From patchwork Tue Dec 18 10:41:20 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Macpaul Lin X-Patchwork-Id: 10735379 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 B5B3113A4 for ; Tue, 18 Dec 2018 10:41:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A69272A47E for ; Tue, 18 Dec 2018 10:41:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9ACB62A4E1; Tue, 18 Dec 2018 10:41:30 +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 F1FE52A47E for ; Tue, 18 Dec 2018 10:41:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726619AbeLRKl2 (ORCPT ); Tue, 18 Dec 2018 05:41:28 -0500 Received: from mailgw01.mediatek.com ([210.61.82.183]:56299 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726421AbeLRKl2 (ORCPT ); Tue, 18 Dec 2018 05:41:28 -0500 X-UUID: b72610880262415eae816ab8b64c335d-20181218 X-UUID: b72610880262415eae816ab8b64c335d-20181218 Received: from mtkcas07.mediatek.inc [(172.21.101.84)] by mailgw01.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 786223791; Tue, 18 Dec 2018 18:41:24 +0800 Received: from mtkcas09.mediatek.inc (172.21.101.178) by mtkmbs03n2.mediatek.inc (172.21.101.182) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Tue, 18 Dec 2018 18:41:22 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkcas09.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Tue, 18 Dec 2018 18:41:23 +0800 From: Macpaul Lin To: Johan Hovold , Oliver Neukum , Greg Kroah-Hartman , , CC: Mediatek WSD Upstream , Macpaul Lin Subject: [PATCH v3] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader. Date: Tue, 18 Dec 2018 18:41:20 +0800 Message-ID: <1545129680-3224-1-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: 469E9BA652471EDB448B64D0860F4AB6736575DDFAA18675024888ED02A9EC5C2000:8 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 --- Changes for v2: - Move quirks testing of DISABLE_ECHO flag into acm_tty_install(). - Change quirks testing into bitwise comparison. Changes for v3: - Replace clear flag operation from driver->init_termios to tty->termios. - Remove parenthesis of ECHO flag. 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..c1b88c3 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -571,6 +571,7 @@ 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); @@ -583,6 +584,13 @@ static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty) tty->driver_data = acm; + /* get normal quirks */ + quirks = acm->quirks; + + /* handle active handshake triggered by device */ + if (quirks & DISABLE_ECHO) + tty->termios.c_lflag &= ~ECHO; + return 0; 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)