[PATCH] PCI: fix up word-aligned 16-bit PCI config access through sysfs

This patch adds the possibility to do word-aligned 16-bit atomic PCI
configuration space accesses via the sysfs PCI interface. As a result, problems
with Emulex LFPC on IBM PowerPC64 are fixed.

Patch is present in SLES 9 SP1.
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/pci-sysfs.c

@@ -91,6 +91,7 @@ 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;
 	loff_t init_off = off;
+	u8 *data = (u8*) buf;
 
 	/* Several chips lock up trying to read undefined config space */
 	if (capable(CAP_SYS_ADMIN)) {
@@ -108,30 +109,47 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 		size = count;
 	}
 
-	while (off & 3) {
-		unsigned char val;
+	if ((off & 1) && size) {
+		u8 val;
 		pci_read_config_byte(dev, off, &val);
-		buf[off - init_off] = val;
+		data[off - init_off] = val;
 		off++;
-		if (--size == 0)
-			break;
+		size--;
+	}
+
+	if ((off & 3) && size > 2) {
+		u16 val;
+		pci_read_config_word(dev, off, &val);
+		data[off - init_off] = val & 0xff;
+		data[off - init_off + 1] = (val >> 8) & 0xff;
+		off += 2;
+		size -= 2;
 	}
 
 	while (size > 3) {
-		unsigned int val;
+		u32 val;
 		pci_read_config_dword(dev, off, &val);
-		buf[off - init_off] = val & 0xff;
-		buf[off - init_off + 1] = (val >> 8) & 0xff;
-		buf[off - init_off + 2] = (val >> 16) & 0xff;
-		buf[off - init_off + 3] = (val >> 24) & 0xff;
+		data[off - init_off] = val & 0xff;
+		data[off - init_off + 1] = (val >> 8) & 0xff;
+		data[off - init_off + 2] = (val >> 16) & 0xff;
+		data[off - init_off + 3] = (val >> 24) & 0xff;
 		off += 4;
 		size -= 4;
 	}
 
-	while (size > 0) {
-		unsigned char val;
+	if (size >= 2) {
+		u16 val;
+		pci_read_config_word(dev, off, &val);
+		data[off - init_off] = val & 0xff;
+		data[off - init_off + 1] = (val >> 8) & 0xff;
+		off += 2;
+		size -= 2;
+	}
+
+	if (size > 0) {
+		u8 val;
 		pci_read_config_byte(dev, off, &val);
-		buf[off - init_off] = val;
+		data[off - init_off] = val;
 		off++;
 		--size;
 	}
@@ -145,6 +163,7 @@ 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;
 	loff_t init_off = off;
+	u8 *data = (u8*) buf;
 
 	if (off > dev->cfg_size)
 		return 0;
@@ -153,25 +172,40 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 		count = size;
 	}
 	
-	while (off & 3) {
-		pci_write_config_byte(dev, off, buf[off - init_off]);
+	if ((off & 1) && size) {
+		pci_write_config_byte(dev, off, data[off - init_off]);
 		off++;
-		if (--size == 0)
-			break;
+		size--;
+	}
+	
+	if ((off & 3) && size > 2) {
+		u16 val = data[off - init_off];
+		val |= (u16) data[off - init_off + 1] << 8;
+                pci_write_config_word(dev, off, val);
+                off += 2;
+                size -= 2;
         }
 
 	while (size > 3) {
-		unsigned int val = buf[off - init_off];
-		val |= (unsigned int) buf[off - init_off + 1] << 8;
-		val |= (unsigned int) buf[off - init_off + 2] << 16;
-		val |= (unsigned int) buf[off - init_off + 3] << 24;
+		u32 val = data[off - init_off];
+		val |= (u32) data[off - init_off + 1] << 8;
+		val |= (u32) data[off - init_off + 2] << 16;
+		val |= (u32) data[off - init_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 - init_off]);
+	if (size >= 2) {
+		u16 val = data[off - init_off];
+		val |= (u16) data[off - init_off + 1] << 8;
+		pci_write_config_word(dev, off, val);
+		off += 2;
+		size -= 2;
+	}
+
+	if (size) {
+		pci_write_config_byte(dev, off, data[off - init_off]);
 		off++;
 		--size;
 	}