From patchwork Thu Apr 23 11:55:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 11505521 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 4568314DD for ; Thu, 23 Apr 2020 11:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C68C2098B for ; Thu, 23 Apr 2020 11:56:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="U6MmSMBA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728235AbgDWL40 (ORCPT ); Thu, 23 Apr 2020 07:56:26 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:41764 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728184AbgDWL4Z (ORCPT ); Thu, 23 Apr 2020 07:56:25 -0400 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 03NBqWu1025463; Thu, 23 Apr 2020 13:56:17 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=STMicroelectronics; bh=BCdNw/6bNXDgvzYMM/yuCjYQaZbw1vGHMQ1wGH6OfQw=; b=U6MmSMBAFtju9TIfyfARL7+zBExJ1rFHpv8Pz9BAqe1QGj43VEk+F6zswnEfuue998Vq y+5/TvErKyfRRYJTjjpLMjqKFYcUijgEAgxLUN9yhopTH5YEJszGDBYwJ8wY9k89kl/i wuh3nk3jveeWSBDi3X6yJamja44ASgWSqlqXHx65lDLbBQ3Z0BgnL/AWOLRlX1PXyqUq VektRD6eJYG55ysqLOPgfaJGUGDBN7yLm5cdTuuf3rQCUg7UqIGlMYvRbIuMhF9jvTG9 AlFbzaU4slX5Gsp6Ie2190uLMQXR2FqGy5eLuSd/PCd2SJRxIfJsbHEVCEAGoNONNOJo 0g== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 30fregvjtv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 23 Apr 2020 13:56:17 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 3003D10002A; Thu, 23 Apr 2020 13:56:17 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 2624E2ADA08; Thu, 23 Apr 2020 13:56:17 +0200 (CEST) Received: from localhost (10.75.127.44) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 23 Apr 2020 13:56:16 +0200 From: Fabrice Gasnier To: , , CC: , , , , Subject: [PATCH v2 2/4] usb: gadget: u_serial: add suspend resume callbacks Date: Thu, 23 Apr 2020 13:55:54 +0200 Message-ID: <1587642956-8157-3-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1587642956-8157-1-git-send-email-fabrice.gasnier@st.com> References: <1587642956-8157-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG8NODE2.st.com (10.75.127.23) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.676 definitions=2020-04-23_07:2020-04-22,2020-04-23 signatures=0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Add suspend resume callbacks to handle the case seen when the bus is suspended by the HOST, and the device opens the port (cat /dev/ttyGS0). Gadget controller (like DWC2) doesn't accept usb requests to be queued in this case (when in L2 state), from the gs_open() call. Error log is printed - configfs-gadget gadget: acm ttyGS0 can't notify serial state, -11 If the HOST resumes (opens) the bus, the port still isn't functional. Use suspend/resume callbacks to monitor the gadget suspended state by using 'suspended' flag. In case the port gets opened (cat /dev/ttyGS0), the I/O stream will be delayed until the bus gets resumed by the HOST. Signed-off-by: Fabrice Gasnier --- drivers/usb/gadget/function/u_serial.c | 57 +++++++++++++++++++++++++++++----- drivers/usb/gadget/function/u_serial.h | 2 ++ 2 files changed, 51 insertions(+), 8 deletions(-) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index 8167d37..3cfc6e2 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -120,6 +120,8 @@ struct gs_port { wait_queue_head_t drain_wait; /* wait while writes drain */ bool write_busy; wait_queue_head_t close_wait; + bool suspended; /* port suspended */ + bool start_delayed; /* delay start when suspended */ /* REVISIT this state ... */ struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ @@ -630,13 +632,19 @@ static int gs_open(struct tty_struct *tty, struct file *file) /* if connected, start the I/O stream */ if (port->port_usb) { - struct gserial *gser = port->port_usb; - - pr_debug("gs_open: start ttyGS%d\n", port->port_num); - gs_start_io(port); - - if (gser->connect) - gser->connect(gser); + /* if port is suspended, wait resume to start I/0 stream */ + if (!port->suspended) { + struct gserial *gser = port->port_usb; + + pr_debug("gs_open: start ttyGS%d\n", port->port_num); + gs_start_io(port); + + if (gser->connect) + gser->connect(gser); + } else { + pr_debug("delay start of ttyGS%d\n", port->port_num); + port->start_delayed = true; + } } pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); @@ -680,7 +688,7 @@ static void gs_close(struct tty_struct *tty, struct file *file) pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); gser = port->port_usb; - if (gser && gser->disconnect) + if (gser && !port->suspended && gser->disconnect) gser->disconnect(gser); /* wait for circular write buffer to drain, disconnect, or at @@ -708,6 +716,7 @@ static void gs_close(struct tty_struct *tty, struct file *file) else kfifo_reset(&port->port_write_buf); + port->start_delayed = false; port->port.count = 0; port->port.tty = NULL; @@ -1403,6 +1412,38 @@ void gserial_disconnect(struct gserial *gser) } EXPORT_SYMBOL_GPL(gserial_disconnect); +void gserial_suspend(struct gserial *gser) +{ + struct gs_port *port = gser->ioport; + unsigned long flags; + + spin_lock_irqsave(&port->port_lock, flags); + port->suspended = true; + spin_unlock_irqrestore(&port->port_lock, flags); +} +EXPORT_SYMBOL_GPL(gserial_suspend); + +void gserial_resume(struct gserial *gser) +{ + struct gs_port *port = gser->ioport; + unsigned long flags; + + spin_lock_irqsave(&port->port_lock, flags); + port->suspended = false; + if (!port->start_delayed) { + spin_unlock_irqrestore(&port->port_lock, flags); + return; + } + + pr_debug("delayed start ttyGS%d\n", port->port_num); + gs_start_io(port); + if (gser->connect) + gser->connect(gser); + port->start_delayed = false; + spin_unlock_irqrestore(&port->port_lock, flags); +} +EXPORT_SYMBOL_GPL(gserial_resume); + static int userial_init(void) { unsigned i; diff --git a/drivers/usb/gadget/function/u_serial.h b/drivers/usb/gadget/function/u_serial.h index e5b08ab..009a959 100644 --- a/drivers/usb/gadget/function/u_serial.h +++ b/drivers/usb/gadget/function/u_serial.h @@ -68,6 +68,8 @@ ssize_t gserial_get_console(unsigned char port_num, char *page); /* connect/disconnect is handled by individual functions */ int gserial_connect(struct gserial *, u8 port_num); void gserial_disconnect(struct gserial *); +void gserial_suspend(struct gserial *p); +void gserial_resume(struct gserial *p); /* functions are bound to configurations by a config or gadget driver */ int gser_bind_config(struct usb_configuration *c, u8 port_num);