From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CF3A917AE11 for ; Fri, 6 Feb 2026 03:40:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770349230; cv=none; b=TGPj4KAYOA28xH9pSiSnjairyBU7yF2/Bu6nIgDlHz2UTu5V08ZU2h+EzvYszq67xTan9mY3ZW+K+biDhaq4Z2QJJrkqI4pwFJLO5kO8ZrtcGff4ssJyfRSJyVeL4A+Yrqu+YHjXbiPBXoF+NgQTywE+yloOr2VlJsEEZjtw36E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770349230; c=relaxed/simple; bh=FODg6UNvIBu/ZybFA9evOhDRmMXlzJppqNIxz1lUES4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B+Thmkg4wyEixYLtP9yai8Bl6An6yLQQl9kQgqyPsHJAjhEcQIZthwzkYoVifUnb7WxtYnUzIHAjz0g4n9lbhJ3vRqkLC1ye6OuBHocg2L3BKMEWkRN6o0e4VAHhuYDMRDJLZSCzpR4TWedixa9rAWHsWVSOZCXQldPEmSXXWBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UGbDFSHK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UGbDFSHK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17BB9C4CEF7; Fri, 6 Feb 2026 03:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770349230; bh=FODg6UNvIBu/ZybFA9evOhDRmMXlzJppqNIxz1lUES4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UGbDFSHKu32A0MBDQvShwysZrEWY04LY9wi7FxWw1eNXl4fs4yLgZ3folOAtj2qnQ MC/+pMH6f20yRAk2eQ4n5Lv5Ah9x6wEUuDw+vxxTYIvvtUyVXiVCHGzq5W5yY2Btz+ +/ZtjL2hE7A/mYfBmM13E22ur+lvAR9pmWQJ7jIm2aRF2IeN4InP8SadGHLI6reRX9 u9g/4ht7FSdkMsixdozPU0Nok+0bN64uuZvlIxDdJcw18/+wJOEjWCemyqh22JlfwX 0+KTUjHlS1NfWnJ1bK38dd2Z7fvNA0Vf6EbKzaNBywLtR6+gCdV4Cx1SfcbnKcpJOk 0ZL5E4OLQUKng== Date: Fri, 6 Feb 2026 03:40:26 +0000 From: Tzung-Bi Shih To: Bjorn Andersson , Mathieu Poirier Cc: Matthias Brugger , AngeloGioacchino Del Regno , Chen-Yu Tsai , linux-remoteproc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH v2] remoteproc: mediatek: Unprepare SCP clock during system suspend Message-ID: References: <20260206033034.3031781-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-remoteproc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260206033034.3031781-1-tzungbi@kernel.org> On Fri, Feb 06, 2026 at 03:30:33AM +0000, Tzung-Bi Shih wrote: > Prior to commit d935187cfb27 ("remoteproc: mediatek: Break lock > dependency to prepare_lock"), `scp->clk` was prepared and enabled only > when it needs to communicate with the SCP. The commit d935187cfb27 > moved the prepare operation to remoteproc's prepare(), keeping the clock > prepared as long as the SCP is running. > > The power consumption due to the prolonged clock preparation can be > negligible when the system is running, as SCP is designed to be a very > power efficient processor. > > However, the clock remains prepared even when the system enters system > suspend. This prevents the underlying clock controller (and potentially > the parent PLLs) from shutting down, which increases power consumption > and may block the system from entering deep sleep states. > > Add suspend and resume callbacks. Unprepare the clock in suspend() if > it was active and re-prepare it in resume() to ensure the clock is > properly disabled during system suspend, while maintaining the "always > prepared" semantics while the system is active. The driver doesn't > implement .attach() callback, hence it only checks for RPROC_RUNNING. > > Fixes: d935187cfb27 ("remoteproc: mediatek: Break lock dependency to prepare_lock") > Reviewed-by: AngeloGioacchino Del Regno > Signed-off-by: Tzung-Bi Shih > --- Pardon me for forgetting to attach changelog before sending the patch. Here is the changelog: v2: - Add note and code comment for RPROC_ATTACHED. - Use __maybe_unused instead of '#ifdef CONFIG_PM_SLEEP'. - Add R-b tag. v1: https://lore.kernel.org/all/20260204085442.1822123-1-tzungbi@kernel.org > drivers/remoteproc/mtk_scp.c | 39 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c > index 4651311aeb07..bb6f6a16d895 100644 > --- a/drivers/remoteproc/mtk_scp.c > +++ b/drivers/remoteproc/mtk_scp.c > @@ -1592,12 +1592,51 @@ static const struct of_device_id mtk_scp_of_match[] = { > }; > MODULE_DEVICE_TABLE(of, mtk_scp_of_match); > > +static int __maybe_unused scp_suspend(struct device *dev) > +{ > + struct mtk_scp *scp = dev_get_drvdata(dev); > + struct rproc *rproc = scp->rproc; > + > + /* > + * Only unprepare if the SCP is running and holding the clock. > + * > + * Note: `scp_ops` doesn't implement .attach() callback, hence > + * `rproc->state` can never be RPROC_ATTACHED. Otherwise, it > + * should also be checked here. > + */ > + if (rproc->state == RPROC_RUNNING) > + clk_unprepare(scp->clk); > + return 0; > +} > + > +static int __maybe_unused scp_resume(struct device *dev) > +{ > + struct mtk_scp *scp = dev_get_drvdata(dev); > + struct rproc *rproc = scp->rproc; > + > + /* > + * Only prepare if the SCP was running and holding the clock. > + * > + * Note: `scp_ops` doesn't implement .attach() callback, hence > + * `rproc->state` can never be RPROC_ATTACHED. Otherwise, it > + * should also be checked here. > + */ > + if (rproc->state == RPROC_RUNNING) > + return clk_prepare(scp->clk); > + return 0; > +} > + > +static const struct dev_pm_ops scp_pm_ops = { > + SET_SYSTEM_SLEEP_PM_OPS(scp_suspend, scp_resume) > +}; > + > static struct platform_driver mtk_scp_driver = { > .probe = scp_probe, > .remove = scp_remove, > .driver = { > .name = "mtk-scp", > .of_match_table = mtk_scp_of_match, > + .pm = &scp_pm_ops, > }, > }; > > -- > 2.53.0.rc2.204.g2597b5adb4-goog >