From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Tue, 16 Jun 2015 06:43:09 +0000 Subject: Re: [PATCH v4 3/3] video: fbdev: vesafb: use arch_phys_wc_add() Message-Id: <557FC57D.7020607@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="flpeUBqK3wC8Wo9wVpxgRBMjWdj1mqpxI" List-Id: 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> <20150615222750.GF11147@wotan.suse.de> In-Reply-To: <20150615222750.GF11147@wotan.suse.de> To: "Luis R. Rodriguez" 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 --flpeUBqK3wC8Wo9wVpxgRBMjWdj1mqpxI Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 16/06/15 01:27, Luis R. Rodriguez wrote: > 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 =3D mtrr_add(base, size, MTRR_TYPE_WRCOMB, 1); >>> +index =3D 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 =3D ioremap_nocache(base, size); >>> +info->screen_base =3D ioremap_wc(base, size); >>> >>> @ ioremap_replace_default depends on mtrr_found @ >>> struct fb_info *info; >>> expression base, size; >>> @@ >>> >>> -info->screen_base =3D ioremap(base, size); >>> +info->screen_base =3D 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/vesaf= b.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 >>> =20 >>> #include