From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 D2DBA396D19; Thu, 15 Jan 2026 12:50:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768481410; cv=none; b=umH9YwF7yCTFd6a4eKIdn4kAMCzMBXAnkmFlwAblrjSj8KLeOr7Hqrhn0CtYzMCQmPzGuwSwyvrqs2q5EV4pwJYz9DxmJoLhDWu0Sc83vrF7lGrazxuVqB13bxsUqh9r8h8ic2q1yzITMYss08OUcycyr6/Kslqz1BDizIkg7EY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768481410; c=relaxed/simple; bh=5oCNQkLZbOnATTH528W78A5Lrg4owMX/yWsMvaTdAho=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bLGtQR1QAtKxXmrOZUcw4ix4Dek/dojDNYrKJSzOe/AC86RpS2EVhBB4yvUyCC6ZQDerjfzGB5b2IDqkdGGdVQHwCMstm5pdKiqIUUSEpca53suNENY9gC0i2z5UJ8zBBZyH3YKYWh99dL1nZBxGQExAOb2o1fkKEGX3Y5udHzo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=X3YM6qt/; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="X3YM6qt/" Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E98D924A; Thu, 15 Jan 2026 13:49:36 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1768481378; bh=5oCNQkLZbOnATTH528W78A5Lrg4owMX/yWsMvaTdAho=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=X3YM6qt/YojIwGjQ1LEpBS9hJKXqOsX4yz+3vHZRl21H6U+mezT2cmXA8zJvx5can VlILippJjC5rQe8Z3jHhQZfYZYh3C9coAqhnN1r2m/MWGVepzY4XHVJRfQmqcI/V7u IM06WATo5qb0oJTs+QPtmOBu7nX/U1L4yo7xnH24= Message-ID: <9bf5fd69-4ff6-40c5-aa22-e6330bf8e323@ideasonboard.com> Date: Thu, 15 Jan 2026 14:50:01 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 19/19] media: ti: j721e-csi2rx: Support system suspend using pm_notifier To: Rishikesh Donadkar Cc: y-abhilashchandra@ti.com, devarsht@ti.com, s-jain1@ti.com, vigneshr@ti.com, mchehab@kernel.org, robh@kernel.org, krzk+dt@kernel.org, p.zabel@pengutronix.de, conor+dt@kernel.org, sakari.ailus@linux.intel.com, hverkuil-cisco@xs4all.nl, jai.luthra@ideasonboard.com, changhuang.liang@starfivetech.com, jack.zhu@starfivetech.com, sjoerd@collabora.com, dan.carpenter@linaro.org, hverkuil+cisco@kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, jai.luthra@linux.dev, laurent.pinchart@ideasonboard.com, mripard@kernel.org References: <20251230083220.2405247-1-r-donadkar@ti.com> <20251230083220.2405247-20-r-donadkar@ti.com> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 30/12/2025 10:32, Rishikesh Donadkar wrote: > From: Jai Luthra > > As this device is the "orchestrator" for the rest of the media > pipeline, we need to stop all on-going streams before system suspend and > enable them back when the system wakes up from sleep. > > Using .suspend/.resume callbacks does not work, as the order of those > callbacks amongst various devices in the camera pipeline like the sensor, > FPD serdes, CSI bridge etc. is impossible to enforce, even with > device links. For example, the Cadence CSI bridge is a child device of > this device, thus we cannot create a device link with the CSI bridge as > a provider and this device as consumer. This can lead to situations > where all the dependencies for the bridge have not yet resumed when we > request the subdev to start streaming again through the .resume callback > defined in this device. > > Instead here we register a notifier callback with the PM framework > which is triggered when the system is fully functional. At this point we > can cleanly stop or start the streams, because we know all other devices > and their dependencies are functional. A downside of this approach is > that the userspace is also alive (not frozen yet, or just thawed), so > the suspend notifier might complete before the userspace has completed > all ioctls, like QBUF/DQBUF/STREAMON/STREAMOFF. It would be good to have at least parts of the explanation here in a comment, before the register_pm_notifier() call. Tomi > Tested-by: Rishikesh Donadkar > Reviewed-by: Rishikesh Donadkar > Signed-off-by: Jai Luthra > Signed-off-by: Rishikesh Donadkar > --- > .../platform/ti/j721e-csi2rx/j721e-csi2rx.c | 128 ++++++++++++++++++ > 1 file changed, 128 insertions(+) > > diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > index 72da58738e16e..f8e55aa402e0b 100644 > --- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > +++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > @@ -132,6 +132,7 @@ struct ti_csi2rx_dev { > struct v4l2_subdev *source; > struct v4l2_subdev subdev; > struct ti_csi2rx_ctx ctx[TI_CSI2RX_MAX_CTX]; > + struct notifier_block pm_notifier; > u8 pix_per_clk; > /* Buffer to drain stale data from PSI-L endpoint */ > struct { > @@ -1539,6 +1540,124 @@ static int ti_csi2rx_runtime_resume(struct device *dev) > return 0; > } > > +static int ti_csi2rx_suspend(struct device *dev) > +{ > + struct ti_csi2rx_dev *csi = dev_get_drvdata(dev); > + enum ti_csi2rx_dma_state state; > + struct ti_csi2rx_ctx *ctx; > + struct ti_csi2rx_dma *dma; > + unsigned long flags = 0; > + int i, ret = 0; > + > + /* If device was not in use we can simply suspend */ > + if (pm_runtime_status_suspended(dev)) > + return 0; > + > + /* > + * If device is running, assert the pixel reset to cleanly stop any > + * on-going streams before we suspend. > + */ > + writel(0, csi->shim + SHIM_CNTL); > + > + for (i = 0; i < csi->num_ctx; i++) { > + ctx = &csi->ctx[i]; > + dma = &ctx->dma; > + > + spin_lock_irqsave(&dma->lock, flags); > + state = dma->state; > + spin_unlock_irqrestore(&dma->lock, flags); > + > + if (state != TI_CSI2RX_DMA_STOPPED) { > + /* Disable source */ > + ret = v4l2_subdev_disable_streams(&csi->subdev, > + TI_CSI2RX_PAD_FIRST_SOURCE + ctx->idx, > + BIT(0)); > + if (ret) > + dev_err(csi->dev, "Failed to stop subdev stream\n"); > + } > + > + /* Stop any on-going streams */ > + writel(0, csi->shim + SHIM_DMACNTX(ctx->idx)); > + > + /* Drain DMA */ > + ti_csi2rx_drain_dma(ctx); > + > + /* Terminate DMA */ > + ret = dmaengine_terminate_sync(ctx->dma.chan); > + if (ret) > + dev_err(csi->dev, "Failed to stop DMA\n"); > + } > + > + return ret; > +} > + > +static int ti_csi2rx_resume(struct device *dev) > +{ > + struct ti_csi2rx_dev *csi = dev_get_drvdata(dev); > + struct ti_csi2rx_ctx *ctx; > + struct ti_csi2rx_dma *dma; > + struct ti_csi2rx_buffer *buf; > + unsigned long flags = 0; > + unsigned int reg; > + int i, ret = 0; > + > + /* If device was not in use, we can simply wakeup */ > + if (pm_runtime_status_suspended(dev)) > + return 0; > + > + /* If device was in use before, restore all the running streams */ > + reg = SHIM_CNTL_PIX_RST; > + writel(reg, csi->shim + SHIM_CNTL); > + > + for (i = 0; i < csi->num_ctx; i++) { > + ctx = &csi->ctx[i]; > + dma = &ctx->dma; > + spin_lock_irqsave(&dma->lock, flags); > + if (dma->state != TI_CSI2RX_DMA_STOPPED) { > + /* Re-submit all previously submitted buffers to DMA */ > + list_for_each_entry(buf, &ctx->dma.submitted, list) { > + ti_csi2rx_start_dma(ctx, buf); > + } > + spin_unlock_irqrestore(&dma->lock, flags); > + > + /* Restore stream config */ > + ti_csi2rx_setup_shim(ctx); > + > + ret = v4l2_subdev_enable_streams(&csi->subdev, > + TI_CSI2RX_PAD_FIRST_SOURCE + ctx->idx, > + BIT(0)); > + if (ret) > + dev_err(ctx->csi->dev, "Failed to start subdev\n"); > + } else { > + spin_unlock_irqrestore(&dma->lock, flags); > + } > + } > + > + return ret; > +} > + > +static int ti_csi2rx_pm_notifier(struct notifier_block *nb, > + unsigned long action, void *data) > +{ > + struct ti_csi2rx_dev *csi = > + container_of(nb, struct ti_csi2rx_dev, pm_notifier); > + > + switch (action) { > + case PM_HIBERNATION_PREPARE: > + case PM_SUSPEND_PREPARE: > + case PM_RESTORE_PREPARE: > + ti_csi2rx_suspend(csi->dev); > + break; > + case PM_POST_SUSPEND: > + case PM_POST_HIBERNATION: > + case PM_POST_RESTORE: > + ti_csi2rx_resume(csi->dev); > + break; > + } > + > + return NOTIFY_DONE; > +} > + > static const struct dev_pm_ops ti_csi2rx_pm_ops = { > RUNTIME_PM_OPS(ti_csi2rx_runtime_suspend, ti_csi2rx_runtime_resume, > NULL) > @@ -1613,6 +1732,13 @@ static int ti_csi2rx_probe(struct platform_device *pdev) > goto err_notifier; > } > > + csi->pm_notifier.notifier_call = ti_csi2rx_pm_notifier; > + ret = register_pm_notifier(&csi->pm_notifier); > + if (ret) { > + dev_err(csi->dev, "Failed to create PM notifier: %d\n", ret); > + goto err_notifier; > + } > + > return 0; > > err_notifier: > @@ -1642,6 +1768,8 @@ static void ti_csi2rx_remove(struct platform_device *pdev) > ti_csi2rx_cleanup_ctx(&csi->ctx[i]); > > ti_csi2rx_cleanup_notifier(csi); > + unregister_pm_notifier(&csi->pm_notifier); > + > ti_csi2rx_cleanup_v4l2(csi); > mutex_destroy(&csi->mutex); > dma_free_coherent(csi->dev, csi->drain.len, csi->drain.vaddr,