rt2x00: change REGISTER_BUSY_COUNT for USB

Because of delays on USB we do not have to iterate so many times on
USB hardware when waiting for H/W register become valid.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2500usb.c

@@ -47,7 +47,7 @@ MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");
  * BBP and RF register require indirect register access,
  * and use the CSR registers BBPCSR and RFCSR to achieve this.
  * These indirect registers work with busy bits,
- * and we will try maximal REGISTER_BUSY_COUNT times to access
+ * and we will try maximal REGISTER_USB_BUSY_COUNT times to access
  * the register while taking a REGISTER_BUSY_DELAY us delay
  * between each attampt. When the busy bit is still set at that time,
  * the access attempt is considered to have failed,
@@ -122,7 +122,7 @@ static int rt2500usb_regbusy_read(struct rt2x00_dev *rt2x00dev,
 {
 	unsigned int i;
 
-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+	for (i = 0; i < REGISTER_USB_BUSY_COUNT; i++) {
 		rt2500usb_register_read_lock(rt2x00dev, offset, reg);
 		if (!rt2x00_get_field16(*reg, field))
 			return 1;
@@ -904,7 +904,7 @@ static int rt2500usb_wait_bbp_ready(struct rt2x00_dev *rt2x00dev)
 	unsigned int i;
 	u8 value;
 
-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+	for (i = 0; i < REGISTER_USB_BUSY_COUNT; i++) {
 		rt2500usb_bbp_read(rt2x00dev, 0, &value);
 		if ((value != 0xff) && (value != 0x00))
 			return 0;
@@ -1023,7 +1023,7 @@ static int rt2500usb_set_state(struct rt2x00_dev *rt2x00dev,
 	 * We must wait until the register indicates that the
 	 * device has entered the correct state.
 	 */
-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+	for (i = 0; i < REGISTER_USB_BUSY_COUNT; i++) {
 		rt2500usb_register_read(rt2x00dev, MAC_CSR17, &reg2);
 		bbp_state = rt2x00_get_field16(reg2, MAC_CSR17_BBP_CURR_STATE);
 		rf_state = rt2x00_get_field16(reg2, MAC_CSR17_RF_CURR_STATE);

drivers/net/wireless/rt2x00/rt2x00.h

@@ -1019,9 +1019,12 @@ struct rt2x00_bar_list_entry {
  * Register defines.
  * Some registers require multiple attempts before success,
  * in those cases REGISTER_BUSY_COUNT attempts should be
- * taken with a REGISTER_BUSY_DELAY interval.
+ * taken with a REGISTER_BUSY_DELAY interval. Due to USB
+ * bus delays, we do not have to loop so many times to wait
+ * for valid register value on that bus.
  */
 #define REGISTER_BUSY_COUNT	100
+#define REGISTER_USB_BUSY_COUNT 20
 #define REGISTER_BUSY_DELAY	100
 
 /*

drivers/net/wireless/rt2x00/rt2x00usb.c

@@ -150,7 +150,7 @@ int rt2x00usb_regbusy_read(struct rt2x00_dev *rt2x00dev,
 	if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
 		return -ENODEV;
 
-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+	for (i = 0; i < REGISTER_USB_BUSY_COUNT; i++) {
 		rt2x00usb_register_read_lock(rt2x00dev, offset, reg);
 		if (!rt2x00_get_field32(*reg, field))
 			return 1;

drivers/net/wireless/rt2x00/rt73usb.c

@@ -1295,7 +1295,7 @@ static int rt73usb_wait_bbp_ready(struct rt2x00_dev *rt2x00dev)
 	unsigned int i;
 	u8 value;
 
-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+	for (i = 0; i < REGISTER_USB_BUSY_COUNT; i++) {
 		rt73usb_bbp_read(rt2x00dev, 0, &value);
 		if ((value != 0xff) && (value != 0x00))
 			return 0;