From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C94EA2DCF68 for ; Thu, 3 Jul 2025 09:57:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751536645; cv=none; b=iq9xlenTzco5EQP3GWyGhVKOUtlGDaF/FcwzgUYLTZOWklaNLG2ibiz/6ibCczI77rBD6fYyyJFcdERN7uiouWZknjYDpn7cg3lN/C5X0lKmV8x3rFdIG9jxddIc/fYi+Kruvgc+Szj2hrXXNAQB6cdKrTpRfKHCaltgQQlCdXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751536645; c=relaxed/simple; bh=c5big+j1eLYqTd9f91QD21CM2Uu+ovktIk2We9V9Kms=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oUCtpqnTmw5lhL+vmLJUscyjUCnjBECNrxJBwarxWiT2vv++K6fneJatgCbhgkrpMgYuhU8kRZcx8TDC5KzjoY5O0l0OZxP9W85AblNu2UG0FxkqSfkt5fhU0rXuVrfcqemOgDFIGsiGYHUfSYPAe/ukczrcspcxh9cUgk32m/c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1uXGgb-0007Za-5y; Thu, 03 Jul 2025 11:56:57 +0200 Message-ID: <8db56c73-191e-48ec-9a28-cbb0da9a8a80@pengutronix.de> Date: Thu, 3 Jul 2025 11:56:56 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 0/6] imx8mp: add support for the IMX AIPSTZ bridge To: Laurentiu Mihalcea , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Sascha Hauer , Fabio Estevam , Daniel Baluta , Shengjiu Wang , Frank Li , Marco Felsch , Marc Kleine-Budde , Alexander Stein Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Pengutronix Kernel Team , imx@lists.linux.dev References: <20250610160152.1113930-1-laurentiumihalcea111@gmail.com> <3615415b-7ebd-45e5-8d7b-8a1b26ac7130@pengutronix.de> <10ef8a9a-6d23-4fb9-933f-71ab493d21c7@gmail.com> Content-Language: en-US, de-DE, de-BE From: Ahmad Fatoum In-Reply-To: <10ef8a9a-6d23-4fb9-933f-71ab493d21c7@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2a0a:edc0:0:900:1d::77 X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Hello Laurentiu, On 7/3/25 10:51, Laurentiu Mihalcea wrote: > > > On 7/3/2025 11:11 AM, Ahmad Fatoum wrote: >> Hello Laurentiu, >> >> On 10.06.25 18:01, Laurentiu Mihalcea wrote: >>> From: Laurentiu Mihalcea >>> >>> The AIPSTZ bridge offers some security-related configurations which can >>> be used to restrict master access to certain peripherals on the bridge. >>> >>> Normally, this could be done from a secure environment such as ATF before >>> Linux boots but the configuration of AIPSTZ5 is lost each time the power >>> domain is powered off and then powered on. Because of this, it has to be >>> configured each time the power domain is turned on and before any master >>> tries to access the peripherals (e.g: AP, CM7, DSP, on i.MX8MP). >> Sorry if this has been asked before, but I hoped the cover letter or patch >> 3/6 would explain if it were. >> >> What is the default configuration for the AIPSTZ before this series? > > the default configuration is the reset configuration since AIPSTZ registers go > back to their reset values during domain power cycling. > >> I assume the SAIs under AIPS5 can be accessed by SDMA already, so why was >> changing the AIPSTZ settings needed for the DSP to work? > > AFAIK SDMA transactions to peripherals don't go through AIPS5. They use SPBA, which > is why SDMA works even w/o this series. As for the DSP: transactions to peripherals go > through AIPS5. With the reset configuration, the DSP is not allowed to access said peripherals, > which is why this series was needed. I see. Thanks for tackling this issue and your explanation. Cheers, Ahmad > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |