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Date: Wed, 15 Jul 2015 17:32:58 +0800
From: Yuan Yao <yao.yuan@...escale.com>
To: <vinod.koul@...el.com>, <stefan@...er.ch>
CC: <dan.j.williams@...el.com>, <dmaengine@...r.kernel.org>,
<linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH] 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 and if it is not idle, stop PM
operation.
In fsl_edma_resume_early:
Enable the eDMA and wait for being used.
Signed-off-by: Yuan Yao <yao.yuan@...escale.com>
---
drivers/dma/fsl-edma.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 91 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index 915eec3..f987a4f 100644
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -116,6 +116,12 @@
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)
+#ifdef CONFIG_PM
+enum fsl_edma_pm_state {
+ RUNNING = 0,
+ SUSPENDED,
+};
+#endif
struct fsl_edma_hw_tcd {
__le32 saddr;
@@ -151,6 +157,11 @@ struct fsl_edma_chan {
struct fsl_edma_desc *edesc;
struct fsl_edma_slave_config fsc;
struct dma_pool *tcd_pool;
+ bool idle;
+#ifdef CONFIG_PM
+ u32 slave_id;
+ enum fsl_edma_pm_state pm_state;
+#endif
};
struct fsl_edma_desc {
@@ -298,6 +309,7 @@ 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 +325,7 @@ 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 +340,7 @@ 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 +662,7 @@ 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 +691,7 @@ 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 +720,7 @@ 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 +741,14 @@ static void fsl_edma_issue_pending(struct dma_chan *chan)
spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
+#ifdef CONFIG_PM
+ if (unlikely(fsl_chan->pm_state != RUNNING)) {
+ spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
+ /* cannot submit due to suspend */
+ return;
+ }
+#endif
+
if (vchan_issue_pending(&fsl_chan->vchan) && !fsl_chan->edesc)
fsl_edma_xfer_desc(fsl_chan);
@@ -750,6 +775,10 @@ static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
chan->device->privatecnt++;
fsl_edma_chan_mux(to_fsl_edma_chan(chan),
dma_spec->args[1], true);
+#ifdef CONFIG_PM
+ to_fsl_edma_chan(chan)->slave_id =
+ dma_spec->args[1];
+#endif
mutex_unlock(&fsl_edma->fsl_edma_mutex);
return chan;
}
@@ -888,7 +917,11 @@ static int fsl_edma_probe(struct platform_device *pdev)
struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];
fsl_chan->edma = fsl_edma;
-
+#ifdef CONFIG_PM
+ fsl_chan->pm_state = RUNNING;
+ fsl_chan->slave_id = 0;
+#endif
+ fsl_chan->idle = true;
fsl_chan->vchan.desc_free = fsl_edma_free_desc;
vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);
@@ -959,6 +992,60 @@ static int fsl_edma_remove(struct platform_device *pdev)
return 0;
}
+#ifdef CONFIG_PM
+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 can not into suspend. */
+ if (unlikely(!fsl_chan->idle))
+ goto out;
+ fsl_chan->pm_state = SUSPENDED;
+ spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
+ }
+ return 0;
+
+out:
+ for (; i >= 0; i--) {
+ fsl_chan = &fsl_edma->chans[i];
+ fsl_chan->pm_state = RUNNING;
+ spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
+ }
+ return -EBUSY;
+}
+
+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;
+}
+
+static const struct dev_pm_ops fsl_edma_pm_ops = {
+ .suspend_late = fsl_edma_suspend_late,
+ .resume_early = fsl_edma_resume_early,
+};
+#endif
+
static const struct of_device_id fsl_edma_dt_ids[] = {
{ .compatible = "fsl,vf610-edma", },
{ /* sentinel */ }
@@ -969,6 +1056,9 @@ static struct platform_driver fsl_edma_driver = {
.driver = {
.name = "fsl-edma",
.of_match_table = fsl_edma_dt_ids,
+#ifdef CONFIG_PM
+ .pm = &fsl_edma_pm_ops,
+#endif
},
.probe = fsl_edma_probe,
.remove = fsl_edma_remove,
--
2.1.0.27.g96db324
--
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