dmaengine: Freescale: add suspend resume functions for DMA driver

This patch adds suspend and resume functions for Freescale DMA driver.

Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

2 files changed, 92 insertions, 0 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index b291e6c65053..465f16dd78e5 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 d56e83599825..f2e0c4dcf901 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);