[PATCH] PCI config space in sysfs

 - Fix a couple of bugs in sysfs's handling of binary files (my fault).
 - Implement pci config space reads and writes in sysfs

drivers/pci/pci-sysfs.c

@@ -3,6 +3,8 @@
  *
  * (C) Copyright 2002 Greg Kroah-Hartman
  * (C) Copyright 2002 IBM Corp.
+ * (C) Copyright 2003 Matthew Wilcox
+ * (C) Copyright 2003 Hewlett-Packard
  *
  * File attributes for PCI devices
  *
@@ -60,6 +62,108 @@ pci_show_resources(struct device * dev, char * buf)
 
 static DEVICE_ATTR(resource,S_IRUGO,pci_show_resources,NULL);
 
+static ssize_t
+pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
+	unsigned int size = 64;
+
+	/* Several chips lock up trying to read undefined config space */
+	if (capable(CAP_SYS_ADMIN)) {
+		size = 256;
+	} else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
+		size = 128;
+	}
+
+	if (off > size)
+		return 0;
+	if (off + count > size) {
+		size -= off;
+		count = size;
+	} else {
+		size = count;
+	}
+
+	while (off & 3) {
+		unsigned char val;
+		pci_read_config_byte(dev, off, &val);
+		buf[off] = val;
+		off++;
+		if (--size == 0)
+			break;
+	}
+
+	while (size > 3) {
+		unsigned int val;
+		pci_read_config_dword(dev, off, &val);
+		buf[off] = val & 0xff;
+		buf[off + 1] = (val >> 8) & 0xff;
+		buf[off + 2] = (val >> 16) & 0xff;
+		buf[off + 3] = (val >> 24) & 0xff;
+		off += 4;
+		size -= 4;
+	}
+
+	while (size > 0) {
+		unsigned char val;
+		pci_read_config_byte(dev, off, &val);
+		buf[off] = val;
+		off++;
+		--size;
+	}
+
+	return count;
+}
+
+static ssize_t
+pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+	struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
+	unsigned int size = count;
+
+	if (off > 256)
+		return 0;
+	if (off + count > 256) {
+		size = 256 - off;
+		count = size;
+	}
+
+	while (off & 3) {
+		pci_write_config_byte(dev, off, buf[off]);
+		off++;
+		if (--size == 0)
+			break;
+	}
+
+	while (size > 3) {
+		unsigned int val = buf[off];
+		val |= (unsigned int) buf[off + 1] << 8;
+		val |= (unsigned int) buf[off + 2] << 16;
+		val |= (unsigned int) buf[off + 3] << 24;
+		pci_write_config_dword(dev, off, val);
+		off += 4;
+		size -= 4;
+	}
+
+	while (size > 0) {
+		pci_write_config_byte(dev, off, buf[off]);
+		off++;
+		--size;
+	}
+
+	return count;
+}
+
+static struct bin_attribute pci_config_attr = {
+	.attr =	{
+		.name = "config",
+		.mode = S_IRUGO | S_IWUSR,
+	},
+	.size = 256,
+	.read = pci_read_config,
+	.write = pci_write_config,
+};
+
 void pci_create_sysfs_dev_files (struct pci_dev *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -72,4 +176,5 @@ void pci_create_sysfs_dev_files (struct pci_dev *pdev)
 	device_create_file (dev, &dev_attr_class);
 	device_create_file (dev, &dev_attr_irq);
 	device_create_file (dev, &dev_attr_resource);
+	sysfs_create_bin_file(&dev->kobj, &pci_config_attr);
 }

fs/sysfs/bin.c

@@ -42,18 +42,17 @@ read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
 
 	ret = fill_read(dentry, buffer, offs, count);
 	if (ret < 0) 
-		goto Done;
+		return ret;
 	count = ret;
 
-	ret = -EFAULT;
-	if (copy_to_user(userbuf, buffer, count) != 0)
-		goto Done;
+	if (copy_to_user(userbuf, buffer + offs, count) != 0)
+		return -EINVAL;
+
+	printk("offs = %lld, *off = %lld, count = %zd\n", offs, *off, count);
 
 	*off = offs + count;
-	ret = count;
 
- Done:
-	return ret;
+	return count;
 }
 
 static int
@@ -72,7 +71,6 @@ static ssize_t write(struct file * file, const char __user * userbuf,
 	struct dentry *dentry = file->f_dentry;
 	int size = dentry->d_inode->i_size;
 	loff_t offs = *off;
-	int ret;
 
 	if (count > PAGE_SIZE)
 		count = PAGE_SIZE;
@@ -83,16 +81,13 @@ static ssize_t write(struct file * file, const char __user * userbuf,
 			count = size - offs;
 	}
 
-	ret = -EFAULT;
-	if (copy_from_user(buffer, userbuf, count))
-		goto Done;
+	if (copy_from_user(buffer + offs, userbuf, count))
+		return -EFAULT;
 
 	count = flush_write(dentry, buffer, offs, count);
 	if (count > 0)
 		*off = offs + count;
-	ret = count;
- Done:
-	return ret;
+	return count;
 }
 
 static int open(struct inode * inode, struct file * file)