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authorLuis R. Rodriguez <mcgrof@suse.com>2015-08-24 12:13:23 -0700
committerIngo Molnar <mingo@kernel.org>2015-08-25 09:59:43 +0200
commitc43996f4001de629af4a4d6713782e883677e5b9 (patch)
tree55f37c67d90ace6fb51277b95df9aeb43068b9b4 /drivers/pci
parent8d58b66ed2b000f27658c88a4ed70e8042e86a58 (diff)
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 _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 <mcgrof@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: <syrjala@sci.fi> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Antonino Daplas <adaplas@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Airlie <airlied@redhat.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Ville Syrjälä <syrjala@sci.fi> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: airlied@linux.ie Cc: benh@kernel.crashing.org Cc: dan.j.williams@intel.com Cc: konrad.wilk@oracle.com Cc: linux-fbdev@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: mst@redhat.com Cc: vinod.koul@intel.com Cc: xen-devel@lists.xensource.com Link: http://lkml.kernel.org/r/1440443613-13696-2-git-send-email-mcgrof@do-not-panic.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0008c950452c..fdae37b473f8 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
#define PCI_FIND_CAP_TTL 48