[PATCH v2 1/4] arm64: enable pci resource mapping using sysfs

[dwmw2@infradead.org (David Woodhouse)]

From: Brijesh Singh <brijess@amazon.com>

To support PCI resource mapping from userspace, pci_mmap_page_range()
must be implemented and HAVE_PCI_MMAP defined. This support was absent
for arm64.

[dwmw2: Add WC support]
Reviewed-by: Erik Quanstrom <quanstro@amazon.com>
Reviewed-by: Anthony Liguori <aliguori@amazon.com>
Signed-off-by: Brijesh Singh <brijess@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
v2: s/pgprot_uncached/pgprot_device/

 arch/arm64/include/asm/pci.h |  4 ++++
 arch/arm64/kernel/pci.c      | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
index b9a7ba9..f73734f 100644
--- a/arch/arm64/include/asm/pci.h
+++ b/arch/arm64/include/asm/pci.h
@@ -37,5 +37,9 @@ static inline int pci_proc_domain(struct pci_bus *bus)
 }
 #endif  /* CONFIG_PCI */
 
+#define HAVE_PCI_MMAP
+extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
+			       enum pci_mmap_state mmap_state, int write_combine);
+
 #endif  /* __KERNEL__ */
 #endif  /* __ASM_PCI_H */
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 4f0e3eb..9a87b2a 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -228,3 +228,22 @@ void pcibios_remove_bus(struct pci_bus *bus)
 }
 
 #endif
+
+int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
+			enum pci_mmap_state mmap_state, int write_combine)
+{
+	if (mmap_state == pci_mmap_io)
+		return -EINVAL;
+
+	if (write_combine)
+		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+	else
+		vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
+
+	if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+			     vma->vm_end - vma->vm_start,
+			     vma->vm_page_prot))
+		return -EAGAIN;
+
+	return 0;
+}
-- 
dwmw2
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 4938 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20170315/21eba039/attachment-0001.bin>