[PATCH v2 3/3] dma: Add Freescale eDMA engine driver support
Vinod Koul
vinod.koul at intel.com
Mon Aug 5 11:45:51 EDT 2013
On Mon, Aug 05, 2013 at 09:53:45AM +0200, Lothar Waßmann wrote:
> Hi,
>
> Jingchang Lu writes:
> > Add Freescale enhanced direct memory(eDMA) controller support.
> > The eDMA controller deploys DMAMUXs routing DMA request sources(slot)
> > to eDMA channels.
> > This module can be found on Vybrid and LS-1 SoCs.
> >
> [...]
> > +static struct fsl_edma_desc *fsl_edma_alloc_desc(struct fsl_edma_chan *fsl_chan,
> > + int sg_len)
> > +{
> > + struct fsl_edma_desc *fsl_desc;
> > + int size, i;
> > +
> > + size = sizeof(struct fsl_edma_desc);
> > + size += sizeof(struct fsl_edma_sw_tcd) * sg_len;
> > + fsl_desc = kzalloc(size, GFP_KERNEL);
> > + if (!fsl_desc)
> > + return NULL;
> > +
> > + fsl_desc->echan = fsl_chan;
> > + fsl_desc->n_tcds = sg_len;
> > + for (i = 0; i < sg_len; i++) {
> > + fsl_desc->tcd[i].vtcd = dma_pool_alloc(fsl_chan->tcd_pool,
> > + GFP_ATOMIC, &fsl_desc->tcd[i].ptcd);
> >
> Why is this called with GFP_ATOMIC while fsl_desc above is being
> allocated with GFP_KERNEL?
Both need to be GFP_ATOMIC, better they need to be GFP_NOWAIT.
~Vinod
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