On 2012-03-13 10:38 PM, Rajkumar Manoharan wrote:
> In the experiment with Azimuth ADEPT-n testbed where the APs transmit
> power was reduced to 25% and the signal strength was futher attenuated
> by 20dB and induced a path loss of ~7dB, the station was reporting
> beacon losses and the following issue were observed.
>
> * rx clear is stuck at low for more than 100ms
> * dcu chain and complete state is stuck at one of the hang signature
>
> This patch triggers the hang detection logic that recovers the chip
> from any of the above conditions. As the issue was originally reported
> in ChromeOs with AR9382 chips, this detection logic is enabled only for
> AR9380/2 chips.
>
> Cc: Paul Stewart <pstew@xxxxxxxxxx>
> Reported-by: Gary Morain <gmorain@xxxxxxxxxx>
> Signed-off-by: Rajkumar Manoharan <rmanohar@xxxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath.h | 1 +
> drivers/net/wireless/ath/ath9k/ath9k.h | 3 ++
> drivers/net/wireless/ath/ath9k/hw.c | 71 ++++++++++++++++++++++++++++++++
> drivers/net/wireless/ath/ath9k/hw.h | 1 +
> drivers/net/wireless/ath/ath9k/init.c | 1 +
> drivers/net/wireless/ath/ath9k/main.c | 66 +++++++++++++++++++++++++++++
> drivers/net/wireless/ath/ath9k/recv.c | 3 ++
> drivers/net/wireless/ath/hw.c | 5 +++
> 8 files changed, 151 insertions(+)
>
> --- a/drivers/net/wireless/ath/ath9k/hw.c
> +++ b/drivers/net/wireless/ath/ath9k/hw.c
> @@ -3045,3 +3045,74 @@ void ath9k_hw_name(struct ath_hw *ah, char *hw_name, size_t len)
> hw_name[used] = '\0';
> }
> EXPORT_SYMBOL(ath9k_hw_name);
> +
> +static bool ath9k_hw_check_dcs(u32 dma_dbg, u32 num_dcu_states,
> + int *hang_state, int *hang_pos)
> +{
> + static u32 dcu_chain_state[] = {5, 6, 9}; /* DCU chain stuck states */
> + u32 chain_state, dcs_pos, i;
> +
> + for (dcs_pos = 0; dcs_pos < num_dcu_states; dcs_pos++) {
> + chain_state = (dma_dbg >> (5 * dcs_pos)) & 0x1f;
> + for (i = 0; i < 3; i++) {
> + if (chain_state == dcu_chain_state[i]) {
> + *hang_state = chain_state;
> + *hang_pos = dcs_pos;
> + return true;
> + }
> + }
> + }
> + return false;
> +}
> +
> +#define DCU_COMPLETE_STATE 1
> +#define DCU_COMPLETE_STATE_MASK 0x3
> +#define NUM_STATUS_READS 50
> +bool ath9k_hw_detect_mac_hang(struct ath_hw *ah)
> +{
> + u32 chain_state, comp_state, dcs_reg = AR_DMADBG_4;
> + u32 i, hang_pos, hang_state, num_state = 6;
> +
> + comp_state = REG_READ(ah, AR_DMADBG_6);
> +
> + if ((comp_state & DCU_COMPLETE_STATE_MASK) != DCU_COMPLETE_STATE) {
> + ath_dbg(ath9k_hw_common(ah), RESET,
> + "MAC Hang signature not found at DCU complete\n");
> + return false;
> + }
> +
> + chain_state = REG_READ(ah, dcs_reg);
> + if (ath9k_hw_check_dcs(chain_state, num_state, &hang_state, &hang_pos))
> + goto hang_check_iter;
> +
> + dcs_reg = AR_DMADBG_5;
> + num_state = 4;
> + chain_state = REG_READ(ah, dcs_reg);
> + if (ath9k_hw_check_dcs(chain_state, num_state, &hang_state, &hang_pos))
> + goto hang_check_iter;
> +
> + ath_dbg(ath9k_hw_common(ah), RESET,
> + "MAC Hang signature 1 not found\n");
> + return false;
> +
> +hang_check_iter:
> + ath_dbg(ath9k_hw_common(ah), RESET,
> + "DCU registers: chain %08x complete %08x Hang: state %d pos %d\n",
> + chain_state, comp_state, hang_state, hang_pos);
> +
> + for (i = 0; i < NUM_STATUS_READS; i++) {
> + chain_state = REG_READ(ah, dcs_reg);
> + chain_state = (chain_state >> (5 * hang_pos)) & 0x1f;
> + comp_state = REG_READ(ah, AR_DMADBG_6);
> +
> + if (((comp_state & DCU_COMPLETE_STATE_MASK) !=
> + DCU_COMPLETE_STATE) ||
> + (chain_state != hang_state))
> + return false;
> + }
> +
> + ath_dbg(ath9k_hw_common(ah), RESET, "MAC Hang signature 1 found\n");
> +
> + return true;
> +}
> +EXPORT_SYMBOL(ath9k_hw_detect_mac_hang);
This could be merged into ath9k_hw_check_alive()
> --- a/drivers/net/wireless/ath/ath9k/main.c
> +++ b/drivers/net/wireless/ath/ath9k/main.c
> @@ -1396,6 +1399,65 @@ static void ath9k_do_vif_add_setup(struct ieee80211_hw *hw,
> }
> }
>
> +void ath_start_rx_poll(struct ath_softc *sc, u32 nmsec)
> +{
> + if (!AR_SREV_9300(sc->sc_ah))
> + return;
> +
> + if (!(sc->sc_flags & SC_OP_PRIM_STA_VIF))
> + return;
> +
> + mod_timer(&sc->rx_poll_timer, jiffies + msecs_to_jiffies(nmsec));
> +}
> +
> +void ath_rx_poll_work(unsigned long data)
> +{
> + struct ath_softc *sc = (struct ath_softc *)data;
> + struct ath_hw *ah = sc->sc_ah;
> + struct ath_common *common = ath9k_hw_common(ah);
> + static u32 iteration, match_count;
> + static u64 last_run;
> + unsigned long flags;
> + u32 rx_clear, rx, tx, nmsec = 10;
> +
> + if (jiffies_to_msecs(jiffies - last_run) > 120)
> + iteration = match_count = 0;
> + else
> + iteration += 1;
> +
> + ath9k_ps_wakeup(sc);
> +
> + spin_lock_irqsave(&common->cc_lock, flags);
> + ath_hw_cycle_counters_update(common);
> +
> + rx_clear = common->cc_rxpoll.rx_busy * 100 / common->cc_rxpoll.cycles;
> + rx = common->cc_rxpoll.rx_frame * 100 / common->cc_rxpoll.cycles;
> + tx = common->cc_rxpoll.tx_frame * 100 / common->cc_rxpoll.cycles;
> + memset(&common->cc_rxpoll, 0, sizeof(common->cc_rxpoll));
> + spin_unlock_irqrestore(&common->cc_lock, flags);
> +
> + last_run = jiffies;
> + if (rx_clear > 98) {
> + ath_dbg(common, RESET,
> + "rx clear %d match count %d iteration %d\n",
> + rx_clear, match_count, iteration);
> + if (match_count++ > 9)
> + goto queue_reset_work;
> + } else if (ath9k_hw_detect_mac_hang(ah))
> + goto queue_reset_work;
> + else if (iteration >= 15) {
> + iteration = match_count = 0;
> + nmsec = 200;
> + }
> + ath9k_ps_restore(sc);
> + ath_start_rx_poll(sc, nmsec);
> + return;
> +
> +queue_reset_work:
> + ath9k_ps_restore(sc);
> + ieee80211_queue_work(sc->hw, &sc->hw_reset_work);
> + iteration = match_count = 0;
> +}
>
> static int ath9k_add_interface(struct ieee80211_hw *hw,
> struct ieee80211_vif *vif)
How about merging this with ath_hw_check() which does similar things?
That way AP mode would get coverage as well.
> diff --git a/drivers/net/wireless/ath/hw.c b/drivers/net/wireless/ath/hw.c
> index 19befb3..f1821ea 100644
> --- a/drivers/net/wireless/ath/hw.c
> +++ b/drivers/net/wireless/ath/hw.c
> @@ -166,6 +166,11 @@ void ath_hw_cycle_counters_update(struct ath_common *common)
> common->cc_survey.rx_busy += busy;
> common->cc_survey.rx_frame += rx;
> common->cc_survey.tx_frame += tx;
> +
> + common->cc_rxpoll.cycles += cycles;
> + common->cc_rxpoll.rx_busy += busy;
> + common->cc_rxpoll.rx_frame += rx;
> + common->cc_rxpoll.tx_frame += tx;
> }
> EXPORT_SYMBOL(ath_hw_cycle_counters_update);
Do we really need yet another cycle counter state here? How about
reusing the survey counters like ath_hw_check() - or even reusing that
chunk of code entirely.
- Felix
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