Re: [PATCH 4/4] ath5k: Use SWI to trigger calibration

 * Get rid of calibration timer, instead use a software interrupt
   to schedule the calibration tasklet.

 Signed-off-by: Nick Kossifidis <mickflemm@xxxxxxxxx>

---
 drivers/net/wireless/ath/ath5k/ath5k.h |   16 ++++++++++++++++
 drivers/net/wireless/ath/ath5k/base.c  |   28 ++++++++++++++++++----------
 drivers/net/wireless/ath/ath5k/base.h  |    3 ++-
 drivers/net/wireless/ath/ath5k/phy.c   |   20 ++++++++++++++++++++
 4 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h 
b/drivers/net/wireless/ath/ath5k/ath5k.h
index 1047a6c..76cf5b2 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -919,6 +919,12 @@ enum ath5k_int {
        AR5K_INT_NOCARD = 0xffffffff
 };
 
+/* Software interrupts used for calibration */
+enum ath5k_software_interrupt {
+       AR5K_SWI_FULL_CALIBRATION = 0x01,
+       AR5K_SWI_SHORT_CALIBRATION = 0x02,
+};
+
 /*
  * Power management
  */
@@ -1123,6 +1129,15 @@ struct ath5k_hw {
        /* noise floor from last periodic calibration */
        s32                     ah_noise_floor;
 
+       /* Calibration timestamp */
+       u32                     ah_cal_tstamp;
+
+       /* Calibration interval (secs) */
+       u8                      ah_cal_intval;
+
+       /* Software interrupt mask */
+       u8                      ah_swi_mask;
+
        /*
         * Function pointers
         */
@@ -1276,6 +1291,7 @@ extern int ath5k_hw_channel(struct ath5k_hw *ah, struct 
ieee80211_channel *chann
 /* PHY calibration */
 extern int ath5k_hw_phy_calibrate(struct ath5k_hw *ah, struct 
ieee80211_channel *channel);
 extern int ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq);
+extern void ath5k_hw_calibration_poll(struct ath5k_hw *ah);
 /* Spur mitigation */
 bool ath5k_hw_chan_has_spur_noise(struct ath5k_hw *ah,
                                struct ieee80211_channel *channel);
diff --git a/drivers/net/wireless/ath/ath5k/base.c 
b/drivers/net/wireless/ath/ath5k/base.c
index b64731b..02fa71a 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -59,7 +59,7 @@
 #include "reg.h"
 #include "debug.h"
 
-static int ath5k_calinterval = 10; /* Calibrate PHY every 10 secs (TODO: 
Fixme) */
+static u8 ath5k_calinterval = 10; /* Calibrate PHY every 10 secs (TODO: Fixme) 
*/
 static int modparam_nohwcrypt;
 module_param_named(nohwcrypt, modparam_nohwcrypt, bool, S_IRUGO);
 MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");
@@ -376,7 +376,7 @@ static int  ath5k_stop_hw(struct ath5k_softc *sc);
 static irqreturn_t ath5k_intr(int irq, void *dev_id);
 static void    ath5k_tasklet_reset(unsigned long data);
 
-static void    ath5k_calibrate(unsigned long data);
+static void    ath5k_tasklet_calibrate(unsigned long data);
 
 /*
  * Module init/exit functions
@@ -799,8 +799,8 @@ ath5k_attach(struct pci_dev *pdev, struct ieee80211_hw *hw)
        tasklet_init(&sc->rxtq, ath5k_tasklet_rx, (unsigned long)sc);
        tasklet_init(&sc->txtq, ath5k_tasklet_tx, (unsigned long)sc);
        tasklet_init(&sc->restq, ath5k_tasklet_reset, (unsigned long)sc);
+       tasklet_init(&sc->calib, ath5k_tasklet_calibrate, (unsigned long)sc);
        tasklet_init(&sc->beacontq, ath5k_tasklet_beacon, (unsigned long)sc);
-       setup_timer(&sc->calib_tim, ath5k_calibrate, (unsigned long)sc);
 
        ret = ath5k_eeprom_read_mac(ah, mac);
        if (ret) {
@@ -2366,7 +2366,7 @@ ath5k_init(struct ath5k_softc *sc)
        sc->curband = &sc->sbands[sc->curchan->band];
        sc->imask = AR5K_INT_RXOK | AR5K_INT_RXERR | AR5K_INT_RXEOL |
                AR5K_INT_RXORN | AR5K_INT_TXDESC | AR5K_INT_TXEOL |
-               AR5K_INT_FATAL | AR5K_INT_GLOBAL;
+               AR5K_INT_FATAL | AR5K_INT_GLOBAL | AR5K_INT_SWI;
        ret = ath5k_reset(sc, NULL);
        if (ret)
                goto done;
@@ -2383,8 +2383,8 @@ ath5k_init(struct ath5k_softc *sc)
        /* Set ack to be sent at low bit-rates */
        ath5k_hw_set_ack_bitrate_high(ah, false);
 
-       mod_timer(&sc->calib_tim, round_jiffies(jiffies +
-                       msecs_to_jiffies(ath5k_calinterval * 1000)));
+       /* Set PHY calibration timestamp and inteval */
+       ah->ah_cal_intval = ath5k_calinterval;
 
        ret = 0;
 done:
@@ -2477,7 +2477,6 @@ ath5k_stop_hw(struct ath5k_softc *sc)
        mmiowb();
        mutex_unlock(&sc->lock);
 
-       del_timer_sync(&sc->calib_tim);
        tasklet_kill(&sc->rxtq);
        tasklet_kill(&sc->txtq);
        tasklet_kill(&sc->restq);
@@ -2536,6 +2535,9 @@ ath5k_intr(int irq, void *dev_id)
                        if (status & AR5K_INT_BMISS) {
                                /* TODO */
                        }
+                       if (status & AR5K_INT_SWI) {
+                               tasklet_schedule(&sc->calib);
+                       }
                        if (status & AR5K_INT_MIB) {
                                /*
                                 * These stats are also used for ANI i think
@@ -2552,6 +2554,8 @@ ath5k_intr(int irq, void *dev_id)
        if (unlikely(!counter))
                ATH5K_WARN(sc, "too many interrupts, giving up for now\n");
 
+       ath5k_hw_calibration_poll(ah);
+
        return IRQ_HANDLED;
 }
 
@@ -2568,11 +2572,15 @@ ath5k_tasklet_reset(unsigned long data)
  * for temperature/environment changes.
  */
 static void
-ath5k_calibrate(unsigned long data)
+ath5k_tasklet_calibrate(unsigned long data)
 {
        struct ath5k_softc *sc = (void *)data;
        struct ath5k_hw *ah = sc->ah;
 
+       /* Only full calibration for now */
+       if (ah->ah_swi_mask != AR5K_SWI_FULL_CALIBRATION)
+               return;
+
        ATH5K_DBG(sc, ATH5K_DEBUG_CALIBRATE, "channel %u/%x\n",
                ieee80211_frequency_to_channel(sc->curchan->center_freq),
                sc->curchan->hw_value);
@@ -2590,8 +2598,8 @@ ath5k_calibrate(unsigned long data)
                        ieee80211_frequency_to_channel(
                                sc->curchan->center_freq));
 
-       mod_timer(&sc->calib_tim, round_jiffies(jiffies +
-                       msecs_to_jiffies(ath5k_calinterval * 1000)));
+       ah->ah_swi_mask = 0;
+
 }
 
 
diff --git a/drivers/net/wireless/ath/ath5k/base.h 
b/drivers/net/wireless/ath/ath5k/base.h
index 778e422..667bd9d 100644
--- a/drivers/net/wireless/ath/ath5k/base.h
+++ b/drivers/net/wireless/ath/ath5k/base.h
@@ -177,6 +177,8 @@ struct ath5k_softc {
 
        struct ath5k_rfkill     rf_kill;
 
+       struct tasklet_struct   calib;          /* calibration tasklet */
+
        spinlock_t              block;          /* protects beacon */
        struct tasklet_struct   beacontq;       /* beacon intr tasklet */
        struct ath5k_buf        *bbuf;          /* beacon buffer */
@@ -187,7 +189,6 @@ struct ath5k_softc {
        unsigned int            nexttbtt;       /* next beacon time in TU */
        struct ath5k_txq        *cabq;          /* content after beacon */
 
-       struct timer_list       calib_tim;      /* calibration timer */
        int                     power_level;    /* Requested tx power in dbm */
        bool                    assoc;          /* assocate state */
        bool                    enable_beacon;  /* true if beacons are on */
diff --git a/drivers/net/wireless/ath/ath5k/phy.c 
b/drivers/net/wireless/ath/ath5k/phy.c
index 6afba98..d30bc3b 100644
--- a/drivers/net/wireless/ath/ath5k/phy.c
+++ b/drivers/net/wireless/ath/ath5k/phy.c
@@ -1104,6 +1104,26 @@ int ath5k_hw_channel(struct ath5k_hw *ah, struct 
ieee80211_channel *channel)
   PHY calibration
 \*****************/
 
+void
+ath5k_hw_calibration_poll(struct ath5k_hw *ah)
+{
+       u32 current_time = (jiffies / HZ);
+       u32 cal_intval = ah->ah_cal_intval;
+
+       if (!ah->ah_cal_tstamp)
+               ah->ah_cal_tstamp = current_time;
+
+       /* For now we always do full calibration
+        * Mark software interrupt mask and fire software
+        * interrupt (bit gets auto-cleared) */
+       if ((current_time - ah->ah_cal_tstamp) >= cal_intval) {
+               ah->ah_cal_tstamp = current_time;
+               ah->ah_swi_mask = AR5K_SWI_FULL_CALIBRATION;
+               AR5K_REG_ENABLE_BITS(ah, AR5K_CR, AR5K_CR_SWI);
+       }
+
+}
+
 /**
  * ath5k_hw_noise_floor_calibration - perform PHY noise floor calibration
  *

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