From 5ca24814247fa4c039b893bf80fc05d0e5d41b00 Mon Sep 17 00:00:00 2001
From: Rolf Eike Beer <eike-kernel@sf-tec.de>
Date: Thu, 19 Jul 2007 17:48:44 -0700
Subject: [PATCH] PCI: Document pci_iomap()
This useful interface is hardly mentioned anywhere in the in-tree
documentation.
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Tejun Heo <htejun@gmail.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
Documentation/DocBook/deviceiobook.tmpl | 3 ++-
include/asm-i386/io.h | 3 +++
lib/iomap.c | 15 ++++++++++++++-
3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/Documentation/DocBook/deviceiobook.tmpl b/Documentation/DocBook/deviceiobook.tmpl
index 90ed23df1f68f..c917de681ccd7 100644
--- a/Documentation/DocBook/deviceiobook.tmpl
+++ b/Documentation/DocBook/deviceiobook.tmpl
@@ -316,7 +316,8 @@ CPU B: spin_unlock_irqrestore(&dev_lock, flags)
<chapter id="pubfunctions">
<title>Public Functions Provided</title>
-!Einclude/asm-i386/io.h
+!Iinclude/asm-i386/io.h
+!Elib/iomap.c
</chapter>
</book>
diff --git a/include/asm-i386/io.h b/include/asm-i386/io.h
index 7b65b5b000343..e8e0bd6411205 100644
--- a/include/asm-i386/io.h
+++ b/include/asm-i386/io.h
@@ -112,6 +112,9 @@ extern void __iomem * __ioremap(unsigned long offset, unsigned long size, unsign
* writew/writel functions and the other mmio helpers. The returned
* address is not guaranteed to be usable directly as a virtual
* address.
+ *
+ * If the area you are trying to map is a PCI BAR you should have a
+ * look at pci_iomap().
*/
static inline void __iomem * ioremap(unsigned long offset, unsigned long size)
diff --git a/lib/iomap.c b/lib/iomap.c
index a57d262a5ed9b..864f2ec1966ec 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -240,7 +240,20 @@ void ioport_unmap(void __iomem *addr)
EXPORT_SYMBOL(ioport_map);
EXPORT_SYMBOL(ioport_unmap);
-/* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
+/**
+ * pci_iomap - create a virtual 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.
+ *
+ * @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(struct pci_dev *dev, int bar, unsigned long maxlen)
{
unsigned long start = pci_resource_start(dev, bar);
--
GitLab