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 332333CA4B9; Thu, 23 Jul 2026 19:01:26 +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=1784833291; cv=none; b=H8OET9ByWH50U7KZW9AIl/txPXMG0YWBQiI0elDz8/ubRjBvUjPMZPd+1Wuc71iT5wudU7gwAVmfLLpHGURzuyiglIf4HEP2CgldW8oSNYANhpFFiCd63Bt1vpU5cCrwfi5jxiSGHclX58y0YEsnt8Z8wnbisVOqczAqfchxSXw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784833291; c=relaxed/simple; bh=EZk2OxD+gEZHGoushqS4qlXklQu9SaQr4xg9e277/AQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WxTv2LY7615M9JKWR5MDnM+BDv+pMnLX54ks6jE+iLYE1iKBx9Qweb7KUvJoAHE/BbbOt1WKAW8GEwBoEn79qbLLXTuxy8jGOHQfOGAC6cmmNuvcXgdxQgKl4PEvN+nyika+F4SA2wysjqjc/DTdvk5wilreSNIhKqDdLzKFa2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C4ibDkz9; 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="C4ibDkz9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC6C81F000E9; Thu, 23 Jul 2026 19:01:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784833285; bh=/iOx7Kdb7RsiadRvbAxhLdFG7t3D5msEa1q1juGjNWc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=C4ibDkz9AkXQAVdjpp+M76TU/m9gT6JzHtD496S9GljsgnnrGkCnHqs5GB/Id/OOc eBsMX4rgoeWi8lPJNLYbztDlHrjkTYlzkBHg9eLpbf6kz19YlGavfSc7vBswWowLcx evoKL8z6p9vjoSky8liSKLTmYRj1omyHBts1UZUF2i2nkuxPNGcSwJ9+dgiwB90atW MYlLTg1zUu67Fz2rCjx/K8RrJypbJGwNCx0QQdPCnKrzpUL8IqSZVNyo8wUdr6qhcH vNoXLVeGK/8uu4oI2aCkjj8LXmm1wtr587HKJiGJlpcgLefidHY/R5B6A9P0z9j+Ij l6nBn+yrWltPg== Message-ID: <1a9d18ce-e6dc-40e0-aa2a-e27f694e1217@kernel.org> Date: Thu, 23 Jul 2026 21:01:17 +0200 Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/2] dt-bindings: mmc: Document no-mmc-poweroff-suspend property To: Kamal Dasu Cc: Ulf Hansson , Florian Fainelli , Wolfram Sang , Oleksij Rempel , Avri Altman , Pedro Demarchi Gomes , Erick Shepherd , Adrian Hunter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260722211417.3702709-1-kamal.dasu@broadcom.com> <20260722211417.3702709-2-kamal.dasu@broadcom.com> <20260723-venerable-infallible-oriole-434b75@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: 8bit On 23/07/2026 20:53, Kamal Dasu wrote: > On Thu, Jul 23, 2026 at 3:51 AM Krzysztof Kozlowski wrote: > >> On Wed, Jul 22, 2026 at 05:14:16PM -0400, Kamal Dasu wrote: >>> On some platforms, firmware accesses the (e)MMC card directly during >>> system resume from Suspend-to-DRAM, before the kernel's own resume >>> path has run, in order to load boot code using hard wired logic that >>> is not field updatable. This requires the card to remain powered >>> and responsive throughout suspend: it cannot be put to sleep, sent a >>> power-off notification, or have its supply removed. >>> >>> Add a no-mmc-poweroff-suspend flag property so affected boards can >>> tell the mmc core to keep the card powered across suspend instead of >>> sleeping or powering it off. >>> >>> Signed-off-by: Kamal Dasu >>> --- >>> Changes in v3: >>> - Renamed from no-mmc-sleep; dropped S_A_TIMEOUT framing per Ulf. >>> >>> Changes in v2: >>> - New patch, replacing v1's card-level quirk, per Ulf. >>> >>> .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git >> a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >> b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>> index 3d7195e9461c..5f7b3f8ef1dd 100644 >>> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml >>> @@ -232,6 +232,16 @@ properties: >>> description: >>> All eMMC HS400 modes are not supported. >>> >>> + no-mmc-poweroff-suspend: >>> + $ref: /schemas/types.yaml#/definitions/flag >>> + description: >>> + On this platform, firmware accesses the attached (e)MMC card >>> + directly during system resume, before the kernel's own resume >>> + path runs. The card must therefore stay powered throughout >>> + suspend, and the controller must not send it a sleep or >>> + power-off notification. The kernel re-initializes the card >>> + after resume, since firmware may have already reset it. >> >> Isn't this exactly the same as keep-power-in-suspend? >> >> > Not quite, though I see why it reads that way from the description > alone. > > keep-power-in-suspend only takes effect through host->pm_flags, which > gets set at runtime via sdio_set_host_pm_flags() -- an SDIO function > driver opts in from its own suspend() callback, per suspend cycle. > The consuming logic lives entirely in mmc_sdio_suspend()/ > mmc_sdio_resume() (drivers/mmc/core/sdio.c); pm_flags is never read > in mmc.c, which is what this series touches. > > no-mmc-poweroff-suspend differs in two ways: > > - It's a fixed platform characteristic, not a per-driver runtime > request. There's no SDIO-style function driver to call an opt-in > API from for a plain (e)MMC storage card -- the requirement here > (firmware always touches the card at resume, on this board) is > always true, not something decided per suspend cycle. > - The resume-side behavior differs. keep-power-in-suspend without a > wake IRQ does nothing at resume: it assumes the card's state > survived untouched. This flag needs the opposite -- keep power, > but still fully re-initialize the card via mmc_init_card(), since > firmware may have reconfigured it while the kernel was suspended. All this is just driver stuff which I did not ask about. The property is described pretty the same - do not power off during suspend/resume. Best regards, Krzysztof