From patchwork Fri Feb 3 14:50:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Starke" X-Patchwork-Id: 650887 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC038C636D4 for ; Fri, 3 Feb 2023 14:50:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231240AbjBCOut (ORCPT ); Fri, 3 Feb 2023 09:50:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231614AbjBCOus (ORCPT ); Fri, 3 Feb 2023 09:50:48 -0500 Received: from mta-65-226.siemens.flowmailer.net (mta-65-226.siemens.flowmailer.net [185.136.65.226]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67EE49D060 for ; Fri, 3 Feb 2023 06:50:45 -0800 (PST) Received: by mta-65-226.siemens.flowmailer.net with ESMTPSA id 2023020314504325054c719bac6333dc for ; Fri, 03 Feb 2023 15:50:43 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=fm1; d=siemens.com; i=daniel.starke@siemens.com; h=Date:From:Subject:To:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Cc:References:In-Reply-To; bh=soWeu6gkV3NEcYNRrfIYl154ZKDvANaWKtl+GG89qaE=; b=Zoq+elDa54uNPWIqcLTvhC6h8SEmYAp7+CC2tc+BukBRK8JfKgI6Lc6sKWeADUWMCy979s mK2dnRwPYk5zS953sx2RfMHa+lhFKXzeRrj/cbjY7ymzsk84F7gMo3+IejoLYtCOI1CJ/e/l k/v9BOA0ogvP2xpqH6oJyjLHgPsIs=; From: "D. Starke" To: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, ilpo.jarvinen@linux.intel.com Cc: linux-kernel@vger.kernel.org, Daniel Starke Subject: [PATCH v3 4/4] tty: n_gsm: add TIOCMIWAIT support Date: Fri, 3 Feb 2023 15:50:23 +0100 Message-Id: <20230203145023.6012-4-daniel.starke@siemens.com> In-Reply-To: <20230203145023.6012-1-daniel.starke@siemens.com> References: <20230203145023.6012-1-daniel.starke@siemens.com> MIME-Version: 1.0 X-Flowmailer-Platform: Siemens Feedback-ID: 519:519-314044:519-21489:flowmailer Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Daniel Starke Add support for the TIOCMIWAIT ioctl on the virtual ttys. This enables the user to wait for virtual modem signals like RING. More work is needed to support also TIOCGICOUNT. Signed-off-by: Daniel Starke --- drivers/tty/n_gsm.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) v2 -> v3: Added appropriate cast of arg in gsm_wait_modem_change() call as remarked in the review. No other changes. Link: https://lore.kernel.org/all/Y9vZOsAuzKjBNArJ@kroah.com/ diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index cf1ab7d619d9..aa3488280f1b 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1542,6 +1542,7 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, if (brk & 0x01) tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); dlci->modem_rx = mlines; + wake_up_interruptible(&dlci->gsm->event); } /** @@ -2129,7 +2130,7 @@ static void gsm_dlci_close(struct gsm_dlci *dlci) /* A DLCI 0 close is a MUX termination so we need to kick that back to userspace somehow */ gsm_dlci_data_kick(dlci); - wake_up(&dlci->gsm->event); + wake_up_all(&dlci->gsm->event); } /** @@ -2339,6 +2340,7 @@ static void gsm_dlci_begin_close(struct gsm_dlci *dlci) dlci->state = DLCI_CLOSING; gsm_command(dlci->gsm, dlci->addr, DISC|PF); mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); + wake_up_interruptible(&gsm->event); } /** @@ -3877,6 +3879,33 @@ static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) return -EPROTONOSUPPORT; } +/** + * gsm_wait_modem_change - wait for modem status line change + * @dlci: channel + * @mask: modem status line bits + * + * The function returns if: + * - any given modem status line bit changed + * - the wait event function got interrupted (e.g. by a signal) + * - the underlying DLCI was closed + * - the underlying ldisc device was removed + */ +static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask) +{ + struct gsm_mux *gsm = dlci->gsm; + u32 old = dlci->modem_rx; + int ret; + + ret = wait_event_interruptible(gsm->event, gsm->dead || + dlci->state != DLCI_OPEN || + (old ^ dlci->modem_rx) & mask); + if (gsm->dead) + return -ENODEV; + if (dlci->state != DLCI_OPEN) + return -EL2NSYNC; + return ret; +} + static bool gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -4136,6 +4165,8 @@ static int gsmtty_ioctl(struct tty_struct *tty, gsm_destroy_network(dlci); mutex_unlock(&dlci->mutex); return 0; + case TIOCMIWAIT: + return gsm_wait_modem_change(dlci, (u32)arg); default: return -ENOIOCTLCMD; }