[PATCH v5 0/3] atyfb: address MTRR corner case

[PATCH v5 0/3] atyfb: address MTRR corner case

[Luis R. Rodriguez]

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

Andrew,

Forgive me for the TL;DR, I'm afraid I need to be crystal clear on this
patchset as its the most complex in the entire series. The skinny is that this
patchset addresses a complex work around with APIs now merged upstream going in
for v4.2, the driver maintainer hasn't followed up with the driver changes for
over a month and no one else has provided Acks for these device driver
changes [0]. We have a few options:

0) Sit and wait for a driver maintainer to review this
1) Merge this as-is and hope for reports
2) go with the nopat requirement as with the ivtv and ipath driver

I'd prefer to merge this as is, and only if reports come back with
issues should we then consider 2) as we'd then have at least a well
documented work effort required for this transformation. This device
driver is also old, so I don't expect much reports anyway.

----

The TL;DR:

As part of the long haul effort to rid the world of direct MTRR use [1] we've
have had to also work on alternative solutions which can co-exist with PAT
interfaces. Most of the transformation of device drivers to use PAT was fairly
easy (TM): so long as ioremap_wc() was used we could then convert over the
drivers using mtrr_add() over to the arch-agnostic and PAT-aware (ignored when
PAT is enabled) arch_phys_wc_add(). This was typically easy to do, for instance
in cases where a full PCI BAR was used for MMIO registers and another PCI BAR
was used with write-combining effects desirable. In some cases we just needed
new WC apis for some buses. This was the case for most modern devices, but a
few old devices had a combined set of MMIO registers and the write-combined
area mixed. In such situations even when using MTRR one had to figure out
creative solutions to make things work, specially considering MTRRs were
limited and they had size constraints: an MTRR base and size must be
a power of two.

The good news is that on Linux there were only three device drivers in total
that we ended up with radical issue with when converting them over to PAT
interfaces. One was with the ivtv media device driver, another was the
infiniband ipath device driver. The other one was the framebuffer atyfb
device driver that this series addresses. For both ivtv and ipath we've
decided to simply require users of those devices to boot with the nopat
kernel parameter because both devices drivers are ancient and the work
required to fully convert to PAT interfaces is significant (in the ipath case)
or nearly almost impossible (ivtv). For details please refer to the respective
and now upstream commits:

7ea402d x86/mm/pat, drivers/infiniband/ipath: Use arch_phys_wc_add() and require PAT disabled
1bf1735 x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled

To demo exactly how much effort would have been required I decided to venture
into atyfb and try to fix that device driver first, considering it had the
worst case situation to address as it used size hackery and MTRR combinations
of different types. In order to accomplish this we needed to map out all
possible combinatorial effects of PAT page entries with write-combining, and
page attributes (PAT, PCD, PWT) with write-combining effects for non-PAT
systems. We did this not only for atyfb's sake but also for any other possible
future driver which might meet these same needs. We needed to take this a bit
more seriously given that our long term goal was also to change the default
behaviour of ioremap_nocache() to use strong UC instead of UC-, we needed
to take this into consideration when converting drivers over. The documentation
table for all these possible combinatorial entries is now upstream:

2f9e897 x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages

Of importance to this patch set is this table:

----------------------------------------------------------------------
MTRR Non-PAT   PAT    Linux ioremap value        Effective memory type
----------------------------------------------------------------------
                                                  Non-PAT |  PAT
     PAT
     |PCD
     ||PWT
     |||
WC   000      WB      _PAGE_CACHE_MODE_WB            WC   |   WC
WC   001      WC      _PAGE_CACHE_MODE_WC            WC*  |   WC
WC   010      UC-     _PAGE_CACHE_MODE_UC_MINUS      WC*  |   UC
WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
----------------------------------------------------------------------

In the atyfb case it used to use two MTRR calls, a large WC MTRR followed by a
UC MTRR "hole" call for the MMIO registers. This was done this way on atyfb
because of the offset and size of the framebuffer area would only work well
this way, otherwise you'd also have to try a series of small MTRR calls and you
might end up running out of MTRRs. For non-PAT systems we take advantage of the
above map to protect an MMIO region with 011 page attributes (this maps to
strong UC for PAT systems) so that if a large MTRR is issued that encompasses
the MMIO region, the MMIO region remains with an effective UC type, while the
desired wc area would have an effective memory type of WC as its region would
have been mapped with ioremap_wc(). This makes use of the newly introduced
ioremap_uc() as otherwise if we would have used ioremap_nocache() we would
not get the UC effective memeory type. This also let us remove the only UC MTRR
call from the kernel :) after this then we'd only have WC MTRR calls in effect
on non-PAT systems on Linux. The more complex patch then is patch 2 which does
most of the magic.

[0] http://lkml.kernel.org/r/CAB=NE6Xy1UGAqZ8CsVc+JzKqsxREaXBYK+1GjZKN8d2FG8xqJg@mail.gmail.com
[1] http://lkml.kernel.org/r/CAB=NE6UgtdSoBsA=8+ueYRAZHDnWUSmQAoHhAaefqudBrSY7Zw@mail.gmail.com

Luis R. Rodriguez (3):
  video: fbdev: atyfb: clarify ioremap() base and length used
  video: fbdev: atyfb: replace MTRR UC hole with strong UC
  video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()

 drivers/video/fbdev/aty/atyfb.h      |  5 +--
 drivers/video/fbdev/aty/atyfb_base.c | 74 +++++++++++-------------------------
 2 files changed, 24 insertions(+), 55 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 0/3] atyfb: address MTRR corner case

[Luis R. Rodriguez]

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

Andrew,

Forgive me for the TL;DR, I'm afraid I need to be crystal clear on this
patchset as its the most complex in the entire series. The skinny is that this
patchset addresses a complex work around with APIs now merged upstream going in
for v4.2, the driver maintainer hasn't followed up with the driver changes for
over a month and no one else has provided Acks for these device driver
changes [0]. We have a few options:

0) Sit and wait for a driver maintainer to review this
1) Merge this as-is and hope for reports
2) go with the nopat requirement as with the ivtv and ipath driver

I'd prefer to merge this as is, and only if reports come back with
issues should we then consider 2) as we'd then have at least a well
documented work effort required for this transformation. This device
driver is also old, so I don't expect much reports anyway.

----

The TL;DR:

As part of the long haul effort to rid the world of direct MTRR use [1] we've
have had to also work on alternative solutions which can co-exist with PAT
interfaces. Most of the transformation of device drivers to use PAT was fairly
easy (TM): so long as ioremap_wc() was used we could then convert over the
drivers using mtrr_add() over to the arch-agnostic and PAT-aware (ignored when
PAT is enabled) arch_phys_wc_add(). This was typically easy to do, for instance
in cases where a full PCI BAR was used for MMIO registers and another PCI BAR
was used with write-combining effects desirable. In some cases we just needed
new WC apis for some buses. This was the case for most modern devices, but a
few old devices had a combined set of MMIO registers and the write-combined
area mixed. In such situations even when using MTRR one had to figure out
creative solutions to make things work, specially considering MTRRs were
limited and they had size constraints: an MTRR base and size must be
a power of two.

The good news is that on Linux there were only three device drivers in total
that we ended up with radical issue with when converting them over to PAT
interfaces. One was with the ivtv media device driver, another was the
infiniband ipath device driver. The other one was the framebuffer atyfb
device driver that this series addresses. For both ivtv and ipath we've
decided to simply require users of those devices to boot with the nopat
kernel parameter because both devices drivers are ancient and the work
required to fully convert to PAT interfaces is significant (in the ipath case)
or nearly almost impossible (ivtv). For details please refer to the respective
and now upstream commits:

7ea402d x86/mm/pat, drivers/infiniband/ipath: Use arch_phys_wc_add() and require PAT disabled
1bf1735 x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled

To demo exactly how much effort would have been required I decided to venture
into atyfb and try to fix that device driver first, considering it had the
worst case situation to address as it used size hackery and MTRR combinations
of different types. In order to accomplish this we needed to map out all
possible combinatorial effects of PAT page entries with write-combining, and
page attributes (PAT, PCD, PWT) with write-combining effects for non-PAT
systems. We did this not only for atyfb's sake but also for any other possible
future driver which might meet these same needs. We needed to take this a bit
more seriously given that our long term goal was also to change the default
behaviour of ioremap_nocache() to use strong UC instead of UC-, we needed
to take this into consideration when converting drivers over. The documentation
table for all these possible combinatorial entries is now upstream:

2f9e897 x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages

Of importance to this patch set is this table:

----------------------------------------------------------------------
MTRR Non-PAT   PAT    Linux ioremap value        Effective memory type
----------------------------------------------------------------------
                                                  Non-PAT |  PAT
     PAT
     |PCD
     ||PWT
     |||
WC   000      WB      _PAGE_CACHE_MODE_WB            WC   |   WC
WC   001      WC      _PAGE_CACHE_MODE_WC            WC*  |   WC
WC   010      UC-     _PAGE_CACHE_MODE_UC_MINUS      WC*  |   UC
WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
----------------------------------------------------------------------

In the atyfb case it used to use two MTRR calls, a large WC MTRR followed by a
UC MTRR "hole" call for the MMIO registers. This was done this way on atyfb
because of the offset and size of the framebuffer area would only work well
this way, otherwise you'd also have to try a series of small MTRR calls and you
might end up running out of MTRRs. For non-PAT systems we take advantage of the
above map to protect an MMIO region with 011 page attributes (this maps to
strong UC for PAT systems) so that if a large MTRR is issued that encompasses
the MMIO region, the MMIO region remains with an effective UC type, while the
desired wc area would have an effective memory type of WC as its region would
have been mapped with ioremap_wc(). This makes use of the newly introduced
ioremap_uc() as otherwise if we would have used ioremap_nocache() we would
not get the UC effective memeory type. This also let us remove the only UC MTRR
call from the kernel :) after this then we'd only have WC MTRR calls in effect
on non-PAT systems on Linux. The more complex patch then is patch 2 which does
most of the magic.

[0] http://lkml.kernel.org/r/CAB=NE6Xy1UGAqZ8CsVc+JzKqsxREaXBYK+1GjZKN8d2FG8xqJg@mail.gmail.com
[1] http://lkml.kernel.org/r/CAB=NE6UgtdSoBsA=8+ueYRAZHDnWUSmQAoHhAaefqudBrSY7Zw@mail.gmail.com

Luis R. Rodriguez (3):
  video: fbdev: atyfb: clarify ioremap() base and length used
  video: fbdev: atyfb: replace MTRR UC hole with strong UC
  video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()

 drivers/video/fbdev/aty/atyfb.h      |  5 +--
 drivers/video/fbdev/aty/atyfb_base.c | 74 +++++++++++-------------------------
 2 files changed, 24 insertions(+), 55 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

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

This has no functional changes, it just adjusts
the ioremap() call for the framebuffer to use
the same values we later use for the framebuffer,
this will make it easier to review the next change.

The size of the framebuffer varies but since this is
for PCI we *know* this defaults to 0x800000.
atyfb_setup_generic() is *only* used on PCI probe.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb_base.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb..8025624 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,9 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

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

This has no functional changes, it just adjusts
the ioremap() call for the framebuffer to use
the same values we later use for the framebuffer,
this will make it easier to review the next change.

The size of the framebuffer varies but since this is
for PCI we *know* this defaults to 0x800000.
atyfb_setup_generic() is *only* used on PCI probe.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb_base.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb..8025624 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,9 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base = NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 2/3] video: fbdev: atyfb: replace MTRR UC hole with strong UC

[Luis R. Rodriguez]

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

Replace a WC MTRR call followed by a UC MTRR "hole" call
with a single WC MTRR call and use strong UC to protect
the MMIO region and account for the device's architecture
and MTRR size requirements.

The atyfb driver relies on two overlapping MTRRs. It
does this to account for the fact that on some devices
it has the MMIO region bundled together with the framebuffer
on the same PCI BAR and the hardware requirement on
MTRRs on both base and size to be powers of two. In the
atyfb driver's case in the worst case the PCI BAR is
of 16 MiB while the MMIO region is on the last 4 KiB of
the same PCI BAR. If we use just one MTRR for WC we can
only end up with an 8 MiB or 16 MiB framebuffer. Using a
16 MiB WC framebuffer area is unacceptable since we need
the MMIO region to not be write-combined. An 8 MiB WC
framebuffer option does not let use quite a bit of framebuffer
space, it would reduce the resolution capability of the device
considerably. An alternative is to use many MTRRs but on
some systems that could mean not having not enough MTRRs
to cover the framebuffer. The current driver solution is
to issue a 16 MiB WC MTRR followed by a 4 KiB UC MTRR on
the last 4 KiB. Its worth mentioning and documenting that
the current ioremap*() strategy as well: the first ioremap()
is used only for the MMIO region, a second ioremap() call
is used for the framebuffer *and* the MMIO region, the MMIO
region then ends up mmap'd twice. Two ioremap() calls are
used since in some situations the framebuffer actually ends
up on a separate auxiliary PCI BAR, but this is not always
true, in the worst case the PCI BAR is shared for both
MMIO and the framebuffer. By allowing overlapping ioremap()
calls the driver enables two types of devices with one
simple ioremap() strategy.

For non PAT systems:

As per Intel SDM "11.5.2.1 Selecting Memory Types for Pentium
Pro and Pentium II Processors" [0] the effect of a WC MTRR for
a region with page attribute settings set to PCD=1, PWT=1
(Linux _PAGE_CACHE_MODE_UC) will render the effective memory
type to UC. A WC MTRR for a region with page attribute settings
set to PCD=1, PWT=0 (Linux _PAGE_CACHE_MODE_UC_MINUS) will render
the effective memory type to WC *but* yet this is considered
implementation defined -- that is, "system designers are
encouraged to avoid these implementation-defined combinations".
A WC MTRR for a region with page attribute settings set to
PCD=0, PWT=1 (Linux _PAGE_CACHE_MODE_WC) will render the
effective memory type to WC *but* this is also implementation
defined. Such is the case for non-PAT systems.

For PAT systems:

As per Intel SDM "11.5.2.2 Selecting Memory Types for Pentium
III and More Recent Processor Families" the ffect of a WC MTRR
for a region with a PAT entry value of UC will be UC. The effect
of a WC MTRR on a region with a PAT entry UC- will be WC. The
effect of a WC MTRR on a regoin with PAT entry WC is WC.

This can all be summarized in the following table:

----------------------------------------------------------------------
MTRR Non-PAT   PAT    Linux ioremap value        Effective memory type
----------------------------------------------------------------------
                                                  Non-PAT |  PAT
     PAT
     |PCD
     ||PWT
     |||
WC   000      WB      _PAGE_CACHE_MODE_WB            WC   |   WC
WC   001      WC      _PAGE_CACHE_MODE_WC            WC*  |   WC
WC   010      UC-     _PAGE_CACHE_MODE_UC_MINUS      WC*  |   UC
WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
----------------------------------------------------------------------

 (*) denotes implementation defined

By default Linux today defaults both and ioremap_nocache()
to use _PAGE_CACHE_MODE_UC_MINUS. On x86 ioremap() aliases
ioremap_nocache(). The preferred value for Linux by may soon
change however, the goal is to use _PAGE_CACHE_MODE_UC by
default in the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems
and use a PAT value of UC for PAT systems. This will ensure the
same settings are in place regardless of what Linux decides to
use by default later and to not regress our MTRR strategy since
the effective memory type will differ depending on the value used.
Using a WC MTRR on such an area will be nullified. This technique
can be used to protect the MMIO region in this driver's case and
address the restrictions of the device's architecture as well as
restrictions set upon us by powers of 2 when using MTRRs.

This allows us to replace the two MTRR calls with a single
16 MiB WC MTRR and use page-attribute settings for non-PAT
and PAT entry values for PAT systems to ensure the
appropriate effective memory type won't have a write-combined
effect on the MMIO region on both non-PAT and PAT systems.
The framebuffer area will be sure to get the write-combined
effective memory type by white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremap'd area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

On both cases an implementation defined (as per above table)
effective memory type of WC is used for the framebuffer for
non-PAT systems.

[0] https://www-ssl.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62..89ec439 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8025624..546f5af 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase == NULL)
 		return -ENOMEM;
 
@@ -3491,7 +3483,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	info->fix.smem_start = addr;
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3563,6 +3558,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3732,10 +3728,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 2/3] video: fbdev: atyfb: replace MTRR UC hole with strong UC

[Luis R. Rodriguez]

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

Replace a WC MTRR call followed by a UC MTRR "hole" call
with a single WC MTRR call and use strong UC to protect
the MMIO region and account for the device's architecture
and MTRR size requirements.

The atyfb driver relies on two overlapping MTRRs. It
does this to account for the fact that on some devices
it has the MMIO region bundled together with the framebuffer
on the same PCI BAR and the hardware requirement on
MTRRs on both base and size to be powers of two. In the
atyfb driver's case in the worst case the PCI BAR is
of 16 MiB while the MMIO region is on the last 4 KiB of
the same PCI BAR. If we use just one MTRR for WC we can
only end up with an 8 MiB or 16 MiB framebuffer. Using a
16 MiB WC framebuffer area is unacceptable since we need
the MMIO region to not be write-combined. An 8 MiB WC
framebuffer option does not let use quite a bit of framebuffer
space, it would reduce the resolution capability of the device
considerably. An alternative is to use many MTRRs but on
some systems that could mean not having not enough MTRRs
to cover the framebuffer. The current driver solution is
to issue a 16 MiB WC MTRR followed by a 4 KiB UC MTRR on
the last 4 KiB. Its worth mentioning and documenting that
the current ioremap*() strategy as well: the first ioremap()
is used only for the MMIO region, a second ioremap() call
is used for the framebuffer *and* the MMIO region, the MMIO
region then ends up mmap'd twice. Two ioremap() calls are
used since in some situations the framebuffer actually ends
up on a separate auxiliary PCI BAR, but this is not always
true, in the worst case the PCI BAR is shared for both
MMIO and the framebuffer. By allowing overlapping ioremap()
calls the driver enables two types of devices with one
simple ioremap() strategy.

For non PAT systems:

As per Intel SDM "11.5.2.1 Selecting Memory Types for Pentium
Pro and Pentium II Processors" [0] the effect of a WC MTRR for
a region with page attribute settings set to PCD=1, PWT=1
(Linux _PAGE_CACHE_MODE_UC) will render the effective memory
type to UC. A WC MTRR for a region with page attribute settings
set to PCD=1, PWT=0 (Linux _PAGE_CACHE_MODE_UC_MINUS) will render
the effective memory type to WC *but* yet this is considered
implementation defined -- that is, "system designers are
encouraged to avoid these implementation-defined combinations".
A WC MTRR for a region with page attribute settings set to
PCD=0, PWT=1 (Linux _PAGE_CACHE_MODE_WC) will render the
effective memory type to WC *but* this is also implementation
defined. Such is the case for non-PAT systems.

For PAT systems:

As per Intel SDM "11.5.2.2 Selecting Memory Types for Pentium
III and More Recent Processor Families" the ffect of a WC MTRR
for a region with a PAT entry value of UC will be UC. The effect
of a WC MTRR on a region with a PAT entry UC- will be WC. The
effect of a WC MTRR on a regoin with PAT entry WC is WC.

This can all be summarized in the following table:

----------------------------------------------------------------------
MTRR Non-PAT   PAT    Linux ioremap value        Effective memory type
----------------------------------------------------------------------
                                                  Non-PAT |  PAT
     PAT
     |PCD
     ||PWT
     |||
WC   000      WB      _PAGE_CACHE_MODE_WB            WC   |   WC
WC   001      WC      _PAGE_CACHE_MODE_WC            WC*  |   WC
WC   010      UC-     _PAGE_CACHE_MODE_UC_MINUS      WC*  |   UC
WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
----------------------------------------------------------------------

 (*) denotes implementation defined

By default Linux today defaults both and ioremap_nocache()
to use _PAGE_CACHE_MODE_UC_MINUS. On x86 ioremap() aliases
ioremap_nocache(). The preferred value for Linux by may soon
change however, the goal is to use _PAGE_CACHE_MODE_UC by
default in the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems
and use a PAT value of UC for PAT systems. This will ensure the
same settings are in place regardless of what Linux decides to
use by default later and to not regress our MTRR strategy since
the effective memory type will differ depending on the value used.
Using a WC MTRR on such an area will be nullified. This technique
can be used to protect the MMIO region in this driver's case and
address the restrictions of the device's architecture as well as
restrictions set upon us by powers of 2 when using MTRRs.

This allows us to replace the two MTRR calls with a single
16 MiB WC MTRR and use page-attribute settings for non-PAT
and PAT entry values for PAT systems to ensure the
appropriate effective memory type won't have a write-combined
effect on the MMIO region on both non-PAT and PAT systems.
The framebuffer area will be sure to get the write-combined
effective memory type by white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremap'd area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

On both cases an implementation defined (as per above table)
effective memory type of WC is used for the framebuffer for
non-PAT systems.

[0] https://www-ssl.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62..89ec439 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8025624..546f5af 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase = NULL)
 		return -ENOMEM;
 
@@ -3491,7 +3483,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	info->fix.smem_start = addr;
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base = NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3563,6 +3558,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3732,10 +3728,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 3/3] video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()

[Luis R. Rodriguez]

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

This driver uses strong UC for the MMIO region, and ioremap_wc()
for the framebuffer to whitelist for the WC MTRR what can be changed
to WC. On PAT systems we don't need the MTRR call so just use
arch_phys_wc_add() there, this lets us remove all those ifdefs.
Lets also be consistent and use ioremap_wc() for ATARI as well.

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 <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec439..63c4842 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 546f5af..96c605c 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3660,7 +3646,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3726,13 +3713,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3848,10 +3830,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4021,7 +4001,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v5 3/3] video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()

[Luis R. Rodriguez]

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

This driver uses strong UC for the MMIO region, and ioremap_wc()
for the framebuffer to whitelist for the WC MTRR what can be changed
to WC. On PAT systems we don't need the MTRR call so just use
arch_phys_wc_add() there, this lets us remove all those ifdefs.
Lets also be consistent and use ioremap_wc() for ATARI as well.

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 <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec439..63c4842 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 546f5af..96c605c 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3660,7 +3646,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3726,13 +3713,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3848,10 +3830,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4021,7 +4001,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif
-- 
2.3.2.209.gd67f9d5.dirty

Re: [PATCH v5 0/3] atyfb: address MTRR corner case

[Luis R. Rodriguez]

On Wed, Jun 24, 2015 at 06:34:17PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Andrew,

Andrew, as Ingo noted please disregard these patches as it seems we'll be
preferring for this to go through the x86 tree.

  Luis

Re: [PATCH v5 0/3] atyfb: address MTRR corner case

[Luis R. Rodriguez]

On Wed, Jun 24, 2015 at 06:34:17PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Andrew,

Andrew, as Ingo noted please disregard these patches as it seems we'll be
preferring for this to go through the x86 tree.

  Luis

Re: [PATCH v5 0/3] atyfb: address MTRR corner case

[Borislav Petkov]

On Wed, Jun 24, 2015 at 06:34:17PM -0700, Luis R. Rodriguez wrote:
> Luis R. Rodriguez (3):
>   video: fbdev: atyfb: clarify ioremap() base and length used
>   video: fbdev: atyfb: replace MTRR UC hole with strong UC
>   video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()
> 
>  drivers/video/fbdev/aty/atyfb.h      |  5 +--
>  drivers/video/fbdev/aty/atyfb_base.c | 74 +++++++++++-------------------------
>  2 files changed, 24 insertions(+), 55 deletions(-)

Took those too along with

"[PATCH] video: fbdev: atyfb: move framebuffer length fudging to helper"

which was missing here.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH v5 0/3] atyfb: address MTRR corner case

[Borislav Petkov]

On Wed, Jun 24, 2015 at 06:34:17PM -0700, Luis R. Rodriguez wrote:
> Luis R. Rodriguez (3):
>   video: fbdev: atyfb: clarify ioremap() base and length used
>   video: fbdev: atyfb: replace MTRR UC hole with strong UC
>   video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()
> 
>  drivers/video/fbdev/aty/atyfb.h      |  5 +--
>  drivers/video/fbdev/aty/atyfb_base.c | 74 +++++++++++-------------------------
>  2 files changed, 24 insertions(+), 55 deletions(-)

Took those too along with

"[PATCH] video: fbdev: atyfb: move framebuffer length fudging to helper"

which was missing here.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Wed, Jun 24, 2015 at 06:34:18PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> This has no functional changes, it just adjusts
> the ioremap() call for the framebuffer to use
> the same values we later use for the framebuffer,
> this will make it easier to review the next change.
> 
> The size of the framebuffer varies but since this is
> for PCI we *know* this defaults to 0x800000.
> atyfb_setup_generic() is *only* used on PCI probe.
> 
> Cc: Toshi Kani <toshi.kani@hp.com>
> Cc: Suresh Siddha <sbsiddha@gmail.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Antonino Daplas <adaplas@gmail.com>
> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: Ville Syrjälä <syrjala@sci.fi>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Mathias Krause <minipli@googlemail.com>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Davidlohr Bueso <dbueso@suse.de>
> Cc: linux-fbdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
> ---
>  drivers/video/fbdev/aty/atyfb_base.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
> index 16936bb..8025624 100644
> --- a/drivers/video/fbdev/aty/atyfb_base.c
> +++ b/drivers/video/fbdev/aty/atyfb_base.c
> @@ -3489,7 +3489,9 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
>  
>  	/* Map in frame buffer */
>  	info->fix.smem_start = addr;
> -	info->screen_base = ioremap(addr, 0x800000);
> +	info->fix.smem_len = 0x800000;
> +
> +	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);

The framebuffer size isn't always 8MB. That's the size of the BAR. So
this change isn't really correct. I suppose it doesn't hurt too much
since smem_len gets overwritten later in aty_init().

>  	if (info->screen_base == NULL) {
>  		ret = -ENOMEM;
>  		goto atyfb_setup_generic_fail;
> -- 
> 2.3.2.209.gd67f9d5.dirty
> 

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Wed, Jun 24, 2015 at 06:34:18PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> This has no functional changes, it just adjusts
> the ioremap() call for the framebuffer to use
> the same values we later use for the framebuffer,
> this will make it easier to review the next change.
> 
> The size of the framebuffer varies but since this is
> for PCI we *know* this defaults to 0x800000.
> atyfb_setup_generic() is *only* used on PCI probe.
> 
> Cc: Toshi Kani <toshi.kani@hp.com>
> Cc: Suresh Siddha <sbsiddha@gmail.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Antonino Daplas <adaplas@gmail.com>
> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: Ville Syrjälä <syrjala@sci.fi>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Mathias Krause <minipli@googlemail.com>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Davidlohr Bueso <dbueso@suse.de>
> Cc: linux-fbdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
> ---
>  drivers/video/fbdev/aty/atyfb_base.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
> index 16936bb..8025624 100644
> --- a/drivers/video/fbdev/aty/atyfb_base.c
> +++ b/drivers/video/fbdev/aty/atyfb_base.c
> @@ -3489,7 +3489,9 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
>  
>  	/* Map in frame buffer */
>  	info->fix.smem_start = addr;
> -	info->screen_base = ioremap(addr, 0x800000);
> +	info->fix.smem_len = 0x800000;
> +
> +	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);

The framebuffer size isn't always 8MB. That's the size of the BAR. So
this change isn't really correct. I suppose it doesn't hurt too much
since smem_len gets overwritten later in aty_init().

>  	if (info->screen_base = NULL) {
>  		ret = -ENOMEM;
>  		goto atyfb_setup_generic_fail;
> -- 
> 2.3.2.209.gd67f9d5.dirty
> 

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> it doesn't hurt too much
> since smem_len gets overwritten later in aty_init().

That's the idea, we set it with a default as it will be overwritten
later anyway.

 Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> it doesn't hurt too much
> since smem_len gets overwritten later in aty_init().

That's the idea, we set it with a default as it will be overwritten
later anyway.

 Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Thu, Jun 25, 2015 at 04:06:45PM -0700, Luis R. Rodriguez wrote:
> On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> > it doesn't hurt too much
> > since smem_len gets overwritten later in aty_init().
> 
> That's the idea, we set it with a default as it will be overwritten
> later anyway.

Maybe toss in a comment? Otherwise it's a bit dishonest and might give
someone the impression that all PCI cards really have 8MB of memory.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Thu, Jun 25, 2015 at 04:06:45PM -0700, Luis R. Rodriguez wrote:
> On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> > it doesn't hurt too much
> > since smem_len gets overwritten later in aty_init().
> 
> That's the idea, we set it with a default as it will be overwritten
> later anyway.

Maybe toss in a comment? Otherwise it's a bit dishonest and might give
someone the impression that all PCI cards really have 8MB of memory.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Fri, Jun 26, 2015 at 02:11:03AM +0300, Ville Syrjälä wrote:
> On Thu, Jun 25, 2015 at 04:06:45PM -0700, Luis R. Rodriguez wrote:
> > On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> > > it doesn't hurt too much
> > > since smem_len gets overwritten later in aty_init().
> > 
> > That's the idea, we set it with a default as it will be overwritten
> > later anyway.
> 
> Maybe toss in a comment? Otherwise it's a bit dishonest and might give
> someone the impression that all PCI cards really have 8MB of memory.

Sure, mind this as a follow up patch if its too late?

  Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Fri, Jun 26, 2015 at 02:11:03AM +0300, Ville Syrjälä wrote:
> On Thu, Jun 25, 2015 at 04:06:45PM -0700, Luis R. Rodriguez wrote:
> > On Thu, Jun 25, 2015 at 4:04 PM, Ville Syrjälä <syrjala@sci.fi> wrote:
> > > it doesn't hurt too much
> > > since smem_len gets overwritten later in aty_init().
> > 
> > That's the idea, we set it with a default as it will be overwritten
> > later anyway.
> 
> Maybe toss in a comment? Otherwise it's a bit dishonest and might give
> someone the impression that all PCI cards really have 8MB of memory.

Sure, mind this as a follow up patch if its too late?

  Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Borislav Petkov]

On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> Sure, mind this as a follow up patch if its too late?

No need, you can send me an updated one - I'll replace it.

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Borislav Petkov]

On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> Sure, mind this as a follow up patch if its too late?

No need, you can send me an updated one - I'll replace it.

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
>> Sure, mind this as a follow up patch if its too late?
>
> No need, you can send me an updated one - I'll replace it.

Will do!

  Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
>> Sure, mind this as a follow up patch if its too late?
>
> No need, you can send me an updated one - I'll replace it.

Will do!

  Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
>> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
>>> Sure, mind this as a follow up patch if its too late?
>>
>> No need, you can send me an updated one - I'll replace it.
>
> Will do!

OK the commend I'm adding:

@@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
*pdev, struct fb_info *info,

        /* Map in frame buffer */
        info->fix.smem_start = addr;
+
+       /*
+        * The framebuffer is not always 8 MiB that's just the size of the
+        * PCI BAR, this is later corrected for use with write-combining
+        * helpers with aty_fudge_framebuffer_len() which will adjust the
+        * framebuffer accordingly depending on the device. We do this
+        * to match semantics over ioremap calls on framebuffer devices
+        * with with other drivers with the info->fix.smem_len.
+        */
        info->fix.smem_len = 0x800000;

        info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);

Will respin.

 Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
>> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
>>> Sure, mind this as a follow up patch if its too late?
>>
>> No need, you can send me an updated one - I'll replace it.
>
> Will do!

OK the commend I'm adding:

@@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
*pdev, struct fb_info *info,

        /* Map in frame buffer */
        info->fix.smem_start = addr;
+
+       /*
+        * The framebuffer is not always 8 MiB that's just the size of the
+        * PCI BAR, this is later corrected for use with write-combining
+        * helpers with aty_fudge_framebuffer_len() which will adjust the
+        * framebuffer accordingly depending on the device. We do this
+        * to match semantics over ioremap calls on framebuffer devices
+        * with with other drivers with the info->fix.smem_len.
+        */
        info->fix.smem_len = 0x800000;

        info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);

Will respin.

 Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Tue, Jul 07, 2015 at 05:24:57PM -0700, Luis R. Rodriguez wrote:
> On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> > On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> >> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> >>> Sure, mind this as a follow up patch if its too late?
> >>
> >> No need, you can send me an updated one - I'll replace it.
> >
> > Will do!
> 
> OK the commend I'm adding:
> 
> @@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
> *pdev, struct fb_info *info,
> 
>         /* Map in frame buffer */
>         info->fix.smem_start = addr;
> +
> +       /*
> +        * The framebuffer is not always 8 MiB that's just the size of the
> +        * PCI BAR, this is later corrected for use with write-combining
> +        * helpers with aty_fudge_framebuffer_len() which will adjust the
> +        * framebuffer accordingly depending on the device.

That somehow gives me the impression that aty_fudge_framebuffer_len()
changes smem_len to match the framebuffer size, which it does
not.

Dunno, maybe something like this?
/*
 * The framebuffer is not always 8 MiB that's just the size of the
 * PCI BAR. We temporarily abuse smem_len here to store the size
 * of the BAR. aty_init() will later correct it to match the actual
 * framebuffer size.
 *
 * On devices that don't have the auxiliary register aperture, the
 * registers are housed at the top end of the framebuffer PCI BAR.
 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
 * overlap with the registers.
 */

> We do this
> +        * to match semantics over ioremap calls on framebuffer devices
> +        * with with other drivers with the info->fix.smem_len.
> +        */
>         info->fix.smem_len = 0x800000;
> 
>         info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
> 
> Will respin.
> 
>  Luis

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Ville Syrjälä]

On Tue, Jul 07, 2015 at 05:24:57PM -0700, Luis R. Rodriguez wrote:
> On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> > On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> >> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> >>> Sure, mind this as a follow up patch if its too late?
> >>
> >> No need, you can send me an updated one - I'll replace it.
> >
> > Will do!
> 
> OK the commend I'm adding:
> 
> @@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
> *pdev, struct fb_info *info,
> 
>         /* Map in frame buffer */
>         info->fix.smem_start = addr;
> +
> +       /*
> +        * The framebuffer is not always 8 MiB that's just the size of the
> +        * PCI BAR, this is later corrected for use with write-combining
> +        * helpers with aty_fudge_framebuffer_len() which will adjust the
> +        * framebuffer accordingly depending on the device.

That somehow gives me the impression that aty_fudge_framebuffer_len()
changes smem_len to match the framebuffer size, which it does
not.

Dunno, maybe something like this?
/*
 * The framebuffer is not always 8 MiB that's just the size of the
 * PCI BAR. We temporarily abuse smem_len here to store the size
 * of the BAR. aty_init() will later correct it to match the actual
 * framebuffer size.
 *
 * On devices that don't have the auxiliary register aperture, the
 * registers are housed at the top end of the framebuffer PCI BAR.
 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
 * overlap with the registers.
 */

> We do this
> +        * to match semantics over ioremap calls on framebuffer devices
> +        * with with other drivers with the info->fix.smem_len.
> +        */
>         info->fix.smem_len = 0x800000;
> 
>         info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
> 
> Will respin.
> 
>  Luis

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Wed, Jul 08, 2015 at 11:38:49AM +0300, Ville Syrjälä wrote:
> On Tue, Jul 07, 2015 at 05:24:57PM -0700, Luis R. Rodriguez wrote:
> > On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> > > On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> > >> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> > >>> Sure, mind this as a follow up patch if its too late?
> > >>
> > >> No need, you can send me an updated one - I'll replace it.
> > >
> > > Will do!
> > 
> > OK the commend I'm adding:
> > 
> > @@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
> > *pdev, struct fb_info *info,
> > 
> >         /* Map in frame buffer */
> >         info->fix.smem_start = addr;
> > +
> > +       /*
> > +        * The framebuffer is not always 8 MiB that's just the size of the
> > +        * PCI BAR, this is later corrected for use with write-combining
> > +        * helpers with aty_fudge_framebuffer_len() which will adjust the
> > +        * framebuffer accordingly depending on the device.
> 
> That somehow gives me the impression that aty_fudge_framebuffer_len()
> changes smem_len to match the framebuffer size, which it does
> not.
> 
> Dunno, maybe something like this?
> /*
>  * The framebuffer is not always 8 MiB that's just the size of the
>  * PCI BAR. We temporarily abuse smem_len here to store the size
>  * of the BAR. aty_init() will later correct it to match the actual
>  * framebuffer size.
>  *
>  * On devices that don't have the auxiliary register aperture, the
>  * registers are housed at the top end of the framebuffer PCI BAR.
>  * aty_fudge_framebuffer_len() is used to reduce smem_len to not
>  * overlap with the registers.
>  */

Thanks Ville, I used that. Will send out a v6 series.

 Luis

Re: [PATCH v5 1/3] video: fbdev: atyfb: clarify ioremap() base and length used

[Luis R. Rodriguez]

On Wed, Jul 08, 2015 at 11:38:49AM +0300, Ville Syrjälä wrote:
> On Tue, Jul 07, 2015 at 05:24:57PM -0700, Luis R. Rodriguez wrote:
> > On Thu, Jul 2, 2015 at 4:23 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> > > On Fri, Jun 26, 2015 at 12:30 AM, Borislav Petkov <bp@suse.de> wrote:
> > >> On Fri, Jun 26, 2015 at 03:09:27AM +0200, Luis R. Rodriguez wrote:
> > >>> Sure, mind this as a follow up patch if its too late?
> > >>
> > >> No need, you can send me an updated one - I'll replace it.
> > >
> > > Will do!
> > 
> > OK the commend I'm adding:
> > 
> > @@ -3489,6 +3489,15 @@ static int atyfb_setup_generic(struct pci_dev
> > *pdev, struct fb_info *info,
> > 
> >         /* Map in frame buffer */
> >         info->fix.smem_start = addr;
> > +
> > +       /*
> > +        * The framebuffer is not always 8 MiB that's just the size of the
> > +        * PCI BAR, this is later corrected for use with write-combining
> > +        * helpers with aty_fudge_framebuffer_len() which will adjust the
> > +        * framebuffer accordingly depending on the device.
> 
> That somehow gives me the impression that aty_fudge_framebuffer_len()
> changes smem_len to match the framebuffer size, which it does
> not.
> 
> Dunno, maybe something like this?
> /*
>  * The framebuffer is not always 8 MiB that's just the size of the
>  * PCI BAR. We temporarily abuse smem_len here to store the size
>  * of the BAR. aty_init() will later correct it to match the actual
>  * framebuffer size.
>  *
>  * On devices that don't have the auxiliary register aperture, the
>  * registers are housed at the top end of the framebuffer PCI BAR.
>  * aty_fudge_framebuffer_len() is used to reduce smem_len to not
>  * overlap with the registers.
>  */

Thanks Ville, I used that. Will send out a v6 series.

 Luis

[PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

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

Ingo,

Boris is on vacation so sending these through you. This v6 addresses one code
comment update requested by Ville. Boris had picked up these patches on his
tree and this series had gone through 0-day bot testing. The only issue it
found was the lack of ioremap_uc() implementation on some architectures which
have an IOMMU. There are two approaches to this issue, one is to go and define
ioremap_uc() on all architectures, another is to provide a default for
ioremap_uc() as architectures catch up. I've gone with the later approach [0],
and so to ensure things won't build-break this patch series must also go
through the same tree as the patch-fixes for ioremap_uc() for missing
ioremap_uc() implementations go through. I intend on following up with
implementing ioremap_uc() for other architectures but for that I need to get
feedback from other architecture developers and that will take time.

Tomi, the framebuffer maintainer had already expressed he was OK for this to go
through you. The driver maintainer, Ville, has been Cc'd on all the series, but
has only provided feedback for the comment request as I noted above. This
series addresses the more complex work on the entire series I've been putting
out and as such I've provided a TL;DR full review of what this series does in
my previous v5 patch series, that can be looked at for more details if needed
[1].

This series depends on the patch which I recently posted to address compilation
issue on architectures missing ioremap_uc() [0]. If that goes through then it
should be safe to apply this series, otherwise we have to sit and wait until
all architectures get ioremap_uc() properly defined.

Please let me know if there are any questions.

[0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
[1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Luis R. Rodriguez (4):
  drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a
    helper
  drivers/video/fbdev/atyfb: Clarify ioremap() base and length used
  drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC
  drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

 drivers/video/fbdev/aty/atyfb.h      |   5 +-
 drivers/video/fbdev/aty/atyfb_base.c | 109 ++++++++++++++++-------------------
 2 files changed, 51 insertions(+), 63 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

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

Ingo,

Boris is on vacation so sending these through you. This v6 addresses one code
comment update requested by Ville. Boris had picked up these patches on his
tree and this series had gone through 0-day bot testing. The only issue it
found was the lack of ioremap_uc() implementation on some architectures which
have an IOMMU. There are two approaches to this issue, one is to go and define
ioremap_uc() on all architectures, another is to provide a default for
ioremap_uc() as architectures catch up. I've gone with the later approach [0],
and so to ensure things won't build-break this patch series must also go
through the same tree as the patch-fixes for ioremap_uc() for missing
ioremap_uc() implementations go through. I intend on following up with
implementing ioremap_uc() for other architectures but for that I need to get
feedback from other architecture developers and that will take time.

Tomi, the framebuffer maintainer had already expressed he was OK for this to go
through you. The driver maintainer, Ville, has been Cc'd on all the series, but
has only provided feedback for the comment request as I noted above. This
series addresses the more complex work on the entire series I've been putting
out and as such I've provided a TL;DR full review of what this series does in
my previous v5 patch series, that can be looked at for more details if needed
[1].

This series depends on the patch which I recently posted to address compilation
issue on architectures missing ioremap_uc() [0]. If that goes through then it
should be safe to apply this series, otherwise we have to sit and wait until
all architectures get ioremap_uc() properly defined.

Please let me know if there are any questions.

[0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
[1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Luis R. Rodriguez (4):
  drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a
    helper
  drivers/video/fbdev/atyfb: Clarify ioremap() base and length used
  drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC
  drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

 drivers/video/fbdev/aty/atyfb.h      |   5 +-
 drivers/video/fbdev/aty/atyfb_base.c | 109 ++++++++++++++++-------------------
 2 files changed, 51 insertions(+), 63 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

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

Ingo,

Boris is on vacation so sending these through you. This v6 addresses one code
comment update requested by Ville. Boris had picked up these patches on his
tree and this series had gone through 0-day bot testing. The only issue it
found was the lack of ioremap_uc() implementation on some architectures which
have an IOMMU. There are two approaches to this issue, one is to go and define
ioremap_uc() on all architectures, another is to provide a default for
ioremap_uc() as architectures catch up. I've gone with the later approach [0],
and so to ensure things won't build-break this patch series must also go
through the same tree as the patch-fixes for ioremap_uc() for missing
ioremap_uc() implementations go through. I intend on following up with
implementing ioremap_uc() for other architectures but for that I need to get
feedback from other architecture developers and that will take time.

Tomi, the framebuffer maintainer had already expressed he was OK for this to go
through you. The driver maintainer, Ville, has been Cc'd on all the series, but
has only provided feedback for the comment request as I noted above. This
series addresses the more complex work on the entire series I've been putting
out and as such I've provided a TL;DR full review of what this series does in
my previous v5 patch series, that can be looked at for more details if needed
[1].

This series depends on the patch which I recently posted to address compilation
issue on architectures missing ioremap_uc() [0]. If that goes through then it
should be safe to apply this series, otherwise we have to sit and wait until
all architectures get ioremap_uc() properly defined.

Please let me know if there are any questions.

[0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
[1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Luis R. Rodriguez (4):
  drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a
    helper
  drivers/video/fbdev/atyfb: Clarify ioremap() base and length used
  drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC
  drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

 drivers/video/fbdev/aty/atyfb.h      |   5 +-
 drivers/video/fbdev/aty/atyfb_base.c | 109 ++++++++++++++++-------------------
 2 files changed, 51 insertions(+), 63 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v6 1/4] drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper

[Luis R. Rodriguez]

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

The size of the framebuffer to be used needs to be fudged to account for
the different type of devices that are out there. This captures what is
required to do well, we'll reuse this later.

This has no functional changes.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-fbdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1435251019-32421-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8789e487b96e..16936bb1f865 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -427,6 +427,20 @@ static struct {
 #endif /* CONFIG_FB_ATY_CT */
 };
 
+/*
+ * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
+ * unless the auxiliary register aperture is used.
+ */
+static void aty_fudge_framebuffer_len(struct fb_info *info)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+
+	if (!par->aux_start &&
+	    (info->fix.smem_len == 0x800000 ||
+	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
+		info->fix.smem_len -= GUI_RESERVE;
+}
+
 static int correct_chipset(struct atyfb_par *par)
 {
 	u8 rev;
@@ -2603,14 +2617,7 @@ static int aty_init(struct fb_info *info)
 	if (par->pll_ops->resume_pll)
 		par->pll_ops->resume_pll(info, &par->pll);
 
-	/*
-	 * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
-	 * unless the auxiliary register aperture is used.
-	 */
-	if (!par->aux_start &&
-	    (info->fix.smem_len == 0x800000 ||
-	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
-		info->fix.smem_len -= GUI_RESERVE;
+	aty_fudge_framebuffer_len(info);
 
 	/*
 	 * Disable register access through the linear aperture
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 1/4] drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper

[Luis R. Rodriguez]

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

The size of the framebuffer to be used needs to be fudged to account for
the different type of devices that are out there. This captures what is
required to do well, we'll reuse this later.

This has no functional changes.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-fbdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1435251019-32421-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8789e487b96e..16936bb1f865 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -427,6 +427,20 @@ static struct {
 #endif /* CONFIG_FB_ATY_CT */
 };
 
+/*
+ * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
+ * unless the auxiliary register aperture is used.
+ */
+static void aty_fudge_framebuffer_len(struct fb_info *info)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+
+	if (!par->aux_start &&
+	    (info->fix.smem_len = 0x800000 ||
+	     (par->bus_type = ISA && info->fix.smem_len = 0x400000)))
+		info->fix.smem_len -= GUI_RESERVE;
+}
+
 static int correct_chipset(struct atyfb_par *par)
 {
 	u8 rev;
@@ -2603,14 +2617,7 @@ static int aty_init(struct fb_info *info)
 	if (par->pll_ops->resume_pll)
 		par->pll_ops->resume_pll(info, &par->pll);
 
-	/*
-	 * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
-	 * unless the auxiliary register aperture is used.
-	 */
-	if (!par->aux_start &&
-	    (info->fix.smem_len = 0x800000 ||
-	     (par->bus_type = ISA && info->fix.smem_len = 0x400000)))
-		info->fix.smem_len -= GUI_RESERVE;
+	aty_fudge_framebuffer_len(info);
 
 	/*
 	 * Disable register access through the linear aperture
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 1/4] drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper

[Luis R. Rodriguez]

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

The size of the framebuffer to be used needs to be fudged to account for
the different type of devices that are out there. This captures what is
required to do well, we'll reuse this later.

This has no functional changes.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-fbdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1435251019-32421-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8789e487b96e..16936bb1f865 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -427,6 +427,20 @@ static struct {
 #endif /* CONFIG_FB_ATY_CT */
 };
 
+/*
+ * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
+ * unless the auxiliary register aperture is used.
+ */
+static void aty_fudge_framebuffer_len(struct fb_info *info)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+
+	if (!par->aux_start &&
+	    (info->fix.smem_len == 0x800000 ||
+	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
+		info->fix.smem_len -= GUI_RESERVE;
+}
+
 static int correct_chipset(struct atyfb_par *par)
 {
 	u8 rev;
@@ -2603,14 +2617,7 @@ static int aty_init(struct fb_info *info)
 	if (par->pll_ops->resume_pll)
 		par->pll_ops->resume_pll(info, &par->pll);
 
-	/*
-	 * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
-	 * unless the auxiliary register aperture is used.
-	 */
-	if (!par->aux_start &&
-	    (info->fix.smem_len == 0x800000 ||
-	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
-		info->fix.smem_len -= GUI_RESERVE;
+	aty_fudge_framebuffer_len(info);
 
 	/*
 	 * Disable register access through the linear aperture
-- 
2.3.2.209.gd67f9d5.dirty

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v6 2/4] drivers/video/fbdev/atyfb: Clarify ioremap() base and length used

[Luis R. Rodriguez]

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

Adjust the ioremap() call for the framebuffer to use the same values we
later use for the framebuffer. This will make it easier to review the
next change.

The size of the framebuffer varies but since this is for PCI we *know*
this defaults to 0x800000. atyfb_setup_generic() is *only* used on PCI
probe.

No functional change.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: syrjala@sci.fi
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb1f865..513e58df9d3f 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,21 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+
+	/*
+	 * The framebuffer is not always 8 MiB that's just the size of the
+	 * PCI BAR. We temporarily abuse smem_len here to store the size
+	 * of the BAR. aty_init() will later correct it to match the actual
+	 * framebuffer size.
+	 *
+	 * On devices that don't have the auxiliary register aperture, the
+	 * registers are housed at the top end of the framebuffer PCI BAR.
+	 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
+	 * overlap with the registers.
+	 */
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 2/4] drivers/video/fbdev/atyfb: Clarify ioremap() base and length used

[Luis R. Rodriguez]

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

Adjust the ioremap() call for the framebuffer to use the same values we
later use for the framebuffer. This will make it easier to review the
next change.

The size of the framebuffer varies but since this is for PCI we *know*
this defaults to 0x800000. atyfb_setup_generic() is *only* used on PCI
probe.

No functional change.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: syrjala@sci.fi
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb1f865..513e58df9d3f 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,21 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+
+	/*
+	 * The framebuffer is not always 8 MiB that's just the size of the
+	 * PCI BAR. We temporarily abuse smem_len here to store the size
+	 * of the BAR. aty_init() will later correct it to match the actual
+	 * framebuffer size.
+	 *
+	 * On devices that don't have the auxiliary register aperture, the
+	 * registers are housed at the top end of the framebuffer PCI BAR.
+	 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
+	 * overlap with the registers.
+	 */
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base = NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 2/4] drivers/video/fbdev/atyfb: Clarify ioremap() base and length used

[Luis R. Rodriguez]

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

Adjust the ioremap() call for the framebuffer to use the same values we
later use for the framebuffer. This will make it easier to review the
next change.

The size of the framebuffer varies but since this is for PCI we *know*
this defaults to 0x800000. atyfb_setup_generic() is *only* used on PCI
probe.

No functional change.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: syrjala@sci.fi
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville SyrjA?lA? <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb_base.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb1f865..513e58df9d3f 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,21 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+
+	/*
+	 * The framebuffer is not always 8 MiB that's just the size of the
+	 * PCI BAR. We temporarily abuse smem_len here to store the size
+	 * of the BAR. aty_init() will later correct it to match the actual
+	 * framebuffer size.
+	 *
+	 * On devices that don't have the auxiliary register aperture, the
+	 * registers are housed at the top end of the framebuffer PCI BAR.
+	 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
+	 * overlap with the registers.
+	 */
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
-- 
2.3.2.209.gd67f9d5.dirty

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v6 3/4] drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC

[Luis R. Rodriguez]

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

Replace a WC MTRR call followed by a UC MTRR "hole" call with a single
WC MTRR call and use strong UC to protect the MMIO region and account
for the device's architecture and MTRR size requirements.

The atyfb driver relies on two overlapping MTRRs. It does this to
account for the fact that, on some devices, it has the MMIO region
bundled together with the framebuffer on the same PCI BAR and the
hardware requirement on MTRRs on both base and size to be powers
of two.

In the worst case, the PCI BAR is of 16 MiB while the MMIO region is on
the last 4 KiB of the same PCI BAR. If we use just one MTRR for WC, we
can only end up with an 8 MiB or 16 MiB framebuffer. Using a 16 MiB WC
framebuffer area is unacceptable since we need the MMIO region to not be
write-combined. An 8 MiB WC framebuffer option does not let use quite a
bit of framebuffer space, it would reduce the resolution capability of
the device considerably.

An alternative is to use many MTRRs but on some systems that could mean
not having enough MTRRs to cover the framebuffer. The current solution
is to issue a 16 MiB WC MTRR followed by a 4 KiB UC MTRR on the last 4
KiB. Its worth mentioning and documenting that the current ioremap*()
strategy as well: the first ioremap() is used only for the MMIO region,
a second ioremap() call is used for the framebuffer *and* the MMIO
region, the MMIO region then ends up mmapped twice.

Two ioremap() calls are used since in some situations the framebuffer
actually ends up on a separate auxiliary PCI BAR, but this is not always
true. In the worst case, the PCI BAR is shared for both MMIO and the
framebuffer. By allowing overlapping ioremap() calls, the driver enables
two types of devices with one simple ioremap() strategy.

See also:

  2f9e897353fc ("x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages")

By default, Linux today defaults both pci_mmap_page_range() and
ioremap_nocache() to use _PAGE_CACHE_MODE_UC_MINUS. On x86, ioremap()
aliases ioremap_nocache(). The preferred value for Linux may soon
change, however, the goal is to use _PAGE_CACHE_MODE_UC by default in
the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems and use
a PAT value of UC for PAT systems. This will ensure the same settings
are in place regardless of what Linux decides to use by default later
and to not regress our MTRR strategy since the effective memory type
will differ depending on the value used. Using a WC MTRR on such an area
will be nullified. This technique can be used to protect the MMIO region
in this driver's case and address the restrictions of the device's
architecture as well as restrictions set upon us by powers of 2 when
using MTRRs.

This allows us to replace the two MTRR calls with a single 16 MiB WC
MTRR and use page-attribute settings for non-PAT and PAT entry values
for PAT systems to ensure the appropriate effective memory type won't
have a write-combining effect on the MMIO region on both non-PAT and PAT
systems. The framebuffer area will be sure to get the write-combined
effective memory type by white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremapped area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

In both cases, an implementation defined (as per 2f9e897353fc) effective
memory type of WC is used for the framebuffer for non-PAT systems.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62f899b..89ec4398d201 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 513e58df9d3f..ea27ba3e5e6d 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase == NULL)
 		return -ENOMEM;
 
@@ -3503,7 +3495,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	 */
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3575,6 +3570,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3744,10 +3740,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 3/4] drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC

[Luis R. Rodriguez]

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

Replace a WC MTRR call followed by a UC MTRR "hole" call with a single
WC MTRR call and use strong UC to protect the MMIO region and account
for the device's architecture and MTRR size requirements.

The atyfb driver relies on two overlapping MTRRs. It does this to
account for the fact that, on some devices, it has the MMIO region
bundled together with the framebuffer on the same PCI BAR and the
hardware requirement on MTRRs on both base and size to be powers
of two.

In the worst case, the PCI BAR is of 16 MiB while the MMIO region is on
the last 4 KiB of the same PCI BAR. If we use just one MTRR for WC, we
can only end up with an 8 MiB or 16 MiB framebuffer. Using a 16 MiB WC
framebuffer area is unacceptable since we need the MMIO region to not be
write-combined. An 8 MiB WC framebuffer option does not let use quite a
bit of framebuffer space, it would reduce the resolution capability of
the device considerably.

An alternative is to use many MTRRs but on some systems that could mean
not having enough MTRRs to cover the framebuffer. The current solution
is to issue a 16 MiB WC MTRR followed by a 4 KiB UC MTRR on the last 4
KiB. Its worth mentioning and documenting that the current ioremap*()
strategy as well: the first ioremap() is used only for the MMIO region,
a second ioremap() call is used for the framebuffer *and* the MMIO
region, the MMIO region then ends up mmapped twice.

Two ioremap() calls are used since in some situations the framebuffer
actually ends up on a separate auxiliary PCI BAR, but this is not always
true. In the worst case, the PCI BAR is shared for both MMIO and the
framebuffer. By allowing overlapping ioremap() calls, the driver enables
two types of devices with one simple ioremap() strategy.

See also:

  2f9e897353fc ("x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages")

By default, Linux today defaults both pci_mmap_page_range() and
ioremap_nocache() to use _PAGE_CACHE_MODE_UC_MINUS. On x86, ioremap()
aliases ioremap_nocache(). The preferred value for Linux may soon
change, however, the goal is to use _PAGE_CACHE_MODE_UC by default in
the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems and use
a PAT value of UC for PAT systems. This will ensure the same settings
are in place regardless of what Linux decides to use by default later
and to not regress our MTRR strategy since the effective memory type
will differ depending on the value used. Using a WC MTRR on such an area
will be nullified. This technique can be used to protect the MMIO region
in this driver's case and address the restrictions of the device's
architecture as well as restrictions set upon us by powers of 2 when
using MTRRs.

This allows us to replace the two MTRR calls with a single 16 MiB WC
MTRR and use page-attribute settings for non-PAT and PAT entry values
for PAT systems to ensure the appropriate effective memory type won't
have a write-combining effect on the MMIO region on both non-PAT and PAT
systems. The framebuffer area will be sure to get the write-combined
effective memory type by white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremapped area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

In both cases, an implementation defined (as per 2f9e897353fc) effective
memory type of WC is used for the framebuffer for non-PAT systems.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62f899b..89ec4398d201 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 513e58df9d3f..ea27ba3e5e6d 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase = NULL)
 		return -ENOMEM;
 
@@ -3503,7 +3495,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	 */
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base = NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3575,6 +3570,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3744,10 +3740,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 3/4] drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC

[Luis R. Rodriguez]

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

Replace a WC MTRR call followed by a UC MTRR "hole" call with a single
WC MTRR call and use strong UC to protect the MMIO region and account
for the device's architecture and MTRR size requirements.

The atyfb driver relies on two overlapping MTRRs. It does this to
account for the fact that, on some devices, it has the MMIO region
bundled together with the framebuffer on the same PCI BAR and the
hardware requirement on MTRRs on both base and size to be powers
of two.

In the worst case, the PCI BAR is of 16 MiB while the MMIO region is on
the last 4 KiB of the same PCI BAR. If we use just one MTRR for WC, we
can only end up with an 8 MiB or 16 MiB framebuffer. Using a 16 MiB WC
framebuffer area is unacceptable since we need the MMIO region to not be
write-combined. An 8 MiB WC framebuffer option does not let use quite a
bit of framebuffer space, it would reduce the resolution capability of
the device considerably.

An alternative is to use many MTRRs but on some systems that could mean
not having enough MTRRs to cover the framebuffer. The current solution
is to issue a 16 MiB WC MTRR followed by a 4 KiB UC MTRR on the last 4
KiB. Its worth mentioning and documenting that the current ioremap*()
strategy as well: the first ioremap() is used only for the MMIO region,
a second ioremap() call is used for the framebuffer *and* the MMIO
region, the MMIO region then ends up mmapped twice.

Two ioremap() calls are used since in some situations the framebuffer
actually ends up on a separate auxiliary PCI BAR, but this is not always
true. In the worst case, the PCI BAR is shared for both MMIO and the
framebuffer. By allowing overlapping ioremap() calls, the driver enables
two types of devices with one simple ioremap() strategy.

See also:

  2f9e897353fc ("x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages")

By default, Linux today defaults both pci_mmap_page_range() and
ioremap_nocache() to use _PAGE_CACHE_MODE_UC_MINUS. On x86, ioremap()
aliases ioremap_nocache(). The preferred value for Linux may soon
change, however, the goal is to use _PAGE_CACHE_MODE_UC by default in
the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems and use
a PAT value of UC for PAT systems. This will ensure the same settings
are in place regardless of what Linux decides to use by default later
and to not regress our MTRR strategy since the effective memory type
will differ depending on the value used. Using a WC MTRR on such an area
will be nullified. This technique can be used to protect the MMIO region
in this driver's case and address the restrictions of the device's
architecture as well as restrictions set upon us by powers of 2 when
using MTRRs.

This allows us to replace the two MTRR calls with a single 16 MiB WC
MTRR and use page-attribute settings for non-PAT and PAT entry values
for PAT systems to ensure the appropriate effective memory type won't
have a write-combining effect on the MMIO region on both non-PAT and PAT
systems. The framebuffer area will be sure to get the write-combined
effective memory type by white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremapped area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

In both cases, an implementation defined (as per 2f9e897353fc) effective
memory type of WC is used for the framebuffer for non-PAT systems.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville SyrjA?lA? <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62f899b..89ec4398d201 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 513e58df9d3f..ea27ba3e5e6d 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase == NULL)
 		return -ENOMEM;
 
@@ -3503,7 +3495,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	 */
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3575,6 +3570,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3744,10 +3740,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
-- 
2.3.2.209.gd67f9d5.dirty

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v6 4/4] drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

[Luis R. Rodriguez]

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

This driver uses strong UC for the MMIO region, and ioremap_wc() for the
framebuffer to whitelist for the WC MTRR that can be changed to WC. On
PAT systems we don't need the MTRR call so just use arch_phys_wc_add()
there, this lets us remove all those ifdefs. Let's also be consistent
and use ioremap_wc() for ATARI as well.

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>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-4-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec4398d201..63c4842eb224 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index ea27ba3e5e6d..a807c0196464 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3672,7 +3658,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3738,13 +3725,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3860,10 +3842,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4033,7 +4013,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 4/4] drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

[Luis R. Rodriguez]

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

This driver uses strong UC for the MMIO region, and ioremap_wc() for the
framebuffer to whitelist for the WC MTRR that can be changed to WC. On
PAT systems we don't need the MTRR call so just use arch_phys_wc_add()
there, this lets us remove all those ifdefs. Let's also be consistent
and use ioremap_wc() for ATARI as well.

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>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-4-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec4398d201..63c4842eb224 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index ea27ba3e5e6d..a807c0196464 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3672,7 +3658,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3738,13 +3725,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3860,10 +3842,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4033,7 +4013,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif
-- 
2.3.2.209.gd67f9d5.dirty

[PATCH v6 4/4] drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

[Luis R. Rodriguez]

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

This driver uses strong UC for the MMIO region, and ioremap_wc() for the
framebuffer to whitelist for the WC MTRR that can be changed to WC. On
PAT systems we don't need the MTRR call so just use arch_phys_wc_add()
there, this lets us remove all those ifdefs. Let's also be consistent
and use ioremap_wc() for ATARI as well.

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>
Cc: airlied@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: benh@kernel.crashing.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: mst@redhat.com
Cc: Rob Clark <robdclark@gmail.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville SyrjA?lA? <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1435196060-27350-4-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec4398d201..63c4842eb224 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index ea27ba3e5e6d..a807c0196464 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3672,7 +3658,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3738,13 +3725,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3860,10 +3842,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4033,7 +4013,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif
-- 
2.3.2.209.gd67f9d5.dirty

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

On Thu, Jul 09, 2015 at 06:24:55PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Ingo,
> 
> Boris is on vacation so sending these through you. This v6 addresses one code
> comment update requested by Ville. Boris had picked up these patches on his
> tree and this series had gone through 0-day bot testing. The only issue it
> found was the lack of ioremap_uc() implementation on some architectures which
> have an IOMMU. There are two approaches to this issue, one is to go and define
> ioremap_uc() on all architectures, another is to provide a default for
> ioremap_uc() as architectures catch up. I've gone with the later approach [0],
> and so to ensure things won't build-break this patch series must also go
> through the same tree as the patch-fixes for ioremap_uc() for missing
> ioremap_uc() implementations go through. I intend on following up with
> implementing ioremap_uc() for other architectures but for that I need to get
> feedback from other architecture developers and that will take time.
> 
> Tomi, the framebuffer maintainer had already expressed he was OK for this to go
> through you. The driver maintainer, Ville, has been Cc'd on all the series, but
> has only provided feedback for the comment request as I noted above. This
> series addresses the more complex work on the entire series I've been putting
> out and as such I've provided a TL;DR full review of what this series does in
> my previous v5 patch series, that can be looked at for more details if needed
> [1].
> 
> This series depends on the patch which I recently posted to address compilation
> issue on architectures missing ioremap_uc() [0]. If that goes through then it
> should be safe to apply this series, otherwise we have to sit and wait until
> all architectures get ioremap_uc() properly defined.
> 
> Please let me know if there are any questions.
> 
> [0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
> [1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Ingo, please let me know if there are any questions or issues with this series.

  Luis

Re: [PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

On Thu, Jul 09, 2015 at 06:24:55PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Ingo,
> 
> Boris is on vacation so sending these through you. This v6 addresses one code
> comment update requested by Ville. Boris had picked up these patches on his
> tree and this series had gone through 0-day bot testing. The only issue it
> found was the lack of ioremap_uc() implementation on some architectures which
> have an IOMMU. There are two approaches to this issue, one is to go and define
> ioremap_uc() on all architectures, another is to provide a default for
> ioremap_uc() as architectures catch up. I've gone with the later approach [0],
> and so to ensure things won't build-break this patch series must also go
> through the same tree as the patch-fixes for ioremap_uc() for missing
> ioremap_uc() implementations go through. I intend on following up with
> implementing ioremap_uc() for other architectures but for that I need to get
> feedback from other architecture developers and that will take time.
> 
> Tomi, the framebuffer maintainer had already expressed he was OK for this to go
> through you. The driver maintainer, Ville, has been Cc'd on all the series, but
> has only provided feedback for the comment request as I noted above. This
> series addresses the more complex work on the entire series I've been putting
> out and as such I've provided a TL;DR full review of what this series does in
> my previous v5 patch series, that can be looked at for more details if needed
> [1].
> 
> This series depends on the patch which I recently posted to address compilation
> issue on architectures missing ioremap_uc() [0]. If that goes through then it
> should be safe to apply this series, otherwise we have to sit and wait until
> all architectures get ioremap_uc() properly defined.
> 
> Please let me know if there are any questions.
> 
> [0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
> [1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Ingo, please let me know if there are any questions or issues with this series.

  Luis

Re: [PATCH v6 0/4] atyfb: atyfb: address MTRR corner case

[Luis R. Rodriguez]

On Thu, Jul 09, 2015 at 06:24:55PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Ingo,
> 
> Boris is on vacation so sending these through you. This v6 addresses one code
> comment update requested by Ville. Boris had picked up these patches on his
> tree and this series had gone through 0-day bot testing. The only issue it
> found was the lack of ioremap_uc() implementation on some architectures which
> have an IOMMU. There are two approaches to this issue, one is to go and define
> ioremap_uc() on all architectures, another is to provide a default for
> ioremap_uc() as architectures catch up. I've gone with the later approach [0],
> and so to ensure things won't build-break this patch series must also go
> through the same tree as the patch-fixes for ioremap_uc() for missing
> ioremap_uc() implementations go through. I intend on following up with
> implementing ioremap_uc() for other architectures but for that I need to get
> feedback from other architecture developers and that will take time.
> 
> Tomi, the framebuffer maintainer had already expressed he was OK for this to go
> through you. The driver maintainer, Ville, has been Cc'd on all the series, but
> has only provided feedback for the comment request as I noted above. This
> series addresses the more complex work on the entire series I've been putting
> out and as such I've provided a TL;DR full review of what this series does in
> my previous v5 patch series, that can be looked at for more details if needed
> [1].
> 
> This series depends on the patch which I recently posted to address compilation
> issue on architectures missing ioremap_uc() [0]. If that goes through then it
> should be safe to apply this series, otherwise we have to sit and wait until
> all architectures get ioremap_uc() properly defined.
> 
> Please let me know if there are any questions.
> 
> [0] http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com
> [1] http://lkml.kernel.org/r/1435196060-27350-1-git-send-email-mcgrof@do-not-panic.com

Ingo, please let me know if there are any questions or issues with this series.

  Luis

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[tip:x86/mm] drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper

[tip-bot for Luis R. Rodriguez]

Commit-ID:  eacd2d542610e55cad0be445966ac8ae79124c6e
Gitweb:     http://git.kernel.org/tip/eacd2d542610e55cad0be445966ac8ae79124c6e
Author:     Luis R. Rodriguez <mcgrof@suse.com>
AuthorDate: Thu, 9 Jul 2015 18:24:56 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 21 Jul 2015 10:47:04 +0200

drivers/video/fbdev/atyfb: Carve out framebuffer length fudging into a helper

The size of the framebuffer to be used needs to be fudged to
account for the different type of devices that are out there.
This captures what is required to do well, we'll reuse this
later.

This has no functional changes.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: airlied@redhat.com
Cc: arnd@arndb.de
Cc: benh@kernel.crashing.org
Cc: dan.j.williams@intel.com
Cc: geert@linux-m68k.org
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: linux-fbdev@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: luto@amacapital.net
Cc: mpe@ellerman.id.au
Cc: mst@redhat.com
Cc: ralf@linux-mips.org
Cc: ross.zwisler@linux.intel.com
Cc: stefan.bader@canonical.com
Cc: syrjala@sci.fi
Cc: tj@kernel.org
Cc: toshi.kani@hp.com
Cc: ville.syrjala@linux.intel.com
Link: http://lkml.kernel.org/r/1435251019-32421-1-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1436491499-3289-2-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/video/fbdev/aty/atyfb_base.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 8789e48..16936bb 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -427,6 +427,20 @@ static struct {
 #endif /* CONFIG_FB_ATY_CT */
 };
 
+/*
+ * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
+ * unless the auxiliary register aperture is used.
+ */
+static void aty_fudge_framebuffer_len(struct fb_info *info)
+{
+	struct atyfb_par *par = (struct atyfb_par *) info->par;
+
+	if (!par->aux_start &&
+	    (info->fix.smem_len == 0x800000 ||
+	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
+		info->fix.smem_len -= GUI_RESERVE;
+}
+
 static int correct_chipset(struct atyfb_par *par)
 {
 	u8 rev;
@@ -2603,14 +2617,7 @@ static int aty_init(struct fb_info *info)
 	if (par->pll_ops->resume_pll)
 		par->pll_ops->resume_pll(info, &par->pll);
 
-	/*
-	 * Last page of 8 MB (4 MB on ISA) aperture is MMIO,
-	 * unless the auxiliary register aperture is used.
-	 */
-	if (!par->aux_start &&
-	    (info->fix.smem_len == 0x800000 ||
-	     (par->bus_type == ISA && info->fix.smem_len == 0x400000)))
-		info->fix.smem_len -= GUI_RESERVE;
+	aty_fudge_framebuffer_len(info);
 
 	/*
 	 * Disable register access through the linear aperture

[tip:x86/mm] drivers/video/fbdev/atyfb: Clarify ioremap() base and length used

[tip-bot for Luis R. Rodriguez]

Commit-ID:  f55de6ec375da89f89f1a76e1b998e5f14878c06
Gitweb:     http://git.kernel.org/tip/f55de6ec375da89f89f1a76e1b998e5f14878c06
Author:     Luis R. Rodriguez <mcgrof@suse.com>
AuthorDate: Thu, 9 Jul 2015 18:24:57 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 21 Jul 2015 10:47:04 +0200

drivers/video/fbdev/atyfb: Clarify ioremap() base and length used

Adjust the ioremap() call for the framebuffer to use the same
values we later use for the framebuffer. This will make it
easier to review the next change.

The size of the framebuffer varies but since this is for PCI we
*know* this defaults to 0x800000. atyfb_setup_generic() is
*only* used on PCI probe.

No functional change.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
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: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: arnd@arndb.de
Cc: benh@kernel.crashing.org
Cc: dan.j.williams@intel.com
Cc: geert@linux-m68k.org
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: linux-fbdev@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-pci@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: mst@redhat.com
Cc: ralf@linux-mips.org
Cc: ross.zwisler@linux.intel.com
Cc: stefan.bader@canonical.com
Cc: tj@kernel.org
Cc: ville.syrjala@linux.intel.com
Link: http://lkml.kernel.org/r/1436491499-3289-3-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/video/fbdev/aty/atyfb_base.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 16936bb..de8f7e0 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -3489,7 +3489,21 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 
 	/* Map in frame buffer */
 	info->fix.smem_start = addr;
-	info->screen_base = ioremap(addr, 0x800000);
+
+	/*
+	 * The framebuffer is not always 8 MiB, that's just the size of the
+	 * PCI BAR. We temporarily abuse smem_len here to store the size
+	 * of the BAR. aty_init() will later correct it to match the actual
+	 * framebuffer size.
+	 *
+	 * On devices that don't have the auxiliary register aperture, the
+	 * registers are housed at the top end of the framebuffer PCI BAR.
+	 * aty_fudge_framebuffer_len() is used to reduce smem_len to not
+	 * overlap with the registers.
+	 */
+	info->fix.smem_len = 0x800000;
+
+	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;

[tip:x86/mm] drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC

[tip-bot for Luis R. Rodriguez]

Commit-ID:  3cc2dac5be3f23414a4efdee0b26d79bed297cac
Gitweb:     http://git.kernel.org/tip/3cc2dac5be3f23414a4efdee0b26d79bed297cac
Author:     Luis R. Rodriguez <mcgrof@suse.com>
AuthorDate: Thu, 9 Jul 2015 18:24:58 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 21 Jul 2015 10:47:05 +0200

drivers/video/fbdev/atyfb: Replace MTRR UC hole with strong UC

Replace a WC MTRR call followed by a UC MTRR "hole" call with a
single WC MTRR call and use strong UC to protect the MMIO region
and account for the device's architecture and MTRR size
requirements.

The atyfb driver relies on two overlapping MTRRs. It does this
to account for the fact that, on some devices, it has the MMIO
region bundled together with the framebuffer on the same PCI BAR
and the hardware requirement on MTRRs on both base and size to
be powers of two.

In the worst case, the PCI BAR is of 16 MiB while the MMIO
region is on the last 4 KiB of the same PCI BAR. If we use just
one MTRR for WC, we can only end up with an 8 MiB or 16 MiB
framebuffer. Using a 16 MiB WC framebuffer area is unacceptable
since we need the MMIO region to not be write-combined. An 8 MiB
WC framebuffer option does not let use quite a bit of
framebuffer space, it would reduce the resolution capability of
the device considerably.

An alternative is to use many MTRRs but on some systems that
could mean not having enough MTRRs to cover the framebuffer. The
current solution is to issue a 16 MiB WC MTRR followed by a 4
KiB UC MTRR on the last 4 KiB. Its worth mentioning and
documenting that the current ioremap*() strategy as well: the
first ioremap() is used only for the MMIO region, a second
ioremap() call is used for the framebuffer *and* the MMIO
region, the MMIO region then ends up mmapped twice.

Two ioremap() calls are used since in some situations the
framebuffer actually ends up on a separate auxiliary PCI BAR,
but this is not always true. In the worst case, the PCI BAR is
shared for both MMIO and the framebuffer. By allowing
overlapping ioremap() calls, the driver enables two types of
devices with one simple ioremap() strategy.

See also:

  2f9e897353fc ("x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages")

By default, Linux today defaults both pci_mmap_page_range() and
ioremap_nocache() to use _PAGE_CACHE_MODE_UC_MINUS. On x86,
ioremap() aliases ioremap_nocache(). The preferred value for
Linux may soon change, however, the goal is to use
_PAGE_CACHE_MODE_UC by default in the future.

We can use ioremap_uc() to set PCD=1, PWT=1 on non-PAT systems
and use a PAT value of UC for PAT systems. This will ensure the
same settings are in place regardless of what Linux decides to
use by default later and to not regress our MTRR strategy since
the effective memory type will differ depending on the value
used. Using a WC MTRR on such an area will be nullified. This
technique can be used to protect the MMIO region in this
driver's case and address the restrictions of the device's
architecture as well as restrictions set upon us by powers of 2
when using MTRRs.

This allows us to replace the two MTRR calls with a single 16
MiB WC MTRR and use page-attribute settings for non-PAT and PAT
entry values for PAT systems to ensure the appropriate effective
memory type won't have a write-combining effect on the MMIO
region on both non-PAT and PAT systems. The framebuffer area
will be sure to get the write-combined effective memory type by
white-listing it with ioremap_wc().

We ensure the desired effective memory types are set by:

0) Using one ioremap_uc() for the MMIO region alone.
   This will set the page attribute settings for the MMIO
   region to PCD=1, PWT=1 for non-PAT systems while using a
   strong UC value on PAT systems.

1) Fixing the framebuffer ioremapped area to exclude the
   MMIO region and using ioremap_wc() instead to whitelist
   the area we want for write-combining.

In both cases, an implementation defined (as per 2f9e897353fc)
effective memory type of WC is used for the framebuffer for
non-PAT systems.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
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: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: arnd@arndb.de
Cc: benh@kernel.crashing.org
Cc: dan.j.williams@intel.com
Cc: geert@linux-m68k.org
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: linux-fbdev@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-pci@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: mst@redhat.com
Cc: ralf@linux-mips.org
Cc: ross.zwisler@linux.intel.com
Cc: stefan.bader@canonical.com
Cc: tj@kernel.org
Cc: ville.syrjala@linux.intel.com
Link: http://lkml.kernel.org/r/1435196060-27350-3-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1436491499-3289-4-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/video/fbdev/aty/atyfb.h      |  1 -
 drivers/video/fbdev/aty/atyfb_base.c | 36 ++++++++++++++----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 1f39a62..89ec439 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -184,7 +184,6 @@ struct atyfb_par {
 	spinlock_t int_lock;
 #ifdef CONFIG_MTRR
 	int mtrr_aper;
-	int mtrr_reg;
 #endif
 	u32 mem_cntl;
 	struct crtc saved_crtc;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index de8f7e0..7770a84 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -2630,21 +2630,13 @@ static int aty_init(struct fb_info *info)
 
 #ifdef CONFIG_MTRR
 	par->mtrr_aper = -1;
-	par->mtrr_reg = -1;
 	if (!nomtrr) {
-		/* Cover the whole resource. */
+		/*
+		 * Only the ioremap_wc()'d area will get WC here
+		 * since ioremap_uc() was used on the entire PCI BAR.
+		 */
 		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
 					  MTRR_TYPE_WRCOMB, 1);
-		if (par->mtrr_aper >= 0 && !par->aux_start) {
-			/* Make a hole for mmio. */
-			par->mtrr_reg = mtrr_add(par->res_start + 0x800000 -
-						 GUI_RESERVE, GUI_RESERVE,
-						 MTRR_TYPE_UNCACHABLE, 1);
-			if (par->mtrr_reg < 0) {
-				mtrr_del(par->mtrr_aper, 0, 0);
-				par->mtrr_aper = -1;
-			}
-		}
 	}
 #endif
 
@@ -2776,10 +2768,6 @@ aty_init_exit:
 	par->pll_ops->set_pll(info, &par->saved_pll);
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;
@@ -3466,7 +3454,11 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	}
 
 	info->fix.mmio_start = raddr;
-	par->ati_regbase = ioremap(info->fix.mmio_start, 0x1000);
+	/*
+	 * By using strong UC we force the MTRR to never have an
+	 * effect on the MMIO region on both non-PAT and PAT systems.
+	 */
+	par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
 	if (par->ati_regbase == NULL)
 		return -ENOMEM;
 
@@ -3503,7 +3495,10 @@ static int atyfb_setup_generic(struct pci_dev *pdev, struct fb_info *info,
 	 */
 	info->fix.smem_len = 0x800000;
 
-	info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+	aty_fudge_framebuffer_len(info);
+
+	info->screen_base = ioremap_wc(info->fix.smem_start,
+				       info->fix.smem_len);
 	if (info->screen_base == NULL) {
 		ret = -ENOMEM;
 		goto atyfb_setup_generic_fail;
@@ -3575,6 +3570,7 @@ static int atyfb_pci_probe(struct pci_dev *pdev,
 		return -ENOMEM;
 	}
 	par = info->par;
+	par->bus_type = PCI;
 	info->fix = atyfb_fix;
 	info->device = &pdev->dev;
 	par->pci_id = pdev->device;
@@ -3744,10 +3740,6 @@ static void atyfb_remove(struct fb_info *info)
 #endif
 
 #ifdef CONFIG_MTRR
-	if (par->mtrr_reg >= 0) {
-		mtrr_del(par->mtrr_reg, 0, 0);
-		par->mtrr_reg = -1;
-	}
 	if (par->mtrr_aper >= 0) {
 		mtrr_del(par->mtrr_aper, 0, 0);
 		par->mtrr_aper = -1;

[tip:x86/mm] drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

[tip-bot for Luis R. Rodriguez]

Commit-ID:  7d89a3cb159aecb1b363ea50cb14c967ff83b5a6
Gitweb:     http://git.kernel.org/tip/7d89a3cb159aecb1b363ea50cb14c967ff83b5a6
Author:     Luis R. Rodriguez <mcgrof@suse.com>
AuthorDate: Thu, 9 Jul 2015 18:24:59 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 21 Jul 2015 10:47:05 +0200

drivers/video/fbdev/atyfb: Use arch_phys_wc_add() and ioremap_wc()

This driver uses strong UC for the MMIO region, and ioremap_wc()
for the framebuffer to whitelist for the WC MTRR that can be
changed to WC. On PAT systems we don't need the MTRR call so
just use arch_phys_wc_add() there, this lets us remove all those
ifdefs. Let's also be consistent and use ioremap_wc() for ATARI
as well.

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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Mel Gorman <mgorman@suse.de>
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: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: arnd@arndb.de
Cc: benh@kernel.crashing.org
Cc: dan.j.williams@intel.com
Cc: geert@linux-m68k.org
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: linux-fbdev@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-pci@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: mst@redhat.com
Cc: ralf@linux-mips.org
Cc: ross.zwisler@linux.intel.com
Cc: stefan.bader@canonical.com
Cc: tj@kernel.org
Cc: ville.syrjala@linux.intel.com
Link: http://lkml.kernel.org/r/1436491499-3289-5-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/video/fbdev/aty/atyfb.h      |  4 +---
 drivers/video/fbdev/aty/atyfb_base.c | 36 +++++++-----------------------------
 2 files changed, 8 insertions(+), 32 deletions(-)

diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h
index 89ec439..63c4842 100644
--- a/drivers/video/fbdev/aty/atyfb.h
+++ b/drivers/video/fbdev/aty/atyfb.h
@@ -182,9 +182,7 @@ struct atyfb_par {
 	unsigned long irq_flags;
 	unsigned int irq;
 	spinlock_t int_lock;
-#ifdef CONFIG_MTRR
-	int mtrr_aper;
-#endif
+	int wc_cookie;
 	u32 mem_cntl;
 	struct crtc saved_crtc;
 	union aty_pll saved_pll;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 7770a84..f34ed47 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -98,9 +98,6 @@
 #ifdef CONFIG_PMAC_BACKLIGHT
 #include <asm/backlight.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 
 /*
  * Debug flags.
@@ -303,9 +300,7 @@ static struct fb_ops atyfb_ops = {
 };
 
 static bool noaccel;
-#ifdef CONFIG_MTRR
 static bool nomtrr;
-#endif
 static int vram;
 static int pll;
 static int mclk;
@@ -2628,17 +2623,13 @@ static int aty_init(struct fb_info *info)
 		aty_st_le32(BUS_CNTL, aty_ld_le32(BUS_CNTL, par) |
 			    BUS_APER_REG_DIS, par);
 
-#ifdef CONFIG_MTRR
-	par->mtrr_aper = -1;
-	if (!nomtrr) {
+	if (!nomtrr)
 		/*
 		 * Only the ioremap_wc()'d area will get WC here
 		 * since ioremap_uc() was used on the entire PCI BAR.
 		 */
-		par->mtrr_aper = mtrr_add(par->res_start, par->res_size,
-					  MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+		par->wc_cookie = arch_phys_wc_add(par->res_start,
+						  par->res_size);
 
 	info->fbops = &atyfb_ops;
 	info->pseudo_palette = par->pseudo_palette;
@@ -2766,13 +2757,8 @@ aty_init_exit:
 	/* restore video mode */
 	aty_set_crtc(par, &par->saved_crtc);
 	par->pll_ops->set_pll(info, &par->saved_pll);
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 	return ret;
 }
 
@@ -3672,7 +3658,8 @@ static int __init atyfb_atari_probe(void)
 		 * Map the video memory (physical address given)
 		 * to somewhere in the kernel address space.
 		 */
-		info->screen_base = ioremap(phys_vmembase[m64_num], phys_size[m64_num]);
+		info->screen_base = ioremap_wc(phys_vmembase[m64_num],
+					       phys_size[m64_num]);
 		info->fix.smem_start = (unsigned long)info->screen_base; /* Fake! */
 		par->ati_regbase = ioremap(phys_guiregbase[m64_num], 0x10000) +
 						0xFC00ul;
@@ -3738,13 +3725,8 @@ static void atyfb_remove(struct fb_info *info)
 	if (M64_HAS(MOBIL_BUS))
 		aty_bl_exit(info->bl_dev);
 #endif
+	arch_phys_wc_del(par->wc_cookie);
 
-#ifdef CONFIG_MTRR
-	if (par->mtrr_aper >= 0) {
-		mtrr_del(par->mtrr_aper, 0, 0);
-		par->mtrr_aper = -1;
-	}
-#endif
 #ifndef __sparc__
 	if (par->ati_regbase)
 		iounmap(par->ati_regbase);
@@ -3860,10 +3842,8 @@ static int __init atyfb_setup(char *options)
 	while ((this_opt = strsep(&options, ",")) != NULL) {
 		if (!strncmp(this_opt, "noaccel", 7)) {
 			noaccel = 1;
-#ifdef CONFIG_MTRR
 		} else if (!strncmp(this_opt, "nomtrr", 6)) {
 			nomtrr = 1;
-#endif
 		} else if (!strncmp(this_opt, "vram:", 5))
 			vram = simple_strtoul(this_opt + 5, NULL, 0);
 		else if (!strncmp(this_opt, "pll:", 4))
@@ -4033,7 +4013,5 @@ module_param(comp_sync, int, 0);
 MODULE_PARM_DESC(comp_sync, "Set composite sync signal to low (0) or high (1)");
 module_param(mode, charp, 0);
 MODULE_PARM_DESC(mode, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
-#ifdef CONFIG_MTRR
 module_param(nomtrr, bool, 0);
 MODULE_PARM_DESC(nomtrr, "bool: disable use of MTRR registers");
-#endif