Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752224AbcKHB7D (ORCPT ); Mon, 7 Nov 2016 20:59:03 -0500 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:51837 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699AbcKHB7B (ORCPT ); Mon, 7 Nov 2016 20:59:01 -0500 Subject: Re: [PATCH v3 2/3] ARCv2: MCIP: Use hwirq instead of virq for resolution of IDU IRQ handlers To: Yuriy Kolerov , References: <1478175788-3118-1-git-send-email-yuriy.kolerov@synopsys.com> <1478175788-3118-3-git-send-email-yuriy.kolerov@synopsys.com> CC: , , Newsgroups: gmane.linux.kernel.arc,gmane.linux.kernel From: Vineet Gupta Message-ID: Date: Mon, 7 Nov 2016 17:58:38 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1478175788-3118-3-git-send-email-yuriy.kolerov@synopsys.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.10.161.65] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3284 Lines: 81 On 11/03/2016 05:23 AM, Yuriy Kolerov wrote: > Multicore ARC configurations use IDU (Interrupt Distribution Unit) for > distributing of common interrupts. In fact IDU is a interrupt controller > on top of main per core interrupt controller. > > All common IRQs are physically and linearly mapped to per core > interrupts. E.g. <0, 1, 2, 3> common IDU interrupts may be mapped to per > core <24, 25, 26, 27> interrupts. An initialization code of IDU > controller (idu_of_init) creates mappings for all parent interrupts > <24, 25, ...> and sets a chained IDU handler for them. In the same > time idu_of_init must save the first met parent hwirq (idu_first_irq) > thus in future it is possible to figure out what common hwirq has come > by subtracting of idu_first_irq from the current parent hwirq (see > idu_cascade_isr). > > The problem is that idu_of_init and idu_cascade_isr use parent virtual > IRQs as hardware IRQs and perform all the above-described manipulations > on virtual IRQs. But it is wrong and hardware IRQs must be used instead. Is this series bisectable ? So if one only applies patch 1/3 (and not 2/3) - as might happen in case of a bisect for some arbit problem, will it still work - to me it seems not. > > Signed-off-by: Yuriy Kolerov > --- > arch/arc/kernel/mcip.c | 20 +++++++++----------- > 1 file changed, 9 insertions(+), 11 deletions(-) > > diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c > index 72f9179..4f4f04b 100644 > --- a/arch/arc/kernel/mcip.c > +++ b/arch/arc/kernel/mcip.c > @@ -219,16 +219,14 @@ static struct irq_chip idu_irq_chip = { > > }; > > -static int idu_first_irq; > +static irq_hw_number_t idu_first_hwirq; > > static void idu_cascade_isr(struct irq_desc *desc) > { > - struct irq_domain *domain = irq_desc_get_handler_data(desc); > - unsigned int core_irq = irq_desc_get_irq(desc); > - unsigned int idu_irq; > - > - idu_irq = core_irq - idu_first_irq; > - generic_handle_irq(irq_find_mapping(domain, idu_irq)); > + struct irq_domain *idu_domain = irq_desc_get_handler_data(desc); > + irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc)); > + irq_hw_number_t idu_hwirq = core_hwirq - idu_first_hwirq; > + generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq)); > } > > static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq) > @@ -294,7 +292,7 @@ idu_of_init(struct device_node *intc, struct device_node *parent) > struct irq_domain *domain; > /* Read IDU BCR to confirm nr_irqs */ > int nr_irqs = of_irq_count(intc); > - int i, irq; > + int i, virq; > > if (!idu_detected) > panic("IDU not detected, but DeviceTree using it"); > @@ -312,11 +310,11 @@ idu_of_init(struct device_node *intc, struct device_node *parent) > * however we need it to get the parent virq and set IDU handler > * as first level isr > */ > - irq = irq_of_parse_and_map(intc, i); > + virq = irq_of_parse_and_map(intc, i); > if (!i) > - idu_first_irq = irq; > + idu_first_hwirq = irqd_to_hwirq(irq_get_irq_data(virq)); > > - irq_set_chained_handler_and_data(irq, idu_cascade_isr, domain); > + irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain); > } > > __mcip_cmd(CMD_IDU_ENABLE, 0); >