Re: [PATCH v17 2/4] dmaengine: tegra: Add tegra gpcdma driver

Dmitry Osipenko
2022-01-30T10:17:30Z

30.01.2022 13:13, Dmitry Osipenko пишет:
> 30.01.2022 13:08, Dmitry Osipenko пишет:
>> 30.01.2022 13:05, Dmitry Osipenko пишет:
>>> static int tegra_dma_device_resume(struct dma_chan *dc)
>>> {
>>> struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
>>> u32 val;
>>>
>>> if (!tdc->tdma->chip_data->hw_support_pause)
>>> return -ENOSYS;
>>>
>>> if (!tdc->dma_desc)
>>> return 0;
>>>
>>> val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
>>> val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
>>> tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
>>>
>>> enable_irq(tdc->irq);
>>
>> Correction:
>>
>> if (tdc->dma_desc) {
>> val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
>> val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
>> tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
>> }
>>
>> enable_irq(tdc->irq);
>
> And apparently, tegra_dma_terminate_all() also needs to take care of
> removing the PAUSE bit. Otherwise it won't be possible to unpause
> channel after the termination.

Although, will be easier to just do this in the resume:

val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);

if (val & TEGRA_GPCDMA_CHAN_CSRE_PAUSE) {
val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
}