From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [RFT PATCH v2] gpiolib: allow gpio irqchip to map irqs dynamically Date: Tue, 1 Aug 2017 09:52:30 +0200 Message-ID: References: <20170721164900.7070-1-grygorii.strashko@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Received: from mail-it0-f51.google.com ([209.85.214.51]:36128 "EHLO mail-it0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751327AbdHAHwc (ORCPT ); Tue, 1 Aug 2017 03:52:32 -0400 Received: by mail-it0-f51.google.com with SMTP id 77so3841513itj.1 for ; Tue, 01 Aug 2017 00:52:32 -0700 (PDT) In-Reply-To: <20170721164900.7070-1-grygorii.strashko@ti.com> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Grygorii Strashko , Bartosz Golaszewski Cc: "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Jerome Brunet On Fri, Jul 21, 2017 at 6:49 PM, Grygorii Strashko wrote: > Now IRQ mappings are always created for all (allowed) GPIOs in gpiochip in > gpiochip_irqchip_add_key() which goes against the idea of SPARSE_IRQ and, > as result, leads to: > - increasing of memory consumption for IRQ descriptors most of which will > never ever be used (espessially on platform with a high number of GPIOs). > (sizeof(struct irq_desc) == 256 on my tested platforms) > - imposibility to use GPIO irqchip APIs by gpio drivers when HW implements > GPIO IRQ functionality as IRQ crossbar/router which has only limited > number of IRQ outputs (example from [1], all GPIOs can be mapped on only 8 > IRQs). > > Hence, remove static IRQ mapping code from gpiochip_irqchip_add_key() and > instead replace irq_find_mapping() with irq_create_mapping() in > gpiochip_to_irq(). Also add additional gpiochip_irqchip_irq_valid() calls > in gpiochip_to_irq() and gpiochip_irq_map(). > > After this change gpio2irq mapping will happen the following way when GPIO > irqchip APIs are used by gpio driver: > - IRQ mappings will be created statically if driver passes first_irq>0 > vlaue in gpiochip_irqchip_add_key(). > - IRQ mappings will be created dynamically from gpio_to_irq() or > of_irq_get(). > > Tested on am335x-evm and dra72-evm-revc. > - dra72-evm-revc: number of created irq mappings decreased from 402 -> 135 > Mem savings 267*256 = 68352 (66kB) > - am335x-evm: number of created irq mappings decreased from 188 -> 63 > Mem savings 125*256 = 32000 (31kB) > > [1] https://lkml.org/lkml/2017/6/15/428 > Signed-off-by: Grygorii Strashko > --- > Changes in v2: > - restored struct gpio_chip->irq_base to fix buld of gpio-mockup.c Applied this rather than v1. But maybe we should get rid of ->irq_base from gpio-mockup.c and delete it, as the base is irqchip-internal. Bartosz what do you say? Do we need this in the mockup? Yours, Linus Walleij