package/kernel/mac80211/patches/307-ath9k-Set-ATH_OP_HW_RESET-before-HW-reset.patch

   1 From: Sujith Manoharan <c_manoha@qca.qualcomm.com>
   2 Date: Fri, 17 Oct 2014 07:40:12 +0530
   3 Subject: [PATCH] ath9k: Set ATH_OP_HW_RESET before HW reset
   4
   5 When a HW reset is done, the interrupt tasklet is
   6 disabled before ISRs are disabled in the HW. This
   7 allows a small window where the HW can still generate
   8 interrupts. Since the tasklet is disabled and not killed,
   9 it is not scheduled but deferred for execution at a later
  10 time.
  11
  12 This happens because ATH_OP_HW_RESET is not set when ath_reset()
  13 is called. When the hw_reset_work workqueue is used, this
  14 problem doesn't arise because ATH_OP_HW_RESET is set
  15 and the ISR bails out.
  16
  17 Set ATH_OP_HW_RESET properly in ath_reset() to avoid
  18 this race - all the ath_reset_internal() callers have
  19 been converted to use ath_reset() in the previous patch.
  20
  21 Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
  22 ---
  23
  24 --- a/drivers/net/wireless/ath/ath9k/main.c
  25 +++ b/drivers/net/wireless/ath/ath9k/main.c
  26 @@ -598,10 +598,17 @@ chip_reset:
  27  #undef SCHED_INTR
  28  }
  29
  30 +/*
  31 + * This function is called when a HW reset cannot be deferred
  32 + * and has to be immediate.
  33 + */
  34  int ath_reset(struct ath_softc *sc, struct ath9k_channel *hchan)
  35  {
  36 +       struct ath_common *common = ath9k_hw_common(sc->sc_ah);
  37         int r;
  38
  39 +       set_bit(ATH_OP_HW_RESET, &common->op_flags);
  40 +
  41         ath9k_ps_wakeup(sc);
  42         r = ath_reset_internal(sc, hchan);
  43         ath9k_ps_restore(sc);
  44 @@ -609,6 +616,11 @@ int ath_reset(struct ath_softc *sc, stru
  45         return r;
  46  }
  47
  48 +/*
  49 + * When a HW reset can be deferred, it is added to the
  50 + * hw_reset_work workqueue, but we set ATH_OP_HW_RESET before
  51 + * queueing.
  52 + */
  53  void ath9k_queue_reset(struct ath_softc *sc, enum ath_reset_type type)
  54  {
  55         struct ath_common *common = ath9k_hw_common(sc->sc_ah);