Re: [PATCH v6 2/4] dmaengine: mediatek-cqdma: remove redundant queue structure

EastL
2020-07-23T02:34:33Z

On Wed, 2020-07-15 at 11:49 +0530, Vinod Koul wrote:
> On 02-07-20, 15:06, EastL Lee wrote:
>
> > static enum dma_status mtk_cqdma_tx_status(struct dma_chan *c,
> > dma_cookie_t cookie,
> > struct dma_tx_state *txstate)
> > {
> > - struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
> > - struct mtk_cqdma_vdesc *cvd;
> > - struct virt_dma_desc *vd;
> > - enum dma_status ret;
> > - unsigned long flags;
> > - size_t bytes = 0;
> > -
> > - ret = dma_cookie_status(c, cookie, txstate);
> > - if (ret == DMA_COMPLETE || !txstate)
> > - return ret;
> > -
> > - spin_lock_irqsave(&cvc->vc.lock, flags);
> > - vd = mtk_cqdma_find_active_desc(c, cookie);
> > - spin_unlock_irqrestore(&cvc->vc.lock, flags);
> > -
> > - if (vd) {
> > - cvd = to_cqdma_vdesc(vd);
> > - bytes = cvd->residue;
> > - }
> > -
> > - dma_set_residue(txstate, bytes);
>
> any reason why you want to remove setting residue?
Because Mediatek CQDMA HW can't support residue.
>
> > -static void mtk_cqdma_free_active_desc(struct dma_chan *c)
> > +static int mtk_cqdma_terminate_all(struct dma_chan *c)
> > {
> > struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
> > - bool sync_needed = false;
> > + struct virt_dma_chan *vc = to_virt_chan(c);
> > unsigned long pc_flags;
> > unsigned long vc_flags;
> > + LIST_HEAD(head);
> > +
> > + /* wait for the VC to be inactive */
> > + if (!wait_for_completion_timeout(&cvc->cmp, msecs_to_jiffies(3000)))
> > + return -EAGAIN;
> >
> > /* acquire PC's lock first due to lock dependency in dma ISR */
> > spin_lock_irqsave(&cvc->pc->lock, pc_flags);
> > spin_lock_irqsave(&cvc->vc.lock, vc_flags);
> >
> > - /* synchronization is required if this VC is active */
> > - if (mtk_cqdma_is_vchan_active(cvc)) {
> > - cvc->issue_synchronize = true;
> > - sync_needed = true;
> > - }
> > + /* get VDs from lists */
> > + vchan_get_all_descriptors(vc, &head);
> > +
> > + /* free all the VDs */
> > + vchan_dma_desc_free_list(vc, &head);
> >
> > spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
> > spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
>
> Good cleanup, do you need both these locks?
Yes, because we will have multiple vc to pc, it will need both lock.