From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-la0-x22f.google.com ([2a00:1450:4010:c03::22f]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y1xKT-0006eJ-Jc for barebox@lists.infradead.org; Fri, 19 Dec 2014 13:10:50 +0000 Received: by mail-la0-f47.google.com with SMTP id hz20so778562lab.20 for ; Fri, 19 Dec 2014 05:10:27 -0800 (PST) Date: Fri, 19 Dec 2014 17:12:19 +0400 From: Antony Pavlov Message-Id: <20141219171219.b672ff943c851cbe6adf5006@gmail.com> In-Reply-To: <20141219064542.GY30369@pengutronix.de> References: <1418941957-6950-1-git-send-email-antonynpavlov@gmail.com> <20141219064542.GY30369@pengutronix.de> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [RFC] introduce ioremap() and dev_ioremap_resource() To: Sascha Hauer Cc: barebox@lists.infradead.org On Fri, 19 Dec 2014 07:45:42 +0100 Sascha Hauer wrote: > On Fri, Dec 19, 2014 at 01:32:37AM +0300, Antony Pavlov wrote: > > The commit > > = > > commit 0d7a21334536cb36b3c9b64d868acc55aec41332 > > Author: Antony Pavlov > > Date: Wed Sep 10 11:42:19 2014 +0400 > > = > > MIPS: dts: use physical addresses (as Linux does) > > = > > With IOMEM() adapted for MIPS we can use physical addresses > > in device tree reg property. > > = > > is premature. Current device tree files unusable on real hardware. > > I'M SO SORRY! > > The patch was tested on qemu, but qemu malta board is tolerant > > of using physical addresses for accesing to device. Real hardware > > can throw an exception in this situation. > > = > > Additional physical address to virtual address translation on MIPS is n= eeded. > > = > > This commit demonstrate a possible (but not very good) solution. > > This solution is copied-and-pasted from linux kernel. > > In linux drivers use devm_ioremap_resource() function, so > > the patch just replicates similar dev_ioremap_resource() function. > > = > > Changing dev_request_mem_region() to dev_ioremap_resource() > > is not a very good idea because there are too many dev_request_mem_regi= on() > > in barebox sources > > = > > barebox$ git grep dev_request_mem_region | wc -l > > 197 > > = > > moreover dev_ioremap_resource() has the second 'struct resource *res' > > argument, so additional dev_get_resource() is needed. > > = > > Can we insert ioremap() into dev_request_mem_region() directly? > > (we also can use already existion IOMEM() macro instead of linux' iorem= ap()). > = > I'm not sure if it's a good idea to put that behind some standard > lookingioremap() call, because its behaviour is not standard. > = > I'm also fine with adding some > = > #ifdef CONFIG_MIPS > return mips_iomem(res->start); > #else > return (void __force __iomem *)res->start; > #endif > = > At least this makes explicit that MIPS has a very special handling. We already have this in include/common.h #if defined(CONFIG_MIPS) #include #define IOMEM(addr) ((void __force __iomem *)CKSEG1ADDR(addr)) #else #define IOMEM(addr) ((void __force __iomem *)(addr)) #endif So can I use just return IOMEM(res->start); in dev_request_mem_region()? --=A0 Best regards, =A0 Antony Pavlov _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox