From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8065D358399; Wed, 12 Aug 2026 10:03:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786528987; cv=none; b=VcLksElZVVVSpdpeS5P4XLc1XsfDEw0m1CUXkTD7YLxSWxPHhyf9KXc43Me2F1aJ6OAnSaEA+ojapr7m7s8FHTh7wfQhyO4RdW1Wzz+kn7iedAEt6x7+YveKELa6A52oDr8Ky+DXz/4Adv06Ry1MYBU3TC0XelaqG/dgrXAUqyU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786528987; c=relaxed/simple; bh=wssolmgJd/cBFSr8Zocs0/SA81bRmq+iJzXTmINeuoE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZOr9TJ5/U2OSlH7FQwfGbyM8EmQaQZgMIaE5XOdmZb5wUTq6i76OYiN2qkCQM40pDlKsrtNj4vtfaa4T45vj/7sinZUnvAmIzr3Wh/I7IIfPJLQjmNRTd1XOaqY3jX69efg1UYbpQuJ6I+n7Xm2zvMx5E4VGa+SmnvJOcRhE4o8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z8F/fftD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Z8F/fftD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4CA31F000E9; Wed, 12 Aug 2026 10:03:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786528986; bh=VUCfF1UAtrr5Sz4037NGCH3ZcjKNMv5UJ6wXb/uvgGE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Z8F/fftDf17dt8VMfG82K31UoEYpifag2Gyi7U0w7Yuwig7vvuUyhvkOCdpBvnFFX dkedhhx8vCot3G+jTLeTXk2hvnWTyGTkefYL1SvjktZE0RELs5p95FVPnhjrEk9r8j J1gtfw1ED2MDkEF3tMiBBGt0OygTcnEtrKStDFWAoRz6I1QpcPT466wvD6RjipjTWL 2eOB+YWwPkh9Rcv7Tm2JKb1IwZs5Ug5+sJyx1eAFCq8ib3OsxpqRuXB/xQNO0bZVbF MSxftiofDrGViSeKOocIxOZH0eeOQ9sa2/7tjjo6VhrAy+9IrV/HSpmGTBoSlIvWgb G/eQ0rqSOmXZA== Message-ID: <9557331b-8d7e-4235-93c5-f8b799df6fff@kernel.org> Date: Wed, 12 Aug 2026 12:02:58 +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 v3 1/4] dt-bindings: remoteproc: add imx-rproc-psci To: Jiafei Pan Cc: "andersson@kernel.org" , "mathieu.poirier@linaro.org" , Peng Fan , Frank Li , "s.hauer@pengutronix.de" , "kernel@pengutronix.de" , "festevam@gmail.com" , "imx@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "Z.Q. Hou" , Mingkai Hu , "linux-remoteproc@vger.kernel.org" , "devicetree@vger.kernel.org" References: <20260511023928.39640-1-Jiafei.Pan@nxp.com> <20260511023928.39640-2-Jiafei.Pan@nxp.com> <20260514-omniscient-futuristic-macaque-af0718@quoll> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGPBBMBCgA5AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJp2mE8AAoJEBuTQ307QWKbeaIP /ihHTkTW4KsN/DQ945JJbyu5tI0J80Wue7QyyLPglyKfhgb5cLLNPpOC8cCIJsc7+W3i2P38 s2c1cOH6CYGE7E9ur3Vfme8NW2S2I/Z8VC7bZnzyS23wT17LrsdS/qCpx4o8U+pt/xdXDKph EGRYrIEmMpUWvyYzyYKGIe25FtaayIIKpq8eZYyFcp2f/sG5IkOW5uZzHPMPdcm87jU7fyuQ rAU2vx9r+ulUfQ/q9Z2roC/ode3l7t2pN7BCBCsUDp6JCrUyZrtT1e7EbA0ZRP3aOBNk2P2E DQOgJGjGdO5Yx2Y9LFtltu6JbsBJHi1syGRX3AtQYOMc4Y1WGoeZJmMlvKj2ZqqXNkcWi2DS IQEWB0uW6CqFsBBIMGDa+6OzdaVO/uAVXWDWml02Men3CILdI1MbVjoh8ECqYUY7OQ+JJvNN vnliuq5WM3Ghd3jg/LZZrxXjdIginRHFQCjIJYLKpLZWm1/iDFedcfzqRNYmTtqscdCNHW41 oT3Z7BmO9xwdjuwBS6nmS6JJwkbf5Ot2QR4pB/DRU7ZwjT1qHe+9r9gF32wXVQatHNGK/VVu sfwOnkdxCWkp/qb2gdQRmZh+SedStWshigH6sNfuHBloF/q+hjMRc8b2m326OZdrbSHwY1Sz vti8Hn7n8NjdHO9LKB7BIdjkA9DA5WsqOuVCzsFNBFVDXDQBEADNkrQYSREUL4D3Gws46JEo Z9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLueMNsWLJBv BaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6eiOMheesVS 5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wAGldWsRxb f3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA6z6lBZn0 WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9YegxWKvX XHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt91pFzBSO IpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gUBLHFTg2h YnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/JoFzZ4B0 p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu4vXVFBYI GmpyNPYzRm0QPwARAQABwsF2BBgBCgAgAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtBYpsFAmna YUkACgkQG5NDfTtBYptX+BAApg32CkxwNucNEi8WfWA8oKkW0y8YDuY6ORMo9FWNGiT/OTy0 vyJrLocrpn86zwfjVp+eCrssPYh8eqJfnWqmYv6ACQtHPYzPZQ3mSo8H97Z01oUxITzCxpXm ZkLgPIqtDPcC2E3dPM/fVxcyowM8XsaMA9wcsaUYrta8toOq2b9tKcjleKMfMrm0gQ9u7wUc QbLkwj6TCLOwucb07GXzLTNF9PZmaDUpKAZjMjmrW+le+SFvQbhamx0rxLWPR0NWntXpbCn+ +ACch03p/JyTBVktxFsFyCt7pTPE1kEaeuXBTe/a2D9iQvRxRW19LvuO2e59/u1wYUiH/orz wbIC2S4dBsPAPihL3ztOU1yE86GPyQtSE0kU+/7snnLt4QGi6PChf3t5gnNjAzjUUovO8rgI c+5yN5heq5loYHgK6OQ9OlHzsPHO9e9MOQcKlFycs1pyijFGzDwdNUm/SchK8iWT2QApTx4A K9bCVaboTA2T77QYkRcRJYSsO1alGX0ome/hMLD1daXlkrNUp1HWa3K4iytLRXjCSIorWiGs n+q3krnpXu3TFkA8qtOFZMdnIiFuiq1yLT8hptsV5xh1TA2nsVvSYiaCr3q4s4BKjS/KrLDb qoxzw8ISjdUp4pA85vb6YLCmb39NgidD+7PmAr65lBNveIFynTgsja1rRQ4= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/08/2026 11:19, Jiafei Pan wrote: > > NXP Confidential > On Wed, May 14, 2026 at 11:38:13AM +0000, Krzysztof Kozlowski wrote: >>> +description: >>> + This binding provides support for managing Cortex-A cores as remote >>> + processors on i.MX platforms using the PSCI (Power State Coordination >>> + Interface) for CPU power management operations. This allows single >>> + Cortex-A core or multiple Cortex-A cores to be controlled by Linux as >>> + a remote processor, enabling them to run RTOS or bare-metal applications. >> >> Describe the hardware, not the binding. > > Will fix. Updated to describe the hardware: > > NXP i.MX SoCs integrate multiple Cortex-A cores. On certain i.MX > platforms, one or more of these cores can be offloaded to run RTOS > or bare-metal firmware as a remote processor, while the remaining > cores run Linux. The cores are powered on and off via PSCI (Power > State Coordination Interface) CPU_ON/CPU_OFF calls to the firmware. > >>> + compatible: >>> + const: fsl,imx-rproc-psci >> >> Why isn't the compatible specific? > > Will fix. Updated to use a SoC-specific compatible with a generic > fallback: > > compatible: > - items: > - enum: > - fsl,imx93-ca53-rproc- > - const: fsl,imx-rproc-psci Don't do generic fallbacks. Works poor, as visible in multiple cases now. > >>> + fsl,cpus-mask: >>> + $ref: /schemas/types.yaml#/definitions/uint32 >>> + description: >>> + Bitmask indicating which CPU cores are assigned to this remote >>> + processor instance. Each bit represents a CPU core, where bit N >>> + corresponds to CPU N. For example, 0x2 (0b10) assigns CPU core 1, >>> + while 0x6 (0b110) assigns CPU cores 1 and 2. >> >> So you partition existing Cortex-A cores? Or how exactly? Why isn't this >> deducible from the compatible (I assume you read carefully writing >> bindings)? > > Yes, we partition existing Cortex-A cores. On i.MX93 for example, > there are 2 Cortex-A55 cores. Core 0 runs Linux as the primary OS, > while core 1 (or any subset of the remaining cores on SoCs with more > cores, e.g. 4x A55) can be assigned to a remoteproc instance to run > RTOS or bare-metal firmware. > > The reason fsl,cpus-mask cannot be deduced from the compatible is > that the assignment is flexible and board/use-case specific. On a > 4-core SoC, the user may assign core 1 only, cores 1+2, cores 2+3, > or all non-primary cores to one or more remoteproc instances. This > runtime flexibility cannot be encoded in the compatible string. > > We considered using a `cpus` phandle list instead, but the CPU nodes > in the DT are already claimed by the Linux CPU topology and do not > naturally represent "remote processor" assignments. The bitmask > approach directly maps to the PSCI CPU_ON/CPU_OFF MPIDR-based > interface used by the firmware. You replied three months after my comment. Well, you have such right but so you know entire context is gone and I am not going to put my time to read the binding again. Just for you know - if you partition the cpus, they are gone from the cpus list as well. Not sure how this affects the bitmask but remember to model only available CPUs properly in DT. Best regards, Krzysztof