wil6210: ignore HALP ICR if already handled

HALP ICR is set as long as the FW should stay awake.
To prevent its multiple handling the driver masks this IRQ bit.
However, if there is a different MISC ICR before the driver clears
this bit, there is a risk of race condition between HALP mask and
unmask. This race leads to HALP timeout, in case it is mistakenly
masked.
Add an atomic flag to indicate if HALP ICR should be handled.
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wil6210/interrupt.c

 /*
  * Copyright (c) 2012-2017 Qualcomm Atheros, Inc.
- * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2018-2019, The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -575,11 +575,15 @@ static irqreturn_t wil6210_irq_misc(int irq, void *cookie)
 	}
 
 	if (isr & BIT_DMA_EP_MISC_ICR_HALP) {
+		isr &= ~BIT_DMA_EP_MISC_ICR_HALP;
+		if (wil->halp.handle_icr) {
+			/* no need to handle HALP ICRs until next vote */
+			wil->halp.handle_icr = false;
 			wil_dbg_irq(wil, "irq_misc: HALP IRQ invoked\n");
 			wil6210_mask_halp(wil);
-		isr &= ~BIT_DMA_EP_MISC_ICR_HALP;
 			complete(&wil->halp.comp);
 		}
+	}
 
 	wil->isr_misc = isr;
 

drivers/net/wireless/ath/wil6210/main.c

@@ -1919,11 +1919,14 @@ void wil_halp_vote(struct wil6210_priv *wil)
 
 	if (++wil->halp.ref_cnt == 1) {
 		reinit_completion(&wil->halp.comp);
+		/* mark to IRQ context to handle HALP ICR */
+		wil->halp.handle_icr = true;
 		wil6210_set_halp(wil);
 		rc = wait_for_completion_timeout(&wil->halp.comp, to_jiffies);
 		if (!rc) {
 			wil_err(wil, "HALP vote timed out\n");
 			/* Mask HALP as done in case the interrupt is raised */
+			wil->halp.handle_icr = false;
 			wil6210_mask_halp(wil);
 		} else {
 			wil_dbg_irq(wil,

drivers/net/wireless/ath/wil6210/wil6210.h

@@ -794,6 +794,7 @@ struct wil_halp {
 	struct mutex		lock; /* protect halp ref_cnt */
 	unsigned int		ref_cnt;
 	struct completion	comp;
+	u8			handle_icr;
 };
 
 struct wil_blob_wrapper {