[PATCH 2/2] dmaengine: fsl-edma: add PM suspend/resume support
From: stefan@agner.ch (Stefan Agner)
Date: 2015-01-30 13:06:07
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On 2014-12-30 09:41, Jingchang Lu wrote:
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This adds power management suspend/resume support for the fsl-edma driver. Signed-off-by: Jingchang Lu <redacted> --- drivers/dma/fsl-edma.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c index e0bd517..6a81699 100644 --- a/drivers/dma/fsl-edma.c +++ b/drivers/dma/fsl-edma.c@@ -1017,6 +1017,43 @@ static int fsl_edma_remove(struct platform_device *pdev) return 0; } +#ifdef CONFIG_PM_SLEEP +static int fsl_edma_pm_suspend(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_edma_chan_mux(fsl_chan, 0, false); + } + + return 0; +} + +static int fsl_edma_pm_resume(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]; + edma_writew(fsl_edma, 0x0, fsl_edma->membase + EDMA_TCD_CSR(i));
What is the expectation of the suspend mode, are the registers and descriptors cleared during suspend? So this makes sure we have all descriptors disabled on wake-up, right?
+ /* restore the channel slave id configuration */ + fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
And here the channel gets muxed again. But the user is expected to reconfigure a channel, e.g. using dmaengine_slave_config and the dmaengine_prep*? Also and cyclic DMA which has been paused before would be interrupted, is this correct? I don't know what the common exception of the API is, I'm just asking so I now what I can expect when using the DMA driver in other device drivers... -- Stefan
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+ } + + edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA, + fsl_edma->membase + EDMA_CR); + + return 0; +} +#endif +static +SIMPLE_DEV_PM_OPS(fsl_edma_pm_ops, fsl_edma_pm_suspend, fsl_edma_pm_resume); + static const struct of_device_id fsl_edma_dt_ids[] = { { .compatible = "fsl,vf610-edma", }, { /* sentinel */ }@@ -1027,6 +1064,7 @@ 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,