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* Re: [PATCH v4 1/6] x86: add ioremap_uc() - force strong UC, PCD=1, PWT=1
From: Borislav Petkov @ 2015-04-30 10:18 UTC (permalink / raw)
  To: Luis R. Rodriguez
  Cc: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied, dledford, awalls, syrjala, luto, mst, cocci,
	linux-kernel, Luis R. Rodriguez, Toshi Kani, Bjorn Helgaas,
	Suresh Siddha, Juergen Gross, Daniel Vetter, Dave Airlie,
	Antonino Daplas, Will Deacon, Thierry Reding, Mike Travis,
	Mel Gorman, Vlastimil Babka, Davidlohr Bueso, x86, linux-fbdev
In-Reply-To: <1430343851-967-2-git-send-email-mcgrof@do-not-panic.com>

On Wed, Apr 29, 2015 at 02:44:06PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> ioremap_nocache() currently uses UC- by default.
> Our goal is to eventually make UC the default.
> Linux maps UC- to PCD=1, PWT=0 page attributes on
> non-PAT systems. Linux maps UC to PCD=1, PWT=1
> page attributes on non-PAT systems. On non-PAT
> and PAT systems a WC MTRR has different effects on
> pages with either of these attributes. In order to
> help with a smooth transition its best to enable
> use of UC (PCD,1, PWT=1) on a region as that ensures
> a WC MTRR will have no effect on a region, this
> however requires us to have an way to declare a
> region as UC and we currently do not have a way
> to do this.
> 
> WC MTRR on non-PAT system with PCD=1, PWT=0 (UC-) yields WC.
> WC MTRR on non-PAT system with PCD=1, PWT=1 (UC)  yields UC.
> 
> WC MTRR on PAT system with PCD=1, PWT=0 (UC-) yields WC.
> WC MTRR on PAT system with PCD=1, PWT=1 (UC)  yields UC.
> 
> A flip of the default ioremap_nocache() behaviour
> from UC- to UC can therefore regress a memory
> region from effective memory type WC to UC if MTRRs
> are used. Use of MTRRs should be phased out and in
> the best case only arch_phys_wc_add() use will remain,
> even if this happens arch_phys_wc_add() will have an
> effect on non-PAT systems and changes to default
> ioremap_nocache() behaviour could regress drivers.
> 
> Now, ideally we'd use ioremap_nocache() on the regions
> in which we'd need uncachable memory types and avoid
> any MTRRs on those regions. There are however some
> restrictions on MTRRs use, such as the requirement of
> having the base and size of variable sized MTRRs
> to be powers of two, which could mean having to use
> a WC MTRR over a large area which includes a region
> in which write-combining effects are undesirable.
> 
> Add ioremap_uc() to help with the both phasing out of
> MTRR use and also provide a way to blacklist small
> WC undesirable regions in devices with mixed regions
> which are size-implicated to use large WC MTRRs. Use
> of ioremap_uc() helps phase out MTRR use by avoiding
> regressions with an eventual flip of default behaviour
> or ioremap_nocache() from UC- to UC.
> 
> Drivers working with WC MTRRs can use the below table
> to review and consider the use of ioremap*() and similar
> helpers to ensure appropriate behaviour long term even
> if default ioremap_nocache() behaviour changes from UC-
> to UC.
> 
> Although ioremap_uc() is being added we leave set_memory_uc()
> to use UC- as only initial memory type setup is required
> to be able to accomodate existing device drivers and phase
> out MTRR use. It should also be clarified that set_memory_uc()
> cannot be used with IO memory, even though its use will
> not return any errors, it really has no effect.
> 
> ----------------------------------------------------------------------
> 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*  |   WC
> WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
> ----------------------------------------------------------------------
> 
> Cc: Toshi Kani <toshi.kani@hp.com>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Bjorn Helgaas <bhelgaas@google.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: 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: Will Deacon <will.deacon@arm.com>
> Cc: Thierry Reding <treding@nvidia.com>
> Cc: Mike Travis <travis@sgi.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: x86@kernel.org
> Cc: linux-fbdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
> ---
>  arch/x86/include/asm/io.h |  1 +
>  arch/x86/mm/ioremap.c     | 36 +++++++++++++++++++++++++++++++++++-
>  arch/x86/mm/pageattr.c    |  3 +++
>  include/asm-generic/io.h  |  8 ++++++++
>  4 files changed, 47 insertions(+), 1 deletion(-)

Looks ok to me. Applied, thanks.

-- 
Regards/Gruss,
    Boris.

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

^ permalink raw reply

* Re: [PATCH V3] staging: sm750: Fix lynxfb_ops_imageblit() if image->depth != 1
From: Sudip Mukherjee @ 2015-04-30  6:20 UTC (permalink / raw)
  To: linux-fbdev
In-Reply-To: <1430273686-21682-1-git-send-email-chenhc@lemote.com>

On Wed, Apr 29, 2015 at 10:14:46AM +0800, Huacai Chen wrote:
> If image->depth != 1, lynxfb_ops_imageblit() should fallback to call
> cfb_imageblit(), not return directly. Otherwise it can't display the
> boot logo.
> 
> Cc: Teddy Wang <teddy.wang@siliconmotion.com>
> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
Thanks Huacai.

Acked-by: Sudip Mukherhee <sudip@vectorindia.org>

^ permalink raw reply

* Re: [RFT PATCH] drm/exynos: Enable DP clock to fix display on Exynos5250 and other
From: Krzysztof Kozlowski @ 2015-04-29 23:56 UTC (permalink / raw)
  To: Kevin Hilman
  Cc: Krzysztof Kozlowski, linux-fbdev, linux-samsung-soc,
	Joonyoung Shim, David Airlie, Jingoo Han, Seung-Woo Kim,
	linux-kernel, dri-devel, Inki Dae, Andrzej Hajda, Kyungmin Park,
	Kukjin Kim, stable, Olof Johansson, Javier Martinez Canillas,
	linux-arm-kernel, Marek Szyprowski
In-Reply-To: <7h8udau9he.fsf@deeprootsystems.com>

2015-04-30 2:31 GMT+09:00 Kevin Hilman <khilman@kernel.org>:
> Krzysztof Kozlowski <k.kozlowski@samsung.com> writes:
>
>> After adding display power domain for Exynos5250 in commit
>> 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250") the
>> display on Chromebook Snow and others stopped working after boot.
>>
>> The reason for this suggested Andrzej Hajda: the DP clock was disabled.
>> This clock is required by Display Port and is enabled by bootloader.
>> However when FIMD driver probing was deferred, the display power domain
>> was turned off. This effectively reset the value of DP clock enable
>> register.
>>
>> When exynos-dp is later probed, the clock is not enabled and display is
>> not properly configured:
>>
>> exynos-dp 145b0000.dp-controller: Timeout of video streamclk ok
>> exynos-dp 145b0000.dp-controller: unable to config video
>>
>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
>> Reported-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
>> Fixes: 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250")
>> Cc: <stable@vger.kernel.org>
>>
>> ---
>>
>> This should fix issue reported by Javier [1][2].
>>
>> Tested on Chromebook Snow (Exynos 5250). More testing would be great,
>> especially on other Exynos 5xxx products.
>
> I hoped to try this on my exynos5 boards, but it doesn't seem to apply
> to linux-next or to Linus' master branch.
>
> Are there some other dependencies here?

It is already applied:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id\x1c363c7cccf64128087002b0779986ad16aff6dc

Best regards,
Krzysztof

^ permalink raw reply

* [PATCH v4 8/8] IB/ipath: use arch_phys_wc_add() and require PAT disabled
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo-X9Un+BFzKDI, tglx-hfZtesqFncYOwBW4kG4KsQ,
	hpa-YMNOUZJC4hwAvxtiuMwx3w, bp-l3A5Bk7waGM,
	plagnioj-sclMFOaUSTBWk0Htik3J/w, tomi.valkeinen-l0cyMroinI0,
	daniel.vetter-ral2JQCrhuEAvxtiuMwx3w, airlied-cv59FeDIM0c
  Cc: dledford-H+wXaHxf7aLQT0dZR+AlfA, awalls-Xoej9cPu4Z+RGvkDC/A1pg,
	syrjala-ORSVBvAovxo, luto-kltTT9wpgjJwATOyAt5JVQ,
	mst-H+wXaHxf7aLQT0dZR+AlfA, cocci-/FJkirnvOdkvYVN+rsErww,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA, Luis R. Rodriguez,
	Hal Rosenstock, Sean Hefty, Suresh Siddha, Rickard Strandqvist,
	Mike Marciniszyn, Roland Dreier, Linus Torvalds, Juergen Gross,
	Daniel Vetter, Dave Airlie, Bjorn Helgaas, Antonino Daplas,
	Mel Gorman, Vlastimil Babka, Davidlohr Bueso, Dave Hansen,
	Arnd Bergmann, Stefan Bader <stefan.>
In-Reply-To: <1430343867-1001-1-git-send-email-mcgrof-3uybbJdB1yH774rrrx3eTA@public.gmane.org>

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

We are burrying direct access to MTRR code support on
x86 in order to take advantage of PAT. In the future we
also want to make the default behaviour of ioremap_nocache()
to use strong UC, use of mtrr_add() on those systems
would make write-combining void.

In order to help both enable us to later make strong
UC default and in order to phase out direct MTRR access
code port the driver over to arch_phys_wc_add() and
annotate that the device driver requires systems to
boot with PAT disabled, with the nopat kernel parameter.

This is a worthy compromise given that the ipath device
driver powers the old HTX bus cards that only work in
AMD systems, while the newer IB/qib device driver
powers all PCI-e cards. The ipath device driver is
obsolete, hardware hard to find and because of this
this its a reasonable compromise to make to require
users of ipath to boot with nopat.

Acked-by: Doug Ledford <dledford@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.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: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: infinipath@intel.com
Cc: linux-rdma@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/infiniband/hw/ipath/Kconfig           |  3 ++
 drivers/infiniband/hw/ipath/ipath_driver.c    | 18 +++++++----
 drivers/infiniband/hw/ipath/ipath_kernel.h    |  4 +--
 drivers/infiniband/hw/ipath/ipath_wc_x86_64.c | 43 ++++++---------------------
 4 files changed, 26 insertions(+), 42 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/Kconfig b/drivers/infiniband/hw/ipath/Kconfig
index 1d9bb11..8fe54ff 100644
--- a/drivers/infiniband/hw/ipath/Kconfig
+++ b/drivers/infiniband/hw/ipath/Kconfig
@@ -9,3 +9,6 @@ config INFINIBAND_IPATH
 	as IP-over-InfiniBand as well as with userspace applications
 	(in conjunction with InfiniBand userspace access).
 	For QLogic PCIe QLE based cards, use the QIB driver instead.
+
+	If you have this hardware you will need to boot with PAT disabled
+	on your x86-64 systems, use the nopat kernel parameter.
diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c b/drivers/infiniband/hw/ipath/ipath_driver.c
index bd0caed..441cfe5 100644
--- a/drivers/infiniband/hw/ipath/ipath_driver.c
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c
@@ -42,6 +42,9 @@
 #include <linux/bitmap.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#ifdef CONFIG_X86_64
+#include <asm/pat.h>
+#endif
 
 #include "ipath_kernel.h"
 #include "ipath_verbs.h"
@@ -395,6 +398,14 @@ static int ipath_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	unsigned long long addr;
 	u32 bar0 = 0, bar1 = 0;
 
+#ifdef CONFIG_X86_64
+	if (WARN(pat_enabled(),
+		 "ipath needs PAT disabled, boot with nopat kernel parameter\n")) {
+		ret = EINVAL;
+		goto bail;
+	}
+#endif
+
 	dd = ipath_alloc_devdata(pdev);
 	if (IS_ERR(dd)) {
 		ret = PTR_ERR(dd);
@@ -542,6 +553,7 @@ static int ipath_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	dd->ipath_kregbase = __ioremap(addr, len,
 		(_PAGE_NO_CACHE|_PAGE_WRITETHRU));
 #else
+	/* XXX: split this properly to enable on PAT */
 	dd->ipath_kregbase = ioremap_nocache(addr, len);
 #endif
 
@@ -587,12 +599,8 @@ static int ipath_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	ret = ipath_enable_wc(dd);
 
-	if (ret) {
-		ipath_dev_err(dd, "Write combining not enabled "
-			      "(err %d): performance may be poor\n",
-			      -ret);
+	if (ret)
 		ret = 0;
-	}
 
 	ipath_verify_pioperf(dd);
 
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index e08db70..f0f9471 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -463,9 +463,7 @@ struct ipath_devdata {
 	/* offset in HT config space of slave/primary interface block */
 	u8 ipath_ht_slave_off;
 	/* for write combining settings */
-	unsigned long ipath_wc_cookie;
-	unsigned long ipath_wc_base;
-	unsigned long ipath_wc_len;
+	int wc_cookie;
 	/* ref count for each pkey */
 	atomic_t ipath_pkeyrefs[4];
 	/* shadow copy of struct page *'s for exp tid pages */
diff --git a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
index 70c1f3a..7b6e4c8 100644
--- a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
+++ b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
@@ -37,7 +37,6 @@
  */
 
 #include <linux/pci.h>
-#include <asm/mtrr.h>
 #include <asm/processor.h>
 
 #include "ipath_kernel.h"
@@ -122,27 +121,14 @@ int ipath_enable_wc(struct ipath_devdata *dd)
 	}
 
 	if (!ret) {
-		int cookie;
-		ipath_cdbg(VERBOSE, "Setting mtrr for chip to WC "
-			   "(addr %llx, len=0x%llx)\n",
-			   (unsigned long long) pioaddr,
-			   (unsigned long long) piolen);
-		cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 1);
-		if (cookie < 0) {
-			{
-				dev_info(&dd->pcidev->dev,
-					 "mtrr_add()  WC for PIO bufs "
-					 "failed (%d)\n",
-					 cookie);
-				ret = -EINVAL;
-			}
-		} else {
-			ipath_cdbg(VERBOSE, "Set mtrr for chip to WC, "
-				   "cookie is %d\n", cookie);
-			dd->ipath_wc_cookie = cookie;
-			dd->ipath_wc_base = (unsigned long) pioaddr;
-			dd->ipath_wc_len = (unsigned long) piolen;
-		}
+		dd->wc_cookie = arch_phys_wc_add(pioaddr, piolen);
+		if (dd->wc_cookie < 0) {
+			ipath_dev_err(dd, "Seting mtrr failed on PIO buffers\n");
+			ret = -ENODEV;
+		} else if (dd->wc_cookie = 0)
+			ipath_cdbg(VERBOSE, "Set mtrr for chip to WC not needed\n");
+		else
+			ipath_cdbg(VERBOSE, "Set mtrr for chip to WC\n");
 	}
 
 	return ret;
@@ -154,16 +140,5 @@ int ipath_enable_wc(struct ipath_devdata *dd)
  */
 void ipath_disable_wc(struct ipath_devdata *dd)
 {
-	if (dd->ipath_wc_cookie) {
-		int r;
-		ipath_cdbg(VERBOSE, "undoing WCCOMB on pio buffers\n");
-		r = mtrr_del(dd->ipath_wc_cookie, dd->ipath_wc_base,
-			     dd->ipath_wc_len);
-		if (r < 0)
-			dev_info(&dd->pcidev->dev,
-				 "mtrr_del(%lx, %lx, %lx) failed: %d\n",
-				 dd->ipath_wc_cookie, dd->ipath_wc_base,
-				 dd->ipath_wc_len, r);
-		dd->ipath_wc_cookie = 0; /* even on failure */
-	}
+	arch_phys_wc_del(dd->wc_cookie);
 }
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 7/8] IB/ipath: add counting for MTRR
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo-X9Un+BFzKDI, tglx-hfZtesqFncYOwBW4kG4KsQ,
	hpa-YMNOUZJC4hwAvxtiuMwx3w, bp-l3A5Bk7waGM,
	plagnioj-sclMFOaUSTBWk0Htik3J/w, tomi.valkeinen-l0cyMroinI0,
	daniel.vetter-ral2JQCrhuEAvxtiuMwx3w, airlied-cv59FeDIM0c
  Cc: dledford-H+wXaHxf7aLQT0dZR+AlfA, awalls-Xoej9cPu4Z+RGvkDC/A1pg,
	syrjala-ORSVBvAovxo, luto-kltTT9wpgjJwATOyAt5JVQ,
	mst-H+wXaHxf7aLQT0dZR+AlfA, cocci-/FJkirnvOdkvYVN+rsErww,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA, Luis R. Rodriguez,
	Toshi Kani, Roland Dreier, Sean Hefty, Hal Rosenstock,
	Suresh Siddha, Juergen Gross, Daniel Vetter, Dave Airlie,
	Antonino Daplas, infinipath-ral2JQCrhuEAvxtiuMwx3w,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA,
	linux-fbdev-u79uwXL29TY76Z2rM5mHXA
In-Reply-To: <1430343867-1001-1-git-send-email-mcgrof-3uybbJdB1yH774rrrx3eTA@public.gmane.org>

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

There is no good reason not to, we eventually delete it as well.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.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: infinipath@intel.com
Cc: linux-rdma@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/infiniband/hw/ipath/ipath_wc_x86_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
index 4ad0b93..70c1f3a 100644
--- a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
+++ b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
@@ -127,7 +127,7 @@ int ipath_enable_wc(struct ipath_devdata *dd)
 			   "(addr %llx, len=0x%llx)\n",
 			   (unsigned long long) pioaddr,
 			   (unsigned long long) piolen);
-		cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 0);
+		cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 1);
 		if (cookie < 0) {
 			{
 				dev_info(&dd->pcidev->dev,
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 6/8] ivtv: use arch_phys_wc_add() and require PAT disabled
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Mauro Carvalho Chehab, Suresh Siddha,
	Juergen Gross, Daniel Vetter, Dave Airlie, Bjorn Helgaas,
	Antonino Daplas, Dave Hansen, Arnd Bergmann, Stefan Bader,
	Mel Gorman, Vlastimil Babka, Davidlohr Bueso, konrad.wilk,
	ville.syrjala, david.vrabel, jbeulich, toshi.kani,
	Roger Pau Monné, linux-fbdev, ivtv-devel, linux-media,
	xen-devel
In-Reply-To: <1430343867-1001-1-git-send-email-mcgrof@do-not-panic.com>

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

We are burrying direct access to MTRR code support on
x86 in order to take advantage of PAT. In the future we
also want to make the default behaviour of ioremap_nocache()
to use strong UC, use of mtrr_add() on those systems
would make write-combining void.

In order to help both enable us to later make strong
UC default and in order to phase out direct MTRR access
code port the driver over to arch_phys_wc_add() and
annotate that the device driver requires systems to
boot with PAT disabled, with the nopat kernel parameter.

This is a worthy comprmise given that the hardware is
really rare these days, and perhaps only some lost souls
in some third world country are expected to be using this
feature of the device driver.

Acked-by: Andy Walls <awalls@md.metrocast.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
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: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: ivtv-devel@ivtvdriver.org
Cc: linux-media@vger.kernel.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/media/pci/ivtv/Kconfig  |  3 +++
 drivers/media/pci/ivtv/ivtvfb.c | 58 ++++++++++++++++-------------------------
 2 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/drivers/media/pci/ivtv/Kconfig b/drivers/media/pci/ivtv/Kconfig
index dd6ee57e..b2a7f88 100644
--- a/drivers/media/pci/ivtv/Kconfig
+++ b/drivers/media/pci/ivtv/Kconfig
@@ -57,5 +57,8 @@ config VIDEO_FB_IVTV
 	  This is used in the Hauppauge PVR-350 card. There is a driver
 	  homepage at <http://www.ivtvdriver.org>.
 
+	  If you have this hardware you will need to boot with PAT disabled
+	  on your x86 systems, use the nopat kernel parameter.
+
 	  To compile this driver as a module, choose M here: the
 	  module will be called ivtvfb.
diff --git a/drivers/media/pci/ivtv/ivtvfb.c b/drivers/media/pci/ivtv/ivtvfb.c
index 9ff1230..7685ae3 100644
--- a/drivers/media/pci/ivtv/ivtvfb.c
+++ b/drivers/media/pci/ivtv/ivtvfb.c
@@ -44,8 +44,8 @@
 #include <linux/ivtvfb.h>
 #include <linux/slab.h>
 
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
+#ifdef CONFIG_X86_64
+#include <asm/pat.h>
 #endif
 
 #include "ivtv-driver.h"
@@ -155,12 +155,11 @@ struct osd_info {
 	/* Buffer size */
 	u32 video_buffer_size;
 
-#ifdef CONFIG_MTRR
 	/* video_base rounded down as required by hardware MTRRs */
 	unsigned long fb_start_aligned_physaddr;
 	/* video_base rounded up as required by hardware MTRRs */
 	unsigned long fb_end_aligned_physaddr;
-#endif
+	int wc_cookie;
 
 	/* Store the buffer offset */
 	int set_osd_coords_x;
@@ -1099,6 +1098,8 @@ static int ivtvfb_init_vidmode(struct ivtv *itv)
 static int ivtvfb_init_io(struct ivtv *itv)
 {
 	struct osd_info *oi = itv->osd_info;
+	/* Find the largest power of two that maps the whole buffer */
+	int size_shift = 31;
 
 	mutex_lock(&itv->serialize_lock);
 	if (ivtv_init_on_first_open(itv)) {
@@ -1132,29 +1133,16 @@ static int ivtvfb_init_io(struct ivtv *itv)
 			oi->video_pbase, oi->video_vbase,
 			oi->video_buffer_size / 1024);
 
-#ifdef CONFIG_MTRR
-	{
-		/* Find the largest power of two that maps the whole buffer */
-		int size_shift = 31;
-
-		while (!(oi->video_buffer_size & (1 << size_shift))) {
-			size_shift--;
-		}
-		size_shift++;
-		oi->fb_start_aligned_physaddr = oi->video_pbase & ~((1 << size_shift) - 1);
-		oi->fb_end_aligned_physaddr = oi->video_pbase + oi->video_buffer_size;
-		oi->fb_end_aligned_physaddr += (1 << size_shift) - 1;
-		oi->fb_end_aligned_physaddr &= ~((1 << size_shift) - 1);
-		if (mtrr_add(oi->fb_start_aligned_physaddr,
-			oi->fb_end_aligned_physaddr - oi->fb_start_aligned_physaddr,
-			     MTRR_TYPE_WRCOMB, 1) < 0) {
-			IVTVFB_INFO("disabled mttr\n");
-			oi->fb_start_aligned_physaddr = 0;
-			oi->fb_end_aligned_physaddr = 0;
-		}
-	}
-#endif
-
+	while (!(oi->video_buffer_size & (1 << size_shift)))
+		size_shift--;
+	size_shift++;
+	oi->fb_start_aligned_physaddr = oi->video_pbase & ~((1 << size_shift) - 1);
+	oi->fb_end_aligned_physaddr = oi->video_pbase + oi->video_buffer_size;
+	oi->fb_end_aligned_physaddr += (1 << size_shift) - 1;
+	oi->fb_end_aligned_physaddr &= ~((1 << size_shift) - 1);
+	oi->wc_cookie = arch_phys_wc_add(oi->fb_start_aligned_physaddr,
+					 oi->fb_end_aligned_physaddr -
+					 oi->fb_start_aligned_physaddr);
 	/* Blank the entire osd. */
 	memset_io(oi->video_vbase, 0, oi->video_buffer_size);
 
@@ -1172,14 +1160,7 @@ static void ivtvfb_release_buffers (struct ivtv *itv)
 
 	/* Release pseudo palette */
 	kfree(oi->ivtvfb_info.pseudo_palette);
-
-#ifdef CONFIG_MTRR
-	if (oi->fb_end_aligned_physaddr) {
-		mtrr_del(-1, oi->fb_start_aligned_physaddr,
-			oi->fb_end_aligned_physaddr - oi->fb_start_aligned_physaddr);
-	}
-#endif
-
+	arch_phys_wc_del(oi->wc_cookie);
 	kfree(oi);
 	itv->osd_info = NULL;
 }
@@ -1284,6 +1265,13 @@ static int __init ivtvfb_init(void)
 	int registered = 0;
 	int err;
 
+#ifdef CONFIG_X86_64
+	if (WARN(pat_enabled(),
+		 "ivtvfb needs PAT disabled, boot with nopat kernel parameter\n")) {
+		return EINVAL;
+	}
+#endif
+
 	if (ivtvfb_card_id < -1 || ivtvfb_card_id >= IVTV_MAX_CARDS) {
 		printk(KERN_ERR "ivtvfb:  ivtvfb_card_id parameter is out of range (valid range: -1 - %d)\n",
 		     IVTV_MAX_CARDS - 1);
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 6/6] video: fbdev: atyfb: use arch_phys_wc_add() and ioremap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Suresh Siddha, Juergen Gross,
	Daniel Vetter, Dave Airlie, Antonino Daplas, Rob Clark,
	Mathias Krause, Andrzej Hajda, Mel Gorman, Vlastimil Babka,
	Davidlohr Bueso, linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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 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 | 37 +++++++-----------------------------
 2 files changed, 8 insertions(+), 33 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..b75c974 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 +300,6 @@ 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 +2622,13 @@ 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 +2756,8 @@ 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 +3645,8 @@ 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 +3712,8 @@ 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 +3829,8 @@ 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 +4000,5 @@ 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


^ permalink raw reply related

* [PATCH v4 5/6] video: fbdev: atyfb: replace MTRR UC hole with strong UC
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Suresh Siddha, Linus Torvalds,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Rob Clark, Mathias Krause, Andrzej Hajda, Mel Gorman,
	Vlastimil Babka, Davidlohr Bueso, linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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


^ permalink raw reply related

* [PATCH v4 4/6] video: fbdev: atyfb: clarify ioremap() base and length used
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Suresh Siddha, Linus Torvalds,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Rob Clark, Mathias Krause, Andrzej Hajda, Mel Gorman,
	Vlastimil Babka, Davidlohr Bueso, linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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


^ permalink raw reply related

* [PATCH v4 3/6] video: fbdev: atyfb: move framebuffer length fudging to helper
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Suresh Siddha, Linus Torvalds,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Rob Clark, Mathias Krause, Andrzej Hajda, Mel Gorman,
	Vlastimil Babka, Davidlohr Bueso, linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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 resuse this later.

This has no functional changes.

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: Rob Clark <robdclark@gmail.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
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 | 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
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 2/6] x86: document WC MTRR effects on PAT / non-PAT pages
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Jonathan Corbet, Dave Hansen,
	Suresh Siddha, Juergen Gross, Daniel Vetter, Dave Airlie,
	Antonino Daplas, Mel Gorman, Vlastimil Babka, Davidlohr Bueso,
	linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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

As part of the effort to phase out MTRR use document
write-combining MTRR effects on pages with different
non-PAT page attributes flags and different PAT entry
values. Extend arch_phys_wc_add() documentation to
clarify power of two sizes / boundary requirements as
we phase out mtrr_add() use.

Lastly hint towards ioremap_uc() for corner cases on
device drivers working with devices with mixed regions
where MTRR size requirements would otherwise not
enable write-combining effective memory types.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: 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: 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>
---
 Documentation/x86/mtrr.txt      | 18 +++++++++++++++---
 Documentation/x86/pat.txt       | 40 +++++++++++++++++++++++++++++++++++++++-
 arch/x86/kernel/cpu/mtrr/main.c |  3 +++
 3 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/Documentation/x86/mtrr.txt b/Documentation/x86/mtrr.txt
index cc071dc..a111a6c 100644
--- a/Documentation/x86/mtrr.txt
+++ b/Documentation/x86/mtrr.txt
@@ -1,7 +1,19 @@
 MTRR (Memory Type Range Register) control
-3 Jun 1999
-Richard Gooch
-<rgooch@atnf.csiro.au>
+
+Richard Gooch <rgooch@atnf.csiro.au> - 3 Jun 1999
+Luis R. Rodriguez <mcgrof@do-not-panic.com> - April 9, 2015
+
+=======================================+Phasing MTRR use
+
+MTRR use is replaced on modern x86 hardware with PAT. Over time the only type
+of effective MTRR that is expected to be supported will be for write-combining.
+As MTRR use is phased out device drivers should use arch_phys_wc_add() to make
+MTRR effective on non-PAT systems while a no-op on PAT enabled systems.
+
+For details refer to Documentation/x86/pat.txt.
+
+======================================= 
   On Intel P6 family processors (Pentium Pro, Pentium II and later)
   the Memory Type Range Registers (MTRRs) may be used to control
diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt
index cf08c9f..7e183e3 100644
--- a/Documentation/x86/pat.txt
+++ b/Documentation/x86/pat.txt
@@ -34,6 +34,8 @@ ioremap                |    --    |    UC-     |       UC-        |
                        |          |            |                  |
 ioremap_cache          |    --    |    WB      |       WB         |
                        |          |            |                  |
+ioremap_uc             |    --    |    UC      |       UC         |
+                       |          |            |                  |
 ioremap_nocache        |    --    |    UC-     |       UC-        |
                        |          |            |                  |
 ioremap_wc             |    --    |    --      |       WC         |
@@ -102,7 +104,43 @@ wants to export a RAM region, it has to do set_memory_uc() or set_memory_wc()
 as step 0 above and also track the usage of those pages and use set_memory_wb()
 before the page is freed to free pool.
 
-
+MTRR effects on PAT / non-PAT systems
+-------------------------------------
+
+The following table provides the effects of using write-combining MTRRs when
+using ioremap*() calls on x86 for both non-PAT and PAT systems. Ideally
+mtrr_add() usage will be phased in favor of arch_phys_wc_add() which will
+be a no-op on PAT enabled systems. The region over which a arch_phys_wc_add()
+is made should already have be ioremap'd with write-combining page attributes
+or PAT entries, this can be done by using ioremap_wc() / or respective helpers.
+Devices which combine areas of IO memory desired to remain uncachable with
+areas where write-combining is desirable and are restricted by the size
+requirements of MTRRs should consider splitting up their IO memory space
+cleanly with ioremap_uc() and ioremap_wc() followed by an arch_phys_wc_add()
+encompassing both regions. Such use is nevertheless heavily discouraged as
+the effective memory type is considered implementation defined. This strategy
+should only be used as last resort on devices with size-contrained regions
+where otherwise MTRR write-combining would not be effective.
+
+Note that you cannot use set_memory_wc() to override / whitelist IO remapped
+memory space mapped with ioremap*() calls, set_memory_wc() can only be used
+on RAM.
+
+----------------------------------------------------------------------
+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*  |   WC
+WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
+----------------------------------------------------------------------
+
+(*) denotes implementation defined and is discouraged
 
 Notes:
 
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index ea5f363..12abdbe 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -538,6 +538,9 @@ EXPORT_SYMBOL(mtrr_del);
  * attempts to add a WC MTRR covering size bytes starting at base and
  * logs an error if this fails.
  *
+ * The caller should expect to need to provide a power of two size on an
+ * equivalent power of two boundary.
+ *
  * Drivers must store the return value to pass to mtrr_del_wc_if_needed,
  * but drivers should not try to interpret that return value.
  */
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 1/6] x86: add ioremap_uc() - force strong UC, PCD=1, PWT=1
From: Luis R. Rodriguez @ 2015-04-29 21:44 UTC (permalink / raw)
  To: mingo, tglx, hpa, bp, plagnioj, tomi.valkeinen, daniel.vetter,
	airlied
  Cc: dledford, awalls, syrjala, luto, mst, cocci, linux-kernel,
	Luis R. Rodriguez, Toshi Kani, Bjorn Helgaas, Suresh Siddha,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Will Deacon, Thierry Reding, Mike Travis, Mel Gorman,
	Vlastimil Babka, Davidlohr Bueso, x86, linux-fbdev
In-Reply-To: <1430343851-967-1-git-send-email-mcgrof@do-not-panic.com>

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

ioremap_nocache() currently uses UC- by default.
Our goal is to eventually make UC the default.
Linux maps UC- to PCD=1, PWT=0 page attributes on
non-PAT systems. Linux maps UC to PCD=1, PWT=1
page attributes on non-PAT systems. On non-PAT
and PAT systems a WC MTRR has different effects on
pages with either of these attributes. In order to
help with a smooth transition its best to enable
use of UC (PCD,1, PWT=1) on a region as that ensures
a WC MTRR will have no effect on a region, this
however requires us to have an way to declare a
region as UC and we currently do not have a way
to do this.

WC MTRR on non-PAT system with PCD=1, PWT=0 (UC-) yields WC.
WC MTRR on non-PAT system with PCD=1, PWT=1 (UC)  yields UC.

WC MTRR on PAT system with PCD=1, PWT=0 (UC-) yields WC.
WC MTRR on PAT system with PCD=1, PWT=1 (UC)  yields UC.

A flip of the default ioremap_nocache() behaviour
from UC- to UC can therefore regress a memory
region from effective memory type WC to UC if MTRRs
are used. Use of MTRRs should be phased out and in
the best case only arch_phys_wc_add() use will remain,
even if this happens arch_phys_wc_add() will have an
effect on non-PAT systems and changes to default
ioremap_nocache() behaviour could regress drivers.

Now, ideally we'd use ioremap_nocache() on the regions
in which we'd need uncachable memory types and avoid
any MTRRs on those regions. There are however some
restrictions on MTRRs use, such as the requirement of
having the base and size of variable sized MTRRs
to be powers of two, which could mean having to use
a WC MTRR over a large area which includes a region
in which write-combining effects are undesirable.

Add ioremap_uc() to help with the both phasing out of
MTRR use and also provide a way to blacklist small
WC undesirable regions in devices with mixed regions
which are size-implicated to use large WC MTRRs. Use
of ioremap_uc() helps phase out MTRR use by avoiding
regressions with an eventual flip of default behaviour
or ioremap_nocache() from UC- to UC.

Drivers working with WC MTRRs can use the below table
to review and consider the use of ioremap*() and similar
helpers to ensure appropriate behaviour long term even
if default ioremap_nocache() behaviour changes from UC-
to UC.

Although ioremap_uc() is being added we leave set_memory_uc()
to use UC- as only initial memory type setup is required
to be able to accomodate existing device drivers and phase
out MTRR use. It should also be clarified that set_memory_uc()
cannot be used with IO memory, even though its use will
not return any errors, it really has no effect.

----------------------------------------------------------------------
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*  |   WC
WC   011      UC      _PAGE_CACHE_MODE_UC            UC   |   UC
----------------------------------------------------------------------

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bjorn Helgaas <bhelgaas@google.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: 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: Will Deacon <will.deacon@arm.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mike Travis <travis@sgi.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: x86@kernel.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 arch/x86/include/asm/io.h |  1 +
 arch/x86/mm/ioremap.c     | 36 +++++++++++++++++++++++++++++++++++-
 arch/x86/mm/pageattr.c    |  3 +++
 include/asm-generic/io.h  |  8 ++++++++
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 34a5b93..4afc05f 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -177,6 +177,7 @@ static inline unsigned int isa_virt_to_bus(volatile void *address)
  * look at pci_iomap().
  */
 extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size);
+extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size);
 extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);
 extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size,
 				unsigned long prot_val);
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 70e7444..a493bb8 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -237,7 +237,8 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 	 *	pat_enabled ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS;
 	 *
 	 * Till we fix all X drivers to use ioremap_wc(), we will use
-	 * UC MINUS.
+	 * UC MINUS. Drivers that are certain they need or can already
+	 * be converted over to strong UC can use ioremap_uc().
 	 */
 	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS;
 
@@ -247,6 +248,39 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 EXPORT_SYMBOL(ioremap_nocache);
 
 /**
+ * ioremap_uc     -   map bus memory into CPU space as strongly uncachable
+ * @phys_addr:    bus address of the memory
+ * @size:      size of the resource to map
+ *
+ * ioremap_uc performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * This version of ioremap ensures that the memory is marked with a strong
+ * preference as completely uncachable on the CPU when possible. For non-PAT
+ * systems this ends up setting page-attribute flags PCD=1, PWT=1. For PAT
+ * systems this will set the PAT entry for the pages as strong UC.  This call
+ * will honor existing caching rules from things like the PCI bus. Note that
+ * there are other caches and buffers on many busses. In particular driver
+ * authors should read up on PCI writes.
+ *
+ * It's useful if some control registers are in such an area and
+ * write combining or read caching is not desirable:
+ *
+ * Must be freed with iounmap.
+ */
+void __iomem *ioremap_uc(resource_size_t phys_addr, unsigned long size)
+{
+	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC;
+
+	return __ioremap_caller(phys_addr, size, pcm,
+				__builtin_return_address(0));
+}
+EXPORT_SYMBOL_GPL(ioremap_uc);
+
+/**
  * ioremap_wc	-	map memory into CPU space write combined
  * @phys_addr:	bus address of the memory
  * @size:	size of the resource to map
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 89af288..49660c0 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1468,6 +1468,9 @@ int _set_memory_uc(unsigned long addr, int numpages)
 {
 	/*
 	 * for now UC MINUS. see comments in ioremap_nocache()
+	 * If you really need strong UC use ioremap_uc(), but note
+	 * that you cannot override IO areas with set_memory_*() as
+	 * these helpers cannot work with IO memory.
 	 */
 	return change_page_attr_set(&addr, numpages,
 				    cachemode2pgprot(_PAGE_CACHE_MODE_UC_MINUS),
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 9db0423..90ccba7 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -769,6 +769,14 @@ static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size)
 }
 #endif
 
+#ifndef ioremap_uc
+#define ioremap_uc ioremap_uc
+static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size)
+{
+	return ioremap_nocache(offset, size);
+}
+#endif
+
 #ifndef ioremap_wc
 #define ioremap_wc ioremap_wc
 static inline void __iomem *ioremap_wc(phys_addr_t offset, size_t size)
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 5/5] video: fbdev: vt8623fb: use arch_phys_wc_add() and pci_iomap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez,
	Rob Clark, Laurent Pinchart, Jingoo Han, Lad, Prabhakar,
	Suresh Siddha, Ingo Molnar, Thomas Gleixner, Juergen Gross,
	Daniel Vetter, Dave Airlie, Antonino Daplas
In-Reply-To: <1430343372-687-1-git-send-email-mcgrof@do-not-panic.com>

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

This driver uses the same area for MTRR as for the ioremap().
Convert the driver from using the x86 specific MTRR code to
the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add()
will avoid MTRR if write-combining is available, in order to
take advantage of that also ensure the ioremap'd area is requested
as write-combining.

There are a few motivations for this:

a) Take advantage of PAT when available

b) Help bury MTRR code away, MTRR is architecture specific and on
   x86 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: Rob Clark <robdclark@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.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: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/vt8623fb.c | 31 ++++++-------------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbdev/vt8623fb.c b/drivers/video/fbdev/vt8623fb.c
index ea7f056..60f24828 100644
--- a/drivers/video/fbdev/vt8623fb.c
+++ b/drivers/video/fbdev/vt8623fb.c
@@ -26,13 +26,9 @@
 #include <linux/console.h> /* Why should fb driver call console functions? because console_lock() */
 #include <video/vga.h>
 
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
-
 struct vt8623fb_info {
 	char __iomem *mmio_base;
-	int mtrr_reg;
+	int wc_cookie;
 	struct vgastate state;
 	struct mutex open_lock;
 	unsigned int ref_count;
@@ -99,10 +95,7 @@ static struct svga_timing_regs vt8623_timing_regs     = {
 /* Module parameters */
 
 static char *mode_option = "640x480-8@60";
-
-#ifdef CONFIG_MTRR
 static int mtrr = 1;
-#endif
 
 MODULE_AUTHOR("(c) 2006 Ondrej Zajicek <santiago@crfreenet.org>");
 MODULE_LICENSE("GPL");
@@ -112,11 +105,8 @@ module_param(mode_option, charp, 0644);
 MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
 module_param_named(mode, mode_option, charp, 0);
 MODULE_PARM_DESC(mode, "Default video mode e.g. '648x480-8@60' (deprecated)");
-
-#ifdef CONFIG_MTRR
 module_param(mtrr, int, 0444);
 MODULE_PARM_DESC(mtrr, "Enable write-combining with MTRR (1=enable, 0=disable, default=1)");
-#endif
 
 
 /* ------------------------------------------------------------------------- */
@@ -710,7 +700,7 @@ static int vt8623_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	info->fix.mmio_len = pci_resource_len(dev, 1);
 
 	/* Map physical IO memory address into kernel space */
-	info->screen_base = pci_iomap(dev, 0, 0);
+	info->screen_base = pci_iomap_wc(dev, 0, 0);
 	if (! info->screen_base) {
 		rc = -ENOMEM;
 		dev_err(info->device, "iomap for framebuffer failed\n");
@@ -781,12 +771,9 @@ static int vt8623_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	/* Record a reference to the driver data */
 	pci_set_drvdata(dev, info);
 
-#ifdef CONFIG_MTRR
-	if (mtrr) {
-		par->mtrr_reg = -1;
-		par->mtrr_reg = mtrr_add(info->fix.smem_start, info->fix.smem_len, MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+	if (mtrr)
+		par->wc_cookie = arch_phys_wc_add(info->fix.smem_start,
+						  info->fix.smem_len);
 
 	return 0;
 
@@ -816,13 +803,7 @@ static void vt8623_pci_remove(struct pci_dev *dev)
 	if (info) {
 		struct vt8623fb_info *par = info->par;
 
-#ifdef CONFIG_MTRR
-		if (par->mtrr_reg >= 0) {
-			mtrr_del(par->mtrr_reg, 0, 0);
-			par->mtrr_reg = -1;
-		}
-#endif
-
+		arch_phys_wc_del(par->wc_cookie);
 		unregister_framebuffer(info);
 		fb_dealloc_cmap(&info->cmap);
 
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 4/5] video: fbdev: s3fb: use arch_phys_wc_add() and pci_iomap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez,
	Jingoo Han, Geert Uytterhoeven, Daniel Vetter, Lad, Prabhakar,
	Rickard Strandqvist, Suresh Siddha, Ingo Molnar, Thomas Gleixner,
	Juergen Gross, Dave Airlie, Antonino Daplas
In-Reply-To: <1430343372-687-1-git-send-email-mcgrof@do-not-panic.com>

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

This driver uses the same area for MTRR as for the ioremap().
Convert the driver from using the x86 specific MTRR code to
the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add()
will avoid MTRR if write-combining is available, in order to
take advantage of that also ensure the ioremap'd area is requested
as write-combining.

There are a few motivations for this:

a) Take advantage of PAT when available

b) Help bury MTRR code away, MTRR is architecture specific and on
   x86 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: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
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: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/s3fb.c | 35 ++++++-----------------------------
 1 file changed, 6 insertions(+), 29 deletions(-)

diff --git a/drivers/video/fbdev/s3fb.c b/drivers/video/fbdev/s3fb.c
index f0ae61a..13b1090 100644
--- a/drivers/video/fbdev/s3fb.c
+++ b/drivers/video/fbdev/s3fb.c
@@ -28,13 +28,9 @@
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
 
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
-
 struct s3fb_info {
 	int chip, rev, mclk_freq;
-	int mtrr_reg;
+	int wc_cookie;
 	struct vgastate state;
 	struct mutex open_lock;
 	unsigned int ref_count;
@@ -154,11 +150,7 @@ static const struct svga_timing_regs s3_timing_regs     = {
 
 
 static char *mode_option;
-
-#ifdef CONFIG_MTRR
 static int mtrr = 1;
-#endif
-
 static int fasttext = 1;
 
 
@@ -170,11 +162,8 @@ module_param(mode_option, charp, 0444);
 MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
 module_param_named(mode, mode_option, charp, 0444);
 MODULE_PARM_DESC(mode, "Default video mode ('640x480-8@60', etc) (deprecated)");
-
-#ifdef CONFIG_MTRR
 module_param(mtrr, int, 0444);
 MODULE_PARM_DESC(mtrr, "Enable write-combining with MTRR (1=enable, 0=disable, default=1)");
-#endif
 
 module_param(fasttext, int, 0644);
 MODULE_PARM_DESC(fasttext, "Enable S3 fast text mode (1=enable, 0=disable, default=1)");
@@ -1168,7 +1157,7 @@ static int s3_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	info->fix.smem_len = pci_resource_len(dev, 0);
 
 	/* Map physical IO memory address into kernel space */
-	info->screen_base = pci_iomap(dev, 0, 0);
+	info->screen_base = pci_iomap_wc(dev, 0, 0);
 	if (! info->screen_base) {
 		rc = -ENOMEM;
 		dev_err(info->device, "iomap for framebuffer failed\n");
@@ -1365,12 +1354,9 @@ static int s3_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	/* Record a reference to the driver data */
 	pci_set_drvdata(dev, info);
 
-#ifdef CONFIG_MTRR
-	if (mtrr) {
-		par->mtrr_reg = -1;
-		par->mtrr_reg = mtrr_add(info->fix.smem_start, info->fix.smem_len, MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
+	if (mtrr)
+		par->wc_cookie = arch_phys_wc_add(info->fix.smem_start,
+						  info->fix.smem_len);
 
 	return 0;
 
@@ -1405,14 +1391,7 @@ static void s3_pci_remove(struct pci_dev *dev)
 
 	if (info) {
 		par = info->par;
-
-#ifdef CONFIG_MTRR
-		if (par->mtrr_reg >= 0) {
-			mtrr_del(par->mtrr_reg, 0, 0);
-			par->mtrr_reg = -1;
-		}
-#endif
-
+		arch_phys_wc_del(par->wc_cookie);
 		unregister_framebuffer(info);
 		fb_dealloc_cmap(&info->cmap);
 
@@ -1551,10 +1530,8 @@ static int  __init s3fb_setup(char *options)
 
 		if (!*opt)
 			continue;
-#ifdef CONFIG_MTRR
 		else if (!strncmp(opt, "mtrr:", 5))
 			mtrr = simple_strtoul(opt + 5, NULL, 0);
-#endif
 		else if (!strncmp(opt, "fasttext:", 9))
 			fasttext = simple_strtoul(opt + 9, NULL, 0);
 		else
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 3/5] video: fbdev: arkfb: use arch_phys_wc_add() and pci_iomap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez,
	Laurent Pinchart, Geert Uytterhoeven, Lad, Prabhakar,
	Suresh Siddha, Ingo Molnar, Thomas Gleixner, Juergen Gross,
	Daniel Vetter, Dave Airlie, Antonino Daplas
In-Reply-To: <1430343372-687-1-git-send-email-mcgrof@do-not-panic.com>

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

Convert the driver from using the x86 specific MTRR code to
the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add()
will avoid MTRR if write-combining is available, in order to
take advantage of that also ensure the ioremap'd area is requested
as write-combining.

There are a few motivations for this:

a) Take advantage of PAT when available

b) Help bury MTRR code away, MTRR is architecture specific and on
   x86 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: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.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: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/video/fbdev/arkfb.c | 36 +++++-------------------------------
 1 file changed, 5 insertions(+), 31 deletions(-)

diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c
index b305a1e..6a317de 100644
--- a/drivers/video/fbdev/arkfb.c
+++ b/drivers/video/fbdev/arkfb.c
@@ -26,13 +26,9 @@
 #include <linux/console.h> /* Why should fb driver call console functions? because console_lock() */
 #include <video/vga.h>
 
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
-
 struct arkfb_info {
 	int mclk_freq;
-	int mtrr_reg;
+	int wc_cookie;
 
 	struct dac_info *dac;
 	struct vgastate state;
@@ -102,10 +98,6 @@ static const struct svga_timing_regs ark_timing_regs     = {
 
 static char *mode_option = "640x480-8@60";
 
-#ifdef CONFIG_MTRR
-static int mtrr = 1;
-#endif
-
 MODULE_AUTHOR("(c) 2007 Ondrej Zajicek <santiago@crfreenet.org>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("fbdev driver for ARK 2000PV");
@@ -115,11 +107,6 @@ MODULE_PARM_DESC(mode_option, "Default video mode ('640x480-8@60', etc)");
 module_param_named(mode, mode_option, charp, 0444);
 MODULE_PARM_DESC(mode, "Default video mode ('640x480-8@60', etc) (deprecated)");
 
-#ifdef CONFIG_MTRR
-module_param(mtrr, int, 0444);
-MODULE_PARM_DESC(mtrr, "Enable write-combining with MTRR (1=enable, 0=disable, default=1)");
-#endif
-
 static int threshold = 4;
 
 module_param(threshold, int, 0644);
@@ -1002,7 +989,7 @@ static int ark_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	info->fix.smem_len = pci_resource_len(dev, 0);
 
 	/* Map physical IO memory address into kernel space */
-	info->screen_base = pci_iomap(dev, 0, 0);
+	info->screen_base = pci_iomap_wc(dev, 0, 0);
 	if (! info->screen_base) {
 		rc = -ENOMEM;
 		dev_err(info->device, "iomap for framebuffer failed\n");
@@ -1057,14 +1044,8 @@ static int ark_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	/* Record a reference to the driver data */
 	pci_set_drvdata(dev, info);
-
-#ifdef CONFIG_MTRR
-	if (mtrr) {
-		par->mtrr_reg = -1;
-		par->mtrr_reg = mtrr_add(info->fix.smem_start, info->fix.smem_len, MTRR_TYPE_WRCOMB, 1);
-	}
-#endif
-
+	par->wc_cookie = arch_phys_wc_add(info->fix.smem_start,
+					  info->fix.smem_len);
 	return 0;
 
 	/* Error handling */
@@ -1092,14 +1073,7 @@ static void ark_pci_remove(struct pci_dev *dev)
 
 	if (info) {
 		struct arkfb_info *par = info->par;
-
-#ifdef CONFIG_MTRR
-		if (par->mtrr_reg >= 0) {
-			mtrr_del(par->mtrr_reg, 0, 0);
-			par->mtrr_reg = -1;
-		}
-#endif
-
+		arch_phys_wc_del(par->wc_cookie);
 		dac_release(par->dac);
 		unregister_framebuffer(info);
 		fb_dealloc_cmap(&info->cmap);
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 2/5] lib: devres: add pcim_iomap_wc() variants
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez,
	Toshi Kani, Suresh Siddha, Ingo Molnar, Thomas Gleixner,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Dave Hansen, Arnd Bergmann, venkatesh.pallipadi, Stefan Bader,
	Ville Syrjälä, Mel Gorman, Vlastimil Babka,
	Borislav Petkov, Davidlohr Bueso, konrad.wilk, ville.syrjala,
	david.vrabel, jbeulich, Roger Pau Monné, xen-devel
In-Reply-To: <1430343372-687-1-git-send-email-mcgrof@do-not-panic.com>

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

Now that we have pci_iomap_wc() add the respective devres helpers.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: venkatesh.pallipadi@intel.com
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
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: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 include/linux/pci.h |  2 ++
 lib/devres.c        | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 490ca41..cb317c4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1619,9 +1619,11 @@ static inline void pci_dev_specific_enable_acs(struct pci_dev *dev) { }
 #endif
 
 void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);
+void __iomem *pcim_iomap_wc(struct pci_dev *pdev, int bar, unsigned long maxlen);
 void pcim_iounmap(struct pci_dev *pdev, void __iomem *addr);
 void __iomem * const *pcim_iomap_table(struct pci_dev *pdev);
 int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name);
+int pcim_iomap_wc_regions(struct pci_dev *pdev, int mask, const char *name);
 int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
 				   const char *name);
 void pcim_iounmap_regions(struct pci_dev *pdev, int mask);
diff --git a/lib/devres.c b/lib/devres.c
index fbe2aac..d59a2b9 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -304,6 +304,30 @@ void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen)
 EXPORT_SYMBOL(pcim_iomap);
 
 /**
+ * pcim_iomap_wc - Managed pcim_iomap_wc()
+ * @pdev: PCI device to iomap for
+ * @bar: BAR to iomap
+ * @maxlen: Maximum length of iomap
+ *
+ * Managed pci_iomap_wc().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *pcim_iomap_wc(struct pci_dev *pdev, int bar, unsigned long maxlen)
+{
+	void __iomem **tbl;
+
+	BUG_ON(bar >= PCIM_IOMAP_MAX);
+
+	tbl = (void __iomem **)pcim_iomap_table(pdev);
+	if (!tbl || tbl[bar])	/* duplicate mappings not allowed */
+		return NULL;
+
+	tbl[bar] = pci_iomap_wc(pdev, bar, maxlen);
+	return tbl[bar];
+}
+EXPORT_SYMBOL_GPL(pcim_iomap_wc);
+
+/**
  * pcim_iounmap - Managed pci_iounmap()
  * @pdev: PCI device to iounmap for
  * @addr: Address to unmap
@@ -383,6 +407,60 @@ int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
 EXPORT_SYMBOL(pcim_iomap_regions);
 
 /**
+ * pcim_iomap_wc_regions - Request and iomap PCI BARs with write-combining
+ * @pdev: PCI device to map IO resources for
+ * @mask: Mask of BARs to request and iomap
+ * @name: Name used when requesting regions
+ *
+ * Request and iomap regions specified by @mask with a preference for
+ * write-combining.
+ */
+int pcim_iomap_wc_regions(struct pci_dev *pdev, int mask, const char *name)
+{
+	void __iomem * const *iomap;
+	int i, rc;
+
+	iomap = pcim_iomap_table(pdev);
+	if (!iomap)
+		return -ENOMEM;
+
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
+		unsigned long len;
+
+		if (!(mask & (1 << i)))
+			continue;
+
+		rc = -EINVAL;
+		len = pci_resource_len(pdev, i);
+		if (!len)
+			goto err_inval;
+
+		rc = pci_request_region(pdev, i, name);
+		if (rc)
+			goto err_inval;
+
+		rc = -ENOMEM;
+		if (!pcim_iomap_wc(pdev, i, 0))
+			goto err_region;
+	}
+
+	return 0;
+
+ err_region:
+	pci_release_region(pdev, i);
+ err_inval:
+	while (--i >= 0) {
+		if (!(mask & (1 << i)))
+			continue;
+		pcim_iounmap(pdev, iomap[i]);
+		pci_release_region(pdev, i);
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pcim_iomap_wc_regions);
+
+/**
  * pcim_iomap_regions_request_all - Request all BARs and iomap specified ones
  * @pdev: PCI device to map IO resources for
  * @mask: Mask of BARs to iomap
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 1/5] pci: add pci_iomap_wc() variants
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez,
	Toshi Kani, Suresh Siddha, Ingo Molnar, Thomas Gleixner,
	Juergen Gross, Daniel Vetter, Dave Airlie, Antonino Daplas,
	Dave Hansen, Arnd Bergmann, venkatesh.pallipadi, Stefan Bader,
	Ville Syrjälä, Mel Gorman, Vlastimil Babka,
	Borislav Petkov, Davidlohr Bueso, konrad.wilk, ville.syrjala,
	david.vrabel, jbeulich, Roger Pau Monné, xen-devel
In-Reply-To: <1430343372-687-1-git-send-email-mcgrof@do-not-panic.com>

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

This allows drivers to take advantage of write-combining
when possible. Ideally we'd have pci_read_bases() just
peg an IORESOURCE_WC flag for us but where exactly
video devices memory lie varies *largely* and at times things
are mixed with MMIO registers, sometimes we can address
the changes in drivers, other times the change requires
intrusive changes.

Although there is also arch_phys_wc_add() that makes use of
architecture specific write-combining alternatives (MTRR on
x86 when a system does not have PAT) we void polluting
pci_iomap() space with it and force drivers and subsystems
that want to use it to be explicit.

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()")

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: venkatesh.pallipadi@intel.com
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: Ville Syrjälä <syrjala@sci.fi>
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: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 include/asm-generic/pci_iomap.h | 14 ++++++++++
 lib/pci_iomap.c                 | 61 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/include/asm-generic/pci_iomap.h b/include/asm-generic/pci_iomap.h
index 7389c87..b1e17fc 100644
--- a/include/asm-generic/pci_iomap.h
+++ b/include/asm-generic/pci_iomap.h
@@ -15,9 +15,13 @@ struct pci_dev;
 #ifdef CONFIG_PCI
 /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
 extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
+extern void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long max);
 extern void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
 				     unsigned long offset,
 				     unsigned long maxlen);
+extern void __iomem *pci_iomap_wc_range(struct pci_dev *dev, int bar,
+					unsigned long offset,
+					unsigned long maxlen);
 /* Create a virtual mapping cookie for a port on a given PCI device.
  * Do not call this directly, it exists to make it easier for architectures
  * to override */
@@ -34,12 +38,22 @@ static inline void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned lon
 	return NULL;
 }
 
+static inline void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long max)
+{
+	return NULL;
+}
 static inline void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
 					    unsigned long offset,
 					    unsigned long maxlen)
 {
 	return NULL;
 }
+static inline void __iomem *pci_iomap_wc_range(struct pci_dev *dev, int bar,
+					       unsigned long offset,
+					       unsigned long maxlen)
+{
+	return NULL;
+}
 #endif
 
 #endif /* __ASM_GENERIC_IO_H */
diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c
index bcce5f1..30b65ae 100644
--- a/lib/pci_iomap.c
+++ b/lib/pci_iomap.c
@@ -52,6 +52,46 @@ void __iomem *pci_iomap_range(struct pci_dev *dev,
 EXPORT_SYMBOL(pci_iomap_range);
 
 /**
+ * pci_iomap_wc_range - create a virtual WC mapping cookie for a PCI BAR
+ * @dev: PCI device that owns the BAR
+ * @bar: BAR number
+ * @offset: map memory at the given offset in BAR
+ * @maxlen: max length of the memory to map
+ *
+ * Using this function you will get a __iomem address to your device BAR.
+ * You can access it using ioread*() and iowrite*(). These functions hide
+ * the details if this is a MMIO or PIO address space and will just do what
+ * you expect from them in the correct way. When possible write combining
+ * is used.
+ *
+ * @maxlen specifies the maximum length to map. If you want to get access to
+ * the complete BAR from offset to the end, pass %0 here.
+ * */
+void __iomem *pci_iomap_wc_range(struct pci_dev *dev,
+				 int bar,
+				 unsigned long offset,
+				 unsigned long maxlen)
+{
+	resource_size_t start = pci_resource_start(dev, bar);
+	resource_size_t len = pci_resource_len(dev, bar);
+	unsigned long flags = pci_resource_flags(dev, bar);
+
+	if (len <= offset || !start)
+		return NULL;
+	len -= offset;
+	start += offset;
+	if (maxlen && len > maxlen)
+		len = maxlen;
+	if (flags & IORESOURCE_IO)
+		return __pci_ioport_map(dev, start, len);
+	if (flags & IORESOURCE_MEM)
+		return ioremap_wc(start, len);
+	/* What? */
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(pci_iomap_wc_range);
+
+/**
  * pci_iomap - create a virtual mapping cookie for a PCI BAR
  * @dev: PCI device that owns the BAR
  * @bar: BAR number
@@ -70,4 +110,25 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
 	return pci_iomap_range(dev, bar, 0, maxlen);
 }
 EXPORT_SYMBOL(pci_iomap);
+
+/**
+ * pci_iomap_wc - create a virtual WC mapping cookie for a PCI BAR
+ * @dev: PCI device that owns the BAR
+ * @bar: BAR number
+ * @maxlen: length of the memory to map
+ *
+ * Using this function you will get a __iomem address to your device BAR.
+ * You can access it using ioread*() and iowrite*(). These functions hide
+ * the details if this is a MMIO or PIO address space and will just do what
+ * you expect from them in the correct way. When possible write combining
+ * is used.
+ *
+ * @maxlen specifies the maximum length to map. If you want to get access to
+ * the complete BAR without checking for its length first, pass %0 here.
+ * */
+void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
+{
+	return pci_iomap_wc_range(dev, bar, 0, maxlen);
+}
+EXPORT_SYMBOL_GPL(pci_iomap_wc);
 #endif /* CONFIG_PCI */
-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply related

* [PATCH v4 0/5] pci/devres: add and use pci_iomap_wc() and pcim_iomap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:36 UTC (permalink / raw)
  To: bhelgaas, mst, plagnioj, tomi.valkeinen, airlied, daniel.vetter
  Cc: linux-fbdev, luto, cocci, linux-kernel, Luis R. Rodriguez

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

This series adds pci_iomap_wc() and the respective devm helper pcim_iomap_wc().

Luis R. Rodriguez (5):
  pci: add pci_iomap_wc() variants
  lib: devres: add pcim_iomap_wc() variants
  video: fbdev: arkfb: use arch_phys_wc_add() and pci_iomap_wc()
  video: fbdev: s3fb: use arch_phys_wc_add() and pci_iomap_wc()
  video: fbdev: vt8623fb: use arch_phys_wc_add() and pci_iomap_wc()

 drivers/video/fbdev/arkfb.c     | 36 +++----------------
 drivers/video/fbdev/s3fb.c      | 35 ++++--------------
 drivers/video/fbdev/vt8623fb.c  | 31 ++++------------
 include/asm-generic/pci_iomap.h | 14 ++++++++
 include/linux/pci.h             |  2 ++
 lib/devres.c                    | 78 +++++++++++++++++++++++++++++++++++++++++
 lib/pci_iomap.c                 | 61 ++++++++++++++++++++++++++++++++
 7 files changed, 172 insertions(+), 85 deletions(-)

-- 
2.3.2.209.gd67f9d5.dirty


^ permalink raw reply

* Re: [PATCH v3 0/6] x86: document and address MTRR corner cases
From: Luis R. Rodriguez @ 2015-04-29 21:12 UTC (permalink / raw)
  To: linux-fbdev
In-Reply-To: <1429647970-17479-1-git-send-email-mcgrof@do-not-panic.com>

On Tue, Apr 21, 2015 at 1:26 PM, Luis R. Rodriguez
<mcgrof@do-not-panic.com> wrote:
> As we phase out MTRR we need to also prepare for the flip of
> the default ioremap() behaviour from UC- to strong UC. There
> are a few remaining drivers which does not allow us to make
> a smooth transition over and which do not allow us to remove
> MTRR use. The atyfb is a good example driver and this series
> addresses the work required to avoid such regressions and
> cover MTRR size contraint use cases.
>
> This series also documents what we've learned along on the
> way in order to address removal of MTRR use and its corner
> cases.
>
> Luis R. Rodriguez (6):
>   x86: add ioremap_uc() - force strong UC, PCD=1, PWT=1
>   x86: document WC MTRR effects on PAT / non-PAT pages
>   video: fbdev: atyfb: move framebuffer length fudging to helper
>   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()

There was so far just one comment fix for this series. I'll repost the
series with the fix but other than that folks seem to be OK with this.

 Luis

^ permalink raw reply

* Re: [PATCH v3 0/4] pci: add and use pci_iomap_wc()
From: Luis R. Rodriguez @ 2015-04-29 21:11 UTC (permalink / raw)
  To: cocci
In-Reply-To: <1429647702-17315-1-git-send-email-mcgrof@do-not-panic.com>

On Tue, Apr 21, 2015 at 1:21 PM, Luis R. Rodriguez
<mcgrof@do-not-panic.com> wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
>
> This series adds pci_iomap_wc() variants and makes use of them
> to framebuffer device drivers.
>
> Luis R. Rodriguez (4):
>   pci: add pci_iomap_wc() variants
>   video: fbdev: arkfb: use arch_phys_wc_add() and pci_iomap_wc()
>   video: fbdev: s3fb: use arch_phys_wc_add() and pci_iomap_wc()
>   video: fbdev: vt8623fb: use arch_phys_wc_add() and pci_iomap_wc()

Bjorn,

I'll repost this series with a the addition of one extra patch that
adds a respective devres helper pcim_iomap_wc().

 Luis

^ permalink raw reply

* Re: [PATCH v3 0/4] pci: add and use pci_ioremap_wc_bar()
From: Luis R. Rodriguez @ 2015-04-29 21:08 UTC (permalink / raw)
  To: cocci
In-Reply-To: <1429647634-17169-1-git-send-email-mcgrof@do-not-panic.com>

On Tue, Apr 21, 2015 at 1:20 PM, Luis R. Rodriguez
<mcgrof@do-not-panic.com> wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
>
> This series adds pci_ioremap_wc_bar() and makes use of it
> on a few framebuffer device drivers.
>
> Luis R. Rodriguez (4):
>   pci: add pci_ioremap_wc_bar()
>   video: fbdev: i740fb: use arch_phys_wc_add() and pci_ioremap_wc_bar()
>   video: fbdev: kyrofb: use arch_phys_wc_add() and pci_ioremap_wc_bar()
>   video: fbdev: gxt4500: use pci_ioremap_wc_bar() for framebuffer

Bjorn,

any feedback on this series?

 Luis

^ permalink raw reply

* Re: [PATCH v3 00/17] framebuffer: simple conversions to arch_phys_wc_add()
From: Luis R. Rodriguez @ 2015-04-29 19:18 UTC (permalink / raw)
  To: cocci
In-Reply-To: <1429647398-16983-1-git-send-email-mcgrof@do-not-panic.com>

On Tue, Apr 21, 2015 at 1:16 PM, Luis R. Rodriguez
<mcgrof@do-not-panic.com> wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
>
> This series addresses simple changes to framebuffer drivers to use
> arch_phys_wc_add() and ioremap_wc() as well as fixing gbefb to add
> missing mtrr_del() calls. These changes are pretty straight forward.
>
> Luis R. Rodriguez (17):
>   video: fbdev: radeonfb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: gbefb: add missing mtrr_del() calls
>   video: fbdev: gbefb: use arch_phys_wc_add() and devm_ioremap_wc()
>   video: fbdev: intelfb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: matrox: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: neofb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: nvidia: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: savagefb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: sisfb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: aty: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: i810: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: pm2fb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: pm3fb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: rivafb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: tdfxfb: use arch_phys_wc_add() and ioremap_wc()
>   video: fbdev: atmel_lcdfb: use ioremap_wc() for framebuffer
>   video: fbdev: geode gxfb: use ioremap_wc() for framebuffer

Hey folks, these are all pretty straight forward, can anyone take them?

 Luis

^ permalink raw reply

* Re: [RFT PATCH] drm/exynos: Enable DP clock to fix display on Exynos5250 and other
From: Kevin Hilman @ 2015-04-29 17:31 UTC (permalink / raw)
  To: Krzysztof Kozlowski
  Cc: Jingoo Han, Inki Dae, Joonyoung Shim, Seung-Woo Kim,
	Kyungmin Park, David Airlie, Kukjin Kim, dri-devel,
	linux-arm-kernel, linux-samsung-soc, linux-kernel, linux-fbdev,
	Marek Szyprowski, Andrzej Hajda, Javier Martinez Canillas, stable,
	Olof Johansson
In-Reply-To: <1427471856-20918-1-git-send-email-k.kozlowski@samsung.com>

Krzysztof Kozlowski <k.kozlowski@samsung.com> writes:

> After adding display power domain for Exynos5250 in commit
> 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250") the
> display on Chromebook Snow and others stopped working after boot.
>
> The reason for this suggested Andrzej Hajda: the DP clock was disabled.
> This clock is required by Display Port and is enabled by bootloader.
> However when FIMD driver probing was deferred, the display power domain
> was turned off. This effectively reset the value of DP clock enable
> register.
>
> When exynos-dp is later probed, the clock is not enabled and display is
> not properly configured:
>
> exynos-dp 145b0000.dp-controller: Timeout of video streamclk ok
> exynos-dp 145b0000.dp-controller: unable to config video
>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Reported-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> Fixes: 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250")
> Cc: <stable@vger.kernel.org>
>
> ---
>
> This should fix issue reported by Javier [1][2].
>
> Tested on Chromebook Snow (Exynos 5250). More testing would be great,
> especially on other Exynos 5xxx products.

I hoped to try this on my exynos5 boards, but it doesn't seem to apply
to linux-next or to Linus' master branch.

Are there some other dependencies here?

Kevin

^ permalink raw reply

* Re: [PATCH] gpio-backlight: Discover driver during boot time
From: Lee Jones @ 2015-04-29 12:33 UTC (permalink / raw)
  To: Arun Bharadwaj
  Cc: linux-fbdev, linux-kernel, Jingoo Han,
	Jean-Christophe Plagniol-Villard, Tomi Valkeinen, Ash Charles
In-Reply-To: <20150429123223.GJ9169@x1>

> Jingoo?

Never mind.

Applied, thanks.

> > The gpio-backlight driver seems to be missing the
> > MODULE_DEVICE_TABLE line which is preventing it from
> > being modprobed during boot time even if the
> > gpio-backlight device exists.
> > 
> > This seems to be a bug and this patch attempts to
> > fix that.
> > 
> > Signed-off-by: Arun Bharadwaj <arun@gumstix.com>
> > Signed-off-by: Ash Charles <ashcharles@gmail.com>
> > ---
> >  drivers/video/backlight/gpio_backlight.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> > index 439feb2..5fbbc2e 100644
> > --- a/drivers/video/backlight/gpio_backlight.c
> > +++ b/drivers/video/backlight/gpio_backlight.c
> > @@ -146,6 +146,8 @@ static struct of_device_id gpio_backlight_of_match[] = {
> >  	{ .compatible = "gpio-backlight" },
> >  	{ /* sentinel */ }
> >  };
> > +
> > +MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
> >  #endif
> >  
> >  static struct platform_driver gpio_backlight_driver = {
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

^ permalink raw reply

* Re: [PATCH] gpio-backlight: Discover driver during boot time
From: Lee Jones @ 2015-04-29 12:32 UTC (permalink / raw)
  To: Arun Bharadwaj
  Cc: linux-fbdev, linux-kernel, Jingoo Han,
	Jean-Christophe Plagniol-Villard, Tomi Valkeinen, Ash Charles
In-Reply-To: <1429143684-3371-1-git-send-email-arun@gumstix.com>

Jingoo?

> The gpio-backlight driver seems to be missing the
> MODULE_DEVICE_TABLE line which is preventing it from
> being modprobed during boot time even if the
> gpio-backlight device exists.
> 
> This seems to be a bug and this patch attempts to
> fix that.
> 
> Signed-off-by: Arun Bharadwaj <arun@gumstix.com>
> Signed-off-by: Ash Charles <ashcharles@gmail.com>
> ---
>  drivers/video/backlight/gpio_backlight.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> index 439feb2..5fbbc2e 100644
> --- a/drivers/video/backlight/gpio_backlight.c
> +++ b/drivers/video/backlight/gpio_backlight.c
> @@ -146,6 +146,8 @@ static struct of_device_id gpio_backlight_of_match[] = {
>  	{ .compatible = "gpio-backlight" },
>  	{ /* sentinel */ }
>  };
> +
> +MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
>  #endif
>  
>  static struct platform_driver gpio_backlight_driver = {

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

^ permalink raw reply


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