[PATCH v4] dmaengine: fsl-edma: add PM suspend/resume support

From: Yuan Yao
Date: Fri Oct 30 2015 - 07:10:50 EST

Next message: Jisheng Zhang: "Re: [PATCH] clocksource: dw_apb_timer_of: support timer-based delay"
Previous message: Jarkko Sakkinen: "Re: [PATCH v1 4/4] keys, trusted: update documentation for 'hash=' option"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

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@xxxxxxxxxxxxx>
---
Changes in v4:
- Add comments for why use suspend_late and resume_early;
Changes in v3:
- Force terminate the active channels in suspend if the channel
is not idle.
Changes in v2: None
---
drivers/dma/fsl-edma.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 82 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index 915eec3..be2e62b 100644
--- 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,
--
2.1.0.27.g96db324

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Jisheng Zhang: "Re: [PATCH] clocksource: dw_apb_timer_of: support timer-based delay"
Previous message: Jarkko Sakkinen: "Re: [PATCH v1 4/4] keys, trusted: update documentation for 'hash=' option"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]