From: "Luis R. Rodriguez" <[email protected]>
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 _PAGE_CACHE_UC over
_PAGE_CACHE_UC_MINUS on x86 on 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 <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Antonino Daplas <[email protected]>
Cc: [email protected]
Cc: Bjorn Helgaas <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jean-Christophe Plagniol-Villard <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mel Gorman <[email protected]>
Cc: [email protected]
Cc: Suresh Siddha <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tomi Valkeinen <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Borislav Petkov <[email protected]>
---
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 8037c27beb05..33867b8a4bc9 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));
}
EXPORT_SYMBOL_GPL(pci_ioremap_bar);
+
+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));
+}
+EXPORT_SYMBOL_GPL(pci_ioremap_wc_bar);
#endif
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 88bee285b93d..2b2d7d44c21a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1701,6 +1701,7 @@ 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);
#ifdef CONFIG_PCI_IOV
int pci_iov_virtfn_bus(struct pci_dev *dev, int id);
--
2.4.3
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