From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QjojJ-00010Q-HM for barebox@lists.infradead.org; Thu, 21 Jul 2011 08:35:42 +0000 From: Juergen Beisert Date: Thu, 21 Jul 2011 10:34:27 +0200 References: <20110721031224.GL15388@game.jcrosoft.org> <20110721062818.GU20587@pengutronix.de> In-Reply-To: <20110721062818.GU20587@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <201107211034.27574.jbe@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: serial_ns16550 driver question To: barebox@lists.infradead.org Sascha Hauer wrote: > On Thu, Jul 21, 2011 at 05:12:24AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > > On 22:31 Wed 20 Jul , Sascha Hauer wrote: > > > On Wed, Jul 20, 2011 at 11:51:04PM +0400, Antony Pavlov wrote: > > > > Hi! > > > > > > > > In include/ns16550.h we have: > > > > > > > > struct NS16550_plat { > > > > unsigned int clock; > > > > unsigned char f_caps; > > > > /** > > > > * register read access capability > > > > */ > > > > unsigned int (*reg_read) (unsigned long base, unsigned char > > > > reg_offset); /** > > > > * register write access capability > > > > */ > > > > void (*reg_write) (unsigned int val, unsigned long base, > > > > unsigned char reg_offset); > > > > }; > > > > > > > > Why reg_read and reg_write's argument base has type unsigned long? > > > > IMHO pointer type (void * or char *) is more natural. > > > > > > You're right, I also wondered about this recently when looking at a > > > patch on the list. I would also rather see void __iomem *. The problem > > > is that this driver is also used on X86 which uses inb/outb which take > > > an integer argument. > > > The Linux driver works around this by having a membase and a iobase > > > field along with different register accessors. While being cleaner > > > I'm unsure if we want to go this way. > > > > we can do it via resoure and the flasgs IORESOURCE_MEM_8BIT, > > IORESOURCE_MEM_168BITi etc.. > > Yes, but this does not solve the problem with different accessor > functions (and their argument type). Why not adapt the x86 inb/outb function to the same arguments types than other archs are using for their memory mapped access? We are in Barebox, not in the kernel. I think we can do so, without damaging something in our _small_ x86 Barebox world. jbe -- Pengutronix e.K. | Juergen Beisert | Linux Solutions for Science and Industry | Phone: +49-5121-206917-5128 | Vertretung Sued/Muenchen, Germany | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de/ | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox