On Thu, 2014-04-10 at 15:10 +0800, hongbo.zh...@freescale.com wrote: > From: Hongbo Zhang <hongbo.zh...@freescale.com> > > This patch adds suspend resume functions for Freescale DMA driver. > .prepare callback is used to stop further descriptors from being added into > the > pending queue, and also issue pending queues into execution if there is any. > .suspend callback makes sure all the pending jobs are cleaned up and all the > channels are idle, and save the mode registers. > .resume callback re-initializes the channels by restore the mode registers.
Like we discussed with Vinod [1] the DMA controller drivers should go to suspend after users and come back before them. After you reconsider this point the patch logic might be modified a lot. (Moreover, you abuse your own position to use only setters/getters to access to the DMAc registers) [1] http://www.spinics.net/lists/kernel/msg1650974.html > > Signed-off-by: Hongbo Zhang <hongbo.zh...@freescale.com> > --- > drivers/dma/fsldma.c | 100 > ++++++++++++++++++++++++++++++++++++++++++++++++++ > drivers/dma/fsldma.h | 16 ++++++++ > 2 files changed, 116 insertions(+) > > diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c > index c9bf54a..d6da222 100644 > --- a/drivers/dma/fsldma.c > +++ b/drivers/dma/fsldma.c > @@ -400,6 +400,14 @@ static dma_cookie_t fsl_dma_tx_submit(struct > dma_async_tx_descriptor *tx) > > spin_lock_bh(&chan->desc_lock); > > +#ifdef CONFIG_PM > + if (unlikely(chan->pm_state != RUNNING)) { > + chan_dbg(chan, "cannot submit due to suspend\n"); > + spin_unlock_bh(&chan->desc_lock); > + return -1; > + } > +#endif > + > /* > * assign cookies to all of the software descriptors > * that make up this transaction > @@ -1311,6 +1319,9 @@ static int fsl_dma_chan_probe(struct fsldma_device > *fdev, > INIT_LIST_HEAD(&chan->ld_running); > INIT_LIST_HEAD(&chan->ld_completed); > chan->idle = true; > +#ifdef CONFIG_PM > + chan->pm_state = RUNNING; > +#endif > > chan->common.device = &fdev->common; > dma_cookie_init(&chan->common); > @@ -1450,6 +1461,92 @@ static int fsldma_of_remove(struct platform_device *op) > return 0; > } > > +#ifdef CONFIG_PM > +static int fsldma_prepare(struct device *dev) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct fsldma_device *fdev = platform_get_drvdata(pdev); > + struct fsldma_chan *chan; > + int i; > + > + for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) { > + chan = fdev->chan[i]; > + if (!chan) > + continue; > + > + spin_lock_bh(&chan->desc_lock); > + chan->pm_state = SUSPENDING; > + if (!list_empty(&chan->ld_pending)) > + fsl_chan_xfer_ld_queue(chan); > + spin_unlock_bh(&chan->desc_lock); > + } > + > + return 0; > +} > + > +static int fsldma_suspend(struct device *dev) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct fsldma_device *fdev = platform_get_drvdata(pdev); > + struct fsldma_chan *chan; > + int i; > + > + for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) { > + chan = fdev->chan[i]; > + if (!chan) > + continue; > + > + spin_lock_bh(&chan->desc_lock); > + if (!chan->idle) > + goto out; > + chan->regs_save.mr = DMA_IN(chan, &chan->regs->mr, 32); > + chan->pm_state = SUSPENDED; > + spin_unlock_bh(&chan->desc_lock); > + } > + return 0; > + > +out: > + for (; i >= 0; i--) { > + chan = fdev->chan[i]; > + if (!chan) > + continue; > + chan->pm_state = RUNNING; > + spin_unlock_bh(&chan->desc_lock); > + } > + return -EBUSY; > +} > + > +static int fsldma_resume(struct device *dev) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct fsldma_device *fdev = platform_get_drvdata(pdev); > + struct fsldma_chan *chan; > + u32 mode; > + int i; > + > + for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) { > + chan = fdev->chan[i]; > + if (!chan) > + continue; > + > + spin_lock_bh(&chan->desc_lock); > + mode = chan->regs_save.mr > + & ~FSL_DMA_MR_CS & ~FSL_DMA_MR_CC & ~FSL_DMA_MR_CA; > + DMA_OUT(chan, &chan->regs->mr, mode, 32); > + chan->pm_state = RUNNING; > + spin_unlock_bh(&chan->desc_lock); > + } > + > + return 0; > +} > + > +static const struct dev_pm_ops fsldma_pm_ops = { > + .prepare = fsldma_prepare, > + .suspend = fsldma_suspend, > + .resume = fsldma_resume, > +}; > +#endif > + > static const struct of_device_id fsldma_of_ids[] = { > { .compatible = "fsl,elo3-dma", }, > { .compatible = "fsl,eloplus-dma", }, > @@ -1462,6 +1559,9 @@ static struct platform_driver fsldma_of_driver = { > .name = "fsl-elo-dma", > .owner = THIS_MODULE, > .of_match_table = fsldma_of_ids, > +#ifdef CONFIG_PM > + .pm = &fsldma_pm_ops, > +#endif > }, > .probe = fsldma_of_probe, > .remove = fsldma_of_remove, > diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h > index ec19517..eecaf9e 100644 > --- a/drivers/dma/fsldma.h > +++ b/drivers/dma/fsldma.h > @@ -134,6 +134,18 @@ struct fsldma_device { > #define FSL_DMA_CHAN_PAUSE_EXT 0x00001000 > #define FSL_DMA_CHAN_START_EXT 0x00002000 > > +#ifdef CONFIG_PM > +struct fsldma_chan_regs_save { > + u32 mr; > +}; > + > +enum fsldma_pm_state { > + RUNNING = 0, > + SUSPENDING, > + SUSPENDED, > +}; > +#endif > + > struct fsldma_chan { > char name[8]; /* Channel name */ > struct fsldma_chan_regs __iomem *regs; > @@ -161,6 +173,10 @@ struct fsldma_chan { > struct tasklet_struct tasklet; > u32 feature; > bool idle; /* DMA controller is idle */ > +#ifdef CONFIG_PM > + struct fsldma_chan_regs_save regs_save; > + enum fsldma_pm_state pm_state; > +#endif > > void (*toggle_ext_pause)(struct fsldma_chan *fsl_chan, int enable); > void (*toggle_ext_start)(struct fsldma_chan *fsl_chan, int enable); -- Andy Shevchenko <andriy.shevche...@linux.intel.com> Intel Finland Oy _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
