rt2x00: Reduce calls to bbp_read()

The link_tuner() function will always call bbp_read()
at the start of the function. Because this is an
indirect register access has some costs attached
to it (especially for USB hardware).

We already store the value read from the register
into the vgc_level value inside the link structure.
Instead of reading from the register we can read that
field directly and base the tuner on that value.

This reduces the time the registers are locked with
the csr_mutex and speeds up the link_tuner processing.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 14 insertions, 13 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2400pci.c b/drivers/net/wireless/rt2x00/rt2400pci.c
index 1afba42cc128..e87ad43e8e8d 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -600,35 +600,36 @@ static void rt2400pci_link_stats(struct rt2x00_dev *rt2x00dev,
         qual->false_cca = bbp;
 }
 
+static inline void rt2400pci_set_vgc(struct rt2x00_dev *rt2x00dev, u8 vgc_level)
+{
+        rt2400pci_bbp_write(rt2x00dev, 13, vgc_level);
+        rt2x00dev->link.vgc_level = vgc_level;
+        rt2x00dev->link.vgc_level_reg = vgc_level;
+}
+
 static void rt2400pci_reset_tuner(struct rt2x00_dev *rt2x00dev)
 {
-        rt2400pci_bbp_write(rt2x00dev, 13, 0x08);
-        rt2x00dev->link.vgc_level = 0x08;
+        rt2400pci_set_vgc(rt2x00dev, 0x08);
 }
 
 static void rt2400pci_link_tuner(struct rt2x00_dev *rt2x00dev)
 {
-        u8 reg;
+        struct link *link = &rt2x00dev->link;
 
         /*
          * The link tuner should not run longer then 60 seconds,
          * and should run once every 2 seconds.
          */
-        if (rt2x00dev->link.count > 60 || !(rt2x00dev->link.count & 1))
+        if (link->count > 60 || !(link->count & 1))
                 return;
 
         /*
          * Base r13 link tuning on the false cca count.
          */
-        rt2400pci_bbp_read(rt2x00dev, 13, &reg);
-
-        if (rt2x00dev->link.qual.false_cca > 512 && reg < 0x20) {
-                rt2400pci_bbp_write(rt2x00dev, 13, ++reg);
-                rt2x00dev->link.vgc_level = reg;
-        } else if (rt2x00dev->link.qual.false_cca < 100 && reg > 0x08) {
-                rt2400pci_bbp_write(rt2x00dev, 13, --reg);
-                rt2x00dev->link.vgc_level = reg;
-        }
+        if ((link->qual.false_cca > 512) && (link->vgc_level < 0x20))
+                rt2400pci_set_vgc(rt2x00dev, ++link->vgc_level);
+        else if ((link->qual.false_cca < 100) && (link->vgc_level > 0x08))
+                rt2400pci_set_vgc(rt2x00dev, --link->vgc_level);
 }
 
 /*