Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753305AbbHETCs (ORCPT ); Wed, 5 Aug 2015 15:02:48 -0400 Received: from mail-qg0-f51.google.com ([209.85.192.51]:36270 "EHLO mail-qg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752398AbbHETCq (ORCPT ); Wed, 5 Aug 2015 15:02:46 -0400 Message-ID: <55C25DD2.4050707@hurleysoftware.com> Date: Wed, 05 Aug 2015 15:02:42 -0400 From: Peter Hurley User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: "Maciej S. Szmigiero" , linux-serial@vger.kernel.org CC: Greg Kroah-Hartman , Jiri Slaby , linux-kernel Subject: Re: [PATCHv2] serial: don't register CIR serial ports References: <55C22F0B.5020803@maciej.szmigiero.name> In-Reply-To: <55C22F0B.5020803@maciej.szmigiero.name> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4331 Lines: 151 On 08/05/2015 11:43 AM, Maciej S. Szmigiero wrote: > CIR type serial ports aren't real serial ports. > > This is just a way to prevent legacy 8250 serial > driver from probing and eventually binding some > resources. > > Since in current state such ports aren't providing > any real functionality and it is not possible > to change their type via setserial/ioctl(TIOCSSERIAL) > (due to UPF_FIXED_PORT flag set on them) > it is simpler and cleaner to not register them at all > with serial core. The only thing I think this patch is missing is either a comment or specific code in serial8250_register_ports() regarding not adding PORT_8250_CIR-type ports. Like either: static void __init serial8250_register_ports(struct uart_driver *drv, struct device *dev) { int i; for (i = 0; i < nr_uarts; i++) { struct uart_8250_port *up = &serial8250_ports[i]; + /* PORT_8250_CIR-type ports must have non-NULL dev */ if (up->port.dev) continue; up->port.dev = dev; or: static void __init serial8250_register_ports(struct uart_driver *drv, struct device *dev) { int i; for (i = 0; i < nr_uarts; i++) { struct uart_8250_port *up = &serial8250_ports[i]; + if (up->port.type == PORT_8250_CIR) + continue; if (up->port.dev) continue; up->port.dev = dev; Regards, Peter Hurley > Print a short message in this case so it is known > to user what has happened. > > This way checks for PORT_8250_CIR in serial port > callbacks can be removed too, since they won't > ever be called. > > Signed-off-by: Maciej Szmigiero > --- > This replaces "serial: don't announce CIR serial ports" > submission. > > Changes from v1: print message using dev_info() > > drivers/tty/serial/8250/8250_core.c | 37 +++++++++++++++++------------------ > 1 files changed, 18 insertions(+), 19 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c > index 37fff12..145b0b37 100644 > --- a/drivers/tty/serial/8250/8250_core.c > +++ b/drivers/tty/serial/8250/8250_core.c > @@ -2129,9 +2129,6 @@ int serial8250_do_startup(struct uart_port *port) > unsigned char lsr, iir; > int retval; > > - if (port->type == PORT_8250_CIR) > - return -ENODEV; > - > if (!port->fifosize) > port->fifosize = uart_config[port->type].fifo_size; > if (!up->tx_loadsz) > @@ -2858,14 +2855,8 @@ static void serial8250_release_port(struct uart_port *port) > static int serial8250_request_port(struct uart_port *port) > { > struct uart_8250_port *up = up_to_u8250p(port); > - int ret; > - > - if (port->type == PORT_8250_CIR) > - return -ENODEV; > - > - ret = serial8250_request_std_resource(up); > > - return ret; > + return serial8250_request_std_resource(up); > } > > static int fcr_get_rxtrig_bytes(struct uart_8250_port *up) > @@ -3013,9 +3004,6 @@ static void serial8250_config_port(struct uart_port *port, int flags) > struct uart_8250_port *up = up_to_u8250p(port); > int ret; > > - if (port->type == PORT_8250_CIR) > - return; > - > /* > * Find the region that we can probe for. This in turn > * tells us whether we can probe for the type of port. > @@ -3889,13 +3877,24 @@ int serial8250_register_8250_port(struct uart_8250_port *up) > if (up->dl_write) > uart->dl_write = up->dl_write; > > - if (serial8250_isa_config != NULL) > - serial8250_isa_config(0, &uart->port, > - &uart->capabilities); > + if (uart->port.type != PORT_8250_CIR) { > + if (serial8250_isa_config != NULL) > + serial8250_isa_config(0, &uart->port, > + &uart->capabilities); > > - ret = uart_add_one_port(&serial8250_reg, &uart->port); > - if (ret == 0) > - ret = uart->port.line; > + ret = uart_add_one_port(&serial8250_reg, > + &uart->port); > + if (ret == 0) > + ret = uart->port.line; > + } else { > + dev_info(uart->port.dev, > + "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n", > + uart->port.iobase, > + (unsigned long long)uart->port.mapbase, > + uart->port.irq); > + > + ret = 0; > + } > } > mutex_unlock(&serial_mutex); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/