Re: [PATCH] Clarify pci_iomap() usage for MMIO-only devices

[Jeff Garzik <jeff@garzik.org>]

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Benjamin Herrenschmidt wrote:
> On Tue, 2007-09-18 at 16:21 -0400, Jeff Garzik wrote:
>> A new pci_mmio_map() helper, to be used with 100% MMIO hardware, might
>> help eliminate confusion. 
> 
> Maybe not the best name in theory but at least would show that it
> relates to existing ioremap would be pci_ioremap()


Easy enough... 'pcimap' branch of
git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/misc-2.6.git

	Jeff



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commit 6e09c71822f76c618353682bf295fc7588284521
Author: Jeff Garzik <jeff@garzik.org>
Date:   Tue Sep 18 19:06:08 2007 -0400

    Add pci_ioremap() to generic iomap lib.
    
    (arches that don't wish to use lib/iomap.c's version may fill in their own)
    
    Signed-off-by: Jeff Garzik <jeff@garzik.org>

 include/asm-generic/iomap.h |    1 +
 lib/iomap.c                 |   34 ++++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

6e09c71822f76c618353682bf295fc7588284521
diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
index cde592f..611e6cf 100644
--- a/include/asm-generic/iomap.h
+++ b/include/asm-generic/iomap.h
@@ -63,6 +63,7 @@ extern void ioport_unmap(void __iomem *);
 /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
 struct pci_dev;
 extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
+extern void __iomem *pci_ioremap(struct pci_dev *dev, int bar, unsigned long max);
 extern void pci_iounmap(struct pci_dev *dev, void __iomem *);
 
 #endif
diff --git a/lib/iomap.c b/lib/iomap.c
index 864f2ec..0338da0 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -275,9 +275,43 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
 	return NULL;
 }
 
+/**
+ * pci_ioremap - create a virtual mapping cookie for a memory-based PCI BAR
+ * @dev: PCI device that owns the BAR
+ * @bar: BAR number
+ * @maxlen: length of MMIO memory to map
+ *
+ * Using this function you will get a __iomem address to your device BAR.
+ * You can access it using read*() and write*().
+ *
+ * @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_ioremap(struct pci_dev *dev, int bar, unsigned long maxlen)
+{
+	unsigned long start = pci_resource_start(dev, bar);
+	unsigned long len = pci_resource_len(dev, bar);
+	unsigned long flags = pci_resource_flags(dev, bar);
+
+	if (!len || !start)
+		return NULL;
+	if (maxlen && len > maxlen)
+		len = maxlen;
+	if (flags & IORESOURCE_IO)
+		return NULL;
+	if (flags & IORESOURCE_MEM) {
+		if (flags & IORESOURCE_CACHEABLE)
+			return ioremap(start, len);
+		return ioremap_nocache(start, len);
+	}
+	/* What? */
+	return NULL;
+}
+
 void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
 {
 	IO_COND(addr, /* nothing */, iounmap(addr));
 }
 EXPORT_SYMBOL(pci_iomap);
+EXPORT_SYMBOL(pci_ioremap);
 EXPORT_SYMBOL(pci_iounmap);