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drivers/video/fbdev/i740fb: Use arch_phys_wc_add() and pci_ioremap_wc_bar()

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Convert the driver from using the x86-specific MTRR code to the
architecture-agnostic arch_phys_wc_add(). It will avoid MTRR 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: Benoit Taine <benoit.taine@lip6.fr>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
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: 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: 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/1440443613-13696-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Luis R. Rodriguez 2015-08-24 12:13:24 -07:00 committed by Ingo Molnar
parent c43996f400
commit c112709809
1 changed files with 6 additions and 29 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

35
drivers/video/fbdev/i740fb.c
View file

@ -27,24 +27,15 @@
#include <linux/console.h>
#include <video/vga.h>
#ifdef CONFIG_MTRR
#include <asm/mtrr.h>
#endif
#include "i740_reg.h"
static char *mode_option;
#ifdef CONFIG_MTRR
static int mtrr = 1;
#endif
struct i740fb_par {
unsigned char __iomem *regs;
bool has_sgram;
#ifdef CONFIG_MTRR
int mtrr_reg;
#endif
int wc_cookie;
bool ddc_registered;
struct i2c_adapter ddc_adapter;
struct i2c_algo_bit_data ddc_algo;
@ -1040,7 +1031,7 @@ static int i740fb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
goto err_request_regions;
}
info->screen_base = pci_ioremap_bar(dev, 0);
info->screen_base = pci_ioremap_wc_bar(dev, 0);
if (!info->screen_base) {
dev_err(info->device, "error remapping base\n");
ret = -ENOMEM;
@ -1144,13 +1135,9 @@ static int i740fb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
fb_info(info, "%s frame buffer device\n", info->fix.id);
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;
err_reg_framebuffer:
@ -1177,13 +1164,7 @@ static void i740fb_remove(struct pci_dev *dev)
if (info) {
struct i740fb_par *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);
if (par->ddc_registered)
@ -1287,10 +1268,8 @@ static int __init i740fb_setup(char *options)
while ((opt = strsep(&options, ",")) != NULL) {
if (!*opt)
continue;
#ifdef CONFIG_MTRR
else if (!strncmp(opt, "mtrr:", 5))
mtrr = simple_strtoul(opt + 5, NULL, 0);
#endif
else
mode_option = opt;
}
@ -1327,7 +1306,5 @@ MODULE_DESCRIPTION("fbdev driver for Intel740");
module_param(mode_option, charp, 0444);
MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
#ifdef CONFIG_MTRR
module_param(mtrr, int, 0444);
MODULE_PARM_DESC(mtrr, "Enable write-combining with MTRR (1=enable, 0=disable, default=1)");
#endif