssam_event_notifier *n) +int ssam_notifier_register(struct ssam_controller *ctrl, struct ssam_event_notifier *n) { u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); - struct ssam_nf_refcount_entry *entry; + struct ssam_nf_refcount_entry *entry = NULL; struct ssam_nf_head *nf_head; struct ssam_nf *nf; int status; @@ -2155,29 +2160,32 @@ int ssam_notifier_register(struct ssam_controller *ctrl, mutex_lock(&nf->lock); - entry = ssam_nf_refcount_inc(nf, n->event.reg, n->event.id); - if (IS_ERR(entry)) { - mutex_unlock(&nf->lock); - return PTR_ERR(entry); - } + if (!(n->flags & SSAM_EVENT_NOTIFIER_OBSERVER)) { + entry = ssam_nf_refcount_inc(nf, n->event.reg, n->event.id); + if (IS_ERR(entry)) { + mutex_unlock(&nf->lock); + return PTR_ERR(entry); + } - ssam_dbg(ctrl, "enabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", - n->event.reg.target_category, n->event.id.target_category, - n->event.id.instance, entry->refcount); + ssam_dbg(ctrl, "enabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", + n->event.reg.target_category, n->event.id.target_category, + n->event.id.instance, entry->refcount); + } status = ssam_nfblk_insert(nf_head, &n->base); if (status) { - entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); - if (entry->refcount == 0) - kfree(entry); + if (entry) { + entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); + if (entry->refcount == 0) + kfree(entry); + } mutex_unlock(&nf->lock); return status; } - if (entry->refcount == 1) { - status = ssam_ssh_event_enable(ctrl, n->event.reg, n->event.id, - n->event.flags); + if (entry && entry->refcount == 1) { + status = ssam_ssh_event_enable(ctrl, n->event.reg, n->event.id, n->event.flags); if (status) { ssam_nfblk_remove(&n->base); kfree(ssam_nf_refcount_dec(nf, n->event.reg, n->event.id)); @@ -2188,7 +2196,7 @@ int ssam_notifier_register(struct ssam_controller *ctrl, entry->flags = n->event.flags; - } else if (entry->flags != n->event.flags) { + } else if (entry && entry->flags != n->event.flags) { ssam_warn(ctrl, "inconsistent flags when enabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", n->event.flags, entry->flags, n->event.reg.target_category, @@ -2205,17 +2213,16 @@ EXPORT_SYMBOL_GPL(ssam_notifier_register); * @ctrl: The controller the notifier has been registered on. * @n: The event notifier to unregister. * - * Unregister an event notifier and decrement the usage counter of the - * associated SAM event. If the usage counter reaches zero, the event will be - * disabled. + * Unregister an event notifier. Decrement the usage counter of the associated + * SAM event if the notifier is not marked as an observer. If the usage counter + * reaches zero, the event will be disabled. * * Return: Returns zero on success, %-ENOENT if the given notifier block has * not been registered on the controller. If the given notifier block was the * last one associated with its specific event, returns the status of the * event-disable EC-command. */ -int ssam_notifier_unregister(struct ssam_controller *ctrl, - struct ssam_event_notifier *n) +int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n) { u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); struct ssam_nf_refcount_entry *entry; @@ -2236,6 +2243,13 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, return -ENOENT; } + /* + * If this is an observer notifier, do not attempt to disable the + * event, just remove it. + */ + if (n->flags & SSAM_EVENT_NOTIFIER_OBSERVER) + goto remove; + entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); if (WARN_ON(!entry)) { /* @@ -2260,8 +2274,7 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, } if (entry->refcount == 0) { - status = ssam_ssh_event_disable(ctrl, n->event.reg, n->event.id, - n->event.flags); + status = ssam_ssh_event_disable(ctrl, n->event.reg, n->event.id, n->event.flags); kfree(entry); } diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h index 0806796eabcb..cf4bb48a850e 100644 --- a/include/linux/surface_aggregator/controller.h +++ b/include/linux/surface_aggregator/controller.h @@ -795,6 +795,20 @@ enum ssam_event_mask { #define SSAM_EVENT_REGISTRY_REG \ SSAM_EVENT_REGISTRY(SSAM_SSH_TC_REG, 0x02, 0x01, 0x02) +/** + * enum ssam_event_notifier_flags - Flags for event notifiers. + * @SSAM_EVENT_NOTIFIER_OBSERVER: + * The corresponding notifier acts as observer. Registering a notifier + * with this flag set will not attempt to enable any event. Equally, + * unregistering will not attempt to disable any event. Note that a + * notifier with this flag may not even correspond to a certain event at + * all, only to a specific event target category. Event matching will not + * be influenced by this flag. + */ +enum ssam_event_notifier_flags { + SSAM_EVENT_NOTIFIER_OBSERVER = BIT(0), +}; + /** * struct ssam_event_notifier - Notifier block for SSAM events. * @base: The base notifier block with callback function and priority. @@ -803,6 +817,7 @@ enum ssam_event_mask { * @event.id: ID specifying the event. * @event.mask: Flags determining how events are matched to the notifier. * @event.flags: Flags used for enabling the event. + * @flags: Notifier flags (see &enum ssam_event_notifier_flags). */ struct ssam_event_notifier { struct ssam_notifier_block base; @@ -813,6 +828,8 @@ struct ssam_event_notifier { enum ssam_event_mask mask; u8 flags; } event; + + unsigned long flags; }; int ssam_notifier_register(struct ssam_controller *ctrl, From patchwork Thu Jun 3 23:45:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298421 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 BC176C47082 for ; Thu, 3 Jun 2021 23:46:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96CFB613E7 for ; Thu, 3 Jun 2021 23:46:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229629AbhFCXsc (ORCPT ); Thu, 3 Jun 2021 19:48:32 -0400 Received: from mail-wm1-f43.google.com ([209.85.128.43]:45622 "EHLO mail-wm1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229576AbhFCXsb (ORCPT ); Thu, 3 Jun 2021 19:48:31 -0400 Received: by mail-wm1-f43.google.com with SMTP id v206-20020a1cded70000b02901a586d3fa23so336949wmg.4; Thu, 03 Jun 2021 16:46:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=J3I7Z3IpYgIYjLPyzXTfQAdZXADJUQoUkUspFp+drRA=; b=KZAM+A4loSh0JysndBSJ72GE6LaT3HPWf12hXAiI0M+tTtsgeNxr98beIQq+ar9Enh 7apS6MNEYcXZF+bM/Y1REo9SViEyYk4rQ/MSdd8HTBreQU/KhMJQjg5+KuICxYvN1/0w emXVj7HZtTtPANDfCKPkNq1DyE/2Ycsp26VOplNzKd0pa4c6pzs5HPaEg8ubbiuW5svA o0IBDJOZNio8LQa4T5KJr0IUvnTNtZfLZ1e802FS6ihnsP7gMoA54pnZaP+Mq1BBHB9z ax5fPZ9o3Pzxz3bFUy62zJ9i5erZaaYUJYNOgRCG6ACiZuEogNKUD55rb6CtAU07eZLZ LaFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=J3I7Z3IpYgIYjLPyzXTfQAdZXADJUQoUkUspFp+drRA=; b=YvoER+EaPsSNLI/AOTVsl/jIUH89dI7SzNQjEzKyHshFZaiLrewosQz4LoloxvAb0r Gh+UpLErEcmx5v5xLbUWrOFayN0fnLQQTzvlSW2YVM2v2gx9ljh6VwBEpqLjOWiw5Xy3 k3QaKZ3qWUxJ9bTVgIGws2CaX/psSr6ostBa4mFEajhqH4BW3tnJd+xXi03/1G5WRIcD VW/exXl/x06791LN7qbvm2K8551TpIj6nsO2juKoSZcYQBrpP+Y8zdA+ScJzAKKzEgR2 k3tWPBpzoYbsG6L3+SU+v7nDHidWOAggpf64QXFbofuyTUSNBkBw9LX779ifnMo2g8Kn Uxww== X-Gm-Message-State: AOAM53268frcWjXDHKZkiGcbql8HqXGtw0dFIEUlM3CpYRDaPSgcKw8V R1t7CPRSAGvks/FfVjOmNSY= X-Google-Smtp-Source: ABdhPJxWcyDMjU0QBHePxiRnwZ8dA9Dk8sTLlahJBH1FRNAawoB75MV30rbGdwq9a97qBUXnyZM94w== X-Received: by 2002:a7b:c30f:: with SMTP id k15mr789432wmj.128.1622763944805; Thu, 03 Jun 2021 16:45:44 -0700 (PDT) Received: from xws.localdomain ([37.58.58.229]) by smtp.gmail.com with ESMTPSA id a11sm4743386wrr.48.2021.06.03.16.45.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jun 2021 16:45:44 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/7] platform/surface: aggregator: Allow enabling of events without notifiers Date: Fri, 4 Jun 2021 01:45:21 +0200 Message-Id: <20210603234526.2503590-3-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org We can already enable and disable SAM events via one of two ways: either via a (non-observer) notifier tied to a specific event group, or a generic event enable/disable request. In some instances, however, neither method may be desirable. The first method will tie the event enable request to a specific notifier, however, when we want to receive notifications for multiple event groups of the same target category and forward this to the same notifier callback, we may receive duplicate events, i.e. one event per registered notifier. The second method will bypass the internal reference counting mechanism, meaning that a disable request will disable the event regardless of any other client driver using it, which may break the functionality of that driver. To address this problem, add new functions that allow enabling and disabling of events via the event reference counting mechanism built into the controller, without needing to register a notifier. This can then be used in combination with observer notifiers to process multiple events of the same target category without duplication in the same callback function. Signed-off-by: Maximilian Luz Reported-by: kernel test robot --- .../platform/surface/aggregator/controller.c | 135 ++++++++++++++++++ include/linux/surface_aggregator/controller.h | 8 ++ 2 files changed, 143 insertions(+) diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c index cd3a6b77f48d..49edddea417e 100644 --- a/drivers/platform/surface/aggregator/controller.c +++ b/drivers/platform/surface/aggregator/controller.c @@ -2287,6 +2287,141 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_not } EXPORT_SYMBOL_GPL(ssam_notifier_unregister); +/** + * ssam_controller_event_enable() - Enable the specified event. + * @ctrl: The controller to enable the event for. + * @reg: The event registry to use for enabling the event. + * @id: The event ID specifying the event to be enabled. + * @flags: The SAM event flags used for enabling the event. + * + * Increment the event reference count of the specified event. If the event has + * not been enabled previously, it will be enabled by this call. + * + * Note: In general, ssam_notifier_register() with a non-observer notifier + * should be preferred for enabling/disabling events, as this will guarantee + * proper ordering and event forwarding in case of errors during event + * enabling/disabling. + * + * Return: Returns zero on success, %-ENOSPC if the reference count for the + * specified event has reached its maximum, %-ENOMEM if the corresponding event + * entry could not be allocated. If this is the first time that this event has + * been enabled (i.e. the reference count was incremented from zero to one by + * this call), returns the status of the event-enable EC-command. + */ +int ssam_controller_event_enable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags) +{ + u16 rqid = ssh_tc_to_rqid(id.target_category); + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_head *nf_head; + struct ssam_nf *nf; + int status; + + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + nf = &ctrl->cplt.event.notif; + nf_head = &nf->head[ssh_rqid_to_event(rqid)]; + + mutex_lock(&nf->lock); + + entry = ssam_nf_refcount_inc(nf, reg, id); + if (IS_ERR(entry)) { + mutex_unlock(&nf->lock); + return PTR_ERR(entry); + } + + ssam_dbg(ctrl, "enabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", + reg.target_category, id.target_category, id.instance, + entry->refcount); + + if (entry->refcount == 1) { + status = ssam_ssh_event_enable(ctrl, reg, id, flags); + if (status) { + kfree(ssam_nf_refcount_dec(nf, reg, id)); + mutex_unlock(&nf->lock); + return status; + } + + entry->flags = flags; + + } else if (entry->flags != flags) { + ssam_warn(ctrl, + "inconsistent flags when enabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", + flags, entry->flags, reg.target_category, + id.target_category, id.instance); + } + + mutex_unlock(&nf->lock); + return 0; +} +EXPORT_SYMBOL_GPL(ssam_controller_event_enable); + +/** + * ssam_controller_event_disable() - Disable the specified event. + * @ctrl: The controller to disable the event for. + * @reg: The event registry to use for disabling the event. + * @id: The event ID specifying the event to be disabled. + * @flags: The flags used when enabling the event. + * + * Decrement the reference count of the specified event. If the reference count + * reaches zero, the event will be disabled. + * + * Note: In general, ssam_notifier_register()/ssam_notifier_unregister() with a + * non-observer notifier should be preferred for enabling/disabling events, as + * this will guarantee proper ordering and event forwarding in case of errors + * during event enabling/disabling. + * + * Return: Returns zero on success, %-ENOENT if the given event has not been + * enabled on the controller. If the reference count of the event reaches zero + * during this call, returns the status of the event-disable EC-command. + */ +int ssam_controller_event_disable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags) +{ + u16 rqid = ssh_tc_to_rqid(id.target_category); + struct ssam_nf_refcount_entry *entry; + struct ssam_nf_head *nf_head; + struct ssam_nf *nf; + int status = 0; + + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + nf = &ctrl->cplt.event.notif; + nf_head = &nf->head[ssh_rqid_to_event(rqid)]; + + mutex_lock(&nf->lock); + + entry = ssam_nf_refcount_dec(nf, reg, id); + if (WARN_ON(!entry)) { + mutex_unlock(&nf->lock); + return -ENOENT; + } + + ssam_dbg(ctrl, "disabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", + reg.target_category, id.target_category, id.instance, + entry->refcount); + + if (entry->flags != flags) { + ssam_warn(ctrl, + "inconsistent flags when disabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", + flags, entry->flags, reg.target_category, + id.target_category, id.instance); + } + + if (entry->refcount == 0) { + status = ssam_ssh_event_disable(ctrl, reg, id, flags); + kfree(entry); + } + + mutex_unlock(&nf->lock); + return status; +} +EXPORT_SYMBOL_GPL(ssam_controller_event_disable); + /** * ssam_notifier_disable_registered() - Disable events for all registered * notifiers. diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h index cf4bb48a850e..7965bdc669c5 100644 --- a/include/linux/surface_aggregator/controller.h +++ b/include/linux/surface_aggregator/controller.h @@ -838,4 +838,12 @@ int ssam_notifier_register(struct ssam_controller *ctrl, int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n); +int ssam_controller_event_enable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags); + +int ssam_controller_event_disable(struct ssam_controller *ctrl, + struct ssam_event_registry reg, + struct ssam_event_id id, u8 flags); + #endif /* _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H */ From patchwork Thu Jun 3 23:45:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298419 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 CC5B4C47098 for ; Thu, 3 Jun 2021 23:46:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B47F2613E7 for ; Thu, 3 Jun 2021 23:46:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229746AbhFCXrr (ORCPT ); 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Thu, 03 Jun 2021 16:45:45 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/7] platform/surface: aggregator: Update copyright Date: Fri, 4 Jun 2021 01:45:22 +0200 Message-Id: <20210603234526.2503590-4-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org It's 2021, update the copyright accordingly. Signed-off-by: Maximilian Luz --- drivers/platform/surface/aggregator/Kconfig | 2 +- drivers/platform/surface/aggregator/Makefile | 2 +- drivers/platform/surface/aggregator/bus.c | 2 +- drivers/platform/surface/aggregator/bus.h | 2 +- drivers/platform/surface/aggregator/controller.c | 2 +- drivers/platform/surface/aggregator/controller.h | 2 +- drivers/platform/surface/aggregator/core.c | 2 +- drivers/platform/surface/aggregator/ssh_msgb.h | 2 +- drivers/platform/surface/aggregator/ssh_packet_layer.c | 2 +- drivers/platform/surface/aggregator/ssh_packet_layer.h | 2 +- drivers/platform/surface/aggregator/ssh_parser.c | 2 +- drivers/platform/surface/aggregator/ssh_parser.h | 2 +- drivers/platform/surface/aggregator/ssh_request_layer.c | 2 +- drivers/platform/surface/aggregator/ssh_request_layer.h | 2 +- drivers/platform/surface/aggregator/trace.h | 2 +- include/linux/surface_aggregator/controller.h | 2 +- include/linux/surface_aggregator/device.h | 2 +- include/linux/surface_aggregator/serial_hub.h | 2 +- 18 files changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/platform/surface/aggregator/Kconfig b/drivers/platform/surface/aggregator/Kconfig index 3aaeea9f0433..fd6dc452f3e8 100644 --- a/drivers/platform/surface/aggregator/Kconfig +++ b/drivers/platform/surface/aggregator/Kconfig @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0+ -# Copyright (C) 2019-2020 Maximilian Luz +# Copyright (C) 2019-2021 Maximilian Luz menuconfig SURFACE_AGGREGATOR tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers" diff --git a/drivers/platform/surface/aggregator/Makefile b/drivers/platform/surface/aggregator/Makefile index c112e2c7112b..c8498c41e758 100644 --- a/drivers/platform/surface/aggregator/Makefile +++ b/drivers/platform/surface/aggregator/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0+ -# Copyright (C) 2019-2020 Maximilian Luz +# Copyright (C) 2019-2021 Maximilian Luz # For include/trace/define_trace.h to include trace.h CFLAGS_core.o = -I$(src) diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c index a9b660af0917..0169677c243e 100644 --- a/drivers/platform/surface/aggregator/bus.c +++ b/drivers/platform/surface/aggregator/bus.c @@ -2,7 +2,7 @@ /* * Surface System Aggregator Module bus and device integration. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/bus.h b/drivers/platform/surface/aggregator/bus.h index 7712baaed6a5..ed032c2cbdb2 100644 --- a/drivers/platform/surface/aggregator/bus.h +++ b/drivers/platform/surface/aggregator/bus.h @@ -2,7 +2,7 @@ /* * Surface System Aggregator Module bus and device integration. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_BUS_H diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c index 49edddea417e..e91ee7e72c14 100644 --- a/drivers/platform/surface/aggregator/controller.c +++ b/drivers/platform/surface/aggregator/controller.c @@ -2,7 +2,7 @@ /* * Main SSAM/SSH controller structure and functionality. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/controller.h b/drivers/platform/surface/aggregator/controller.h index 8297d34e7489..a0963c3562ff 100644 --- a/drivers/platform/surface/aggregator/controller.h +++ b/drivers/platform/surface/aggregator/controller.h @@ -2,7 +2,7 @@ /* * Main SSAM/SSH controller structure and functionality. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_CONTROLLER_H diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index 8dc2c267bcd6..5d780e55f4a1 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -7,7 +7,7 @@ * Handles communication via requests as well as enabling, disabling, and * relaying of events. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/ssh_msgb.h b/drivers/platform/surface/aggregator/ssh_msgb.h index 1221f642dda1..e562958ffdf0 100644 --- a/drivers/platform/surface/aggregator/ssh_msgb.h +++ b/drivers/platform/surface/aggregator/ssh_msgb.h @@ -2,7 +2,7 @@ /* * SSH message builder functions. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_SSH_MSGB_H diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.c b/drivers/platform/surface/aggregator/ssh_packet_layer.c index 15d96eac6811..5e08049fc3ac 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.c +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.c @@ -2,7 +2,7 @@ /* * SSH packet transport layer. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.h b/drivers/platform/surface/aggregator/ssh_packet_layer.h index e8757d03f279..2eb329f0b91a 100644 --- a/drivers/platform/surface/aggregator/ssh_packet_layer.h +++ b/drivers/platform/surface/aggregator/ssh_packet_layer.h @@ -2,7 +2,7 @@ /* * SSH packet transport layer. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H diff --git a/drivers/platform/surface/aggregator/ssh_parser.c b/drivers/platform/surface/aggregator/ssh_parser.c index e2dead8de94a..b77912f8f13b 100644 --- a/drivers/platform/surface/aggregator/ssh_parser.c +++ b/drivers/platform/surface/aggregator/ssh_parser.c @@ -2,7 +2,7 @@ /* * SSH message parser. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/ssh_parser.h b/drivers/platform/surface/aggregator/ssh_parser.h index 63c38d350988..3bd6e180fd16 100644 --- a/drivers/platform/surface/aggregator/ssh_parser.h +++ b/drivers/platform/surface/aggregator/ssh_parser.h @@ -2,7 +2,7 @@ /* * SSH message parser. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_SSH_PARSER_H diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.c b/drivers/platform/surface/aggregator/ssh_request_layer.c index 52a83a8fcf82..bfe1aaf38065 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.c +++ b/drivers/platform/surface/aggregator/ssh_request_layer.c @@ -2,7 +2,7 @@ /* * SSH request transport layer. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #include diff --git a/drivers/platform/surface/aggregator/ssh_request_layer.h b/drivers/platform/surface/aggregator/ssh_request_layer.h index cb35815858d1..9c3cbae2d4bd 100644 --- a/drivers/platform/surface/aggregator/ssh_request_layer.h +++ b/drivers/platform/surface/aggregator/ssh_request_layer.h @@ -2,7 +2,7 @@ /* * SSH request transport layer. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _SURFACE_AGGREGATOR_SSH_REQUEST_LAYER_H diff --git a/drivers/platform/surface/aggregator/trace.h b/drivers/platform/surface/aggregator/trace.h index eb332bb53ae4..de64cf169060 100644 --- a/drivers/platform/surface/aggregator/trace.h +++ b/drivers/platform/surface/aggregator/trace.h @@ -2,7 +2,7 @@ /* * Trace points for SSAM/SSH. * - * Copyright (C) 2020 Maximilian Luz + * Copyright (C) 2020-2021 Maximilian Luz */ #undef TRACE_SYSTEM diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h index 7965bdc669c5..068e1982ad37 100644 --- a/include/linux/surface_aggregator/controller.h +++ b/include/linux/surface_aggregator/controller.h @@ -6,7 +6,7 @@ * managing access and communication to and from the SSAM EC, as well as main * communication structures and definitions. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _LINUX_SURFACE_AGGREGATOR_CONTROLLER_H diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h index 6ff9c58b3e17..f636c5310321 100644 --- a/include/linux/surface_aggregator/device.h +++ b/include/linux/surface_aggregator/device.h @@ -7,7 +7,7 @@ * Provides support for non-platform/non-ACPI SSAM clients via dedicated * subsystem. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _LINUX_SURFACE_AGGREGATOR_DEVICE_H diff --git a/include/linux/surface_aggregator/serial_hub.h b/include/linux/surface_aggregator/serial_hub.h index 64276fbfa1d5..c3de43edcffa 100644 --- a/include/linux/surface_aggregator/serial_hub.h +++ b/include/linux/surface_aggregator/serial_hub.h @@ -6,7 +6,7 @@ * Surface System Aggregator Module (SSAM). Provides the interface for basic * packet- and request-based communication with the SSAM EC via SSH. * - * Copyright (C) 2019-2020 Maximilian Luz + * Copyright (C) 2019-2021 Maximilian Luz */ #ifndef _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H From patchwork Thu Jun 3 23:45:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298425 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 1763FC47082 for ; Thu, 3 Jun 2021 23:46:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDE0A6141C for ; Thu, 3 Jun 2021 23:46:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbhFCXsm (ORCPT ); Thu, 3 Jun 2021 19:48:42 -0400 Received: from mail-wm1-f45.google.com ([209.85.128.45]:45625 "EHLO mail-wm1-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229852AbhFCXsl (ORCPT ); Thu, 3 Jun 2021 19:48:41 -0400 Received: by mail-wm1-f45.google.com with SMTP id v206-20020a1cded70000b02901a586d3fa23so337001wmg.4; Thu, 03 Jun 2021 16:46:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=h5zwHb5JJpo7v5xTk/X/GqdyEimkvpYSrxpNmqWP23Y=; b=bN1w0yQKeM5MbS+v0lz/I/j20yyU0TcE+yfj3f/55xei3sn2yWcNVbx183hhCDWwqm Jc5giLduHvXtDmhbX/FHEV3/6x1vdeRq3/YRZuHz5uPtM6VOQJcC/mQy4RrP5BV2n4jP +Y1utTAFehpnScXu4gt9QI8sxv9VN5V9QpBXgHHPYTlbl6KOVRTxpCGPxo4lmgNF2TE6 eOGoCcvvO51q9kcc5aHKaC+wO1V00oKnaiejijdI969ybk67uKezUyQMXRJm9QAAdRME vQBn1AiQ7jRr6+no8wAfi5LBeEU0joufINL6sc0jvj/TaDWlCR6DmkpVNi2z5EXHYJat 99HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=h5zwHb5JJpo7v5xTk/X/GqdyEimkvpYSrxpNmqWP23Y=; b=E8pXfWHTKgQDyqXuq0yEubueNLTZsXD01EpXyfc90qUKr6R5x95Grj320PTTDEcoq2 4ClpzC/301h7vlBYVXlji4WFZ3l5kXQT+c266eO3GPMoSX3tJ3OHyY+rCn6MIx2fmA6i to+KSIYuE6RzB4FHWff1iXHgOTOnBXxOrvIrWZ1UIv/CVV1n+JxWu8h75OaSI5/AVJRN LzaWYzNfA+aSeqQZyHkqYdjSwiOuQR6jewKOZdThTHAUM5UAcBFXa8WDsdXo7O9ohZNb ahy1zX1Od07k/uvGcLmfXZq8cyruIK8ykTF9N71uiHWO9eYGybHkl5H9E5R0QVwwVqp0 4/Wg== X-Gm-Message-State: AOAM532k5pw3CuWI2Fc/jnx+AdBXJr37A9D6fDAz0qQQpp6UV/6yOkCv kaIlzM953BHKAf/ciEBRlSI= X-Google-Smtp-Source: ABdhPJwje2cv3aVrpDJVp0nOgnB3Us+W4tqHIRM6ck4imuzZUnYjDaQ1IDJvevMIx7BL6+/u1fdPMA== X-Received: by 2002:a7b:c92e:: with SMTP id h14mr756207wml.51.1622763947291; Thu, 03 Jun 2021 16:45:47 -0700 (PDT) Received: from xws.localdomain ([37.58.58.229]) by smtp.gmail.com with ESMTPSA id a11sm4743386wrr.48.2021.06.03.16.45.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jun 2021 16:45:46 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , Jonathan Corbet , platform-driver-x86@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/7] platform/surface: aggregator_cdev: Add support for forwarding events to user-space Date: Fri, 4 Jun 2021 01:45:23 +0200 Message-Id: <20210603234526.2503590-5-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Currently, debugging unknown events requires writing a custom driver. This is somewhat difficult, slow to adapt, and not entirely user-friendly for quickly trying to figure out things on devices of some third-party user. We can do better. We already have a user-space interface intended for debugging SAM EC requests, so let's add support for receiving events to that. This commit provides support for receiving events by reading from the controller file. It additionally introduces two new IOCTLs to control which event categories will be forwarded. Specifically, a user-space client can specify which target categories it wants to receive events from by registering the corresponding notifier(s) via the IOCTLs and after that, read the received events by reading from the controller device. Signed-off-by: Maximilian Luz --- .../userspace-api/ioctl/ioctl-number.rst | 2 +- .../surface/surface_aggregator_cdev.c | 457 +++++++++++++++++- include/uapi/linux/surface_aggregator/cdev.h | 41 +- 3 files changed, 474 insertions(+), 26 deletions(-) diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 9bfc2b510c64..1409e40e6345 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -325,7 +325,7 @@ Code Seq# Include File Comments 0xA3 90-9F linux/dtlk.h 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem 0xA4 00-1F uapi/asm/sgx.h -0xA5 01 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator +0xA5 01-05 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator 0xA5 20-2F linux/surface_aggregator/dtx.h Microsoft Surface DTX driver diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index 79e28fab7e40..807930144039 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -3,29 +3,69 @@ * Provides user-space access to the SSAM EC via the /dev/surface/aggregator * misc device. Intended for debugging and development. * - * Copyright (C) 2020 Maximilian Luz + * Copyright (C) 2020-2021 Maximilian Luz */ #include +#include #include +#include #include #include #include #include +#include #include #include #include +#include #include #include +#include #define SSAM_CDEV_DEVICE_NAME "surface_aggregator_cdev" + +/* -- Main structures. ------------------------------------------------------ */ + +enum ssam_cdev_device_state { + SSAM_CDEV_DEVICE_SHUTDOWN_BIT = BIT(0), +}; + struct ssam_cdev { struct kref kref; struct rw_semaphore lock; + + struct device *dev; struct ssam_controller *ctrl; struct miscdevice mdev; + unsigned long flags; + + struct rw_semaphore client_lock; /* Guards client list. */ + struct list_head client_list; +}; + +struct ssam_cdev_client; + +struct ssam_cdev_notifier { + struct ssam_cdev_client *client; + struct ssam_event_notifier nf; +}; + +struct ssam_cdev_client { + struct ssam_cdev *cdev; + struct list_head node; + + struct mutex notifier_lock; /* Guards notifier access for registration */ + struct ssam_cdev_notifier *notifier[SSH_NUM_EVENTS]; + + struct mutex read_lock; /* Guards FIFO buffer read access */ + struct mutex write_lock; /* Guards FIFO buffer write access */ + DECLARE_KFIFO(buffer, u8, 4096); + + wait_queue_head_t waitq; + struct fasync_struct *fasync; }; static void __ssam_cdev_release(struct kref *kref) @@ -47,24 +87,169 @@ static void ssam_cdev_put(struct ssam_cdev *cdev) kref_put(&cdev->kref, __ssam_cdev_release); } -static int ssam_cdev_device_open(struct inode *inode, struct file *filp) + +/* -- Notifier handling. ---------------------------------------------------- */ + +static u32 ssam_cdev_notifier(struct ssam_event_notifier *nf, const struct ssam_event *in) { - struct miscdevice *mdev = filp->private_data; - struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev); + struct ssam_cdev_notifier *cdev_nf = container_of(nf, struct ssam_cdev_notifier, nf); + struct ssam_cdev_client *client = cdev_nf->client; + struct ssam_cdev_event event; + size_t n = struct_size(&event, data, in->length); + + /* Translate event. */ + event.target_category = in->target_category; + event.target_id = in->target_id; + event.command_id = in->command_id; + event.instance_id = in->instance_id; + event.length = in->length; + + mutex_lock(&client->write_lock); + + /* Make sure we have enough space. */ + if (kfifo_avail(&client->buffer) < n) { + dev_warn(client->cdev->dev, + "buffer full, dropping event (tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", + in->target_category, in->target_id, in->command_id, in->instance_id); + mutex_unlock(&client->write_lock); + return 0; + } - filp->private_data = ssam_cdev_get(cdev); - return stream_open(inode, filp); + /* Copy event header and payload. */ + kfifo_in(&client->buffer, (const u8 *)&event, struct_size(&event, data, 0)); + kfifo_in(&client->buffer, &in->data[0], in->length); + + mutex_unlock(&client->write_lock); + + /* Notify waiting readers. */ + kill_fasync(&client->fasync, SIGIO, POLL_IN); + wake_up_interruptible(&client->waitq); + + /* + * Don't mark events as handled, this is the job of a proper driver and + * not the debugging interface. + */ + return 0; } -static int ssam_cdev_device_release(struct inode *inode, struct file *filp) +static int ssam_cdev_notifier_register(struct ssam_cdev_client *client, u8 tc, int priority) { - ssam_cdev_put(filp->private_data); - return 0; + const u16 rqid = ssh_tc_to_rqid(tc); + const u16 event = ssh_rqid_to_event(rqid); + struct ssam_cdev_notifier *nf; + int status; + + /* Validate notifier target category. */ + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + mutex_lock(&client->notifier_lock); + + /* Check if the notifier has already been registered. */ + if (client->notifier[event]) { + mutex_unlock(&client->notifier_lock); + return -EEXIST; + } + + /* Allocate new notifier. */ + nf = kzalloc(sizeof(*nf), GFP_KERNEL); + if (!nf) { + mutex_unlock(&client->notifier_lock); + return -ENOMEM; + } + + /* + * Create a dummy notifier with the minimal required fields for + * observer registration. Note that we can skip fully specifying event + * and registry here as we do not need any matching and use silent + * registration, which does not enable the corresponding event. + */ + nf->client = client; + nf->nf.base.fn = ssam_cdev_notifier; + nf->nf.base.priority = priority; + nf->nf.event.id.target_category = tc; + nf->nf.event.mask = 0; /* Do not do any matching. */ + nf->nf.flags = SSAM_EVENT_NOTIFIER_OBSERVER; + + /* Register notifier. */ + status = ssam_notifier_register(client->cdev->ctrl, &nf->nf); + if (status) + kfree(nf); + else + client->notifier[event] = nf; + + mutex_unlock(&client->notifier_lock); + return status; } -static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) +static int ssam_cdev_notifier_unregister(struct ssam_cdev_client *client, u8 tc) +{ + const u16 rqid = ssh_tc_to_rqid(tc); + const u16 event = ssh_rqid_to_event(rqid); + int status; + + /* Validate notifier target category. */ + if (!ssh_rqid_is_event(rqid)) + return -EINVAL; + + mutex_lock(&client->notifier_lock); + + /* Check if the notifier is currently registered. */ + if (!client->notifier[event]) { + mutex_unlock(&client->notifier_lock); + return -ENOENT; + } + + /* Unregister and free notifier. */ + status = ssam_notifier_unregister(client->cdev->ctrl, &client->notifier[event]->nf); + kfree(client->notifier[event]); + client->notifier[event] = NULL; + + mutex_unlock(&client->notifier_lock); + return status; +} + +static void ssam_cdev_notifier_unregister_all(struct ssam_cdev_client *client) +{ + int i; + + down_read(&client->cdev->lock); + + /* + * This function may be used during shutdown, thus we need to test for + * cdev->ctrl instead of the SSAM_CDEV_DEVICE_SHUTDOWN_BIT bit. + */ + if (client->cdev->ctrl) { + for (i = 0; i < SSH_NUM_EVENTS; i++) + ssam_cdev_notifier_unregister(client, i + 1); + + } else { + int count = 0; + + /* + * Device has been shut down. Any notifier remaining is a bug, + * so warn about that as this would otherwise hardly be + * noticeable. Nevertheless, free them as well. + */ + mutex_lock(&client->notifier_lock); + for (i = 0; i < SSH_NUM_EVENTS; i++) { + count += !!(client->notifier[i]); + kfree(client->notifier[i]); + client->notifier[i] = NULL; + } + mutex_unlock(&client->notifier_lock); + + WARN_ON(count > 0); + } + + up_read(&client->cdev->lock); +} + + +/* -- IOCTL functions. ------------------------------------------------------ */ + +static long ssam_cdev_request(struct ssam_cdev_client *client, struct ssam_cdev_request __user *r) { - struct ssam_cdev_request __user *r; struct ssam_cdev_request rqst; struct ssam_request spec = {}; struct ssam_response rsp = {}; @@ -72,7 +257,6 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) void __user *rspdata; int status = 0, ret = 0, tmp; - r = (struct ssam_cdev_request __user *)arg; ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r)); if (ret) goto out; @@ -152,7 +336,7 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) } /* Perform request. */ - status = ssam_request_sync(cdev->ctrl, &spec, &rsp); + status = ssam_request_sync(client->cdev->ctrl, &spec, &rsp); if (status) goto out; @@ -177,48 +361,244 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) return ret; } -static long __ssam_cdev_device_ioctl(struct ssam_cdev *cdev, unsigned int cmd, +static long ssam_cdev_notif_register(struct ssam_cdev_client *client, + const struct ssam_cdev_notifier_desc __user *d) +{ + struct ssam_cdev_notifier_desc desc; + long ret; + + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); + if (ret) + return ret; + + return ssam_cdev_notifier_register(client, desc.target_category, desc.priority); +} + +static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client, + const struct ssam_cdev_notifier_desc __user *d) +{ + struct ssam_cdev_notifier_desc desc; + long ret; + + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); + if (ret) + return ret; + + return ssam_cdev_notifier_unregister(client, desc.target_category); +} + + +/* -- File operations. ------------------------------------------------------ */ + +static int ssam_cdev_device_open(struct inode *inode, struct file *filp) +{ + struct miscdevice *mdev = filp->private_data; + struct ssam_cdev_client *client; + struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev); + + /* Initialize client */ + client = vzalloc(sizeof(*client)); + if (!client) + return -ENOMEM; + + client->cdev = ssam_cdev_get(cdev); + + INIT_LIST_HEAD(&client->node); + + mutex_init(&client->notifier_lock); + + mutex_init(&client->read_lock); + mutex_init(&client->write_lock); + INIT_KFIFO(client->buffer); + init_waitqueue_head(&client->waitq); + + filp->private_data = client; + + /* Attach client. */ + down_write(&cdev->client_lock); + + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) { + up_write(&cdev->client_lock); + ssam_cdev_put(client->cdev); + vfree(client); + return -ENODEV; + } + list_add_tail(&client->node, &cdev->client_list); + + up_write(&cdev->client_lock); + + stream_open(inode, filp); + return 0; +} + +static int ssam_cdev_device_release(struct inode *inode, struct file *filp) +{ + struct ssam_cdev_client *client = filp->private_data; + + /* Force-unregister all remaining notifiers of this client. */ + ssam_cdev_notifier_unregister_all(client); + + /* Detach client. */ + down_write(&client->cdev->client_lock); + list_del(&client->node); + up_write(&client->cdev->client_lock); + + /* Free client. */ + mutex_destroy(&client->write_lock); + mutex_destroy(&client->read_lock); + + mutex_destroy(&client->notifier_lock); + + ssam_cdev_put(client->cdev); + vfree(client); + + return 0; +} + +static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned int cmd, unsigned long arg) { switch (cmd) { case SSAM_CDEV_REQUEST: - return ssam_cdev_request(cdev, arg); + return ssam_cdev_request(client, (struct ssam_cdev_request __user *)arg); + + case SSAM_CDEV_NOTIF_REGISTER: + return ssam_cdev_notif_register(client, + (struct ssam_cdev_notifier_desc __user *)arg); + + case SSAM_CDEV_NOTIF_UNREGISTER: + return ssam_cdev_notif_unregister(client, + (struct ssam_cdev_notifier_desc __user *)arg); default: return -ENOTTY; } } -static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) +static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct ssam_cdev *cdev = file->private_data; + struct ssam_cdev_client *client = file->private_data; long status; /* Ensure that controller is valid for as long as we need it. */ + if (down_read_killable(&client->cdev->lock)) + return -ERESTARTSYS; + + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &client->cdev->flags)) { + up_read(&client->cdev->lock); + return -ENODEV; + } + + status = __ssam_cdev_device_ioctl(client, cmd, arg); + + up_read(&client->cdev->lock); + return status; +} + +static ssize_t ssam_cdev_read(struct file *file, char __user *buf, size_t count, loff_t *offs) +{ + struct ssam_cdev_client *client = file->private_data; + struct ssam_cdev *cdev = client->cdev; + unsigned int copied; + int status = 0; + if (down_read_killable(&cdev->lock)) return -ERESTARTSYS; - if (!cdev->ctrl) { + /* Make sure we're not shut down. */ + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) { up_read(&cdev->lock); return -ENODEV; } - status = __ssam_cdev_device_ioctl(cdev, cmd, arg); + do { + /* Check availability, wait if necessary. */ + if (kfifo_is_empty(&client->buffer)) { + up_read(&cdev->lock); + + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + status = wait_event_interruptible(client->waitq, + !kfifo_is_empty(&client->buffer) || + test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, + &cdev->flags)); + if (status < 0) + return status; + + if (down_read_killable(&cdev->lock)) + return -ERESTARTSYS; + + /* Need to check that we're not shut down again. */ + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) { + up_read(&cdev->lock); + return -ENODEV; + } + } + + /* Try to read from FIFO. */ + if (mutex_lock_interruptible(&client->read_lock)) { + up_read(&cdev->lock); + return -ERESTARTSYS; + } + + status = kfifo_to_user(&client->buffer, buf, count, &copied); + mutex_unlock(&client->read_lock); + + if (status < 0) { + up_read(&cdev->lock); + return status; + } + + /* We might not have gotten anything, check this here. */ + if (copied == 0 && (file->f_flags & O_NONBLOCK)) { + up_read(&cdev->lock); + return -EAGAIN; + } + } while (copied == 0); up_read(&cdev->lock); - return status; + return copied; +} + +static __poll_t ssam_cdev_poll(struct file *file, struct poll_table_struct *pt) +{ + struct ssam_cdev_client *client = file->private_data; + __poll_t events = 0; + + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &client->cdev->flags)) + return EPOLLHUP | EPOLLERR; + + poll_wait(file, &client->waitq, pt); + + if (!kfifo_is_empty(&client->buffer)) + events |= EPOLLIN | EPOLLRDNORM; + + return events; +} + +static int ssam_cdev_fasync(int fd, struct file *file, int on) +{ + struct ssam_cdev_client *client = file->private_data; + + return fasync_helper(fd, file, on, &client->fasync); } static const struct file_operations ssam_controller_fops = { .owner = THIS_MODULE, .open = ssam_cdev_device_open, .release = ssam_cdev_device_release, + .read = ssam_cdev_read, + .poll = ssam_cdev_poll, + .fasync = ssam_cdev_fasync, .unlocked_ioctl = ssam_cdev_device_ioctl, .compat_ioctl = ssam_cdev_device_ioctl, - .llseek = noop_llseek, + .llseek = no_llseek, }; + +/* -- Device and driver setup ----------------------------------------------- */ + static int ssam_dbg_device_probe(struct platform_device *pdev) { struct ssam_controller *ctrl; @@ -236,6 +616,7 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) kref_init(&cdev->kref); init_rwsem(&cdev->lock); cdev->ctrl = ctrl; + cdev->dev = &pdev->dev; cdev->mdev.parent = &pdev->dev; cdev->mdev.minor = MISC_DYNAMIC_MINOR; @@ -243,6 +624,9 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) cdev->mdev.nodename = "surface/aggregator"; cdev->mdev.fops = &ssam_controller_fops; + init_rwsem(&cdev->client_lock); + INIT_LIST_HEAD(&cdev->client_list); + status = misc_register(&cdev->mdev); if (status) { kfree(cdev); @@ -256,8 +640,32 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) static int ssam_dbg_device_remove(struct platform_device *pdev) { struct ssam_cdev *cdev = platform_get_drvdata(pdev); + struct ssam_cdev_client *client; - misc_deregister(&cdev->mdev); + /* + * Mark device as shut-down. Prevent new clients from being added and + * new operations from being executed. + */ + set_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags); + + down_write(&cdev->client_lock); + + /* Remove all notifiers registered by us. */ + list_for_each_entry(client, &cdev->client_list, node) { + ssam_cdev_notifier_unregister_all(client); + } + + /* Wake up async clients. */ + list_for_each_entry(client, &cdev->client_list, node) { + kill_fasync(&client->fasync, SIGIO, POLL_HUP); + } + + /* Wake up blocking clients. */ + list_for_each_entry(client, &cdev->client_list, node) { + wake_up_interruptible(&client->waitq); + } + + up_write(&cdev->client_lock); /* * The controller is only guaranteed to be valid for as long as the @@ -266,8 +674,11 @@ static int ssam_dbg_device_remove(struct platform_device *pdev) */ down_write(&cdev->lock); cdev->ctrl = NULL; + cdev->dev = NULL; up_write(&cdev->lock); + misc_deregister(&cdev->mdev); + ssam_cdev_put(cdev); return 0; } diff --git a/include/uapi/linux/surface_aggregator/cdev.h b/include/uapi/linux/surface_aggregator/cdev.h index fbcce04abfe9..4f393fafc235 100644 --- a/include/uapi/linux/surface_aggregator/cdev.h +++ b/include/uapi/linux/surface_aggregator/cdev.h @@ -6,7 +6,7 @@ * device. This device provides direct user-space access to the SSAM EC. * Intended for debugging and development. * - * Copyright (C) 2020 Maximilian Luz + * Copyright (C) 2020-2021 Maximilian Luz */ #ifndef _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H @@ -73,6 +73,43 @@ struct ssam_cdev_request { } response; } __attribute__((__packed__)); -#define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request) +/** + * struct ssam_cdev_notifier_desc - Notifier descriptor. + * @priority: Priority value determining the order in which notifier + * callbacks will be called. A higher value means higher + * priority, i.e. the associated callback will be executed + * earlier than other (lower priority) callbacks. + * @target_category: The event target category for which this notifier should + * receive events. + * + * Specifies the notifier that should be registered or unregistered, + * specifically with which priority and for which target category of events. + */ +struct ssam_cdev_notifier_desc { + __s32 priority; + __u8 target_category; +} __attribute__((__packed__)); + +/** + * struct ssam_cdev_event - SSAM event sent by the EC. + * @target_category: Target category of the event source. See &enum ssam_ssh_tc. + * @target_id: Target ID of the event source. + * @command_id: Command ID of the event. + * @instance_id: Instance ID of the event source. + * @length: Length of the event payload in bytes. + * @data: Event payload data. + */ +struct ssam_cdev_event { + __u8 target_category; + __u8 target_id; + __u8 command_id; + __u8 instance_id; + __u16 length; + __u8 data[]; +} __attribute__((__packed__)); + +#define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request) +#define SSAM_CDEV_NOTIF_REGISTER _IOW(0xA5, 2, struct ssam_cdev_notifier_desc) +#define SSAM_CDEV_NOTIF_UNREGISTER _IOW(0xA5, 3, struct ssam_cdev_notifier_desc) #endif /* _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H */ From patchwork Thu Jun 3 23:45:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298431 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 3777FC47082 for ; Thu, 3 Jun 2021 23:47:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2245260E08 for ; Thu, 3 Jun 2021 23:47:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229926AbhFCXsv (ORCPT ); Thu, 3 Jun 2021 19:48:51 -0400 Received: from mail-wr1-f52.google.com ([209.85.221.52]:34389 "EHLO mail-wr1-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229953AbhFCXsu (ORCPT ); Thu, 3 Jun 2021 19:48:50 -0400 Received: by mail-wr1-f52.google.com with SMTP id q5so7495386wrm.1; Thu, 03 Jun 2021 16:46:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=5jQpvGaCiBdiuAbKnU33PQlmCshsXsotPLm5iLgMP/8=; b=T6RWuNZjWgBAMFIwcT4gkrRCiPxaqanlKkAgnkvAnay7wPPlu2hT2tBUhlWDt7nOCU Qvs6FKun7ykH2Wlo0VI7Fd9gdv2IFi18IvfAsgzRJFSc2pWX+xL1c8jXH0sT652l1jnF EF41iY1HRv7nCMb0lmPC2D3X2HWaJjqzyOZtc1gXpSoQpIikCs7NItwVWpaXGKLa7xRA tLfFkSq5AmqheVMMWKe5t9seRvuw/++C4KaDE1S0hZrYPcyTSx7SFtFDTPlvcFX1uJMF 5fL/5KWPpt4AfQNQyymQgpYuQfJAVs76Yo+EeEvQaG/91V6BANqSSmw71ZR/guVLo3Tx 4d6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=5jQpvGaCiBdiuAbKnU33PQlmCshsXsotPLm5iLgMP/8=; b=EsErU1lK/jdZrZU4Ae5VQkmvCgQIVbNOh6G1N8ffjK+gDHhlM4PwmlbArgQ11dqU5h SQQIMiPHep3rrlK4mGj9HLEXD773Wob36lN+BdSmuGL8UVfEvKVRdueAjLvsETNnH0Mn i/fPleWYa1wKd7LTsRWwTuYqklVJnngMRJeWgo66BPsjLpvUR/MQETumvBpLKjocLyer tDVsjfdbvt7jGuw9p9BoeLW5oohC3THz275L3L+Ap6I/dSsB1Sb8PJ8Ztxbx6McVUH2L AU8EI5Fw8l5vjWJbUIY7QurLFFomre8a87gXvd+RLkHOIflamrA/qu36MzOdElHVuoBv tnHA== X-Gm-Message-State: AOAM533MRde+Lj1qjOtUcKbv6q7roxxvfkiPvDg//zaW7X+5HCwEw8Yn opfS7d2WgDpY+TTnmsEPqis= X-Google-Smtp-Source: ABdhPJwxkbHwWEKAKVOMFQ96tZwScVfITXBMpWcs88OEEpveZvPZ5FMkYniNbxU5FlHRLGLxQQ4ZsQ== X-Received: by 2002:adf:f990:: with SMTP id f16mr851015wrr.340.1622763948396; Thu, 03 Jun 2021 16:45:48 -0700 (PDT) Received: from xws.localdomain ([37.58.58.229]) by smtp.gmail.com with ESMTPSA id a11sm4743386wrr.48.2021.06.03.16.45.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jun 2021 16:45:47 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/7] platform/surface: aggregator_cdev: Allow enabling of events from user-space Date: Fri, 4 Jun 2021 01:45:24 +0200 Message-Id: <20210603234526.2503590-6-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org While events can already be enabled and disabled via the generic request IOCTL, this bypasses the internal reference counting mechanism of the controller. Due to that, disabling an event will turn it off regardless of any other client having requested said event, which may break functionality of that client. To solve this, add IOCTLs wrapping the ssam_controller_event_enable() and ssam_controller_event_disable() functions, which have been previously introduced for this specific purpose. Signed-off-by: Maximilian Luz --- .../surface/surface_aggregator_cdev.c | 58 +++++++++++++++++++ include/uapi/linux/surface_aggregator/cdev.h | 32 ++++++++++ 2 files changed, 90 insertions(+) diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index 807930144039..e0f3c437b8ee 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -387,6 +387,58 @@ static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client, return ssam_cdev_notifier_unregister(client, desc.target_category); } +static long ssam_cdev_event_enable(struct ssam_cdev_client *client, + const struct ssam_cdev_event_desc __user *d) +{ + struct ssam_cdev_event_desc desc; + struct ssam_event_registry reg; + struct ssam_event_id id; + long ret; + + /* Read descriptor from user-space. */ + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); + if (ret) + return ret; + + /* Translate descriptor. */ + reg.target_category = desc.reg.target_category; + reg.target_id = desc.reg.target_id; + reg.cid_enable = desc.reg.cid_enable; + reg.cid_disable = desc.reg.cid_disable; + + id.target_category = desc.id.target_category; + id.instance = desc.id.instance; + + /* Disable event. */ + return ssam_controller_event_enable(client->cdev->ctrl, reg, id, desc.flags); +} + +static long ssam_cdev_event_disable(struct ssam_cdev_client *client, + const struct ssam_cdev_event_desc __user *d) +{ + struct ssam_cdev_event_desc desc; + struct ssam_event_registry reg; + struct ssam_event_id id; + long ret; + + /* Read descriptor from user-space. */ + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); + if (ret) + return ret; + + /* Translate descriptor. */ + reg.target_category = desc.reg.target_category; + reg.target_id = desc.reg.target_id; + reg.cid_enable = desc.reg.cid_enable; + reg.cid_disable = desc.reg.cid_disable; + + id.target_category = desc.id.target_category; + id.instance = desc.id.instance; + + /* Disable event. */ + return ssam_controller_event_disable(client->cdev->ctrl, reg, id, desc.flags); +} + /* -- File operations. ------------------------------------------------------ */ @@ -470,6 +522,12 @@ static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned i return ssam_cdev_notif_unregister(client, (struct ssam_cdev_notifier_desc __user *)arg); + case SSAM_CDEV_EVENT_ENABLE: + return ssam_cdev_event_enable(client, (struct ssam_cdev_event_desc __user *)arg); + + case SSAM_CDEV_EVENT_DISABLE: + return ssam_cdev_event_disable(client, (struct ssam_cdev_event_desc __user *)arg); + default: return -ENOTTY; } diff --git a/include/uapi/linux/surface_aggregator/cdev.h b/include/uapi/linux/surface_aggregator/cdev.h index 4f393fafc235..08f46b60b151 100644 --- a/include/uapi/linux/surface_aggregator/cdev.h +++ b/include/uapi/linux/surface_aggregator/cdev.h @@ -90,6 +90,36 @@ struct ssam_cdev_notifier_desc { __u8 target_category; } __attribute__((__packed__)); +/** + * struct ssam_cdev_event_desc - Event descriptor. + * @reg: Registry via which the event will be enabled/disabled. + * @reg.target_category: Target category for the event registry requests. + * @reg.target_id: Target ID for the event registry requests. + * @reg.cid_enable: Command ID for the event-enable request. + * @reg.cid_disable: Command ID for the event-disable request. + * @id: ID specifying the event. + * @id.target_category: Target category of the event source. + * @id.instance: Instance ID of the event source. + * @flags: Flags used for enabling the event. + * + * Specifies which event should be enabled/disabled and how to do that. + */ +struct ssam_cdev_event_desc { + struct { + __u8 target_category; + __u8 target_id; + __u8 cid_enable; + __u8 cid_disable; + } reg; + + struct { + __u8 target_category; + __u8 instance; + } id; + + __u8 flags; +} __attribute__((__packed__)); + /** * struct ssam_cdev_event - SSAM event sent by the EC. * @target_category: Target category of the event source. See &enum ssam_ssh_tc. @@ -111,5 +141,7 @@ struct ssam_cdev_event { #define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request) #define SSAM_CDEV_NOTIF_REGISTER _IOW(0xA5, 2, struct ssam_cdev_notifier_desc) #define SSAM_CDEV_NOTIF_UNREGISTER _IOW(0xA5, 3, struct ssam_cdev_notifier_desc) +#define SSAM_CDEV_EVENT_ENABLE _IOW(0xA5, 4, struct ssam_cdev_event_desc) +#define SSAM_CDEV_EVENT_DISABLE _IOW(0xA5, 5, struct ssam_cdev_event_desc) #endif /* _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H */ From patchwork Thu Jun 3 23:45:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298427 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 61282C47082 for ; Thu, 3 Jun 2021 23:47:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4764F613F1 for ; Thu, 3 Jun 2021 23:47:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229924AbhFCXss (ORCPT ); Thu, 3 Jun 2021 19:48:48 -0400 Received: from mail-wr1-f52.google.com ([209.85.221.52]:39927 "EHLO mail-wr1-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229852AbhFCXss (ORCPT ); Thu, 3 Jun 2021 19:48:48 -0400 Received: by mail-wr1-f52.google.com with SMTP id l2so7486961wrw.6; Thu, 03 Jun 2021 16:46:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=/+4tVIHgjtiD7zpIPHC41efEy59vHCwGq9x9fWYbAw4=; b=ZsX9ZsQorLDF63ZXy5f5ZVLHy3r6XlbE2ZuQXtDpS+tANbxNXwvIGtTxYhg2xXJnMp i5KdYXJwPa4VFBaBzV7UsXk3vJJWnoIm+JuZR6+1Brs7gxCvElLDKDPqhnSqTZlyB2Ui wp83uydfNV8nzwOMCwLwVx3xzGkASjOT9j3VK8GumwQy13dvT44cTX4fDs90P2h4ienK DjYQWCxTl1NB+hN4VDYZVmJczOBnfWul67mKBaUVmpj6idNYnwiDUIEUMbJRbJiydk4x JeqsSVOp26PUJ4wMXnglxiR63RN8AJjQQg2G3aVD5temsKBblvzYYy1LgdLsZRYWPpoq LF2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=/+4tVIHgjtiD7zpIPHC41efEy59vHCwGq9x9fWYbAw4=; b=YZK6h63SHTVBlkmXZtQYLgCyi1AoU0TLcBWTM5WGQkB9G+/3LD3FGbrZkaXzpMxMM7 1wcvdh/XNeAYSPfadYiKrPAfYYNR3tuHEvyNPuuNkSuFELDV2Nrm5dgF6yM3sLQUWzSV GxR7K8nDV7d9TANODMI0ACnLgVRi1aVrZaBgY5wqGDDp5dSaBCrxSy8nJvxkz564Oeil wHm9LuvnOmSIwYIS/Dv2j9/qDIjYcbCu1gYD+jUJElWMJweeGcDToeuqLSmDSTdi7xF3 /GwWIMg/SpZyB08fu2xCcSHMPh4P9CkiOKf9djACaAwwMHdjRzI8ey5qAQDC+RdzZjYU PPLw== X-Gm-Message-State: AOAM531jrY3BLEZvq28K+045exvqjeoe0fN1Opb3gy+ffk61hKhLuwC9 q5Y2wlxaSN/Uc4iPqOXtu64= X-Google-Smtp-Source: ABdhPJxCb5UO5XxtOtL2TColYdqLS6aAGxDGP73s8L3jDyZPDZQGmVDk1SvEU+CRzOuBFu2pHCs/8w== X-Received: by 2002:a5d:440a:: with SMTP id z10mr783242wrq.323.1622763949466; Thu, 03 Jun 2021 16:45:49 -0700 (PDT) Received: from xws.localdomain ([37.58.58.229]) by smtp.gmail.com with ESMTPSA id a11sm4743386wrr.48.2021.06.03.16.45.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jun 2021 16:45:48 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/7] platform/surface: aggregator_cdev: Add lockdep support Date: Fri, 4 Jun 2021 01:45:25 +0200 Message-Id: <20210603234526.2503590-7-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Mark functions with locking requirements via the corresponding lockdep calls for debugging and documentary purposes. Signed-off-by: Maximilian Luz --- .../platform/surface/surface_aggregator_cdev.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index e0f3c437b8ee..f3247cd15f6d 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -139,6 +139,8 @@ static int ssam_cdev_notifier_register(struct ssam_cdev_client *client, u8 tc, i struct ssam_cdev_notifier *nf; int status; + lockdep_assert_held_read(&client->cdev->lock); + /* Validate notifier target category. */ if (!ssh_rqid_is_event(rqid)) return -EINVAL; @@ -188,6 +190,8 @@ static int ssam_cdev_notifier_unregister(struct ssam_cdev_client *client, u8 tc) const u16 event = ssh_rqid_to_event(rqid); int status; + lockdep_assert_held_read(&client->cdev->lock); + /* Validate notifier target category. */ if (!ssh_rqid_is_event(rqid)) return -EINVAL; @@ -257,6 +261,8 @@ static long ssam_cdev_request(struct ssam_cdev_client *client, struct ssam_cdev_ void __user *rspdata; int status = 0, ret = 0, tmp; + lockdep_assert_held_read(&client->cdev->lock); + ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r)); if (ret) goto out; @@ -367,6 +373,8 @@ static long ssam_cdev_notif_register(struct ssam_cdev_client *client, struct ssam_cdev_notifier_desc desc; long ret; + lockdep_assert_held_read(&client->cdev->lock); + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); if (ret) return ret; @@ -380,6 +388,8 @@ static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client, struct ssam_cdev_notifier_desc desc; long ret; + lockdep_assert_held_read(&client->cdev->lock); + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); if (ret) return ret; @@ -395,6 +405,8 @@ static long ssam_cdev_event_enable(struct ssam_cdev_client *client, struct ssam_event_id id; long ret; + lockdep_assert_held_read(&client->cdev->lock); + /* Read descriptor from user-space. */ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); if (ret) @@ -421,6 +433,8 @@ static long ssam_cdev_event_disable(struct ssam_cdev_client *client, struct ssam_event_id id; long ret; + lockdep_assert_held_read(&client->cdev->lock); + /* Read descriptor from user-space. */ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); if (ret) @@ -510,6 +524,8 @@ static int ssam_cdev_device_release(struct inode *inode, struct file *filp) static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned int cmd, unsigned long arg) { + lockdep_assert_held_read(&client->cdev->lock); + switch (cmd) { case SSAM_CDEV_REQUEST: return ssam_cdev_request(client, (struct ssam_cdev_request __user *)arg); From patchwork Thu Jun 3 23:45:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Luz X-Patchwork-Id: 12298429 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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 5DE99C47098 for ; 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Thu, 03 Jun 2021 16:45:50 -0700 (PDT) From: Maximilian Luz To: Hans de Goede Cc: Maximilian Luz , Mark Gross , Jonathan Corbet , platform-driver-x86@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 7/7] docs: driver-api: Update Surface Aggregator user-space interface documentation Date: Fri, 4 Jun 2021 01:45:26 +0200 Message-Id: <20210603234526.2503590-8-luzmaximilian@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210603234526.2503590-1-luzmaximilian@gmail.com> References: <20210603234526.2503590-1-luzmaximilian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Update the controller-device user-space interface (cdev) documentation for the newly introduced IOCTLs and event interface. Signed-off-by: Maximilian Luz --- .../surface_aggregator/clients/cdev.rst | 127 +++++++++++++++++- 1 file changed, 122 insertions(+), 5 deletions(-) diff --git a/Documentation/driver-api/surface_aggregator/clients/cdev.rst b/Documentation/driver-api/surface_aggregator/clients/cdev.rst index 248c1372d879..0134a841a079 100644 --- a/Documentation/driver-api/surface_aggregator/clients/cdev.rst +++ b/Documentation/driver-api/surface_aggregator/clients/cdev.rst @@ -1,9 +1,8 @@ .. SPDX-License-Identifier: GPL-2.0+ -.. |u8| replace:: :c:type:`u8 ` -.. |u16| replace:: :c:type:`u16 ` .. |ssam_cdev_request| replace:: :c:type:`struct ssam_cdev_request ` .. |ssam_cdev_request_flags| replace:: :c:type:`enum ssam_cdev_request_flags ` +.. |ssam_cdev_event| replace:: :c:type:`struct ssam_cdev_event ` ============================== User-Space EC Interface (cdev) @@ -23,6 +22,40 @@ These IOCTLs and their respective input/output parameter structs are defined in A small python library and scripts for accessing this interface can be found at https://github.com/linux-surface/surface-aggregator-module/tree/master/scripts/ssam. +.. contents:: + + +Receiving Events +================ + +Events can be received by reading from the device-file. The are represented by +the |ssam_cdev_event| datatype. + +Before events are available to be read, however, the desired notifiers must be +registered via the ``SSAM_CDEV_NOTIF_REGISTER`` IOCTL. Notifiers are, in +essence, callbacks, called when the EC sends an event. They are, in this +interface, associated with a specific target category and device-file-instance. +They forward any event of this category to the buffer of the corresponding +instance, from which it can then be read. + +Notifiers themselves do not enable events on the EC. Thus, it may additionally +be necessary to enable events via the ``SSAM_CDEV_EVENT_ENABLE`` IOCTL. While +notifiers work per-client (i.e. per-device-file-instance), events are enabled +globally, for the EC and all of its clients (regardless of userspace or +non-userspace). The ``SSAM_CDEV_EVENT_ENABLE`` and ``SSAM_CDEV_EVENT_DISABLE`` +IOCTLs take care of reference counting the events, such that an event is +enabled as long as there is a client that has requested it. + +Note that enabled events are not automatically disabled once the client +instance is closed. Therefore any client process (or group of processes) should +balance their event enable calls with the corresponding event disable calls. It +is, however, perfectly valid to enable and disable events on different client +instances. For example, it is valid to set up notifiers and read events on +client instance ``A``, enable those events on instance ``B`` (note that these +will also be received by A since events are enabled/disabled globally), and +after no more events are desired, disable the previously enabled events via +instance ``C``. + Controller IOCTLs ================= @@ -45,9 +78,33 @@ The following IOCTLs are provided: - ``REQUEST`` - Perform synchronous SAM request. + * - ``0xA5`` + - ``2`` + - ``W`` + - ``NOTIF_REGISTER`` + - Register event notifier. -``REQUEST`` ------------ + * - ``0xA5`` + - ``3`` + - ``W`` + - ``NOTIF_UNREGISTER`` + - Unregister event notifier. + + * - ``0xA5`` + - ``4`` + - ``W`` + - ``EVENT_ENABLE`` + - Enable event source. + + * - ``0xA5`` + - ``5`` + - ``W`` + - ``EVENT_DISABLE`` + - Disable event source. + + +``SSAM_CDEV_REQUEST`` +--------------------- Defined as ``_IOWR(0xA5, 1, struct ssam_cdev_request)``. @@ -82,6 +139,66 @@ submitted, and completed (i.e. handed back to user-space) successfully from inside the IOCTL, but the request ``status`` member may still be negative in case the actual execution of the request failed after it has been submitted. -A full definition of the argument struct is provided below: +A full definition of the argument struct is provided below. + +``SSAM_CDEV_NOTIF_REGISTER`` +---------------------------- + +Defined as ``_IOW(0xA5, 2, struct ssam_cdev_notifier_desc)``. + +Register a notifier for the event target category specified in the given +notifier description with the specified priority. Notifiers registration is +required to receive events, but does not enable events themselves. After a +notifier for a specific target category has been registered, all events of that +category will be forwarded to the userspace client and can then be read from +the device file instance. Note that events may have to be enabled, e.g. via the +``SSAM_CDEV_EVENT_ENABLE`` IOCTL, before the EC will send them. + +Only one notifier can be registered per target category and client instance. If +a notifier has already been registered, this IOCTL will fail with ``-EEXIST``. + +Notifiers will automatically be removed when the device file instance is +closed. + +``SSAM_CDEV_NOTIF_UNREGISTER`` +------------------------------ + +Defined as ``_IOW(0xA5, 3, struct ssam_cdev_notifier_desc)``. + +Unregisters the notifier associated with the specified target category. The +priority field will be ignored by this IOCTL. If no notifier has been +registered for this client instance and the given category, this IOCTL will +fail with ``-ENOENT``. + +``SSAM_CDEV_EVENT_ENABLE`` +-------------------------- + +Defined as ``_IOW(0xA5, 4, struct ssam_cdev_event_desc)``. + +Enable the event associated with the given event descriptor. + +Note that this call will not register a notifier itself, it will only enable +events on the controller. If you want to receive events by reading from the +device file, you will need to register the corresponding notifier(s) on that +instance. + +Events are not automatically disabled when the device file is closed. This must +be done manually, via a call to the ``SSAM_CDEV_EVENT_DISABLE`` IOCTL. + +``SSAM_CDEV_EVENT_DISABLE`` +--------------------------- + +Defined as ``_IOW(0xA5, 5, struct ssam_cdev_event_desc)``. + +Disable the event associated with the given event descriptor. + +Note that this will not unregister any notifiers. Events may still be received +and forwarded to user-space after this call. The only safe way of stopping +events from being received is unregistering all previously registered +notifiers. + + +Structures and Enums +==================== .. kernel-doc:: include/uapi/linux/surface_aggregator/cdev.h