[PATCH v8 12/13] PCI: Add pcim_iomap_range()

[Philipp Stanner <pstanner@redhat.com>]

The only managed mapping function currently is pcim_iomap() which
doesn't allow for mapping an area starting at a certain offset, which
many drivers want.

Add pcim_iomap_range() as an exported function.

Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
 drivers/pci/devres.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pci.h  |  2 ++
 2 files changed, 46 insertions(+)

diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index e92a8802832f..96f18243742b 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -1015,3 +1015,47 @@ void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
 	}
 }
 EXPORT_SYMBOL(pcim_iounmap_regions);
+
+/**
+ * pcim_iomap_range - Create a ranged __iomap mapping within a PCI BAR
+ * @pdev: PCI device to map IO resources for
+ * @bar: Index of the BAR
+ * @offset: Offset from the begin of the BAR
+ * @len: Length in bytes for the mapping
+ *
+ * Returns: __iomem pointer on success, an IOMEM_ERR_PTR on failure.
+ *
+ * Creates a new IO-Mapping within the specified @bar, ranging from @offset to
+ * @offset + @len.
+ *
+ * The mapping will automatically get unmapped on driver detach. If desired,
+ * release manually only with pcim_iounmap().
+ */
+void __iomem *pcim_iomap_range(struct pci_dev *pdev, int bar,
+		unsigned long offset, unsigned long len)
+{
+	void __iomem *mapping;
+	struct pcim_addr_devres *res;
+
+	res = pcim_addr_devres_alloc(pdev);
+	if (!res)
+		return IOMEM_ERR_PTR(-ENOMEM);
+
+	mapping = pci_iomap_range(pdev, bar, offset, len);
+	if (!mapping) {
+		pcim_addr_devres_free(res);
+		return IOMEM_ERR_PTR(-EINVAL);
+	}
+
+	res->type = PCIM_ADDR_DEVRES_TYPE_MAPPING;
+	res->baseaddr = mapping;
+
+	/*
+	 * Ranged mappings don't get added to the legacy-table, since the table
+	 * only ever keeps track of whole BARs.
+	 */
+
+	devres_add(&pdev->dev, res);
+	return mapping;
+}
+EXPORT_SYMBOL(pcim_iomap_range);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cc9247f78158..bee1b2754219 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2304,6 +2304,8 @@ int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name);
 int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
 				   const char *name);
 void pcim_iounmap_regions(struct pci_dev *pdev, int mask);
+void __iomem *pcim_iomap_range(struct pci_dev *pdev, int bar,
+				unsigned long offset, unsigned long len);
 
 extern int pci_pci_problems;
 #define PCIPCI_FAIL		1	/* No PCI PCI DMA */
-- 
2.45.0