From: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
This patch adds suspend and resume functions for Freescale DMA driver.
Signed-off-by: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
---
drivers/dma/fsldma.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/dma/fsldma.h | 15 ++++++++++
2 files changed, 92 insertions(+)
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index b291e6c..465f16d 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -400,6 +400,14 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
spin_lock_bh(&chan->desc_lock);
+#ifdef CONFIG_PM
+ if (unlikely(chan->pm_state != RUNNING)) {
+ chan_dbg(chan, "cannot submit due to suspend\n");
+ spin_unlock_bh(&chan->desc_lock);
+ return -1;
+ }
+#endif
+
/*
* assign cookies to all of the software descriptors
* that make up this transaction
@@ -1221,6 +1229,9 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
INIT_LIST_HEAD(&chan->ld_pending);
INIT_LIST_HEAD(&chan->ld_running);
chan->idle = true;
+#ifdef CONFIG_PM
+ chan->pm_state = RUNNING;
+#endif
chan->common.device = &fdev->common;
dma_cookie_init(&chan->common);
@@ -1360,6 +1371,69 @@ static int fsldma_of_remove(struct platform_device *op)
return 0;
}
+#ifdef CONFIG_PM
+static int fsldma_suspend_late(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct fsldma_device *fdev = platform_get_drvdata(pdev);
+ struct fsldma_chan *chan;
+ int i;
+
+ for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+ chan = fdev->chan[i];
+ if (!chan)
+ continue;
+
+ spin_lock_bh(&chan->desc_lock);
+ if (unlikely(!chan->idle))
+ goto out;
+ chan->regs_save.mr = get_mr(chan);
+ chan->pm_state = SUSPENDED;
+ spin_unlock_bh(&chan->desc_lock);
+ }
+ return 0;
+
+out:
+ for (; i >= 0; i--) {
+ chan = fdev->chan[i];
+ if (!chan)
+ continue;
+ chan->pm_state = RUNNING;
+ spin_unlock_bh(&chan->desc_lock);
+ }
+ return -EBUSY;
+}
+
+static int fsldma_resume_early(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct fsldma_device *fdev = platform_get_drvdata(pdev);
+ struct fsldma_chan *chan;
+ u32 mode;
+ int i;
+
+ for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+ chan = fdev->chan[i];
+ if (!chan)
+ continue;
+
+ spin_lock_bh(&chan->desc_lock);
+ mode = chan->regs_save.mr
+ & ~FSL_DMA_MR_CS & ~FSL_DMA_MR_CC & ~FSL_DMA_MR_CA;
+ set_mr(chan, mode);
+ chan->pm_state = RUNNING;
+ spin_unlock_bh(&chan->desc_lock);
+ }
+
+ return 0;
+}
+
+static const struct dev_pm_ops fsldma_pm_ops = {
+ .suspend_late = fsldma_suspend_late,
+ .resume_early = fsldma_resume_early,
+};
+#endif
+
static const struct of_device_id fsldma_of_ids[] = {
{ .compatible = "fsl,elo3-dma", },
{ .compatible = "fsl,eloplus-dma", },
@@ -1372,6 +1446,9 @@ static struct platform_driver fsldma_of_driver = {
.name = "fsl-elo-dma",
.owner = THIS_MODULE,
.of_match_table = fsldma_of_ids,
+#ifdef CONFIG_PM
+ .pm = &fsldma_pm_ops,
+#endif
},
.probe = fsldma_of_probe,
.remove = fsldma_of_remove,
diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
index d56e835..f2e0c4d 100644
--- a/drivers/dma/fsldma.h
+++ b/drivers/dma/fsldma.h
@@ -134,6 +134,17 @@ struct fsldma_device {
#define FSL_DMA_CHAN_PAUSE_EXT 0x00001000
#define FSL_DMA_CHAN_START_EXT 0x00002000
+#ifdef CONFIG_PM
+struct fsldma_chan_regs_save {
+ u32 mr;
+};
+
+enum fsldma_pm_state {
+ RUNNING = 0,
+ SUSPENDED,
+};
+#endif
+
struct fsldma_chan {
char name[8]; /* Channel name */
struct fsldma_chan_regs __iomem *regs;
@@ -148,6 +159,10 @@ struct fsldma_chan {
struct tasklet_struct tasklet;
u32 feature;
bool idle; /* DMA controller is idle */
+#ifdef CONFIG_PM
+ struct fsldma_chan_regs_save regs_save;
+ enum fsldma_pm_state pm_state;
+#endif
void (*toggle_ext_pause)(struct fsldma_chan *fsl_chan, int enable);
void (*toggle_ext_start)(struct fsldma_chan *fsl_chan, int enable);
--
1.7.9.5
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