Messages in this thread | | | From | Gerd Hoffmann <> | Subject | Re: [PATCH 21/32] mmc: bcm2835-sdhost: Add new driver for the internal SD controller. | Date | Tue, 21 Jun 2016 12:33:59 +0000 (UTC) |
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Hi,
> > + mmiowb(); > > +} > > What is the barrier for? Same question for all the other instances
No idea. Removed them all, seems to work fine still. Guess writel() & friends have the needed barriers on arm?
> > + > > +static void bcm2835_sdhost_reset(struct mmc_host *mmc) > > +{ > > + struct bcm2835_host *host = mmc_priv(mmc); > > + unsigned long flags; > > + > > + spin_lock_irqsave(&host->lock, flags); > > + bcm2835_sdhost_reset_internal(host); > > + spin_unlock_irqrestore(&host->lock, flags); > > +} > > The spinlock seems to only protect the reset from happening concurrently > with bcm2835_sdhost_dma_complete() here. So if you ensure that this > function is no longer pending, you can probably use msleep() above.
There is also a tasklet. And IRQs. But bcm2835_sdhost_reset_internal clears hcfg (temporately), so IRQs shouldn't be a problem I think. So how about this?
@@ -334,9 +334,10 @@ static void bcm2835_sdhost_reset(struct mmc_host *mmc) struct bcm2835_host *host = mmc_priv(mmc); unsigned long flags;
- spin_lock_irqsave(&host->lock, flags); + if (host->dma_chan) + dmaengine_terminate_sync(host->dma_chan); + tasklet_kill(&host->finish_tasklet); bcm2835_sdhost_reset_internal(host); - spin_unlock_irqrestore(&host->lock, flags); }
> > + if (IS_ERR_OR_NULL(host->dma_chan_tx) || > > + IS_ERR_OR_NULL(host->dma_chan_rx)) { > > + pr_err("%s: unable to initialise DMA channels. Falling back to PIO\n", > > + mmc_hostname(mmc)); > > When are these ever NULL?
When there are no dma channels configured in the device tree.
cheers, Gerd
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