From patchwork Mon Oct 24 06:36:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 618055 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 5DFBEFA373F for ; Mon, 24 Oct 2022 06:36:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230320AbiJXGgc (ORCPT ); Mon, 24 Oct 2022 02:36:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230149AbiJXGgW (ORCPT ); Mon, 24 Oct 2022 02:36:22 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EF858183AB; Sun, 23 Oct 2022 23:36:17 -0700 (PDT) Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id EDFEC822A; Mon, 24 Oct 2022 06:27:01 +0000 (UTC) From: Tony Lindgren To: Greg Kroah-Hartman Cc: Johan Hovold , Sebastian Andrzej Siewior , Vignesh Raghavendra , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, Merlijn Wajer , Romain Naour , Ivaylo Dimitrov Subject: [PATCH] serial: 8250: omap: Fix missing PM runtime calls for omap8250_set_mctrl() Date: Mon, 24 Oct 2022 09:36:13 +0300 Message-Id: <20221024063613.25943-1-tony@atomide.com> X-Mailer: git-send-email 2.37.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org There are cases where omap8250_set_mctrl() may get called after the UART has already autoidled causing an asynchronous external abort. This can happen on ttyport_open(): mem_serial_in from omap8250_set_mctrl+0x38/0xa0 omap8250_set_mctrl from uart_update_mctrl+0x4c/0x58 uart_update_mctrl from uart_dtr_rts+0x60/0xa8 uart_dtr_rts from tty_port_block_til_ready+0xd0/0x2a8 tty_port_block_til_ready from uart_open+0x14/0x1c uart_open from ttyport_open+0x64/0x148 And on ttyport_close(): omap8250_set_mctrl from uart_update_mctrl+0x3c/0x48 uart_update_mctrl from uart_dtr_rts+0x54/0x9c uart_dtr_rts from tty_port_shutdown+0x78/0x9c tty_port_shutdown from tty_port_close+0x3c/0x74 tty_port_close from ttyport_close+0x40/0x58 It can also happen on disassociate_ctty() calling uart_shutdown() that ends up calling omap8250_set_mctrl(). Let's fix the issue by adding missing PM runtime calls to omap8250_set_mctrl(). To do this, we need to add __omap8250_set_mctrl() that can be called from both omap8250_set_mctrl(), and from runtime PM resume path when restoring the registers. Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver") Depends-on: dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") Reported-by: Merlijn Wajer Reported-by: Romain Naour Reported-by: Ivaylo Dimitrov Tested-by: Ivaylo Dimitrov Signed-off-by: Tony Lindgren Tested-by: Romain Naour --- drivers/tty/serial/8250/8250_omap.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -157,7 +157,11 @@ static u32 uart_read(struct uart_8250_port *up, u32 reg) return readl(up->port.membase + (reg << up->port.regshift)); } -static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) +/* + * Called on runtime PM resume path from omap8250_restore_regs(), and + * omap8250_set_mctrl(). + */ +static void __omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct uart_8250_port *up = up_to_u8250p(port); struct omap8250_priv *priv = up->port.private_data; @@ -181,6 +185,20 @@ static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) } } +static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + int err; + + err = pm_runtime_resume_and_get(port->dev); + if (err) + return; + + __omap8250_set_mctrl(port, mctrl); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); +} + /* * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) * The access to uart register after MDR1 Access @@ -341,7 +359,7 @@ static void omap8250_restore_regs(struct uart_8250_port *up) omap8250_update_mdr1(up, priv); - up->port.ops->set_mctrl(&up->port, up->port.mctrl); + __omap8250_set_mctrl(&up->port, up->port.mctrl); if (up->port.rs485.flags & SER_RS485_ENABLED) serial8250_em485_stop_tx(up);