[PATCH v7 1/9] pci: add pci_ioremap_wc_bar()

From: Luis R. Rodriguez
Date: Fri Jun 19 2015 - 18:13:14 EST

From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>

This lets drivers take advantage of PAT when available. This
should help with the transition of converting video drivers over
to ioremap_wc() to help with the goal of eventually using
ioremap_nocache() (de33c442e titled "x86 PAT: fix performance
drop for glx, use UC minus for ioremap(), ioremap_nocache() and

Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Suresh Siddha <sbsiddha@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Antonino Daplas <adaplas@xxxxxxxxx>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@xxxxxxxxxxxx>
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Ville SyrjÃlà <syrjala@xxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
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 c0dd4ab..1193975 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1657,6 +1657,7 @@ 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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