drivers/video/fbdev/vt8623fb: Use arch_phys_wc_add() and pci_iomap_wc()

This driver uses the same area for MTRR as for the ioremap().

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@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: benh@kernel.crashing.org
Cc: bhelgaas@google.com
Cc: dan.j.williams@intel.com
Cc: konrad.wilk@oracle.com
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: mst@redhat.com
Cc: toshi.kani@hp.com
Cc: vinod.koul@intel.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1440443613-13696-9-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/video/fbdev/vt8623fb.c b/drivers/video/fbdev/vt8623fb.c
index 8bac309c24b99c7134737ac901933fb0ed0155b5..dd0f18e42d3e5e6ec645c4c61348a90f6dc9c511 100644 (file)
--- a/drivers/video/fbdev/vt8623fb.c
+++ b/drivers/video/fbdev/vt8623fb.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 vt8623fb_info {
        char __iomem *mmio_base;
-       int mtrr_reg;
+       int wc_cookie;
        struct vgastate state;
        struct mutex open_lock;
        unsigned int ref_count;
@@ -99,10 +95,7 @@ static struct svga_timing_regs vt8623_timing_regs     = {
 /* Module parameters */
 
 static char *mode_option = "640x480-8@60";
-
-#ifdef CONFIG_MTRR
 static int mtrr = 1;
-#endif
 
 MODULE_AUTHOR("(c) 2006 Ondrej Zajicek <santiago@crfreenet.org>");
 MODULE_LICENSE("GPL");
@@ -112,11 +105,8 @@ module_param(mode_option, charp, 0644);
 MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
 module_param_named(mode, mode_option, charp, 0);
 MODULE_PARM_DESC(mode, "Default video mode e.g. '648x480-8@60' (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
 
 
 /* ------------------------------------------------------------------------- */
@@ -710,7 +700,7 @@ static int vt8623_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
        info->fix.mmio_len = pci_resource_len(dev, 1);
 
        /* 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");
@@ -781,12 +771,9 @@ static int vt8623_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
+       if (mtrr)
+               par->wc_cookie = arch_phys_wc_add(info->fix.smem_start,
+                                                 info->fix.smem_len);
 
        return 0;
 
@@ -816,13 +803,7 @@ static void vt8623_pci_remove(struct pci_dev *dev)
        if (info) {
                struct vt8623fb_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);
                unregister_framebuffer(info);
                fb_dealloc_cmap(&info->cmap);