Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030609AbdDTMNL (ORCPT ); Thu, 20 Apr 2017 08:13:11 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:33763 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967045AbdDTMNJ (ORCPT ); Thu, 20 Apr 2017 08:13:09 -0400 From: Sjoerd Simons To: linux-serial@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Russell King , Jiri Slaby Subject: [PATCH v2 1/2] serial: pl010: Move uart_register_driver call to device probe Date: Thu, 20 Apr 2017 14:13:00 +0200 Message-Id: <20170420121301.382-2-sjoerd.simons@collabora.co.uk> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170420121301.382-1-sjoerd.simons@collabora.co.uk> References: <20170420121301.382-1-sjoerd.simons@collabora.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2563 Lines: 97 uart_register_driver call binds the driver to a specific device node through tty_register_driver call. This should typically happen during device probe call. In a multiplatform scenario, it is possible that multiple serial drivers are part of the kernel. Currently the driver registration fails if multiple serial drivers with overlapping major/minor numbers are included. Signed-off-by: Sjoerd Simons --- Changes in v2: - Add locking to prevent issues when two probes run in parallel drivers/tty/serial/amba-pl010.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c index f2f251075109..24180adb1cbb 100644 --- a/drivers/tty/serial/amba-pl010.c +++ b/drivers/tty/serial/amba-pl010.c @@ -697,6 +697,7 @@ static struct console amba_console = { #define AMBA_CONSOLE NULL #endif +static DEFINE_MUTEX(amba_reg_lock); static struct uart_driver amba_reg = { .owner = THIS_MODULE, .driver_name = "ttyAM", @@ -749,6 +750,19 @@ static int pl010_probe(struct amba_device *dev, const struct amba_id *id) amba_ports[i] = uap; amba_set_drvdata(dev, uap); + + mutex_lock(&amba_reg_lock); + if (!amba_reg.state) { + ret = uart_register_driver(&amba_reg); + if (ret < 0) { + mutex_unlock(&amba_reg_lock); + dev_err(uap->port.dev, + "Failed to register AMBA-PL010 driver\n"); + return ret; + } + } + mutex_unlock(&amba_reg_lock); + ret = uart_add_one_port(&amba_reg, &uap->port); if (ret) amba_ports[i] = NULL; @@ -760,12 +774,18 @@ static int pl010_remove(struct amba_device *dev) { struct uart_amba_port *uap = amba_get_drvdata(dev); int i; + bool busy = false; uart_remove_one_port(&amba_reg, &uap->port); for (i = 0; i < ARRAY_SIZE(amba_ports); i++) if (amba_ports[i] == uap) amba_ports[i] = NULL; + else if (amba_ports[i]) + busy = true; + + if (!busy) + uart_unregister_driver(&amba_reg); return 0; } @@ -816,23 +836,14 @@ static struct amba_driver pl010_driver = { static int __init pl010_init(void) { - int ret; - printk(KERN_INFO "Serial: AMBA driver\n"); - ret = uart_register_driver(&amba_reg); - if (ret == 0) { - ret = amba_driver_register(&pl010_driver); - if (ret) - uart_unregister_driver(&amba_reg); - } - return ret; + return amba_driver_register(&pl010_driver); } static void __exit pl010_exit(void) { amba_driver_unregister(&pl010_driver); - uart_unregister_driver(&amba_reg); } module_init(pl010_init); -- 2.11.0