From patchwork Tue Nov 24 17:47:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11929469 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D49CDC64E7B for ; Tue, 24 Nov 2020 17:48:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D7702087C for ; Tue, 24 Nov 2020 17:48:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="PuNaFOUD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404020AbgKXRrs (ORCPT ); Tue, 24 Nov 2020 12:47:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404021AbgKXRrq (ORCPT ); Tue, 24 Nov 2020 12:47:46 -0500 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26C09C061A4D for ; Tue, 24 Nov 2020 09:47:45 -0800 (PST) Received: by mail-pf1-x442.google.com with SMTP id w202so3416280pff.10 for ; Tue, 24 Nov 2020 09:47:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8ckt5NlFQBUj9ad7Wcfnzxmq4bS87/8gcDcZUE4/+ro=; b=PuNaFOUDQZ0VIxY0XaAbtfd5SDpQK9q04/AaC1rPeDrPSW0yP8HpXqIEpt1foMV/oZ acqddNjTYpYjz8E1ABr/T1xxKkisF8YQMgh7Do4VcCJ9MqRQzxvpQjKt984jxMK2N1Ik TkgrOAosOxTyzdpiK/sbdu5uZrvWO5Tv20GoQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8ckt5NlFQBUj9ad7Wcfnzxmq4bS87/8gcDcZUE4/+ro=; b=JpSKEHjoer+al5xF1VcjGjtwLH73akvgUWuydQniseDg72ktqroic9m+yylRvK4kZ/ +VKUWuxyySwQFTx7VbXlkTzQ17FZo8kJX0ARmEj19F2OEZaJQ8jVljqAhvboZwZUDNVa QobtuccNUY9FNcPRywZCNHIA+EbAdo7/j6sBbjk1yT8LGaNcctDBRVde9isNmcpf9ysE 1KwvSqQuZEorE4MCn7BOptehVv7AaALyiFHqgDkD0Y/Vq1TlTLwqik/6eyHMSKfSWxeU u7s5M5CsjOcTUUVZ12UITcS66UObcNIWBLnwc6Fs04ZMrD76/LE6FA/wjBE48xs5bY7+ HvSw== X-Gm-Message-State: AOAM533l9VWgxsgIGpge/9tsZSB9c+5/T25kGRg42RCPrfhc2OAOCM6r 4fPDE6p/mMdmNwvlGLPnUQw3du9506GUMA== X-Google-Smtp-Source: ABdhPJwoLRiT+KykvFRT+U8sBkabFveCDhERGqz1LJCJk2ftAle9VsTy6P52AxNwRMydIWiUKQQz0A== X-Received: by 2002:a63:34c:: with SMTP id 73mr4524428pgd.172.1606240064368; Tue, 24 Nov 2020 09:47:44 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:42b0:34ff:fe3d:58e6]) by smtp.gmail.com with ESMTPSA id i4sm13480459pgg.67.2020.11.24.09.47.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 09:47:43 -0800 (PST) From: Douglas Anderson To: Marc Zyngier , Thomas Gleixner , Jason Cooper , Linus Walleij Cc: linux-gpio@vger.kernel.org, Neeraj Upadhyay , Stephen Boyd , Bjorn Andersson , Srinivas Ramana , linux-arm-msm@vger.kernel.org, Maulik Shah , Rajendra Nayak , Douglas Anderson , Andy Gross , Archana Sathyakumar , Lina Iyer , linux-kernel@vger.kernel.org Subject: [PATCH v2 1/3] irqchip: qcom-pdc: Fix phantom irq when changing between rising/falling Date: Tue, 24 Nov 2020 09:47:19 -0800 Message-Id: <20201124094636.v2.1.I2702919afc253e2a451bebc3b701b462b2d22344@changeid> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org We have a problem if we use gpio-keys and configure wakeups such that we only want one edge to wake us up. AKA: wakeup-event-action = ; wakeup-source; Specifically we end up with a phantom interrupt that blocks suspend if the line was already high and we want wakeups on rising edges (AKA we want the GPIO to go low and then high again before we wake up). The opposite is also problematic. Specifically, here's what's happening today: 1. Normally, gpio-keys configures to look for both edges. Due to the current workaround introduced in commit c3c0c2e18d94 ("pinctrl: qcom: Handle broken/missing PDC dual edge IRQs on sc7180"), if the line was high we'd configure for falling edges. 2. At suspend time, we change to look for rising edges. 3. After qcom_pdc_gic_set_type() runs, we get a phantom interrupt. We can solve this by just clearing the phantom interrupt. NOTE: it is possible that this could cause problems for a client with very specific needs, but there's not much we can do with this hardware. As an example, let's say the interrupt signal is currently high and the client is looking for falling edges. The client now changes to look for rising edges. The client could possibly expect that if the line has a short pulse low (and back high) that it would always be detected. Specifically no matter when the pulse happened, it should either have tripped the (old) falling edge trigger or the (new) rising edge trigger. We will simply not trip it. We could narrow down the race a bit by polling our parent before changing types, but no matter what we do there will still be a period of time where we can't tell the difference between a real transition (or more than one transition) and the phantom. Fixes: f55c73aef890 ("irqchip/pdc: Add PDC interrupt controller for QCOM SoCs") Signed-off-by: Douglas Anderson Reviewed-by: Maulik Shah Tested-by: Maulik Shah --- There are no dependencies between this patch and patch #2/#3. It can go in by itself. Patches are only grouped together in one series because they address similar issues. Changes in v2: - 0 => false - If irq_chip_set_type_parent() fails don't bother clearing. - Add Fixes tag. drivers/irqchip/qcom-pdc.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c index bd39e9de6ecf..f91e7d5aea25 100644 --- a/drivers/irqchip/qcom-pdc.c +++ b/drivers/irqchip/qcom-pdc.c @@ -159,6 +159,8 @@ static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type) { int pin_out = d->hwirq; enum pdc_irq_config_bits pdc_type; + enum pdc_irq_config_bits old_pdc_type; + int ret; if (pin_out == GPIO_NO_WAKE_IRQ) return 0; @@ -187,9 +189,26 @@ static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type) return -EINVAL; } + old_pdc_type = pdc_reg_read(IRQ_i_CFG, pin_out); pdc_reg_write(IRQ_i_CFG, pin_out, pdc_type); - return irq_chip_set_type_parent(d, type); + ret = irq_chip_set_type_parent(d, type); + if (ret) + return ret; + + /* + * When we change types the PDC can give a phantom interrupt. + * Clear it. Specifically the phantom shows up if a line is already + * high and we change to rising or if a line is already low and we + * change to falling but let's be consistent and clear it always. + * + * Doing this works because we have IRQCHIP_SET_TYPE_MASKED so the + * interrupt will be cleared before the rest of the system sees it. + */ + if (old_pdc_type != pdc_type) + irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, false); + + return 0; } static struct irq_chip qcom_pdc_gic_chip = {