From nobody Thu Apr 10 23:09:48 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 167576479323589.61774880067571; Tue, 7 Feb 2023 02:13:13 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pPKuD-0000l9-FU; Tue, 07 Feb 2023 05:08:53 -0500 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 1pPKtu-0000V2-0X; Tue, 07 Feb 2023 05:08:35 -0500 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 1pPKts-0002Sb-1E; Tue, 07 Feb 2023 05:08:33 -0500 Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4P9zNb00rSz4xyj; Tue, 7 Feb 2023 21:08:31 +1100 (AEDT) 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 4P9zNX5Dl2z4xyF; Tue, 7 Feb 2023 21:08:28 +1100 (AEDT) From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: Peter Maydell , Peter Delevoryas , Joel Stanley , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Corey Minyard Subject: [PULL 14/25] hw/nvram/eeprom_at24c: Make reset behavior more like hardware Date: Tue, 7 Feb 2023 11:07:33 +0100 Message-Id: <20230207100744.698694-15-clg@kaod.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230207100744.698694-1-clg@kaod.org> References: <20230207100744.698694-1-clg@kaod.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2404:9400:2221:ea00::3; envelope-from=SRS0=a43c=6D=kaod.org=clg@ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -39 X-Spam_score: -4.0 X-Spam_bar: ---- X-Spam_report: (-4.0 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1675764794548100003 From: Peter Delevoryas EEPROM's are a form of non-volatile memory. After power-cycling an EEPROM, I would expect the I2C state machine to be reset to default values, but I wouldn't really expect the memory to change at all. The current implementation of the at24c EEPROM resets its internal memory on reset. This matches the specification in docs/devel/reset.rst: Cold reset is supported by every resettable object. In QEMU, it means we = reset to the initial state corresponding to the start of QEMU; this might differ from what is a real hardware cold reset. It differs from other resets (li= ke warm or bus resets) which may keep certain parts untouched. But differs from my intuition. For example, if someone writes some informat= ion to an EEPROM, then AC power cycles their board, they would expect the EEPRO= M to retain that information. It's very useful to be able to test things like th= is in QEMU as well, to verify software instrumentation like determining the ca= use of a reboot. Fixes: 5d8424dbd3e8 ("nvram: add AT24Cx i2c eeprom") Signed-off-by: Peter Delevoryas Reviewed-by: Joel Stanley Reviewed-by: C=C3=A9dric Le Goater Reviewed-by: Corey Minyard Link: https://lore.kernel.org/r/20230128060543.95582-6-peter@pjd.dev Signed-off-by: C=C3=A9dric Le Goater --- hw/nvram/eeprom_at24c.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c index 05598699dc..3328c32814 100644 --- a/hw/nvram/eeprom_at24c.c +++ b/hw/nvram/eeprom_at24c.c @@ -184,18 +184,6 @@ static void at24c_eeprom_realize(DeviceState *dev, Err= or **errp) } =20 ee->mem =3D g_malloc0(ee->rsize); - -} - -static -void at24c_eeprom_reset(DeviceState *state) -{ - EEPROMState *ee =3D AT24C_EE(state); - - ee->changed =3D false; - ee->cur =3D 0; - ee->haveaddr =3D 0; - memset(ee->mem, 0, ee->rsize); =20 if (ee->init_rom) { @@ -213,6 +201,16 @@ void at24c_eeprom_reset(DeviceState *state) } } =20 +static +void at24c_eeprom_reset(DeviceState *state) +{ + EEPROMState *ee =3D AT24C_EE(state); + + ee->changed =3D false; + ee->cur =3D 0; + ee->haveaddr =3D 0; +} + static Property at24c_eeprom_props[] =3D { DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0), DEFINE_PROP_BOOL("writable", EEPROMState, writable, true), --=20 2.39.1