rt2x00: Move firmware checksumming to driver

rt2x00lib depended on 2 crc algorithms because rt61/rt73
use a different algorithm then rt2800. This means that
even when only 1 algorithm was needed, the dependency was
still present for both.
By moving the checksum generation to the driver we can clean
up 2 annoying flags (which indicated which checksum was required)
and move the dependency to where it belongs: the driver.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 82dd4ce..72c2827 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -24,6 +24,7 @@
 	Supported chipsets: rt2571W & rt2671.
  */
 
+#include <linux/crc-itu-t.h>
 #include <linux/delay.h>
 #include <linux/etherdevice.h>
 #include <linux/init.h>
@@ -817,16 +818,30 @@
 }
 
 /*
- * Firmware name function.
+ * Firmware functions
  */
 static char *rt73usb_get_firmware_name(struct rt2x00_dev *rt2x00dev)
 {
 	return FIRMWARE_RT2571;
 }
 
-/*
- * Initialization functions.
- */
+static u16 rt73usb_get_firmware_crc(void *data, const size_t len)
+{
+	u16 crc;
+
+	/*
+	 * Use the crc itu-t algorithm.
+	 * The last 2 bytes in the firmware array are the crc checksum itself,
+	 * this means that we should never pass those 2 bytes to the crc
+	 * algorithm.
+	 */
+	crc = crc_itu_t(0, data, len - 2);
+	crc = crc_itu_t_byte(crc, 0);
+	crc = crc_itu_t_byte(crc, 0);
+
+	return crc;
+}
+
 static int rt73usb_load_firmware(struct rt2x00_dev *rt2x00dev, void *data,
 				 const size_t len)
 {
@@ -896,6 +911,9 @@
 	return 0;
 }
 
+/*
+ * Initialization functions.
+ */
 static int rt73usb_init_registers(struct rt2x00_dev *rt2x00dev)
 {
 	u32 reg;
@@ -1852,7 +1870,6 @@
 	 * This device requires firmware.
 	 */
 	__set_bit(DRIVER_REQUIRE_FIRMWARE, &rt2x00dev->flags);
-	__set_bit(DRIVER_REQUIRE_FIRMWARE_CRC_ITU_T, &rt2x00dev->flags);
 
 	/*
 	 * Set the rssi offset.
@@ -2061,6 +2078,7 @@
 static const struct rt2x00lib_ops rt73usb_rt2x00_ops = {
 	.probe_hw		= rt73usb_probe_hw,
 	.get_firmware_name	= rt73usb_get_firmware_name,
+	.get_firmware_crc	= rt73usb_get_firmware_crc,
 	.load_firmware		= rt73usb_load_firmware,
 	.initialize		= rt2x00usb_initialize,
 	.uninitialize		= rt2x00usb_uninitialize,