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 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
