From b53611fb1ce9b1786bd18205473e0c1d6bfa8934 Mon Sep 17 00:00:00 2001
From: Jon Hunter <jonathanh@nvidia.com>
Date: Thu, 16 May 2019 16:53:52 +0100
Subject: [PATCH] dmaengine: tegra210-adma: Fix crash during probe
Git-commit: b53611fb1ce9b1786bd18205473e0c1d6bfa8934
Patch-mainline: v5.2-rc4
References: bsc#1111666

Commit f33e7bb3eb92 ("dmaengine: tegra210-adma: restore channel status")
added support to save and restore the DMA channel registers when runtime
suspending the ADMA. This change is causing the kernel to crash when
probing the ADMA, if the device is probed deferred when looking up the
channel interrupts. The crash occurs because not all of the channel base
addresses have been setup at this point and in the clean-up path of the
probe, pm_runtime_suspend() is called invoking its callback which
expects all the channel base addresses to be initialised.

Although this could be fixed by simply checking for a NULL address, on
further review of the driver it seems more appropriate that we only call
pm_runtime_get_sync() after all the channel interrupts and base
addresses have been configured. Therefore, fix this crash by moving the
calls to pm_runtime_enable(), pm_runtime_get_sync() and
tegra_adma_init() after the DMA channels have been initialised.

Fixes: f33e7bb3eb92 ("dmaengine: tegra210-adma: restore channel status")

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/dma/tegra210-adma.c |   26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -743,16 +743,6 @@ static int tegra_adma_probe(struct platf
 	if (ret)
 		goto clk_destroy;
 
-	pm_runtime_enable(&pdev->dev);
-
-	ret = pm_runtime_get_sync(&pdev->dev);
-	if (ret < 0)
-		goto rpm_disable;
-
-	ret = tegra_adma_init(tdma);
-	if (ret)
-		goto rpm_put;
-
 	INIT_LIST_HEAD(&tdma->dma_dev.channels);
 	for (i = 0; i < tdma->nr_channels; i++) {
 		struct tegra_adma_chan *tdc = &tdma->channels[i];
@@ -770,6 +760,16 @@ static int tegra_adma_probe(struct platf
 		tdc->tdma = tdma;
 	}
 
+	pm_runtime_enable(&pdev->dev);
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0)
+		goto rpm_disable;
+
+	ret = tegra_adma_init(tdma);
+	if (ret)
+		goto rpm_put;
+
 	dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
 	dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
 	dma_cap_set(DMA_CYCLIC, tdma->dma_dev.cap_mask);
@@ -811,13 +811,13 @@ static int tegra_adma_probe(struct platf
 
 dma_remove:
 	dma_async_device_unregister(&tdma->dma_dev);
-irq_dispose:
-	while (--i >= 0)
-		irq_dispose_mapping(tdma->channels[i].irq);
 rpm_put:
 	pm_runtime_put_sync(&pdev->dev);
 rpm_disable:
 	pm_runtime_disable(&pdev->dev);
+irq_dispose:
+	while (--i >= 0)
+		irq_dispose_mapping(tdma->channels[i].irq);
 clk_destroy:
 	pm_clk_destroy(&pdev->dev);