From patchwork Mon Oct 7 17:28:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 11178213 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A13AD1575 for ; Mon, 7 Oct 2019 17:28:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8ABE02133F for ; Mon, 7 Oct 2019 17:28:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728915AbfJGR2E (ORCPT ); Mon, 7 Oct 2019 13:28:04 -0400 Received: from muru.com ([72.249.23.125]:35738 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728079AbfJGR2E (ORCPT ); Mon, 7 Oct 2019 13:28:04 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id D92638191; Mon, 7 Oct 2019 17:28:36 +0000 (UTC) From: Tony Lindgren To: Kalle Valo Cc: Eyal Reizer , Kishon Vijay Abraham I , Guy Mishol , linux-wireless@vger.kernel.org, linux-omap@vger.kernel.org, Anders Roxell , John Stultz , Ulf Hansson Subject: [PATCHv2] wlcore: fix race for WL1271_FLAG_IRQ_RUNNING Date: Mon, 7 Oct 2019 10:28:00 -0700 Message-Id: <20191007172800.64249-1-tony@atomide.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org We set WL1271_FLAG_IRQ_RUNNING in the beginning of wlcore_irq(), and test for it in wlcore_runtime_resume(). But WL1271_FLAG_IRQ_RUNNING currently gets cleared too early by wlcore_irq_locked() before wlcore_irq() is done calling it. And this will race against wlcore_runtime_resume() testing it. Let's set and clear IRQ_RUNNING in wlcore_irq() so wlcore_runtime_resume() can rely on it. And let's remove old comments about hardirq, that's no longer the case as we're using request_threaded_irq(). This fixes occasional annoying wlcore firmware reboots stat start with "wlcore: WARNING ELP wakeup timeout!" followed by a multisecond latency when the wlcore firmware gets wrongly rebooted waiting for an ELP wake interrupt that won't be coming. Note that I also suspect some form of this issue was the root cause why the wlcore GPIO interrupt has been often configured as a level interrupt instead of edge as an attempt to work around the ELP wake timeout errors. Fixes: fa2648a34e73 ("wlcore: Add support for runtime PM") Cc: Anders Roxell Cc: Eyal Reizer Cc: Guy Mishol Cc: John Stultz Cc: Ulf Hansson Signed-off-by: Tony Lindgren --- Changes since v1: - Add locking around clear_bit like we do elsewhere in the driver drivers/net/wireless/ti/wlcore/main.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c --- a/drivers/net/wireless/ti/wlcore/main.c +++ b/drivers/net/wireless/ti/wlcore/main.c @@ -544,11 +544,6 @@ static int wlcore_irq_locked(struct wl1271 *wl) } while (!done && loopcount--) { - /* - * In order to avoid a race with the hardirq, clear the flag - * before acknowledging the chip. - */ - clear_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags); smp_mb__after_atomic(); ret = wlcore_fw_status(wl, wl->fw_status); @@ -668,7 +663,7 @@ static irqreturn_t wlcore_irq(int irq, void *cookie) disable_irq_nosync(wl->irq); pm_wakeup_event(wl->dev, 0); spin_unlock_irqrestore(&wl->wl_lock, flags); - return IRQ_HANDLED; + goto out_handled; } spin_unlock_irqrestore(&wl->wl_lock, flags); @@ -692,6 +687,11 @@ static irqreturn_t wlcore_irq(int irq, void *cookie) mutex_unlock(&wl->mutex); +out_handled: + spin_lock_irqsave(&wl->wl_lock, flags); + clear_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags); + spin_unlock_irqrestore(&wl->wl_lock, flags); + return IRQ_HANDLED; }