From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Hounschell Subject: Re: Out of tree GPL serial tty driver help? Date: Fri, 26 Apr 2013 08:58:09 -0400 Message-ID: <517A79E1.8060504@compro.net> References: <51781A19.5030707@compro.net> <1366926071.3452.17.camel@thor.lan> Reply-To: markh@compro.net Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.compro.net ([12.186.155.4]:21832 "EHLO mx2.compro.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752536Ab3DZM6K (ORCPT ); Fri, 26 Apr 2013 08:58:10 -0400 In-Reply-To: <1366926071.3452.17.camel@thor.lan> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Peter Hurley Cc: linux-serial@vger.kernel.org, Mark Hounschell On 04/25/2013 05:41 PM, Peter Hurley wrote: > On Wed, 2013-04-24 at 13:44 -0400, Mark Hounschell wrote: >> I've been sort of maintaining a couple of Digi International serial port >> card (XP and AP) drivers for years now because, well, they just won't do >> it anymore. In any case, I'm moving from a 3.4.x kernel, that works just >> fine, to a 3.8.8 kernel, that does not. I have code that does something >> like this: >> >> tty_set_operations(&SerialDriver, &SerialOps); >> tty_register_driver(&SerialDriver); >> maxminor = NumBoards * 64; >> for (i = 0; i < maxminor; i++) >> tty_register_device(&SerialDriver, i, NULL); > > You're correct in diagnosing the problem to cdevs == NULL. > You're missing: > > maxminor = min(num_boards * 64, 256); > serial_driver = alloc_tty_driver(maxminor); > > then, > /* Fill in pertinent tty_driver fields, esp. */ > serial_driver->flags = TTY_DRIVER_DYNAMIC_DEV; > > tty_set_operations(serial_driver, &serial_ops); > tty_register_driver(serial_driver); > for (i = 0; i < maxminor; i++) > tty_register_device(serial_driver, i, NULL); > > Thanks for responding Peter. Earlier in the code they do this: static struct tty_driver SerialDriver and things like SerialDriver.termios = kmalloc((maxminor - 256) * sizeof(TERMIOS *), GFP_KERNEL); So is the above no longer going to work and I _must_ now use alloc_tty_driver? If alloc_tty_driver is now a requirement, how much is it going to do for me? There are several things like the termios above that are manually allocated. How much if any of this is alloc_tty_driver going to do for me? or might this work static struct tty_driver SerialDriver . . . serial_driver.flags = TTY_DRIVER_DYNAMIC_DEV; SerialDriver.cdevs = kcalloc(maxminor, sizeof(SerialDriver.cdevs), GFP_KERNEL); tty_set_operations(&serial_driver, &serial_ops); tty_register_driver(&serial_driver); for (i = 0; i < maxminor; i++) tty_register_device(&serial_driver, i, NULL); ??? > > PS - Each board supports 64 individual serial ports?? No, this particular card comes in 4, 8, and 16 port flavors. I never did understand why they create so many device entries. I just figured they had a reason. For a single card, no matter how many ports, they create 64 normal serial tty entries (tty_dgdm_G0 - tty_dgdm_G63), 64 serial printer entries (lp_dgdm_G0 - lp_dgdm_G63), and then 64 serial modem entries (cu_dgdm_G0 - cu_dgdm_G63). Don't know why. Thanks again Mark