dmaengine: fsl-edma: add PM suspend/resume support

This add power management suspend/resume support for the fsl-edma
driver.

eDMA acted as a basic function used by others. What it needs to do
is the two steps below to support power management.

In fsl_edma_suspend_late:
Check whether the DMA chan is idle, if it is not idle disable DMA
request.

In fsl_edma_resume_early:
Enable the eDMA and wait for being used.

Signed-off-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index 915eec3cc279c90f3111ad5849d16ba9a469cb35..be2e62b879481f592aa965d4fe165b4ae8771896 100644 (file)
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -116,6 +116,10 @@
                                BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)
+enum fsl_edma_pm_state {
+       RUNNING = 0,
+       SUSPENDED,
+};
 
 struct fsl_edma_hw_tcd {
        __le32  saddr;
@@ -147,6 +151,9 @@ struct fsl_edma_slave_config {
 struct fsl_edma_chan {
        struct virt_dma_chan            vchan;
        enum dma_status                 status;
+       enum fsl_edma_pm_state          pm_state;
+       bool                            idle;
+       u32                             slave_id;
        struct fsl_edma_engine          *edma;
        struct fsl_edma_desc            *edesc;
        struct fsl_edma_slave_config    fsc;
@@ -298,6 +305,7 @@ static int fsl_edma_terminate_all(struct dma_chan *chan)
        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
        fsl_edma_disable_request(fsl_chan);
        fsl_chan->edesc = NULL;
+       fsl_chan->idle = true;
        vchan_get_all_descriptors(&fsl_chan->vchan, &head);
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
@@ -313,6 +321,7 @@ static int fsl_edma_pause(struct dma_chan *chan)
        if (fsl_chan->edesc) {
                fsl_edma_disable_request(fsl_chan);
                fsl_chan->status = DMA_PAUSED;
+               fsl_chan->idle = true;
        }
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        return 0;
@@ -327,6 +336,7 @@ static int fsl_edma_resume(struct dma_chan *chan)
        if (fsl_chan->edesc) {
                fsl_edma_enable_request(fsl_chan);
                fsl_chan->status = DMA_IN_PROGRESS;
+               fsl_chan->idle = false;
        }
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        return 0;
@@ -648,6 +658,7 @@ static void fsl_edma_xfer_desc(struct fsl_edma_chan *fsl_chan)
        fsl_edma_set_tcd_regs(fsl_chan, fsl_chan->edesc->tcd[0].vtcd);
        fsl_edma_enable_request(fsl_chan);
        fsl_chan->status = DMA_IN_PROGRESS;
+       fsl_chan->idle = false;
 }
 
 static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
@@ -676,6 +687,7 @@ static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
                                vchan_cookie_complete(&fsl_chan->edesc->vdesc);
                                fsl_chan->edesc = NULL;
                                fsl_chan->status = DMA_COMPLETE;
+                               fsl_chan->idle = true;
                        } else {
                                vchan_cyclic_callback(&fsl_chan->edesc->vdesc);
                        }
@@ -704,6 +716,7 @@ static irqreturn_t fsl_edma_err_handler(int irq, void *dev_id)
                        edma_writeb(fsl_edma, EDMA_CERR_CERR(ch),
                                fsl_edma->membase + EDMA_CERR);
                        fsl_edma->chans[ch].status = DMA_ERROR;
+                       fsl_edma->chans[ch].idle = true;
                }
        }
        return IRQ_HANDLED;
@@ -724,6 +737,12 @@ static void fsl_edma_issue_pending(struct dma_chan *chan)
 
        spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
 
+       if (unlikely(fsl_chan->pm_state != RUNNING)) {
+               spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
+               /* cannot submit due to suspend */
+               return;
+       }
+
        if (vchan_issue_pending(&fsl_chan->vchan) && !fsl_chan->edesc)
                fsl_edma_xfer_desc(fsl_chan);
 
@@ -735,6 +754,7 @@ static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
 {
        struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
        struct dma_chan *chan, *_chan;
+       struct fsl_edma_chan *fsl_chan;
        unsigned long chans_per_mux = fsl_edma->n_chans / DMAMUX_NR;
 
        if (dma_spec->args_count != 2)
@@ -748,8 +768,10 @@ static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
                        chan = dma_get_slave_channel(chan);
                        if (chan) {
                                chan->device->privatecnt++;
-                               fsl_edma_chan_mux(to_fsl_edma_chan(chan),
-                                       dma_spec->args[1], true);
+                               fsl_chan = to_fsl_edma_chan(chan);
+                               fsl_chan->slave_id = dma_spec->args[1];
+                               fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id,
+                                               true);
                                mutex_unlock(&fsl_edma->fsl_edma_mutex);
                                return chan;
                        }
@@ -888,7 +910,9 @@ static int fsl_edma_probe(struct platform_device *pdev)
                struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];
 
                fsl_chan->edma = fsl_edma;
-
+               fsl_chan->pm_state = RUNNING;
+               fsl_chan->slave_id = 0;
+               fsl_chan->idle = true;
                fsl_chan->vchan.desc_free = fsl_edma_free_desc;
                vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);
 
@@ -959,6 +983,60 @@ static int fsl_edma_remove(struct platform_device *pdev)
        return 0;
 }
 
+static int fsl_edma_suspend_late(struct device *dev)
+{
+       struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
+       struct fsl_edma_chan *fsl_chan;
+       unsigned long flags;
+       int i;
+
+       for (i = 0; i < fsl_edma->n_chans; i++) {
+               fsl_chan = &fsl_edma->chans[i];
+               spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
+               /* Make sure chan is idle or will force disable. */
+               if (unlikely(!fsl_chan->idle)) {
+                       dev_warn(dev, "WARN: There is non-idle channel.");
+                       fsl_edma_disable_request(fsl_chan);
+                       fsl_edma_chan_mux(fsl_chan, 0, false);
+               }
+
+               fsl_chan->pm_state = SUSPENDED;
+               spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
+       }
+
+       return 0;
+}
+
+static int fsl_edma_resume_early(struct device *dev)
+{
+       struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
+       struct fsl_edma_chan *fsl_chan;
+       int i;
+
+       for (i = 0; i < fsl_edma->n_chans; i++) {
+               fsl_chan = &fsl_edma->chans[i];
+               fsl_chan->pm_state = RUNNING;
+               edma_writew(fsl_edma, 0x0, fsl_edma->membase + EDMA_TCD_CSR(i));
+               if (fsl_chan->slave_id != 0)
+                       fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
+       }
+
+       edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA,
+                       fsl_edma->membase + EDMA_CR);
+
+       return 0;
+}
+
+/*
+ * eDMA provides the service to others, so it should be suspend late
+ * and resume early. When eDMA suspend, all of the clients should stop
+ * the DMA data transmission and let the channel idle.
+ */
+static const struct dev_pm_ops fsl_edma_pm_ops = {
+       .suspend_late   = fsl_edma_suspend_late,
+       .resume_early   = fsl_edma_resume_early,
+};
+
 static const struct of_device_id fsl_edma_dt_ids[] = {
        { .compatible = "fsl,vf610-edma", },
        { /* sentinel */ }
@@ -969,6 +1047,7 @@ static struct platform_driver fsl_edma_driver = {
        .driver         = {
                .name   = "fsl-edma",
                .of_match_table = fsl_edma_dt_ids,
+               .pm     = &fsl_edma_pm_ops,
        },
        .probe          = fsl_edma_probe,
        .remove         = fsl_edma_remove,