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Subject[PATCH RFC v2 2/7] pci: add pci_iomap_range
From: Michael S Tsirkin <mst@redhat.com>

Virtio drivers should map the part of the BAR they need, not necessarily
all of it.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
include/asm-generic/pci_iomap.h | 10 ++++++++++
lib/pci_iomap.c | 35 ++++++++++++++++++++++++++++++-----
2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/include/asm-generic/pci_iomap.h b/include/asm-generic/pci_iomap.h
index ce37349..7389c87 100644
--- a/include/asm-generic/pci_iomap.h
+++ b/include/asm-generic/pci_iomap.h
@@ -15,6 +15,9 @@ struct pci_dev;
#ifdef CONFIG_PCI
/* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
+extern void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
+ unsigned long offset,
+ unsigned long maxlen);
/* Create a virtual mapping cookie for a port on a given PCI device.
* Do not call this directly, it exists to make it easier for architectures
* to override */
@@ -30,6 +33,13 @@ static inline void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned lon
{
return NULL;
}
+
+static inline void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
+ unsigned long offset,
+ unsigned long maxlen)
+{
+ return NULL;
+}
#endif

#endif /* __ASM_GENERIC_IO_H */
diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c
index 0d83ea8..bcce5f1 100644
--- a/lib/pci_iomap.c
+++ b/lib/pci_iomap.c
@@ -10,10 +10,11 @@

#ifdef CONFIG_PCI
/**
- * pci_iomap - create a virtual mapping cookie for a PCI BAR
+ * pci_iomap_range - 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
+ * @offset: map memory at the given offset in BAR
+ * @maxlen: max 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
@@ -21,16 +22,21 @@
* 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.
+ * the complete BAR from offset to the end, pass %0 here.
* */
-void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
+void __iomem *pci_iomap_range(struct pci_dev *dev,
+ int bar,
+ unsigned long offset,
+ unsigned long maxlen)
{
resource_size_t start = pci_resource_start(dev, bar);
resource_size_t len = pci_resource_len(dev, bar);
unsigned long flags = pci_resource_flags(dev, bar);

- if (!len || !start)
+ if (len <= offset || !start)
return NULL;
+ len -= offset;
+ start += offset;
if (maxlen && len > maxlen)
len = maxlen;
if (flags & IORESOURCE_IO)
@@ -43,6 +49,25 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
/* What? */
return NULL;
}
+EXPORT_SYMBOL(pci_iomap_range);

+/**
+ * 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)
+{
+ return pci_iomap_range(dev, bar, 0, maxlen);
+}
EXPORT_SYMBOL(pci_iomap);
#endif /* CONFIG_PCI */
--
MST


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