Message-Id: <20241220021109.2102294-1-joy.zou@nxp.com>
Date: Fri, 20 Dec 2024 10:11:09 +0800
From: Joy Zou <joy.zou@....com>
To: frank.li@....com,
	vkoul@...nel.org,
	shengjiu.wang@....com
Cc: imx@...ts.linux.dev,
	dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1] dmaengine: fsl-edma: add runtime suspend/resume support

Introduce runtime suspend and resume support for FSL eDMA. Enable
per-channel power domain management to facilitate runtime suspend and
resume operations.

Implement runtime suspend and resume functions for the eDMA engine and
individual channels.

Link per-channel power domain device to eDMA per-channel device instead of
eDMA engine device. So Power Manage framework manage power state of linked
domain device when per-channel device request runtime resume/suspend.

Trigger the eDMA engine's runtime suspend when all channels are suspended,
disabling all common clocks through the runtime PM framework.

Signed-off-by: Joy Zou <joy.zou@....com>
Signed-off-by: Frank Li <Frank.Li@....com>
---
 drivers/dma/fsl-edma-common.c |  15 ++---
 drivers/dma/fsl-edma-main.c   | 115 ++++++++++++++++++++++++++++++----
 2 files changed, 110 insertions(+), 20 deletions(-)

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
index b7f15ab96855..fcdb53b21f38 100644
--- a/drivers/dma/fsl-edma-common.c
+++ b/drivers/dma/fsl-edma-common.c
@@ -243,9 +243,6 @@ int fsl_edma_terminate_all(struct dma_chan *chan)
 	spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
 	vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
 
-	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_PD)
-		pm_runtime_allow(fsl_chan->pd_dev);
-
 	return 0;
 }
 
@@ -805,8 +802,12 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
 	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
 	int ret;
 
-	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
-		clk_prepare_enable(fsl_chan->clk);
+	ret = pm_runtime_get_sync(&fsl_chan->vchan.chan.dev->device);
+	if (ret < 0) {
+		dev_err(&fsl_chan->vchan.chan.dev->device, "pm_runtime_get_sync() failed\n");
+		pm_runtime_disable(&fsl_chan->vchan.chan.dev->device);
+		return ret;
+	}
 
 	fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device->dev,
 				fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_TCD64 ?
@@ -819,6 +820,7 @@ int fsl_edma_alloc_chan_resources(struct dma_chan *chan)
 
 		if (ret) {
 			dma_pool_destroy(fsl_chan->tcd_pool);
+			pm_runtime_put_sync_suspend(&fsl_chan->vchan.chan.dev->device);
 			return ret;
 		}
 	}
@@ -851,8 +853,7 @@ void fsl_edma_free_chan_resources(struct dma_chan *chan)
 	fsl_chan->is_sw = false;
 	fsl_chan->srcid = 0;
 	fsl_chan->is_remote = false;
-	if (fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_HAS_CHCLK)
-		clk_disable_unprepare(fsl_chan->clk);
+	pm_runtime_put_sync_suspend(&fsl_chan->vchan.chan.dev->device);
 }
 
 void fsl_edma_cleanup_vchan(struct dma_device *dmadev)
diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-main.c
index 60de1003193a..75d6c8984c8e 100644
--- a/drivers/dma/fsl-edma-main.c
+++ b/drivers/dma/fsl-edma-main.c
@@ -420,7 +420,6 @@ MODULE_DEVICE_TABLE(of, fsl_edma_dt_ids);
 static int fsl_edma3_attach_pd(struct platform_device *pdev, struct fsl_edma_engine *fsl_edma)
 {
 	struct fsl_edma_chan *fsl_chan;
-	struct device_link *link;
 	struct device *pd_chan;
 	struct device *dev;
 	int i;
@@ -439,24 +438,39 @@ static int fsl_edma3_attach_pd(struct platform_device *pdev, struct fsl_edma_eng
 			return -EINVAL;
 		}
 
-		link = device_link_add(dev, pd_chan, DL_FLAG_STATELESS |
-					     DL_FLAG_PM_RUNTIME |
-					     DL_FLAG_RPM_ACTIVE);
-		if (!link) {
-			dev_err(dev, "Failed to add device_link to %d\n", i);
-			return -EINVAL;
-		}
-
 		fsl_chan->pd_dev = pd_chan;
-
-		pm_runtime_use_autosuspend(fsl_chan->pd_dev);
-		pm_runtime_set_autosuspend_delay(fsl_chan->pd_dev, 200);
-		pm_runtime_set_active(fsl_chan->pd_dev);
 	}
 
 	return 0;
 }
 
+/* Per channel dma power domain */
+static int fsl_edma_chan_runtime_suspend(struct device *dev)
+{
+	struct fsl_edma_chan *fsl_chan = dev_get_drvdata(dev);
+	int ret = 0;
+
+	clk_disable_unprepare(fsl_chan->clk);
+
+	return ret;
+}
+
+static int fsl_edma_chan_runtime_resume(struct device *dev)
+{
+	struct fsl_edma_chan *fsl_chan = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(fsl_chan->clk);
+
+	return ret;
+}
+
+static struct dev_pm_domain fsl_edma_chan_pm_domain = {
+	.ops = {
+		RUNTIME_PM_OPS(fsl_edma_chan_runtime_suspend, fsl_edma_chan_runtime_resume, NULL)
+	}
+};
+
 static int fsl_edma_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -583,10 +597,15 @@ static int fsl_edma_probe(struct platform_device *pdev)
 		fsl_chan->pdev = pdev;
 		vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);
 
+		if (fsl_chan->pd_dev)
+			pm_runtime_get_sync(fsl_chan->pd_dev);
+
 		edma_write_tcdreg(fsl_chan, cpu_to_le32(0), csr);
 		fsl_edma_chan_mux(fsl_chan, 0, false);
 		if (fsl_chan->edma->drvdata->flags & FSL_EDMA_DRV_HAS_CHCLK)
 			clk_disable_unprepare(fsl_chan->clk);
+		if (fsl_chan->pd_dev)
+			pm_runtime_put_sync_suspend(fsl_chan->pd_dev);
 	}
 
 	ret = fsl_edma->drvdata->setup_irq(pdev, fsl_edma);
@@ -645,6 +664,34 @@ static int fsl_edma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	pm_runtime_enable(&pdev->dev);
+
+	for (i = 0; i < fsl_edma->n_chans; i++) {
+		struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];
+		struct device *chan_dev;
+
+		if (fsl_edma->chan_masked & BIT(i))
+			continue;
+
+		chan_dev = &fsl_chan->vchan.chan.dev->device;
+		dev_set_drvdata(chan_dev, fsl_chan);
+		dev_pm_domain_set(chan_dev, &fsl_edma_chan_pm_domain);
+
+		if (fsl_chan->pd_dev) {
+			struct device_link *link;
+
+			link = device_link_add(chan_dev, fsl_chan->pd_dev, DL_FLAG_STATELESS |
+									   DL_FLAG_PM_RUNTIME |
+									   DL_FLAG_RPM_ACTIVE);
+			if (!link)
+				return dev_err_probe(&pdev->dev, -EINVAL,
+						     "Failed to add device_link to %d\n", i);
+			pm_runtime_put_sync_suspend(fsl_chan->pd_dev);
+		}
+
+		pm_runtime_enable(chan_dev);
+	}
+
 	ret = of_dma_controller_register(np,
 			drvdata->flags & FSL_EDMA_DRV_SPLIT_REG ? fsl_edma3_xlate : fsl_edma_xlate,
 			fsl_edma);
@@ -685,6 +732,13 @@ static int fsl_edma_suspend_late(struct device *dev)
 		fsl_chan = &fsl_edma->chans[i];
 		if (fsl_edma->chan_masked & BIT(i))
 			continue;
+
+		if (pm_runtime_status_suspended(&fsl_chan->vchan.chan.dev->device) ||
+		    (!(fsl_edma->drvdata->flags & FSL_EDMA_DRV_HAS_PD) &&
+		     (fsl_edma->drvdata->flags & FSL_EDMA_DRV_SPLIT_REG) &&
+		     !fsl_chan->srcid))
+			continue;
+
 		spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
 		/* Make sure chan is idle or will force disable. */
 		if (unlikely(fsl_chan->status == DMA_IN_PROGRESS)) {
@@ -711,6 +765,13 @@ static int fsl_edma_resume_early(struct device *dev)
 		fsl_chan = &fsl_edma->chans[i];
 		if (fsl_edma->chan_masked & BIT(i))
 			continue;
+
+		if (pm_runtime_status_suspended(&fsl_chan->vchan.chan.dev->device) ||
+		    (!(fsl_edma->drvdata->flags & FSL_EDMA_DRV_HAS_PD) &&
+		     (fsl_edma->drvdata->flags & FSL_EDMA_DRV_SPLIT_REG) &&
+		     !fsl_chan->srcid))
+			continue;
+
 		fsl_chan->pm_state = RUNNING;
 		edma_write_tcdreg(fsl_chan, 0, csr);
 		if (fsl_chan->srcid != 0)
@@ -723,6 +784,33 @@ static int fsl_edma_resume_early(struct device *dev)
 	return 0;
 }
 
+/* edma engine runtime system/resume */
+static int fsl_edma_runtime_suspend(struct device *dev)
+{
+	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < fsl_edma->drvdata->dmamuxs; i++)
+		clk_disable_unprepare(fsl_edma->muxclk[i]);
+
+	clk_disable_unprepare(fsl_edma->dmaclk);
+
+	return 0;
+}
+
+static int fsl_edma_runtime_resume(struct device *dev)
+{
+	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < fsl_edma->drvdata->dmamuxs; i++)
+		clk_prepare_enable(fsl_edma->muxclk[i]);
+
+	clk_prepare_enable(fsl_edma->dmaclk);
+
+	return 0;
+}
+
 /*
  * eDMA provides the service to others, so it should be suspend late
  * and resume early. When eDMA suspend, all of the clients should stop
@@ -731,6 +819,7 @@ static int fsl_edma_resume_early(struct device *dev)
 static const struct dev_pm_ops fsl_edma_pm_ops = {
 	.suspend_late   = fsl_edma_suspend_late,
 	.resume_early   = fsl_edma_resume_early,
+	 RUNTIME_PM_OPS(fsl_edma_runtime_suspend, fsl_edma_runtime_resume, NULL)
 };
 
 static struct platform_driver fsl_edma_driver = {
-- 
2.37.1

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