Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940861AbcKOCtt (ORCPT ); Mon, 14 Nov 2016 21:49:49 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:24923 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933542AbcKOCtr (ORCPT ); Mon, 14 Nov 2016 21:49:47 -0500 Message-ID: <1479178179.10566.0.camel@mtksdaap41> Subject: Re: [PATCH v2 2/3] irqchip: mtk-cirq: Add mediatek mtk-cirq implement From: Youlin Pei To: Marc Zyngier CC: Rob Herring , Matthias Brugger , Thomas Gleixner , "Jason Cooper" , Mark Rutland , Russell King , , , , , , , , , Date: Tue, 15 Nov 2016 10:49:39 +0800 In-Reply-To: <1f8f7b9f-7788-18c4-19c5-3c9a7623c188@arm.com> References: <1478001122-8664-1-git-send-email-youlin.pei@mediatek.com> <1478001122-8664-3-git-send-email-youlin.pei@mediatek.com> <86twbrj586.fsf@arm.com> <1478234577.7975.29.camel@mtksdaap41> <867f8ilwcl.fsf@arm.com> <1478573833.32099.11.camel@mtksdaap41> <1f8f7b9f-7788-18c4-19c5-3c9a7623c188@arm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7597 Lines: 189 On Thu, 2016-11-10 at 18:24 +0000, Marc Zyngier wrote: > On 08/11/16 02:57, Youlin Pei wrote: > > On Fri, 2016-11-04 at 22:21 +0000, Marc Zyngier wrote: > >> On Fri, Nov 04 2016 at 04:42:57 AM, Youlin Pei wrote: > >>> On Tue, 2016-11-01 at 20:49 +0000, Marc Zyngier wrote: > >>>> On Tue, Nov 01 2016 at 11:52:01 AM, Youlin Pei wrote: > >>>>> In Mediatek SOCs, the CIRQ is a low power interrupt controller > >>>>> designed to works outside MCUSYS which comprises with Cortex-Ax > >>>>> cores,CCI and GIC. > >>>>> > >>>>> The CIRQ controller is integrated in between MCUSYS( include > >>>>> Cortex-Ax, CCI and GIC ) and interrupt sources as the second > >>>>> level interrupt controller. The external interrupts which outside > >>>>> MCUSYS will feed through CIRQ then bypass to GIC. CIRQ can monitors > >>>>> all edge trigger interupts. When an edge interrupt is triggered, > >>>>> CIRQ can record the status and generate a pulse signal to GIC when > >>>>> flush command executed. > >>>>> > >>>>> When system enters sleep mode, MCUSYS will be turned off to improve > >>>>> power consumption, also GIC is power down. The edge trigger interrupts > >>>>> will be lost in this scenario without CIRQ. > >>>>> > >>>>> This commit provides the CIRQ irqchip implement. > >>>>> > >>>>> Signed-off-by: Youlin Pei > >>>>> --- > >>>>> drivers/irqchip/Makefile | 2 +- > >>>>> drivers/irqchip/irq-mtk-cirq.c | 262 ++++++++++++++++++++++++++++++++++++++++ > >>>>> 2 files changed, 263 insertions(+), 1 deletion(-) > >>>>> create mode 100644 drivers/irqchip/irq-mtk-cirq.c > >>>>> > >>>>> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile > >>>>> index e4dbfc8..8f33580 100644 > >>>>> --- a/drivers/irqchip/Makefile > >>>>> +++ b/drivers/irqchip/Makefile > >>>>> @@ -60,7 +60,7 @@ obj-$(CONFIG_BCM7120_L2_IRQ) += irq-bcm7120-l2.o > >>>>> obj-$(CONFIG_BRCMSTB_L2_IRQ) += irq-brcmstb-l2.o > >>>>> obj-$(CONFIG_KEYSTONE_IRQ) += irq-keystone.o > >>>>> obj-$(CONFIG_MIPS_GIC) += irq-mips-gic.o > >>>>> -obj-$(CONFIG_ARCH_MEDIATEK) += irq-mtk-sysirq.o > >>>>> +obj-$(CONFIG_ARCH_MEDIATEK) += irq-mtk-sysirq.o irq-mtk-cirq.o > >>>>> obj-$(CONFIG_ARCH_DIGICOLOR) += irq-digicolor.o > >>>>> obj-$(CONFIG_RENESAS_H8300H_INTC) += irq-renesas-h8300h.o > >>>>> obj-$(CONFIG_RENESAS_H8S_INTC) += irq-renesas-h8s.o > >>>>> diff --git a/drivers/irqchip/irq-mtk-cirq.c b/drivers/irqchip/irq-mtk-cirq.c > >>>>> new file mode 100644 > >>>>> index 0000000..fc43ef3 > >>>>> --- /dev/null > >>>>> +++ b/drivers/irqchip/irq-mtk-cirq.c > >>>>> @@ -0,0 +1,262 @@ > >>>>> +/* > >>>>> + * Copyright (c) 2016 MediaTek Inc. > >>>>> + * Author: Youlin.Pei > >>>>> + * > >>>>> + * This program is free software; you can redistribute it and/or modify > >>>>> + * it under the terms of the GNU General Public License version 2 as > >>>>> + * published by the Free Software Foundation. > >>>>> + * > >>>>> + * This program is distributed in the hope that it will be useful, > >>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of > >>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > >>>>> + * GNU General Public License for more details. > >>>>> + */ > >>>>> + > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> +#include > >>>>> + > >>>>> +#define CIRQ_ACK 0x40 > >>>>> +#define CIRQ_MASK_SET 0xc0 > >>>>> +#define CIRQ_MASK_CLR 0x100 > >>>>> +#define CIRQ_SENS_SET 0x180 > >>>>> +#define CIRQ_SENS_CLR 0x1c0 > >>>>> +#define CIRQ_POL_SET 0x240 > >>>>> +#define CIRQ_POL_CLR 0x280 > >>>>> +#define CIRQ_CONTROL 0x300 > >>>>> + > >>>>> +#define CIRQ_EN 0x1 > >>>>> +#define CIRQ_EDGE 0x2 > >>>>> +#define CIRQ_FLUSH 0x4 > >>>>> + > >>>>> +#define CIRQ_IRQ_NUM 0x200 > >>>>> + > >>>>> +struct mtk_cirq_chip_data { > >>>>> + void __iomem *base; > >>>>> + unsigned int ext_irq_start; > >>>>> +}; > >>>>> + > >>>>> +static struct mtk_cirq_chip_data *cirq_data; > >>>> > >>>> Are you guaranteed that you'll only ever have a single CIRQ in any > >>>> system? > >>> > >>> In Mediatek's SOC, only hace a single CIRQ. > >>> > >>>> > >>>>> + > >>>>> +static void mtk_cirq_write_mask(struct irq_data *data, unsigned int offset) > >>>>> +{ > >>>>> + struct mtk_cirq_chip_data *chip_data = data->chip_data; > >>>>> + unsigned int cirq_num = data->hwirq; > >>>>> + u32 mask = 1 << (cirq_num % 32); > >>>>> + > >>>>> + writel(mask, chip_data->base + offset + (cirq_num / 32) * 4); > >>>> > >>>> Why can't you use the relaxed accessors? > >>> > >>> It seems that i use wrong function, i will change the writel to > >>> writel_relaxed in next ve > >>> > >>>> > >>>>> +} > >>>>> + > >>>>> +static void mtk_cirq_mask(struct irq_data *data) > >>>>> +{ > >>>>> + mtk_cirq_write_mask(data, CIRQ_MASK_SET); > >>>>> + irq_chip_mask_parent(data); > >>>>> +} > >>>>> + > >>>>> +static void mtk_cirq_unmask(struct irq_data *data) > >>>>> +{ > >>>>> + mtk_cirq_write_mask(data, CIRQ_MASK_CLR); > >>>>> + irq_chip_unmask_parent(data); > >>>>> +} > >>>>> + > >>>>> +static void mtk_cirq_eoi(struct irq_data *data) > >>>>> +{ > >>>>> + mtk_cirq_write_mask(data, CIRQ_ACK); > >>>> > >>>> EOI and ACK have very different semantics. What is this write actually > >>>> doing? Also, you're now doing an additional MMIO write on each interrupt > >>>> EOI, doubling its cost. Do you really need to do actually signal the HW > >>>> that we've EOIed an interrupt? I would have hoped that you'd be able to > >>>> put it in "bypass" mode as long as you're not suspending... > >>>> > >>> > >>> When external interrupt happened, CIRQ status register record the status > >>> even CIRQ is not enabled. when execute the flush command, CIRQ will > >>> resend the signals according to the status. So if don't clear the > >>> status, CIRQ will resend the wrong signals. the ACK write operation will > >>> clear the status. > >> > >> But at this time, we haven't suspended yet, and there is nothing to > >> replay. Also, you only enable the edge capture when suspending. So what > >> are you ACKing here? Can't you simply clear everything right when > >> suspending and not do it at all on the fast path? > > > > I had planned to ACK the status in cirq suspend callback, but > > encountered a problem. > > following is a piece of code from > > http://lxr.free-electrons.com/source/kernel/power/suspend.c#L361 > > > > arch_suspend_disable_irqs(); ---step1 > > BUG_ON(!irqs_disabled()); > > > > error = syscore_suspend(); > > | > > ---cirq suspend(); ---step2 > > > > if ack the status in cirq suspend, the interrupts will be lost which > > happened during step1 to step2. > > > > So would you mind give me some suggestions about this? > > Thanks a lot! > > Right. So maybe there is a way: > - On suspend you can iterate over all the cirq interrupts that have been > recorded > - For each of those, you inspect if it is pending at the GIC level > (using the irq_get_irqchip_state helper) > - if not pending, you Ack it, because it cannot be delivered anymore > - If it is pending, then you know it happened between step 1 and step 2. > - You then have the choice of either going into suspend and waking up > immediately, or failing the suspend. > > Thoughts? Will use this solution in next version. Thanks a lot! > > M.