[tip:x86/mm] PCI: Add pci_ioremap_wc_bar()

From: tip-bot for Luis R. Rodriguez
Date: Tue Aug 25 2015 - 04:24:43 EST

Commit-ID: c43996f4001de629af4a4d6713782e883677e5b9
Gitweb: http://git.kernel.org/tip/c43996f4001de629af4a4d6713782e883677e5b9
Author: Luis R. Rodriguez <mcgrof@xxxxxxxx>
AuthorDate: Mon, 24 Aug 2015 12:13:23 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 25 Aug 2015 09:59:43 +0200

PCI: Add pci_ioremap_wc_bar()

This lets drivers take advantage of PAT when available. It
should help with the transition of converting video drivers over
to ioremap_wc() to help with the goal of eventually using
ioremap_nocache(), see:

de33c442ed2a ("x86 PAT: fix performance drop for glx, use UC minus for ioremap(), ioremap_nocache() and pci_mmap_page_range()")

Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Cc: <syrjala@xxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Antonino Daplas <adaplas@xxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@xxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Suresh Siddha <sbsiddha@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: Ville SyrjÃlà <syrjala@xxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: airlied@xxxxxxxx
Cc: benh@xxxxxxxxxxxxxxxxxxx
Cc: dan.j.williams@xxxxxxxxx
Cc: konrad.wilk@xxxxxxxxxx
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: mst@xxxxxxxxxx
Cc: vinod.koul@xxxxxxxxx
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1440443613-13696-2-git-send-email-mcgrof@xxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
drivers/pci/pci.c | 14 ++++++++++++++
include/linux/pci.h | 1 +
2 files changed, 15 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0008c95..fdae37b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -138,6 +138,20 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
return ioremap_nocache(res->start, resource_size(res));
+void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar)
+ /*
+ * Make sure the BAR is actually a memory resource, not an IO resource
+ */
+ if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
+ WARN_ON(1);
+ return NULL;
+ }
+ return ioremap_wc(pci_resource_start(pdev, bar),
+ pci_resource_len(pdev, bar));

#define PCI_FIND_CAP_TTL 48
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8a0321a..985dd39 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1661,6 +1661,7 @@ static inline void pci_mmcfg_late_init(void) { }
int pci_ext_cfg_avail(void);

void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar);
+void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar);

int pci_iov_virtfn_bus(struct pci_dev *dev, int id);
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