b43: Rewrite TX power adjustment

This patch rewrites the TX power recalculation algorithms to scale better
with changed enviromnent. If there's low
TX traffic, the power will be checked against the desired values
every 60 seconds.
If there is high TX traffic, the check is redone every 2 seconds. This improves
the reaction times a lot and confuses the rate control less.
It will also reduce the time it initially takes to tune to a new TX power
value. With the old algorithm it could take about 30 to 45 seconds to settle to
a new power value. This will happen in about two to four seconds now.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 72 insertions, 3 deletions

diff --git a/drivers/net/wireless/b43/phy_common.h b/drivers/net/wireless/b43/phy_common.h
index 9b9635eda9c4..f8db9f40df5d 100644
--- a/drivers/net/wireless/b43/phy_common.h
+++ b/drivers/net/wireless/b43/phy_common.h
@@ -61,6 +61,17 @@ enum {
 };
 
 /**
+ * enum b43_txpwr_result - Return value for the recalc_txpower PHY op.
+ *
+ * @B43_TXPWR_RES_NEED_ADJUST:  Values changed. Hardware adjustment is needed.
+ * @B43_TXPWR_RES_DONE:         No more work to do. Everything is done.
+ */
+enum b43_txpwr_result {
+        B43_TXPWR_RES_NEED_ADJUST,
+        B43_TXPWR_RES_DONE,
+};
+
+/**
  * struct b43_phy_operations - Function pointers for PHY ops.
  *
  * @prepare:            Prepare the PHY. This is called before @init.
@@ -96,8 +107,23 @@ enum {
  * @interf_mitigation:  Switch the Interference Mitigation mode.
  *                      Can be NULL, if not supported.
  *
- * @xmitpower:          FIXME REMOVEME
+ * @recalc_txpower:     Recalculate the transmission power parameters.
+ *                      This callback has to recalculate the TX power settings,
+ *                      but does not need to write them to the hardware, yet.
+ *                      Returns enum b43_txpwr_result to indicate whether the hardware
+ *                      needs to be adjusted.
+ *                      If B43_TXPWR_NEED_ADJUST is returned, @adjust_txpower
+ *                      will be called later.
+ *                      If the parameter "ignore_tssi" is true, the TSSI values should
+ *                      be ignored and a recalculation of the power settings should be
+ *                      done even if the TSSI values did not change.
+ *                      This callback is called with wl->irq_lock held and must not sleep.
  *                      Must not be NULL.
+ * @adjust_txpower:     Write the previously calculated TX power settings
+ *                      (from @recalc_txpower) to the hardware.
+ *                      This function may sleep.
+ *                      Can be NULL, if (and ONLY if) @recalc_txpower _always_
+ *                      returns B43_TXPWR_RES_DONE.
  *
  * @pwork_15sec:        Periodic work. Called every 15 seconds.
  *                      Can be NULL, if not required.
@@ -127,7 +153,9 @@ struct b43_phy_operations {
                                  enum b43_interference_mitigation new_mode);
 
         /* Transmission power adjustment */
-        void (*xmitpower)(struct b43_wldev *dev);
+        enum b43_txpwr_result (*recalc_txpower)(struct b43_wldev *dev,
+                                                bool ignore_tssi);
+        void (*adjust_txpower)(struct b43_wldev *dev);
 
         /* Misc */
         void (*pwork_15sec)(struct b43_wldev *dev);
@@ -183,11 +211,15 @@ struct b43_phy {
 
         /* Desired TX power level (in dBm).
          * This is set by the user and adjusted in b43_phy_xmitpower(). */
-        u8 power_level;
+        int desired_txpower;
 
         /* Hardware Power Control enabled? */
         bool hardware_power_control;
 
+        /* The time (in absolute jiffies) when the next TX power output
+         * check is needed. */
+        unsigned long next_txpwr_check_time;
+
         /* current channel */
         unsigned int channel;
 
@@ -309,4 +341,41 @@ int b43_switch_channel(struct b43_wldev *dev, unsigned int new_channel);
  */
 void b43_software_rfkill(struct b43_wldev *dev, enum rfkill_state state);
 
+/**
+ * b43_phy_txpower_check - Check TX power output.
+ *
+ * Compare the current TX power output to the desired power emission
+ * and schedule an adjustment in case it mismatches.
+ * Requires wl->irq_lock locked.
+ *
+ * @flags:      OR'ed enum b43_phy_txpower_check_flags flags.
+ *              See the docs below.
+ */
+void b43_phy_txpower_check(struct b43_wldev *dev, unsigned int flags);
+/**
+ * enum b43_phy_txpower_check_flags - Flags for b43_phy_txpower_check()
+ *
+ * @B43_TXPWR_IGNORE_TIME: Ignore the schedule time and force-redo
+ *                         the check now.
+ * @B43_TXPWR_IGNORE_TSSI: Redo the recalculation, even if the average
+ *                         TSSI did not change.
+ */
+enum b43_phy_txpower_check_flags {
+        B43_TXPWR_IGNORE_TIME           = (1 << 0),
+        B43_TXPWR_IGNORE_TSSI           = (1 << 1),
+};
+
+struct work_struct;
+void b43_phy_txpower_adjust_work(struct work_struct *work);
+
+/**
+ * b43_phy_shm_tssi_read - Read the average of the last 4 TSSI from SHM.
+ *
+ * @shm_offset:         The SHM address to read the values from.
+ *
+ * Returns the average of the 4 TSSI values, or a negative error code.
+ */
+int b43_phy_shm_tssi_read(struct b43_wldev *dev, u16 shm_offset);
+
+
 #endif /* LINUX_B43_PHY_COMMON_H_ */