From patchwork Fri Jul 24 02:05:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Badhri Jagan Sridharan X-Patchwork-Id: 11681897 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4443A13B4 for ; Fri, 24 Jul 2020 02:05:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11F1A2065E for ; Fri, 24 Jul 2020 02:05:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jPVQGwIg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726983AbgGXCF5 (ORCPT ); Thu, 23 Jul 2020 22:05:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbgGXCF4 (ORCPT ); Thu, 23 Jul 2020 22:05:56 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5718C0619D3 for ; Thu, 23 Jul 2020 19:05:56 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id f5so5288320pfa.22 for ; Thu, 23 Jul 2020 19:05:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=5aq7lvgbPI0yY0ktvMY4HSJk6lzevca6F80kF3dvzrE=; b=jPVQGwIg0GiX4KtlyMpzJwDgm/r7Xdmu0P2fnQiNpQyVh7Tj1QJCMf3mBwwEq8UQhN 2ZhgheD7xAwJwEkp1xdB51RpbgMeUfpgtr1iOgC7rqiJWNbJ6JENcJ4zpaURAnJWLcCO EccFaSIqQFAC/lrut0Er0SzepwM9+UY3ucU3GM4f2Ja3CJbeeJtS2pyd8zZjX2VQGf73 r+PEKNJWcIvqVi6To8CqJpbbQc3r4jZZsNRzKDhJ46zjI1VAcwrVE3oivJ952B88PEht NmR6LQyP1+nFZnYrY3vdwk+HoJYrMH8lFiTbFi0a5Ff59WydC2I/e2oJHEyq/nFbCbdu u8Pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=5aq7lvgbPI0yY0ktvMY4HSJk6lzevca6F80kF3dvzrE=; b=dOdIlAmbHSJ84o0W5TcyHRuh86yMS3bihv9b8b3Gm4ovTHg+O1cLitk89bIl+HVin3 4CM0dud2sM6N9T5PHLCCFqOaFjAh4bvCc93D2yEktJ5ZMUyBlOexXGzUIbK3Cc7UgNp5 P58zEW/+5IBSD/jR12eLLp2ZJx3jX6Bk9u0SgLNRY4u01EGUXABgqZRHvO8fwyxSAVKz SnI81siV+13NOwkIOpHkzyVsBvC3yAEVIr/ghp2JFqjgkyk/Y8v30+Lk5CElGzGkyv6o B+8qCZ45Sy+xhgfLo8DxkvGRuc2pNghX5Rjqcu1ydxCnSu1ZwiXilGgHPZiNhiURNh7s b2jQ== X-Gm-Message-State: AOAM530VJ/yStIsCVxTZiwBKaKp5qTp8kLtobiXPmAiaNH8taFprPDR1 QrsuwSbINADsPi5DhndfKNSo6cBRUUc= X-Google-Smtp-Source: ABdhPJx0GFKrM7N8cz9nMm4kBTbS4cxBB0lCJYzrs8BnwiLomuLfU/NmtUZkYyePvFGlfl/or9P/NjcMnvk= X-Received: by 2002:a17:90a:bd8b:: with SMTP id z11mr1440845pjr.0.1595556355812; Thu, 23 Jul 2020 19:05:55 -0700 (PDT) Date: Thu, 23 Jul 2020 19:05:51 -0700 Message-Id: <20200724020551.2737376-1-badhri@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.rc0.142.g3c755180ce-goog Subject: [PATCH v2] usb: typec: tcpm: Migrate workqueue to RT priority for processing events From: Badhri Jagan Sridharan To: Guenter Roeck , Heikki Krogerus , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Badhri Jagan Sridharan Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org "tReceiverResponse 15 ms Section 6.6.2 The receiver of a Message requiring a response Shall respond within tReceiverResponse in order to ensure that the sender’s SenderResponseTimer does not expire." When the cpu complex is busy running other lower priority work items, TCPM's work queue sometimes does not get scheduled on time to meet the above requirement from the spec. Moving to kthread_work apis to run with real time priority. Just lower than the default threaded irq priority, MAX_USER_RT_PRIO/2 + 1. (Higher number implies lower priority). Further, as observed in 1ff688209e2e, moving to hrtimers to overcome scheduling latency while scheduling the delayed work. TCPM has three work streams: 1. tcpm_state_machine 2. vdm_state_machine 3. event_work tcpm_state_machine and vdm_state_machine both schedule work in future i.e. delayed. Hence each of them have a corresponding hrtimer, tcpm_state_machine_timer & vdm_state_machine_timer. When work is queued right away kthread_queue_work is used. Else, the relevant timer is programmed and made to queue the kthread_work upon timer expiry. kthread_create_worker only creates one kthread worker thread, hence single threadedness of workqueue is retained. Signed-off-by: Badhri Jagan Sridharan Reviewed-by: Guenter Roeck Reviewed-by: Heikki Krogerus --- Changes since v1:(Guenter's suggestions) - Remove redundant call to hrtimer_cancel while calling hrtimer_start. --- drivers/usb/typec/tcpm/tcpm.c | 140 ++++++++++++++++++++++------------ 1 file changed, 92 insertions(+), 48 deletions(-) diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index ff1cbd2147ca8a..fa9002944dc766 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -8,8 +8,10 @@ #include #include #include +#include #include #include +#include #include #include #include @@ -28,7 +30,8 @@ #include #include #include -#include + +#include #define FOREACH_STATE(S) \ S(INVALID_STATE), \ @@ -195,7 +198,7 @@ struct tcpm_port { struct device *dev; struct mutex lock; /* tcpm state machine lock */ - struct workqueue_struct *wq; + struct kthread_worker *wq; struct typec_capability typec_caps; struct typec_port *typec_port; @@ -239,15 +242,17 @@ struct tcpm_port { enum tcpm_state prev_state; enum tcpm_state state; enum tcpm_state delayed_state; - unsigned long delayed_runtime; + ktime_t delayed_runtime; unsigned long delay_ms; spinlock_t pd_event_lock; u32 pd_events; - struct work_struct event_work; - struct delayed_work state_machine; - struct delayed_work vdm_state_machine; + struct kthread_work event_work; + struct hrtimer state_machine_timer; + struct kthread_work state_machine; + struct hrtimer vdm_state_machine_timer; + struct kthread_work vdm_state_machine; bool state_machine_running; struct completion tx_complete; @@ -332,7 +337,7 @@ struct tcpm_port { }; struct pd_rx_event { - struct work_struct work; + struct kthread_work work; struct tcpm_port *port; struct pd_message msg; }; @@ -906,6 +911,27 @@ static int tcpm_pd_send_sink_caps(struct tcpm_port *port) return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg); } +static void mod_tcpm_delayed_work(struct tcpm_port *port, unsigned int delay_ms) +{ + if (delay_ms) { + hrtimer_start(&port->state_machine_timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL); + } else { + hrtimer_cancel(&port->state_machine_timer); + kthread_queue_work(port->wq, &port->state_machine); + } +} + +static void mod_vdm_delayed_work(struct tcpm_port *port, unsigned int delay_ms) +{ + if (delay_ms) { + hrtimer_start(&port->vdm_state_machine_timer, ms_to_ktime(delay_ms), + HRTIMER_MODE_REL); + } else { + hrtimer_cancel(&port->vdm_state_machine_timer); + kthread_queue_work(port->wq, &port->vdm_state_machine); + } +} + static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state, unsigned int delay_ms) { @@ -914,9 +940,8 @@ static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state, tcpm_states[port->state], tcpm_states[state], delay_ms); port->delayed_state = state; - mod_delayed_work(port->wq, &port->state_machine, - msecs_to_jiffies(delay_ms)); - port->delayed_runtime = jiffies + msecs_to_jiffies(delay_ms); + mod_tcpm_delayed_work(port, delay_ms); + port->delayed_runtime = ktime_add(ktime_get(), ms_to_ktime(delay_ms)); port->delay_ms = delay_ms; } else { tcpm_log(port, "state change %s -> %s", @@ -931,7 +956,7 @@ static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state, * machine. */ if (!port->state_machine_running) - mod_delayed_work(port->wq, &port->state_machine, 0); + mod_tcpm_delayed_work(port, 0); } } @@ -952,7 +977,7 @@ static void tcpm_queue_message(struct tcpm_port *port, enum pd_msg_request message) { port->queued_message = message; - mod_delayed_work(port->wq, &port->state_machine, 0); + mod_tcpm_delayed_work(port, 0); } /* @@ -1238,8 +1263,7 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port, port->vdm_state = VDM_STATE_WAIT_RSP_BUSY; port->vdo_retry = (p0 & ~VDO_CMDT_MASK) | CMDT_INIT; - mod_delayed_work(port->wq, &port->vdm_state_machine, - msecs_to_jiffies(PD_T_VDM_BUSY)); + mod_vdm_delayed_work(port, PD_T_VDM_BUSY); return; } port->vdm_state = VDM_STATE_DONE; @@ -1250,7 +1274,7 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port, if (rlen > 0) { tcpm_queue_vdm(port, response[0], &response[1], rlen - 1); - mod_delayed_work(port->wq, &port->vdm_state_machine, 0); + mod_vdm_delayed_work(port, 0); } } @@ -1267,7 +1291,7 @@ static void tcpm_send_vdm(struct tcpm_port *port, u32 vid, int cmd, 1 : (PD_VDO_CMD(cmd) <= CMD_ATTENTION), cmd); tcpm_queue_vdm(port, header, data, count); - mod_delayed_work(port->wq, &port->vdm_state_machine, 0); + mod_vdm_delayed_work(port, 0); } static unsigned int vdm_ready_timeout(u32 vdm_hdr) @@ -1334,8 +1358,7 @@ static void vdm_run_state_machine(struct tcpm_port *port) port->vdm_retries = 0; port->vdm_state = VDM_STATE_BUSY; timeout = vdm_ready_timeout(port->vdo_data[0]); - mod_delayed_work(port->wq, &port->vdm_state_machine, - timeout); + mod_vdm_delayed_work(port, timeout); } break; case VDM_STATE_WAIT_RSP_BUSY: @@ -1364,10 +1387,9 @@ static void vdm_run_state_machine(struct tcpm_port *port) } } -static void vdm_state_machine_work(struct work_struct *work) +static void vdm_state_machine_work(struct kthread_work *work) { - struct tcpm_port *port = container_of(work, struct tcpm_port, - vdm_state_machine.work); + struct tcpm_port *port = container_of(work, struct tcpm_port, vdm_state_machine); enum vdm_states prev_state; mutex_lock(&port->lock); @@ -1515,7 +1537,7 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo) header |= VDO_OPOS(altmode->mode); tcpm_queue_vdm(port, header, vdo, vdo ? 1 : 0); - mod_delayed_work(port->wq, &port->vdm_state_machine, 0); + mod_vdm_delayed_work(port, 0); mutex_unlock(&port->lock); return 0; @@ -1531,7 +1553,7 @@ static int tcpm_altmode_exit(struct typec_altmode *altmode) header |= VDO_OPOS(altmode->mode); tcpm_queue_vdm(port, header, NULL, 0); - mod_delayed_work(port->wq, &port->vdm_state_machine, 0); + mod_vdm_delayed_work(port, 0); mutex_unlock(&port->lock); return 0; @@ -1544,7 +1566,7 @@ static int tcpm_altmode_vdm(struct typec_altmode *altmode, mutex_lock(&port->lock); tcpm_queue_vdm(port, header, data, count - 1); - mod_delayed_work(port->wq, &port->vdm_state_machine, 0); + mod_vdm_delayed_work(port, 0); mutex_unlock(&port->lock); return 0; @@ -1961,7 +1983,7 @@ static void tcpm_pd_ext_msg_request(struct tcpm_port *port, } } -static void tcpm_pd_rx_handler(struct work_struct *work) +static void tcpm_pd_rx_handler(struct kthread_work *work) { struct pd_rx_event *event = container_of(work, struct pd_rx_event, work); @@ -2023,10 +2045,10 @@ void tcpm_pd_receive(struct tcpm_port *port, const struct pd_message *msg) if (!event) return; - INIT_WORK(&event->work, tcpm_pd_rx_handler); + kthread_init_work(&event->work, tcpm_pd_rx_handler); event->port = port; memcpy(&event->msg, msg, sizeof(*msg)); - queue_work(port->wq, &event->work); + kthread_queue_work(port->wq, &event->work); } EXPORT_SYMBOL_GPL(tcpm_pd_receive); @@ -2079,9 +2101,9 @@ static bool tcpm_send_queued_message(struct tcpm_port *port) } while (port->queued_message != PD_MSG_NONE); if (port->delayed_state != INVALID_STATE) { - if (time_is_after_jiffies(port->delayed_runtime)) { - mod_delayed_work(port->wq, &port->state_machine, - port->delayed_runtime - jiffies); + if (ktime_after(port->delayed_runtime, ktime_get())) { + mod_tcpm_delayed_work(port, ktime_to_ms(ktime_sub(port->delayed_runtime, + ktime_get()))); return true; } port->delayed_state = INVALID_STATE; @@ -3214,10 +3236,9 @@ static void run_state_machine(struct tcpm_port *port) case SNK_DISCOVERY_DEBOUNCE_DONE: if (!tcpm_port_is_disconnected(port) && tcpm_port_is_sink(port) && - time_is_after_jiffies(port->delayed_runtime)) { + ktime_after(port->delayed_runtime, ktime_get())) { tcpm_set_state(port, SNK_DISCOVERY, - jiffies_to_msecs(port->delayed_runtime - - jiffies)); + ktime_to_ms(ktime_sub(port->delayed_runtime, ktime_get()))); break; } tcpm_set_state(port, unattached_state(port), 0); @@ -3612,10 +3633,9 @@ static void run_state_machine(struct tcpm_port *port) } } -static void tcpm_state_machine_work(struct work_struct *work) +static void tcpm_state_machine_work(struct kthread_work *work) { - struct tcpm_port *port = container_of(work, struct tcpm_port, - state_machine.work); + struct tcpm_port *port = container_of(work, struct tcpm_port, state_machine); enum tcpm_state prev_state; mutex_lock(&port->lock); @@ -3975,7 +3995,7 @@ static void _tcpm_pd_hard_reset(struct tcpm_port *port) 0); } -static void tcpm_pd_event_handler(struct work_struct *work) +static void tcpm_pd_event_handler(struct kthread_work *work) { struct tcpm_port *port = container_of(work, struct tcpm_port, event_work); @@ -4016,7 +4036,7 @@ void tcpm_cc_change(struct tcpm_port *port) spin_lock(&port->pd_event_lock); port->pd_events |= TCPM_CC_EVENT; spin_unlock(&port->pd_event_lock); - queue_work(port->wq, &port->event_work); + kthread_queue_work(port->wq, &port->event_work); } EXPORT_SYMBOL_GPL(tcpm_cc_change); @@ -4025,7 +4045,7 @@ void tcpm_vbus_change(struct tcpm_port *port) spin_lock(&port->pd_event_lock); port->pd_events |= TCPM_VBUS_EVENT; spin_unlock(&port->pd_event_lock); - queue_work(port->wq, &port->event_work); + kthread_queue_work(port->wq, &port->event_work); } EXPORT_SYMBOL_GPL(tcpm_vbus_change); @@ -4034,7 +4054,7 @@ void tcpm_pd_hard_reset(struct tcpm_port *port) spin_lock(&port->pd_event_lock); port->pd_events = TCPM_RESET_EVENT; spin_unlock(&port->pd_event_lock); - queue_work(port->wq, &port->event_work); + kthread_queue_work(port->wq, &port->event_work); } EXPORT_SYMBOL_GPL(tcpm_pd_hard_reset); @@ -4742,10 +4762,28 @@ static int devm_tcpm_psy_register(struct tcpm_port *port) return PTR_ERR_OR_ZERO(port->psy); } +static enum hrtimer_restart state_machine_timer_handler(struct hrtimer *timer) +{ + struct tcpm_port *port = container_of(timer, struct tcpm_port, state_machine_timer); + + kthread_queue_work(port->wq, &port->state_machine); + return HRTIMER_NORESTART; +} + +static enum hrtimer_restart vdm_state_machine_timer_handler(struct hrtimer *timer) +{ + struct tcpm_port *port = container_of(timer, struct tcpm_port, vdm_state_machine_timer); + + kthread_queue_work(port->wq, &port->vdm_state_machine); + return HRTIMER_NORESTART; +} + struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc) { struct tcpm_port *port; int err; + /* Priority just lower than default irq thread priority */ + struct sched_param param = {.sched_priority = (MAX_USER_RT_PRIO / 2) + 1,}; if (!dev || !tcpc || !tcpc->get_vbus || !tcpc->set_cc || !tcpc->get_cc || @@ -4763,12 +4801,18 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc) mutex_init(&port->lock); mutex_init(&port->swap_lock); - port->wq = create_singlethread_workqueue(dev_name(dev)); - if (!port->wq) - return ERR_PTR(-ENOMEM); - INIT_DELAYED_WORK(&port->state_machine, tcpm_state_machine_work); - INIT_DELAYED_WORK(&port->vdm_state_machine, vdm_state_machine_work); - INIT_WORK(&port->event_work, tcpm_pd_event_handler); + port->wq = kthread_create_worker(0, dev_name(dev)); + if (IS_ERR(port->wq)) + return (struct tcpm_port *)port->wq; + sched_setscheduler(port->wq->task, SCHED_FIFO, ¶m); + + kthread_init_work(&port->state_machine, tcpm_state_machine_work); + kthread_init_work(&port->vdm_state_machine, vdm_state_machine_work); + kthread_init_work(&port->event_work, tcpm_pd_event_handler); + hrtimer_init(&port->state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + port->state_machine_timer.function = state_machine_timer_handler; + hrtimer_init(&port->vdm_state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + port->vdm_state_machine_timer.function = vdm_state_machine_timer_handler; spin_lock_init(&port->pd_event_lock); @@ -4820,7 +4864,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc) usb_role_switch_put(port->role_sw); out_destroy_wq: tcpm_debugfs_exit(port); - destroy_workqueue(port->wq); + kthread_destroy_worker(port->wq); return ERR_PTR(err); } EXPORT_SYMBOL_GPL(tcpm_register_port); @@ -4835,7 +4879,7 @@ void tcpm_unregister_port(struct tcpm_port *port) typec_unregister_port(port->typec_port); usb_role_switch_put(port->role_sw); tcpm_debugfs_exit(port); - destroy_workqueue(port->wq); + kthread_destroy_worker(port->wq); } EXPORT_SYMBOL_GPL(tcpm_unregister_port);