From patchwork Fri Jan 8 17:35:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 12007109 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=-19.0 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 5A5BCC4332B for ; Fri, 8 Jan 2021 17:37:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 392F723A00 for ; Fri, 8 Jan 2021 17:37:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728520AbhAHRhI (ORCPT ); Fri, 8 Jan 2021 12:37:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728519AbhAHRhH (ORCPT ); Fri, 8 Jan 2021 12:37:07 -0500 Received: from mail-pg1-x534.google.com (mail-pg1-x534.google.com [IPv6:2607:f8b0:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E085C06129F for ; Fri, 8 Jan 2021 09:35:52 -0800 (PST) Received: by mail-pg1-x534.google.com with SMTP id n10so8029275pgl.10 for ; Fri, 08 Jan 2021 09:35:52 -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:in-reply-to:references :mime-version:content-transfer-encoding; bh=qJxj/FpYvZvPaV8YwpHtvsP0jgiqVzfBNAujDbm4i4o=; b=a7B4zVipAI5Ae8bsdl35Y+6rsvVJiVp8OEo1X7LA2PbnvrWHB1oWgpwBbnl0ylAUox vQTiqBlt8MvVlFZdYJzztwmcg6Fd5ICtmdXja1gE5eOy7vuGu0kHd/tKt74fV+pnf6TD Spn6YKy0vxtZN/0sF5CSu+Z+HqHAP8yCZ/HEM= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=qJxj/FpYvZvPaV8YwpHtvsP0jgiqVzfBNAujDbm4i4o=; b=jVmUjRRG4902AfVJqSp91gg8m3NkiJmlZO0UR44Vlws8yAkovJwXKulSzu/6W3qR4N Kd1GLGTHizR2hKNaQdcByw93GvhubFSHWxlBJ0l3qObFZo7KNfgdQP+JZTMziCJB5Ze5 SU3x09ko1D04M6j8YUIFiXSjEghS4qGQKz4hQzagW9QhFdErfpo+gdM/UYbaYkopiRsW LCiRJpnNUGdSscvUQlomvPzzByaDmJ9m3iMpyo6ZBCDN4n0XyCLeFQ5K84ahBpvXyKZe 5SncblU9uILAYuQ7I5DE/IKlMX65iq9isLHkuGQwFjiQ88dFWxJt63N2Y5ysI2sn7ueP jm+w== X-Gm-Message-State: AOAM530t1Wh3wi6T68XACuCUjALmFqYIdUqy+CFVRfqXelPUul9AmfaO Gv1iJSBIMYeVGanNeVlktMvNug== X-Google-Smtp-Source: ABdhPJyQbZ60izOyrJ4ubXVQ1sf18D8u+mdyz7KI+Q08P0rftjV+C2OBDimYuM2M5vChzxZDu4e0zg== X-Received: by 2002:a63:ce42:: with SMTP id r2mr8161235pgi.8.1610127351916; Fri, 08 Jan 2021 09:35:51 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:42b0:34ff:fe3d:58e6]) by smtp.gmail.com with ESMTPSA id z23sm10245619pfj.143.2021.01.08.09.35.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 Jan 2021 09:35:51 -0800 (PST) From: Douglas Anderson To: Marc Zyngier , Thomas Gleixner , Jason Cooper , Linus Walleij Cc: Bjorn Andersson , Neeraj Upadhyay , Rajendra Nayak , Stephen Boyd , Maulik Shah , linux-gpio@vger.kernel.org, Srinivas Ramana , linux-arm-msm@vger.kernel.org, Douglas Anderson , Andy Gross , linux-kernel@vger.kernel.org Subject: [PATCH v5 4/4] pinctrl: qcom: Don't clear pending interrupts when enabling Date: Fri, 8 Jan 2021 09:35:16 -0800 Message-Id: <20210108093339.v5.4.I7cf3019783720feb57b958c95c2b684940264cd1@changeid> X-Mailer: git-send-email 2.29.2.729.g45daf8777d-goog In-Reply-To: <20210108093339.v5.1.I3ad184e3423d8e479bc3e86f5b393abb1704a1d1@changeid> References: <20210108093339.v5.1.I3ad184e3423d8e479bc3e86f5b393abb1704a1d1@changeid> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org In Linux, if a driver does disable_irq() and later does enable_irq() on its interrupt, I believe it's expecting these properties: * If an interrupt was pending when the driver disabled then it will still be pending after the driver re-enables. * If an edge-triggered interrupt comes in while an interrupt is disabled it should assert when the interrupt is re-enabled. If you think that the above sounds a lot like the disable_irq() and enable_irq() are supposed to be masking/unmasking the interrupt instead of disabling/enabling it then you've made an astute observation. Specifically when talking about interrupts, "mask" usually means to stop posting interrupts but keep tracking them and "disable" means to fully shut off interrupt detection. It's unfortunate that this is so confusing, but presumably this is all the way it is for historical reasons. Perhaps more confusing than the above is that, even though clients of IRQs themselves don't have a way to request mask/unmask vs. disable/enable calls, IRQ chips themselves can implement both. ...and yet more confusing is that if an IRQ chip implements disable/enable then they will be called when a client driver calls disable_irq() / enable_irq(). It does feel like some of the above could be cleared up. However, without any other core interrupt changes it should be clear that when an IRQ chip gets a request to "disable" an IRQ that it has to treat it like a mask of that IRQ. In any case, after that long interlude you can see that the "unmask and clear" can break things. Maulik tried to fix it so that we no longer did "unmask and clear" in commit 71266d9d3936 ("pinctrl: qcom: Move clearing pending IRQ to .irq_request_resources callback"), but it only handled the PDC case and it had problems (it caused sc7180-trogdor devices to fail to suspend). Let's fix. From my understanding the source of the phantom interrupt in the were these two things: 1. One that could have been introduced in msm_gpio_irq_set_type() (only for the non-PDC case). 2. Edges could have been detected when a GPIO was muxed away. Fixing case #1 is easy. We can just add a clear in msm_gpio_irq_set_type(). Fixing case #2 is harder. Let's use a concrete example. In sc7180-trogdor.dtsi we configure the uart3 to have two pinctrl states, sleep and default, and mux between the two during runtime PM and system suspend (see geni_se_resources_{on,off}() for more details). The difference between the sleep and default state is that the RX pin is muxed to a GPIO during sleep and muxed to the UART otherwise. As per Qualcomm, when we mux the pin over to the UART function the PDC (or the non-PDC interrupt detection logic) is still watching it / latching edges. These edges don't cause interrupts because the current code masks the interrupt unless we're entering suspend. However, as soon as we enter suspend we unmask the interrupt and it's counted as a wakeup. Let's deal with the problem like this: * When we mux away, we'll mask our interrupt. This isn't necessary in the above case since the client already masked us, but it's a good idea in general. * When we mux back will clear any interrupts and unmask. Fixes: 4b7618fdc7e6 ("pinctrl: qcom: Add irq_enable callback for msm gpio") Fixes: 71266d9d3936 ("pinctrl: qcom: Move clearing pending IRQ to .irq_request_resources callback") Signed-off-by: Douglas Anderson Reviewed-by: Maulik Shah Tested-by: Maulik Shah --- Note that patch #1 of v4 has now landed so it's dropped from the v5 post. Also note that there is no dependency of this series on the v4 patch #1 so no special coordination need happen for that. I didn't add Rajendra's and Stephen's tags from v4 since there were enough changes from v4 to v5 to warrant a re-review. My tests here for the non-PDC case are mostly synthetic and I don't have any good way to test the case that the original patch was added for. Hopefully it's all good? Changes in v5: - Re-combined PDC and non-PDC since non-PDC their issues are similar. - "it" => "the interrupt" in comment. - Handle 2nd case where edges came when muxed away. - Handle controllers where you write 1 to Ack. Changes in v4: - Split non-PDC fix and PDC fix in two. - Totally rewrote again with my new understanding of the world. Changes in v3: - Fixed bug in msm_gpio_direction_output() (s/oldval =/oldval = val =/) - Add back "if !skip_wake_irqs" test in msm_gpio_irq_enable() - For non-PDC, clear 1st interrupt in msm_gpio_irq_set_type() Changes in v2: - 0 => false - If skip_wake_irqs, don't need to clear normal intr. - Add comment about glitches in both output and input. drivers/pinctrl/qcom/pinctrl-msm.c | 74 +++++++++++++++++++----------- 1 file changed, 46 insertions(+), 28 deletions(-) diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c index a6b0c17e2f78..d5d1f3430c6c 100644 --- a/drivers/pinctrl/qcom/pinctrl-msm.c +++ b/drivers/pinctrl/qcom/pinctrl-msm.c @@ -51,6 +51,7 @@ * @dual_edge_irqs: Bitmap of irqs that need sw emulated dual edge * detection. * @skip_wake_irqs: Skip IRQs that are handled by wakeup interrupt controller + * @disabled_for_mux: These IRQs were disabled because we muxed away. * @soc: Reference to soc_data of platform specific data. * @regs: Base addresses for the TLMM tiles. * @phys_base: Physical base address @@ -72,6 +73,7 @@ struct msm_pinctrl { DECLARE_BITMAP(dual_edge_irqs, MAX_NR_GPIO); DECLARE_BITMAP(enabled_irqs, MAX_NR_GPIO); DECLARE_BITMAP(skip_wake_irqs, MAX_NR_GPIO); + DECLARE_BITMAP(disabled_for_mux, MAX_NR_GPIO); const struct msm_pinctrl_soc_data *soc; void __iomem *regs[MAX_NR_TILES]; @@ -179,6 +181,10 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned group) { struct msm_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev); + struct gpio_chip *gc = &pctrl->chip; + unsigned int irq = irq_find_mapping(gc->irq.domain, group); + struct irq_data *d = irq_get_irq_data(irq); + unsigned int gpio_func = pctrl->soc->gpio_func; const struct msm_pingroup *g; unsigned long flags; u32 val, mask; @@ -195,6 +201,20 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev, if (WARN_ON(i == g->nfuncs)) return -EINVAL; + /* + * If an GPIO interrupt is setup on this pin then we need special + * handling. Specifically interrupt detection logic will still see + * the pin twiddle even when we're muxed away. + * + * When we see a pin with an interrupt setup on it then we'll disable + * (mask) interrupts on it when we mux away until we mux back. Note + * that disable_irq() refcounts and interrupts are disabled as long as + * at least one disable_irq() has been called. + */ + if (d && i != gpio_func && + !test_and_set_bit(d->hwirq, pctrl->disabled_for_mux)) + disable_irq(irq); + raw_spin_lock_irqsave(&pctrl->lock, flags); val = msm_readl_ctl(pctrl, g); @@ -204,6 +224,20 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev, raw_spin_unlock_irqrestore(&pctrl->lock, flags); + if (d && i == gpio_func && + test_and_clear_bit(d->hwirq, pctrl->disabled_for_mux)) { + /* + * Clear interrupts detected while not GPIO since we only + * masked things. + */ + if (d->parent_data && test_bit(d->hwirq, pctrl->skip_wake_irqs)) + irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, false); + else + msm_ack_intr_status(pctrl, g); + + enable_irq(irq); + } + return 0; } @@ -782,7 +816,7 @@ static void msm_gpio_irq_mask(struct irq_data *d) raw_spin_unlock_irqrestore(&pctrl->lock, flags); } -static void msm_gpio_irq_clear_unmask(struct irq_data *d, bool status_clear) +static void msm_gpio_irq_unmask(struct irq_data *d) { struct gpio_chip *gc = irq_data_get_irq_chip_data(d); struct msm_pinctrl *pctrl = gpiochip_get_data(gc); @@ -800,14 +834,6 @@ static void msm_gpio_irq_clear_unmask(struct irq_data *d, bool status_clear) raw_spin_lock_irqsave(&pctrl->lock, flags); - /* - * clear the interrupt status bit before unmask to avoid - * any erroneous interrupts that would have got latched - * when the interrupt is not in use. - */ - if (status_clear) - msm_ack_intr_status(pctrl, g); - val = msm_readl_intr_cfg(pctrl, g); val |= BIT(g->intr_raw_status_bit); val |= BIT(g->intr_enable_bit); @@ -827,7 +853,7 @@ static void msm_gpio_irq_enable(struct irq_data *d) irq_chip_enable_parent(d); if (!test_bit(d->hwirq, pctrl->skip_wake_irqs)) - msm_gpio_irq_clear_unmask(d, true); + msm_gpio_irq_unmask(d); } static void msm_gpio_irq_disable(struct irq_data *d) @@ -842,11 +868,6 @@ static void msm_gpio_irq_disable(struct irq_data *d) msm_gpio_irq_mask(d); } -static void msm_gpio_irq_unmask(struct irq_data *d) -{ - msm_gpio_irq_clear_unmask(d, false); -} - /** * msm_gpio_update_dual_edge_parent() - Prime next edge for IRQs handled by parent. * @d: The irq dta. @@ -935,6 +956,7 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type) struct msm_pinctrl *pctrl = gpiochip_get_data(gc); const struct msm_pingroup *g; unsigned long flags; + bool was_enabled; u32 val; if (msm_gpio_needs_dual_edge_parent_workaround(d, type)) { @@ -996,6 +1018,7 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type) * could cause the INTR_STATUS to be set for EDGE interrupts. */ val = msm_readl_intr_cfg(pctrl, g); + was_enabled = val & BIT(g->intr_raw_status_bit); val |= BIT(g->intr_raw_status_bit); if (g->intr_detection_width == 2) { val &= ~(3 << g->intr_detection_bit); @@ -1045,6 +1068,14 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type) } msm_writel_intr_cfg(val, pctrl, g); + /* + * The first time we set RAW_STATUS_EN it could trigger an interrupt. + * Clear the interrupt. This is safe because we have + * IRQCHIP_SET_TYPE_MASKED. + */ + if (!was_enabled) + msm_ack_intr_status(pctrl, g); + if (test_bit(d->hwirq, pctrl->dual_edge_irqs)) msm_gpio_update_dual_edge_pos(pctrl, g, d); @@ -1096,19 +1127,6 @@ static int msm_gpio_irq_reqres(struct irq_data *d) ret = -EINVAL; goto out; } - - /* - * Clear the interrupt that may be pending before we enable - * the line. - * This is especially a problem with the GPIOs routed to the - * PDC. These GPIOs are direct-connect interrupts to the GIC. - * Disabling the interrupt line at the PDC does not prevent - * the interrupt from being latched at the GIC. The state at - * GIC needs to be cleared before enabling. - */ - if (d->parent_data && test_bit(d->hwirq, pctrl->skip_wake_irqs)) - irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, 0); - return 0; out: module_put(gc->owner);