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

From: Yao Yuan
Date: Wed Nov 25 2015 - 04:59:31 EST

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Hi vinod,

Thanks for your review.
I have updated the patch as your comments before.
And then send the v4.
Do you have any comments for it?

Thanks.

Best Regards,
Yuan Yao

> -----Original Message-----
> From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx]
> On Behalf Of Yuan Yao
> Sent: Friday, October 30, 2015 7:04 PM
> To: vinod.koul@xxxxxxxxx; stefan@xxxxxxxx; arnd@xxxxxxxx
> Cc: dmaengine@xxxxxxxxxxxxxxx; dan.j.williams@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: [PATCH v4] 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@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
>
>
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> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
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Next message: Clemens Ladisch: "Re: [kernel-hardening] [PATCH 0/2] introduce post-init read-only memory"
Previous message: Borislav Petkov: "Re: [V5 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]