Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756060AbbFOW2D (ORCPT ); Mon, 15 Jun 2015 18:28:03 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53936 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751353AbbFOW14 (ORCPT ); Mon, 15 Jun 2015 18:27:56 -0400 Date: Tue, 16 Jun 2015 00:27:50 +0200 From: "Luis R. Rodriguez" To: Tomi Valkeinen Cc: "Luis R. Rodriguez" , plagnioj@jcrosoft.com, bp@suse.de, hpa@zytor.com, linux-fbdev@vger.kernel.org, luto@amacapital.net, toshi.kani@hp.com, sbsiddha@gmail.com, mingo@elte.hu, tglx@linutronix.de, jgross@suse.com, daniel.vetter@ffwll.ch, airlied@redhat.com, adaplas@gmail.com, robdclark@gmail.com, jg1.han@samsung.com, wsa@the-dreams.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 3/3] video: fbdev: vesafb: use arch_phys_wc_add() Message-ID: <20150615222750.GF11147@wotan.suse.de> References: <1433436288-16792-1-git-send-email-mcgrof@do-not-panic.com> <1433436288-16792-4-git-send-email-mcgrof@do-not-panic.com> <557AA08E.6050606@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <557AA08E.6050606@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6325 Lines: 180 On Fri, Jun 12, 2015 at 12:04:14PM +0300, Tomi Valkeinen wrote: > > > On 04/06/15 19:44, Luis R. Rodriguez wrote: > > From: "Luis R. Rodriguez" > > > > This driver uses the same area for MTRR as for the ioremap_wc(), if > > anything it just uses a smaller size in case MTRR reservation fails. > > ioremap_wc() API is already used to take advantage of architecture > > write-combining when available. > > > > Convert the driver from using the x86 specific MTRR code to > > the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add() > > will avoid MTRR if write-combining is available. > > > > There are a few motivations for this: > > > > a) Take advantage of PAT when available > > > > b) Help bury MTRR code away, MTRR is architecture specific and on > > x86 its replaced by PAT > > > > c) Help with the goal of eventually using _PAGE_CACHE_UC over > > _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit > > de33c442e titled "x86 PAT: fix performance drop for glx, > > use UC minus for ioremap(), ioremap_nocache() and > > pci_mmap_page_range()") > > > > The conversion done is expressed by the following Coccinelle > > SmPL patch, it additionally required manual intervention to > > address all the #ifdery and removal of redundant things which > > arch_phys_wc_add() already addresses such as verbose message > > about when MTRR fails and doing nothing when we didn't get > > an MTRR. > > > > @ mtrr_found @ > > expression index, base, size; > > @@ > > > > -index = mtrr_add(base, size, MTRR_TYPE_WRCOMB, 1); > > +index = arch_phys_wc_add(base, size); > > > > @ mtrr_rm depends on mtrr_found @ > > expression mtrr_found.index, mtrr_found.base, mtrr_found.size; > > @@ > > > > -mtrr_del(index, base, size); > > +arch_phys_wc_del(index); > > > > @ mtrr_rm_zero_arg depends on mtrr_found @ > > expression mtrr_found.index; > > @@ > > > > -mtrr_del(index, 0, 0); > > +arch_phys_wc_del(index); > > > > @ mtrr_rm_fb_info depends on mtrr_found @ > > struct fb_info *info; > > expression mtrr_found.index; > > @@ > > > > -mtrr_del(index, info->fix.smem_start, info->fix.smem_len); > > +arch_phys_wc_del(index); > > > > @ ioremap_replace_nocache depends on mtrr_found @ > > struct fb_info *info; > > expression base, size; > > @@ > > > > -info->screen_base = ioremap_nocache(base, size); > > +info->screen_base = ioremap_wc(base, size); > > > > @ ioremap_replace_default depends on mtrr_found @ > > struct fb_info *info; > > expression base, size; > > @@ > > > > -info->screen_base = ioremap(base, size); > > +info->screen_base = ioremap_wc(base, size); > > > > Generated-by: Coccinelle SmPL > > Cc: Toshi Kani > > Cc: Suresh Siddha > > Cc: Ingo Molnar > > Cc: Thomas Gleixner > > Cc: Juergen Gross > > Cc: Daniel Vetter > > Cc: Andy Lutomirski > > Cc: Dave Airlie > > Cc: Antonino Daplas > > Cc: Jean-Christophe Plagniol-Villard > > Cc: Rob Clark > > Cc: Jingoo Han > > Cc: Wolfram Sang > > Cc: Tomi Valkeinen > > Cc: linux-fbdev@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Signed-off-by: Luis R. Rodriguez > > --- > > drivers/video/fbdev/vesafb.c | 29 ++++++++--------------------- > > 1 file changed, 8 insertions(+), 21 deletions(-) > > > > diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c > > index 3db3908..528fe91 100644 > > --- a/drivers/video/fbdev/vesafb.c > > +++ b/drivers/video/fbdev/vesafb.c > > @@ -19,10 +19,9 @@ > > #include > > #include > > #include > > +#include > > > > #include