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 <pramod.gu...@linaro.org>
---
Changes since v1:
- Removed unnecessary extra line additions and remavals
drivers/dma/qcom/bam_dma.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)
diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 5b427c4..f2a8b17 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -48,6 +48,7 @@
#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"
@@ -58,6 +59,8 @@ struct bam_desc_hw {
u16 flags;
};
+#define BAM_DMA_AUTOSUSPEND_DELAY 100
+
#define DESC_FLAG_INT BIT(15)
#define DESC_FLAG_EOT BIT(14)
#define DESC_FLAG_EOB BIT(13)
@@ -535,6 +538,7 @@ static void bam_free_chan(struct dma_chan *chan)
return;
}
+ pm_runtime_get_sync(bdev->dev);
spin_lock_irqsave(&bchan->vc.lock, flags);
bam_reset_channel(bchan);
spin_unlock_irqrestore(&bchan->vc.lock, flags);
@@ -550,6 +554,8 @@ static void bam_free_chan(struct dma_chan *chan)
/* disable irq */
writel_relaxed(0, bam_addr(bdev, bchan->id, BAM_P_IRQ_EN));
+ pm_runtime_mark_last_busy(bdev->dev);
+ pm_runtime_put_autosuspend(bdev->dev);
}
/**
@@ -696,10 +702,13 @@ static int bam_pause(struct dma_chan *chan)
struct bam_device *bdev = bchan->bdev;
unsigned long flag;
+ pm_runtime_get_sync(bdev->dev);
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;
}
@@ -715,10 +724,13 @@ static int bam_resume(struct dma_chan *chan)
struct bam_device *bdev = bchan->bdev;
unsigned long flag;
+ pm_runtime_get_sync(bdev->dev);
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;
}
@@ -967,6 +979,9 @@ static void dma_tasklet(unsigned long data)
bam_start_dma(bchan);
spin_unlock_irqrestore(&bchan->vc.lock, flags);
}
+
+ pm_runtime_mark_last_busy(bdev->dev);
+ pm_runtime_put_autosuspend(bdev->dev);
}
/**
@@ -978,8 +993,12 @@ static void dma_tasklet(unsigned long data)
static void bam_issue_pending(struct dma_chan *chan)
{
struct bam_chan *bchan = to_bam_chan(chan);
+ struct bam_device *bdev = bchan->bdev;
unsigned long flags;
+ if (pm_runtime_status_suspended(bdev->dev))
+ pm_runtime_get_sync(bdev->dev);
+
spin_lock_irqsave(&bchan->vc.lock, flags);
/* if work pending and idle, start a transaction */
@@ -1210,6 +1229,13 @@ static int bam_dma_probe(struct platform_device *pdev)
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:
@@ -1252,16 +1278,76 @@ static int bam_dma_remove(struct platform_device *pdev)
tasklet_kill(&bdev->task);
+ pm_runtime_get_sync(&pdev->dev);
clk_disable_unprepare(bdev->bamclk);
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+
+ 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,
},
};
--
1.8.2.1
