From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6DE60C77B73 for ; Wed, 31 May 2023 06:37:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q4FSK-0006v1-5V; Wed, 31 May 2023 02:37:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q4FS5-0006Yd-Vn; Wed, 31 May 2023 02:36:57 -0400 Received: from mail.ozlabs.org ([2404:9400:2221:ea00::3] helo=gandalf.ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q4FS3-0003UP-9l; Wed, 31 May 2023 02:36:57 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4QWKL34nKYz4x46; Wed, 31 May 2023 16:36:43 +1000 (AEST) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4QWKKy0wc8z4x42; Wed, 31 May 2023 16:36:37 +1000 (AEST) Message-ID: <54d781f8-35d0-9e68-c2ec-743dd8f6a88e@kaod.org> Date: Wed, 31 May 2023 08:36:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 05/12] hw/ssi: Introduce a ssi_get_cs() helper Content-Language: en-US To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-arm@nongnu.org Cc: qemu-devel@nongnu.org, Peter Maydell , Joel Stanley , Andrew Jeffery , Alistair Francis , Mark Cave-Ayland , Eduardo Habkost , Bernhard Beschow , Markus Armbruster , Thomas Huth References: <20230508075859.3326566-1-clg@kaod.org> <20230508075859.3326566-6-clg@kaod.org> <40c8647d-201e-3ceb-97ca-ec98bdc84e88@linaro.org> <0d11b78e-56f7-553a-3e85-0edef9b649ac@linaro.org> <523179dd-7842-7f03-14d6-678ed680a017@kaod.org> <6bfba08e-ce3e-539b-952d-697c8791fab2@linaro.org> From: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= In-Reply-To: <6bfba08e-ce3e-539b-952d-697c8791fab2@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2404:9400:2221:ea00::3; envelope-from=SRS0=vahk=BU=kaod.org=clg@ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, NICE_REPLY_A=-0.09, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 5/31/23 08:17, Philippe Mathieu-Daudé wrote: > +QOM tinkerers > > On 31/5/23 07:59, Cédric Le Goater wrote: >> On 5/30/23 23:15, Philippe Mathieu-Daudé wrote: >>> On 30/5/23 22:34, Philippe Mathieu-Daudé wrote: >>>> On 8/5/23 09:58, Cédric Le Goater wrote: >>>>> Simple routine to retrieve a DeviceState object on a SPI bus using its >>>>> address/cs. It will be useful for the board to wire the CS lines. >>>>> >>>>> Cc: Alistair Francis >>>>> Signed-off-by: Cédric Le Goater >>>>> --- >>>>>   include/hw/ssi/ssi.h |  2 ++ >>>>>   hw/ssi/ssi.c         | 15 +++++++++++++++ >>>>>   2 files changed, 17 insertions(+) >>>>> >>>>> diff --git a/include/hw/ssi/ssi.h b/include/hw/ssi/ssi.h >>>>> index ffd3a34ba4..c7beabdb09 100644 >>>>> --- a/include/hw/ssi/ssi.h >>>>> +++ b/include/hw/ssi/ssi.h >>>>> @@ -112,4 +112,6 @@ SSIBus *ssi_create_bus(DeviceState *parent, const char *name); >>>>>   uint32_t ssi_transfer(SSIBus *bus, uint32_t val); >>>>> +DeviceState *ssi_get_cs(SSIBus *bus, int addr); >>> >>> Also, this helper should (preferably) return a SSIPeripheral type. >> >> Well, having a DeviceState is handy for the callers (today) and >> ssi_create_peripheral() returns a DeviceState. Let's keep it that >> way. > > Yes I know it is handy :) I'm not against your patch; besides other > APIs do that. I'm wondering about QOM design here. Having Foo device, > should FOO API return the common qdev abstract type (DeviceState) or > a Foo type? Either ways we keep QOM-casting around, but I still tend > to consider FOO API returning Foo pointer provides some type check > safety, and also provides the API user hints about what is used. > Need more coffee. It is used in two code paths today: ... DeviceState *dev = ssi_get_cs(bmc->soc.fmc.spi, 0); BlockBackend *fmc0 = dev ? m25p80_get_blk(dev) : NULL; ... and ... DeviceState *dev = ssi_get_cs(s->spi, i); if (dev) { qemu_irq cs_line = qdev_get_gpio_in_named(dev, SSI_GPIO_CS, 0); ... Changing the interface is not a radical change, it will add two QOM-casts. I can give it a try in v2. Thanks, C.