PCI: Allow read/write access to sysfs I/O port resources
PCI sysfs resource files currently only allow mmap'ing. On x86 this
works fine for memory backed BARs, but doesn't work at all for I/O
port backed BARs. Add read/write to I/O port PCI sysfs resource
files to allow userspace access to these device regions.
Acked-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 5935b85..f7692dc 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -778,6 +778,70 @@
return pci_mmap_resource(kobj, attr, vma, 1);
}
+static ssize_t
+pci_resource_io(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t off, size_t count, bool write)
+{
+ struct pci_dev *pdev = to_pci_dev(container_of(kobj,
+ struct device, kobj));
+ struct resource *res = attr->private;
+ unsigned long port = off;
+ int i;
+
+ for (i = 0; i < PCI_ROM_RESOURCE; i++)
+ if (res == &pdev->resource[i])
+ break;
+ if (i >= PCI_ROM_RESOURCE)
+ return -ENODEV;
+
+ port += pci_resource_start(pdev, i);
+
+ if (port > pci_resource_end(pdev, i))
+ return 0;
+
+ if (port + count - 1 > pci_resource_end(pdev, i))
+ return -EINVAL;
+
+ switch (count) {
+ case 1:
+ if (write)
+ outb(*(u8 *)buf, port);
+ else
+ *(u8 *)buf = inb(port);
+ return 1;
+ case 2:
+ if (write)
+ outw(*(u16 *)buf, port);
+ else
+ *(u16 *)buf = inw(port);
+ return 2;
+ case 4:
+ if (write)
+ outl(*(u32 *)buf, port);
+ else
+ *(u32 *)buf = inl(port);
+ return 4;
+ }
+ return -EINVAL;
+}
+
+static ssize_t
+pci_read_resource_io(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t off, size_t count)
+{
+ return pci_resource_io(filp, kobj, attr, buf, off, count, false);
+}
+
+static ssize_t
+pci_write_resource_io(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t off, size_t count)
+{
+ return pci_resource_io(filp, kobj, attr, buf, off, count, true);
+}
+
/**
* pci_remove_resource_files - cleanup resource files
* @pdev: dev to cleanup
@@ -828,6 +892,10 @@
sprintf(res_attr_name, "resource%d", num);
res_attr->mmap = pci_mmap_resource_uc;
}
+ if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
+ res_attr->read = pci_read_resource_io;
+ res_attr->write = pci_write_resource_io;
+ }
res_attr->attr.name = res_attr_name;
res_attr->attr.mode = S_IRUSR | S_IWUSR;
res_attr->size = pci_resource_len(pdev, num);