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Commit edd3bdbe authored by Jon Hunter's avatar Jon Hunter Committed by Vinod Koul
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dmaengine: tegra-apb: Correct runtime-pm usage 



The tegra-apb DMA driver enables runtime-pm but never calls
pm_runtime_get/put and hence the runtime-pm callbacks are never invoked.
The driver manages the clocks by directly calling clk_prepare_enable()
and clk_unprepare_disable().

Fix this by replacing the clk_prepare_enable() and clk_disable_unprepare()
with pm_runtime_get_sync() and pm_runtime_put(), respectively. Note that
the consequence of this is that if runtime-pm is disabled, then the clocks
will remain on the entire time the driver is loaded. However, if
runtime-pm is disabled, then power is not most likely not a concern.

Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 8005c49d

drivers/dma/tegra20-apb-dma.c

+18 −25
Original line number Diff line number Diff line
@@ -1186,10 +1186,12 @@ static int tegra_dma_alloc_chan_resources(struct dma_chan *dc) 


	dma_cookie_init(&tdc->dma_chan);

	tdc->config_init = false;

	ret = clk_prepare_enable(tdma->dma_clk);



	ret = pm_runtime_get_sync(tdma->dev);

	if (ret < 0)

		dev_err(tdc2dev(tdc), "clk_prepare_enable failed: %d\n", ret);

		return ret;



	return 0;

}



static void tegra_dma_free_chan_resources(struct dma_chan *dc)
@@ -1232,7 +1234,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc) 
		list_del(&sg_req->node);

		kfree(sg_req);

	}

	clk_disable_unprepare(tdma->dma_clk);

	pm_runtime_put(tdma->dev);



	tdc->slave_id = 0;

}
@@ -1356,20 +1358,14 @@ static int tegra_dma_probe(struct platform_device *pdev) 
	spin_lock_init(&tdma->global_lock);



	pm_runtime_enable(&pdev->dev);

	if (!pm_runtime_enabled(&pdev->dev)) {

	if (!pm_runtime_enabled(&pdev->dev))

		ret = tegra_dma_runtime_resume(&pdev->dev);

		if (ret) {

			dev_err(&pdev->dev, "dma_runtime_resume failed %d\n",

				ret);

			goto err_pm_disable;

		}

	}

	else

		ret = pm_runtime_get_sync(&pdev->dev);



	/* Enable clock before accessing registers */

	ret = clk_prepare_enable(tdma->dma_clk);

	if (ret < 0) {

		dev_err(&pdev->dev, "clk_prepare_enable failed: %d\n", ret);

		goto err_pm_disable;

		pm_runtime_disable(&pdev->dev);

		return ret;

	}



	/* Reset DMA controller */
@@ -1382,7 +1378,7 @@ static int tegra_dma_probe(struct platform_device *pdev) 
	tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);

	tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul);



	clk_disable_unprepare(tdma->dma_clk);

	pm_runtime_put(&pdev->dev);



	INIT_LIST_HEAD(&tdma->dma_dev.channels);

	for (i = 0; i < cdata->nr_channels; i++) {
@@ -1485,7 +1481,6 @@ static int tegra_dma_probe(struct platform_device *pdev) 
		tasklet_kill(&tdc->tasklet);

	}



err_pm_disable:

	pm_runtime_disable(&pdev->dev);

	if (!pm_runtime_status_suspended(&pdev->dev))

		tegra_dma_runtime_suspend(&pdev->dev);
@@ -1543,7 +1538,7 @@ static int tegra_dma_pm_suspend(struct device *dev) 
	int ret;



	/* Enable clock before accessing register */

	ret = tegra_dma_runtime_resume(dev);

	ret = pm_runtime_get_sync(dev);

	if (ret < 0)

		return ret;
@@ -1560,7 +1555,7 @@ static int tegra_dma_pm_suspend(struct device *dev) 
	}



	/* Disable clock */

	tegra_dma_runtime_suspend(dev);

	pm_runtime_put(dev);

	return 0;

}
@@ -1571,7 +1566,7 @@ static int tegra_dma_pm_resume(struct device *dev) 
	int ret;



	/* Enable clock before accessing register */

	ret = tegra_dma_runtime_resume(dev);

	ret = pm_runtime_get_sync(dev);

	if (ret < 0)

		return ret;
@@ -1592,16 +1587,14 @@ static int tegra_dma_pm_resume(struct device *dev) 
	}



	/* Disable clock */

	tegra_dma_runtime_suspend(dev);

	pm_runtime_put(dev);

	return 0;

}

#endif



static const struct dev_pm_ops tegra_dma_dev_pm_ops = {

#ifdef CONFIG_PM

	.runtime_suspend = tegra_dma_runtime_suspend,

	.runtime_resume = tegra_dma_runtime_resume,

#endif

	SET_RUNTIME_PM_OPS(tegra_dma_runtime_suspend, tegra_dma_runtime_resume,

			   NULL)

	SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)

};