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Message-Id: <1436406859-1280-7-git-send-email-mcgrof@do-not-panic.com>
Date:	Wed,  8 Jul 2015 18:54:17 -0700
From:	"Luis R. Rodriguez" <mcgrof@...not-panic.com>
To:	mingo@...nel.org
Cc:	bp@...e.de, arnd@...db.de, bhelgaas@...gle.com,
	luto@...capital.net, akpm@...ux-foundation.org,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	tomi.valkeinen@...com, mst@...hat.com, toshi.kani@...com,
	linux-fbdev@...r.kernel.org, xen-devel@...ts.xensource.com,
	benh@...nel.crashing.org, "Luis R. Rodriguez" <mcgrof@...e.com>,
	Antonino Daplas <adaplas@...il.com>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Dave Airlie <airlied@...hat.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Juergen Gross <jgross@...e.com>,
	"Lad, Prabhakar" <prabhakar.csengg@...il.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Suresh Siddha <sbsiddha@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH v9 6/8] drivers/video/fbdev/arkfb.c: Use arch_phys_wc_add() and pci_iomap_wc()

From: "Luis R. Rodriguez" <mcgrof@...e.com>

Convert the driver from using the x86-specific MTRR code to the
architecture-agnostic arch_phys_wc_add(). It will avoid MTRRs if
write-combining is available. In order to take advantage of that also
ensure the ioremapped area is requested as write-combining.

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 it is being 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 ifdeffery 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);

Signed-off-by: Luis R. Rodriguez <mcgrof@...e.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@...com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Antonino Daplas <adaplas@...il.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: benh@...nel.crashing.org
Cc: bhelgaas@...gle.com
Cc: Daniel Vetter <daniel.vetter@...ll.ch>
Cc: Dave Airlie <airlied@...hat.com>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: linux-fbdev@...r.kernel.org
Cc: linux-pci@...r.kernel.org
Cc: mst@...hat.com
Cc: Suresh Siddha <sbsiddha@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: toshi.kani@...com
Link: http://lkml.kernel.org/r/1435195342-26879-8-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 drivers/video/fbdev/arkfb.c | 36 +++++-------------------------------
 1 file changed, 5 insertions(+), 31 deletions(-)

diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c
index b305a1e7cc76..6a317de7082c 100644
--- a/drivers/video/fbdev/arkfb.c
+++ b/drivers/video/fbdev/arkfb.c
@@ -26,13 +26,9 @@
 #include <linux/console.h> /* Why should fb driver call console functions? because console_lock() */
 #include <video/vga.h>
 
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
-
 struct arkfb_info {
 	int mclk_freq;
-	int mtrr_reg;
+	int wc_cookie;
 
 	struct dac_info *dac;
 	struct vgastate state;
@@ -102,10 +98,6 @@ static const struct svga_timing_regs ark_timing_regs     = {
 
 static char *mode_option = "640x480-8@60";
 
-#ifdef CONFIG_MTRR
-static int mtrr = 1;
-#endif
-
 MODULE_AUTHOR("(c) 2007 Ondrej Zajicek <santiago@...reenet.org>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("fbdev driver for ARK 2000PV");
@@ -115,11 +107,6 @@ MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
 module_param_named(mode, mode_option, charp, 0444);
 MODULE_PARM_DESC(mode, "Default video mode ('640x480-8@60', etc) (deprecated)");
 
-#ifdef CONFIG_MTRR
-module_param(mtrr, int, 0444);
-MODULE_PARM_DESC(mtrr, "Enable write-combining with MTRR (1=enable, 0=disable, default=1)");
-#endif
-
 static int threshold = 4;
 
 module_param(threshold, int, 0644);
@@ -1002,7 +989,7 @@ static int ark_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	info->fix.smem_len = pci_resource_len(dev, 0);
 
 	/* Map physical IO memory address into kernel space */
-	info->screen_base = pci_iomap(dev, 0, 0);
+	info->screen_base = pci_iomap_wc(dev, 0, 0);
 	if (! info->screen_base) {
 		rc = -ENOMEM;
 		dev_err(info->device, "iomap for framebuffer failed\n");
@@ -1057,14 +1044,8 @@ static int ark_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	/* Record a reference to the driver data */
 	pci_set_drvdata(dev, info);
-
-#ifdef CONFIG_MTRR
-	if (mtrr) {
-		par->mtrr_reg = -1;
-		par->mtrr_reg = mtrr_add(info->fix.smem_start, info->fix.smem_len, MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
-
+	par->wc_cookie = arch_phys_wc_add(info->fix.smem_start,
+					  info->fix.smem_len);
 	return 0;
 
 	/* Error handling */
@@ -1092,14 +1073,7 @@ static void ark_pci_remove(struct pci_dev *dev)
 
 	if (info) {
 		struct arkfb_info *par = info->par;
-
-#ifdef CONFIG_MTRR
-		if (par->mtrr_reg >= 0) {
-			mtrr_del(par->mtrr_reg, 0, 0);
-			par->mtrr_reg = -1;
-		}
-#endif
-
+		arch_phys_wc_del(par->wc_cookie);
 		dac_release(par->dac);
 		unregister_framebuffer(info);
 		fb_dealloc_cmap(&info->cmap);
-- 
2.3.2.209.gd67f9d5.dirty

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