dmaengine: fsl-edma: implement the cleanup path of fsl_edma3_attach_pd()

JIRA: https://issues.redhat.com/browse/RHEL-115725

commit ccfa313
Author: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Date:   Sat Dec 21 16:57:12 2024 +0900

    dmaengine: fsl-edma: implement the cleanup path of fsl_edma3_attach_pd()

    Current implementation of fsl_edma3_attach_pd() does not provide a
    cleanup path, resulting in a memory leak. For example,
    dev_pm_domain_detach() is not called after dev_pm_domain_attach_by_id(),
    and the device link created with the DL_FLAG_STATELESS is not released
    explicitly.

    Therefore, provide a cleanup function fsl_edma3_detach_pd() and call it
    upon failure. Also add a devm_add_action_or_reset() call with this
    function after a successful fsl_edma3_attach_pd().

    Fixes: 72f5801 ("dmaengine: fsl-edma: integrate v3 support")
    Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
    Link: https://lore.kernel.org/r/20241221075712.3297200-1-joe@pf.is.s.u-tokyo.ac.jp
    Signed-off-by: Vinod Koul <vkoul@kernel.org>

Signed-off-by: Jared Kangas <jkangas@redhat.com>

Author: rh-jkangas

drivers/dma/fsl-edma-common.h

@@ -168,6 +168,7 @@ struct fsl_edma_chan {
 	struct work_struct		issue_worker;
 	struct platform_device		*pdev;
 	struct device			*pd_dev;
+	struct device_link		*pd_dev_link;
 	u32				srcid;
 	struct clk			*clk;
 	int                             priority;

drivers/dma/fsl-edma-main.c

@@ -524,10 +524,33 @@ static const struct of_device_id fsl_edma_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, fsl_edma_dt_ids);
 
+static void fsl_edma3_detach_pd(struct fsl_edma_engine *fsl_edma)
+{
+	struct fsl_edma_chan *fsl_chan;
+	int i;
+
+	for (i = 0; i < fsl_edma->n_chans; i++) {
+		if (fsl_edma->chan_masked & BIT(i))
+			continue;
+		fsl_chan = &fsl_edma->chans[i];
+		if (fsl_chan->pd_dev_link)
+			device_link_del(fsl_chan->pd_dev_link);
+		if (fsl_chan->pd_dev) {
+			dev_pm_domain_detach(fsl_chan->pd_dev, false);
+			pm_runtime_dont_use_autosuspend(fsl_chan->pd_dev);
+			pm_runtime_set_suspended(fsl_chan->pd_dev);
+		}
+	}
+}
+
+static void devm_fsl_edma3_detach_pd(void *data)
+{
+	fsl_edma3_detach_pd(data);
+}
+
 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;
@@ -543,15 +566,16 @@ static int fsl_edma3_attach_pd(struct platform_device *pdev, struct fsl_edma_eng
 		pd_chan = dev_pm_domain_attach_by_id(dev, i);
 		if (IS_ERR_OR_NULL(pd_chan)) {
 			dev_err(dev, "Failed attach pd %d\n", i);
-			return -EINVAL;
+			goto detach;
 		}
 
-		link = device_link_add(dev, pd_chan, DL_FLAG_STATELESS |
+		fsl_chan->pd_dev_link = device_link_add(dev, pd_chan, DL_FLAG_STATELESS |
 					     DL_FLAG_PM_RUNTIME |
 					     DL_FLAG_RPM_ACTIVE);
-		if (!link) {
+		if (!fsl_chan->pd_dev_link) {
 			dev_err(dev, "Failed to add device_link to %d\n", i);
-			return -EINVAL;
+			dev_pm_domain_detach(pd_chan, false);
+			goto detach;
 		}
 
 		fsl_chan->pd_dev = pd_chan;
@@ -562,6 +586,10 @@ static int fsl_edma3_attach_pd(struct platform_device *pdev, struct fsl_edma_eng
 	}
 
 	return 0;
+
+detach:
+	fsl_edma3_detach_pd(fsl_edma);
+	return -EINVAL;
 }
 
 static int fsl_edma_probe(struct platform_device *pdev)
@@ -647,6 +675,9 @@ static int fsl_edma_probe(struct platform_device *pdev)
 		ret = fsl_edma3_attach_pd(pdev, fsl_edma);
 		if (ret)
 			return ret;
+		ret = devm_add_action_or_reset(&pdev->dev, devm_fsl_edma3_detach_pd, fsl_edma);
+		if (ret)
+			return ret;
 	}
 
 	if (drvdata->flags & FSL_EDMA_DRV_TCD64)