From patchwork Tue Dec 18 05:00:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Macpaul Lin X-Patchwork-Id: 10734831 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 82FF26C2 for ; Tue, 18 Dec 2018 05:00:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 720B82A1E8 for ; Tue, 18 Dec 2018 05:00:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 65F162A2DC; Tue, 18 Dec 2018 05:00:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B6E812A1E8 for ; Tue, 18 Dec 2018 05:00:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726584AbeLRFAk (ORCPT ); Tue, 18 Dec 2018 00:00:40 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:47974 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726312AbeLRFAj (ORCPT ); Tue, 18 Dec 2018 00:00:39 -0500 X-UUID: 0cf07ff5fc5f42e7bdfd9fd4ad943e41-20181218 X-UUID: 0cf07ff5fc5f42e7bdfd9fd4ad943e41-20181218 Received: from mtkcas08.mediatek.inc [(172.21.101.126)] by mailgw02.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 1342698512; Tue, 18 Dec 2018 13:00:27 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs03n2.mediatek.inc (172.21.101.182) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Tue, 18 Dec 2018 13:00:25 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Tue, 18 Dec 2018 13:00:25 +0800 From: Macpaul Lin To: Johan Hovold , Oliver Neukum , Greg Kroah-Hartman , , CC: Mediatek WSD Upstream , Macpaul Lin Subject: [PATCH v2] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader. Date: Tue, 18 Dec 2018 13:00:22 +0800 Message-ID: <1545109222-25073-1-git-send-email-macpaul.lin@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1544671676-23912-1-git-send-email-macpaul.lin@mediatek.com> References: <1544671676-23912-1-git-send-email-macpaul.lin@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: 7664044F74AE5253EDD18617C84B066DAE7036D0C4BBAE527C061A0C16DC6A242000:8 X-MTK: N Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Mediatek Preloader is a proprietary embedded boot loader for loading Little Kernel and Linux into device DRAM. This boot loader also handle firmware update. Mediatek Preloader will be enumerated as a virtual COM port when the device is connected to Windows or Linux OS via CDC-ACM class driver. When the USB enumeration has been done, Mediatek Preloader will send out handshake command "READY" to PC actively instead of waiting command from the download tool. Since Linux 4.12, the commit "tty: reset termios state on device registration" (93857edd9829e144acb6c7e72d593f6e01aead66) causes Mediatek Preloader receiving some abnoraml command like "READYXX" as it sent. This will be recognized as an incorrect response. The behavior change also causes the download handshake fail. By disabling the ECHO termios flag could avoid this problem. However, it cannot be done by user space configuration when download tool open /dev/ttyACM0. This is because the device running Mediatek Preloader will send handshake command "READY" immediately once the CDC-ACM driver is ready. This patch wants to fix above problem by introducing "DISABLE_ECHO" property in driver_info. When Mediatek Preloader is connected, the CDC-ACM driver could disable ECHO flag in termios to avoid the problem. Signed-off-by: Macpaul Lin --- Change for v2: - Move quirks testing of DISABLE_ECHO flag into acm_tty_install(). - Change quirks testing into bitwise comparison. drivers/usb/class/cdc-acm.c | 13 ++++++++++++- drivers/usb/class/cdc-acm.h | 1 + 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 1b68fed..f1a914d 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -571,12 +571,20 @@ static void acm_softint(struct work_struct *work) static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty) { struct acm *acm; + unsigned long quirks; int retval; acm = acm_get_by_minor(tty->index); if (!acm) return -ENODEV; + /* get normal quirks */ + quirks = acm->quirks; + + /* handle active handshake triggered by device */ + if (quirks & DISABLE_ECHO) + driver->init_termios.c_lflag &= ~(ECHO); + retval = tty_standard_install(driver, tty); if (retval) goto error_init_termios; @@ -1655,7 +1663,10 @@ static int acm_pre_reset(struct usb_interface *intf) .driver_info = NO_UNION_NORMAL, /* has no union descriptor */ }, { USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */ - .driver_info = NO_UNION_NORMAL, /* has no union descriptor */ + .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */ + }, + { USB_DEVICE(0x0e8d, 0x2000), /* FIREFLY, MediaTek Inc; Preloader */ + .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */ }, { USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */ .driver_info = NO_UNION_NORMAL, /* has no union descriptor */ diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h index ca06b20..515aad0 100644 --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -140,3 +140,4 @@ struct acm { #define QUIRK_CONTROL_LINE_STATE BIT(6) #define CLEAR_HALT_CONDITIONS BIT(7) #define SEND_ZERO_PACKET BIT(8) +#define DISABLE_ECHO BIT(9)