dmaengine: qcom-bam-dma: Add pm_runtime support

Adds pm_runtime support for BAM DMA so that clock is enabled only
when there is a transaction going on to help save power.

Signed-off-by: Pramod Gurav <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/qcom/bam_dma.c

···
 #include <linux/of_dma.h>
 #include <linux/clk.h>
 #include <linux/dmaengine.h>
+#include <linux/pm_runtime.h>
 
 #include "../dmaengine.h"
 #include "../virt-dma.h"
···
 	__le16 size;		/* Buffer size in bytes */
 	__le16 flags;
 };
+
+#define BAM_DMA_AUTOSUSPEND_DELAY 100
 
 #define DESC_FLAG_INT BIT(15)
 #define DESC_FLAG_EOT BIT(14)
···
 	struct bam_device *bdev = bchan->bdev;
 	u32 val;
 	unsigned long flags;
+	int ret;
+
+	ret = pm_runtime_get_sync(bdev->dev);
+	if (ret < 0)
+		return;
 
 	vchan_free_chan_resources(to_virt_chan(chan));
 
 	if (bchan->curr_txd) {
 		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
-		return;
+		goto err;
 	}
 
 	spin_lock_irqsave(&bchan->vc.lock, flags);
···
 
 	/* disable irq */
 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
+
+err:
+	pm_runtime_mark_last_busy(bdev->dev);
+	pm_runtime_put_autosuspend(bdev->dev);
 }
 
 /**
···
 	struct bam_chan *bchan = to_bam_chan(chan);
 	struct bam_device *bdev = bchan->bdev;
 	unsigned long flag;
+	int ret;
+
+	ret = pm_runtime_get_sync(bdev->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&bchan->vc.lock, flag);
 	writel_relaxed(1, bam_addr(bdev, bchan->id, BAM_P_HALT));
 	bchan->paused = 1;
 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
+	pm_runtime_mark_last_busy(bdev->dev);
+	pm_runtime_put_autosuspend(bdev->dev);
 
 	return 0;
 }
···
 	struct bam_chan *bchan = to_bam_chan(chan);
 	struct bam_device *bdev = bchan->bdev;
 	unsigned long flag;
+	int ret;
+
+	ret = pm_runtime_get_sync(bdev->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&bchan->vc.lock, flag);
 	writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_HALT));
 	bchan->paused = 0;
 	spin_unlock_irqrestore(&bchan->vc.lock, flag);
+	pm_runtime_mark_last_busy(bdev->dev);
+	pm_runtime_put_autosuspend(bdev->dev);
 
 	return 0;
 }
···
 {
 	struct bam_device *bdev = data;
 	u32 clr_mask = 0, srcs = 0;
+	int ret;
 
 	srcs |= process_channel_irqs(bdev);
 
 	/* kick off tasklet to start next dma transfer */
 	if (srcs & P_IRQ)
 		tasklet_schedule(&bdev->task);
+
+	ret = pm_runtime_get_sync(bdev->dev);
+	if (ret < 0)
+		return ret;
 
 	if (srcs & BAM_IRQ) {
 		clr_mask = readl_relaxed(bam_addr(bdev, 0, BAM_IRQ_STTS));
···
 
 		writel_relaxed(clr_mask, bam_addr(bdev, 0, BAM_IRQ_CLR));
 	}
+
+	pm_runtime_mark_last_busy(bdev->dev);
+	pm_runtime_put_autosuspend(bdev->dev);
 
 	return IRQ_HANDLED;
 }
···
 	struct bam_desc_hw *desc;
 	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
 					sizeof(struct bam_desc_hw));
+	int ret;
 
 	lockdep_assert_held(&bchan->vc.lock);
 
···
 
 	async_desc = container_of(vd, struct bam_async_desc, vd);
 	bchan->curr_txd = async_desc;
+
+	ret = pm_runtime_get_sync(bdev->dev);
+	if (ret < 0)
+		return;
 
 	/* on first use, initialize the channel hardware */
 	if (!bchan->initialized)
···
 	wmb();
 	writel_relaxed(bchan->tail * sizeof(struct bam_desc_hw),
 			bam_addr(bdev, bchan->id, BAM_P_EVNT_REG));
+
+	pm_runtime_mark_last_busy(bdev->dev);
+	pm_runtime_put_autosuspend(bdev->dev);
 }
 
 /**
···
 			bam_start_dma(bchan);
 		spin_unlock_irqrestore(&bchan->vc.lock, flags);
 	}
+
 }
 
 /**
···
 	if (ret)
 		goto err_unregister_dma;
 
+	pm_runtime_irq_safe(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, BAM_DMA_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
 	return 0;
 
 err_unregister_dma:
···
 {
 	struct bam_device *bdev = platform_get_drvdata(pdev);
 	u32 i;
+
+	pm_runtime_force_suspend(&pdev->dev);
 
 	of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&bdev->common);
···
 	return 0;
 }
 
+static int bam_dma_runtime_suspend(struct device *dev)
+{
+	struct bam_device *bdev = dev_get_drvdata(dev);
+
+	clk_disable(bdev->bamclk);
+
+	return 0;
+}
+
+static int bam_dma_runtime_resume(struct device *dev)
+{
+	struct bam_device *bdev = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_enable(bdev->bamclk);
+	if (ret < 0) {
+		dev_err(dev, "clk_enable failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+#ifdef CONFIG_PM_SLEEP
+static int bam_dma_suspend(struct device *dev)
+{
+	struct bam_device *bdev = dev_get_drvdata(dev);
+
+	pm_runtime_force_suspend(dev);
+
+	clk_unprepare(bdev->bamclk);
+
+	return 0;
+}
+
+static int bam_dma_resume(struct device *dev)
+{
+	struct bam_device *bdev = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare(bdev->bamclk);
+	if (ret)
+		return ret;
+
+	pm_runtime_force_resume(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops bam_dma_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(bam_dma_suspend, bam_dma_resume)
+	SET_RUNTIME_PM_OPS(bam_dma_runtime_suspend, bam_dma_runtime_resume,
+				NULL)
+};
+
 static struct platform_driver bam_dma_driver = {
 	.probe = bam_dma_probe,
 	.remove = bam_dma_remove,
 	.driver = {
 		.name = "bam-dma-engine",
+		.pm = &bam_dma_pm_ops,
 		.of_match_table = bam_of_match,
 	},
 };