msm: ipa: handle missing interrupts

In GSI 2.2 and 2.5 there is a limitation that can lead
to losing an interrupt. For these versions an
explicit check is needed after enabling the interrupt

Change-Id: I3907ea1750ceaece42c8b3ca0f63850e2d7d7f3e
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Acked-by: Ashok Vuyyuru <avuyyuru@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

drivers/platform/msm/gsi/gsi.c

@@ -3267,6 +3267,33 @@ int gsi_config_channel_mode(unsigned long chan_hdl, enum gsi_chan_mode mode)
 			mode == GSI_CHAN_MODE_CALLBACK) {
 		atomic_set(&ctx->poll_mode, mode);
 		__gsi_config_ieob_irq(gsi_ctx->per.ee, 1 << ctx->evtr->id, ~0);
+
+		/*
+		 * In GSI 2.2 and 2.5 there is a limitation that can lead
+		 * to losing an interrupt. For these versions an
+		 * explicit check is needed after enabling the interrupt
+		 */
+		if (gsi_ctx->per.ver == GSI_VER_2_2 ||
+		    gsi_ctx->per.ver == GSI_VER_2_5) {
+			u32 src = gsi_readl(gsi_ctx->base +
+				GSI_EE_n_CNTXT_SRC_IEOB_IRQ_OFFS(
+					gsi_ctx->per.ee));
+			if (src & (1 << ctx->evtr->id)) {
+				__gsi_config_ieob_irq(
+					gsi_ctx->per.ee, 1 << ctx->evtr->id, 0);
+				gsi_writel(1 << ctx->evtr->id, gsi_ctx->base +
+					GSI_EE_n_CNTXT_SRC_IEOB_IRQ_CLR_OFFS(
+							gsi_ctx->per.ee));
+				spin_unlock_irqrestore(&gsi_ctx->slock, flags);
+				spin_lock_irqsave(&ctx->ring.slock, flags);
+				atomic_set(
+					&ctx->poll_mode, GSI_CHAN_MODE_POLL);
+				spin_unlock_irqrestore(
+					&ctx->ring.slock, flags);
+				ctx->stats.poll_pending_irq++;
+				return -GSI_STATUS_PENDING_IRQ;
+			}
+		}
 		ctx->stats.poll_to_callback++;
 	}
 	spin_unlock_irqrestore(&gsi_ctx->slock, flags);

drivers/platform/msm/gsi/gsi.h

@@ -120,6 +120,7 @@ struct gsi_chan_stats {
 	unsigned long completed;
 	unsigned long callback_to_poll;
 	unsigned long poll_to_callback;
+	unsigned long poll_pending_irq;
 	unsigned long invalid_tre_error;
 	unsigned long poll_ok;
 	unsigned long poll_empty;

drivers/platform/msm/gsi/gsi_dbg.c

@@ -273,9 +273,10 @@ static void gsi_dump_ch_stats(struct gsi_chan_ctx *ctx)
 	PRT_STAT("queued=%lu compl=%lu\n",
 		ctx->stats.queued,
 		ctx->stats.completed);
-	PRT_STAT("cb->poll=%lu poll->cb=%lu\n",
+	PRT_STAT("cb->poll=%lu poll->cb=%lu poll_pend_irq=%lu\n",
 		ctx->stats.callback_to_poll,
-		ctx->stats.poll_to_callback);
+		ctx->stats.poll_to_callback,
+		ctx->stats.poll_pending_irq);
 	PRT_STAT("invalid_tre_error=%lu\n",
 		ctx->stats.invalid_tre_error);
 	PRT_STAT("poll_ok=%lu poll_empty=%lu\n",

drivers/platform/msm/ipa/ipa_v3/ipa_dp.c

@@ -752,27 +752,24 @@ static int ipa3_handle_rx_core(struct ipa3_sys_context *sys, bool process_all,
 /**
  * ipa3_rx_switch_to_intr_mode() - Operate the Rx data path in interrupt mode
  */
-static void ipa3_rx_switch_to_intr_mode(struct ipa3_sys_context *sys)
+static int ipa3_rx_switch_to_intr_mode(struct ipa3_sys_context *sys)
 {
 	int ret;
 
-	if (!atomic_read(&sys->curr_polling_state)) {
-		IPAERR("already in intr mode\n");
-		goto fail;
-	}
 	atomic_set(&sys->curr_polling_state, 0);
 	ipa3_dec_release_wakelock();
 	ret = gsi_config_channel_mode(sys->ep->gsi_chan_hdl,
 		GSI_CHAN_MODE_CALLBACK);
 	if (ret != GSI_STATUS_SUCCESS) {
-		IPAERR("Failed to switch to intr mode.\n");
-		goto fail;
+		if (ret == -GSI_STATUS_PENDING_IRQ) {
+			ipa3_inc_acquire_wakelock();
+			atomic_set(&sys->curr_polling_state, 1);
+		} else {
+			IPAERR("Failed to switch to intr mode.\n");
+		}
 	}
-	return;
 
-fail:
-	queue_delayed_work(sys->wq, &sys->switch_to_intr_work,
-			msecs_to_jiffies(1));
+	return ret;
 }
 
 /**
@@ -785,13 +782,16 @@ fail:
  */
 static void ipa3_handle_rx(struct ipa3_sys_context *sys)
 {
-	int inactive_cycles = 0;
+	int inactive_cycles;
 	int cnt;
+	int ret;
 
 	if (ipa3_ctx->use_ipa_pm)
 		ipa_pm_activate_sync(sys->pm_hdl);
 	else
 		IPA_ACTIVE_CLIENTS_INC_SIMPLE();
+start_poll:
+	inactive_cycles = 0;
 	do {
 		cnt = ipa3_handle_rx_core(sys, true, true);
 		if (cnt == 0)
@@ -814,7 +814,10 @@ static void ipa3_handle_rx(struct ipa3_sys_context *sys)
 	} while (inactive_cycles <= POLLING_INACTIVITY_RX);
 
 	trace_poll_to_intr3(sys->ep->client);
-	ipa3_rx_switch_to_intr_mode(sys);
+	ret = ipa3_rx_switch_to_intr_mode(sys);
+	if (ret == -GSI_STATUS_PENDING_IRQ)
+		goto start_poll;
+
 	if (ipa3_ctx->use_ipa_pm)
 		ipa_pm_deferred_deactivate(sys->pm_hdl);
 	else
@@ -4059,6 +4062,7 @@ int ipa3_rx_poll(u32 clnt_hdl, int weight)
 	}
 
 	ep = &ipa3_ctx->ep[clnt_hdl];
+start_poll:
 	while (remain_aggr_weight > 0 &&
 			atomic_read(&ep->sys->curr_polling_state)) {
 		atomic_set(&ipa3_ctx->transport_pm.eot_activity, 1);
@@ -4086,7 +4090,11 @@ int ipa3_rx_poll(u32 clnt_hdl, int weight)
 	cnt += weight - remain_aggr_weight * IPA_WAN_AGGR_PKT_CNT;
 	if (cnt < weight) {
 		napi_complete(ep->sys->napi_obj);
-		ipa3_rx_switch_to_intr_mode(ep->sys);
+		ret = ipa3_rx_switch_to_intr_mode(ep->sys);
+		if (ret == -GSI_STATUS_PENDING_IRQ &&
+				napi_reschedule(ep->sys->napi_obj))
+			goto start_poll;
+
 		if (ipa3_ctx->use_ipa_pm)
 			ipa_pm_deferred_deactivate(ep->sys->pm_hdl);
 		else

drivers/platform/msm/ipa/ipa_v3/ipa_utils.c

@@ -6694,6 +6694,15 @@ void ipa3_suspend_apps_pipes(bool suspend)
 	if (ep->valid) {
 		IPADBG("%s pipe %d\n", suspend ? "suspend" : "unsuspend",
 			ipa_ep_idx);
+		/*
+		 * move the channel to callback mode.
+		 * This needs to happen before starting the channel to make
+		 * sure we don't loose any interrupt
+		 */
+		if (!suspend && !atomic_read(&ep->sys->curr_polling_state))
+			gsi_config_channel_mode(ep->gsi_chan_hdl,
+				GSI_CHAN_MODE_CALLBACK);
+
 		if (ipa3_ctx->ipa_hw_type >= IPA_HW_v4_0) {
 			if (suspend) {
 				res = __ipa3_stop_gsi_channel(ipa_ep_idx);
@@ -6713,9 +6722,6 @@ void ipa3_suspend_apps_pipes(bool suspend)
 		}
 		if (suspend)
 			ipa3_gsi_poll_after_suspend(ep);
-		else if (!atomic_read(&ep->sys->curr_polling_state))
-			gsi_config_channel_mode(ep->gsi_chan_hdl,
-				GSI_CHAN_MODE_CALLBACK);
 	}
 
 	ipa_ep_idx = ipa_get_ep_mapping(IPA_CLIENT_APPS_WAN_CONS);
@@ -6728,6 +6734,14 @@ void ipa3_suspend_apps_pipes(bool suspend)
 	if (ep->valid) {
 		IPADBG("%s pipe %d\n", suspend ? "suspend" : "unsuspend",
 			ipa_ep_idx);
+		/*
+		 * move the channel to callback mode.
+		 * This needs to happen before starting the channel to make
+		 * sure we don't loose any interrupt
+		 */
+		if (!suspend && !atomic_read(&ep->sys->curr_polling_state))
+			gsi_config_channel_mode(ep->gsi_chan_hdl,
+				GSI_CHAN_MODE_CALLBACK);
 		if (ipa3_ctx->ipa_hw_type >= IPA_HW_v4_0) {
 			if (suspend) {
 				res = __ipa3_stop_gsi_channel(ipa_ep_idx);
@@ -6747,9 +6761,6 @@ void ipa3_suspend_apps_pipes(bool suspend)
 		}
 		if (suspend)
 			ipa3_gsi_poll_after_suspend(ep);
-		else if (!atomic_read(&ep->sys->curr_polling_state))
-			gsi_config_channel_mode(ep->gsi_chan_hdl,
-				GSI_CHAN_MODE_CALLBACK);
 	}
 }
 

include/linux/msm_gsi.h

@@ -39,6 +39,7 @@ enum gsi_status {
 	GSI_STATUS_EVT_RING_INCOMPATIBLE = 10,
 	GSI_STATUS_TIMED_OUT = 11,
 	GSI_STATUS_AGAIN = 12,
+	GSI_STATUS_PENDING_IRQ = 13,
 };
 
 enum gsi_per_evt {