dmaengine: pxa: handle bus errors (e093bf60) · Commits · 戴 / test

In the current state, upon bus error the driver will spin endlessly, relaunching the last tx, which will fail again and again : - a bus error happens - pxad_chan_handler() is called - as PXA_DCSR_STOPSTATE is true, the last non-terminated transaction is lauched, which is the one triggering the bus error, as it didn't terminate - moreover, the STOP interrupt fires a new, as the STOPIRQEN is still active Break this logic by stopping the automatic relaunch of a dma channel upon a bus error, even if there are still pending issued requests on it. As dma_cookie_status() seems unable to return DMA_ERROR in its current form, ie. there seems no way to mark a DMA_ERROR on a per-async-tx basis, it is chosen in this patch to remember on the channel which transaction failed, and report it in pxad_tx_status(). It's a bit misleading because if T1, T2, T3 and T4 were queued, and T1 was completed while T2 causes a bus error, the status of T3 and T4 will be reported as DMA_IN_PROGRESS, while the channel is actually stopped. Signed-off-by:

Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by:

Vinod Koul <vinod.koul@intel.com>

drivers/dma/pxa_dma.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -117,6 +117,7 @@ struct pxad_chan {
		/* protected by vc->lock */
		struct pxad_phy *phy;
		struct dma_pool desc_pool; / Descriptors pool */
		dma_cookie_t bus_error;
		};

		struct pxad_device {
		@@ -563,6 +564,7 @@ static void pxad_launch_chan(struct pxad_chan *chan,
		return;
		}
		}
		chan->bus_error = 0;

		/*
		* Program the descriptor's address into the DMA controller,
		@@ -666,6 +668,7 @@ static irqreturn_t pxad_chan_handler(int irq, void *dev_id)
		struct virt_dma_desc vd, tmp;
		unsigned int dcsr;
		unsigned long flags;
		dma_cookie_t last_started = 0;

		BUG_ON(!chan);

		@@ -678,6 +681,7 @@ static irqreturn_t pxad_chan_handler(int irq, void *dev_id)
		dev_dbg(&chan->vc.chan.dev->device,
		"%s(): checking txd %p[%x]: completed=%d\n",
		__func__, vd, vd->tx.cookie, is_desc_completed(vd));
		last_started = vd->tx.cookie;
		if (to_pxad_sw_desc(vd)->cyclic) {
		vchan_cyclic_callback(vd);
		break;
		@@ -690,7 +694,12 @@ static irqreturn_t pxad_chan_handler(int irq, void *dev_id)
		}
		}

		if (dcsr & PXA_DCSR_STOPSTATE) {
		if (dcsr & PXA_DCSR_BUSERR) {
		chan->bus_error = last_started;
		phy_disable(phy);
		}

		if (!chan->bus_error && dcsr & PXA_DCSR_STOPSTATE) {
		dev_dbg(&chan->vc.chan.dev->device,
		"%s(): channel stopped, submitted_empty=%d issued_empty=%d",
		__func__,
		@@ -1249,6 +1258,9 @@ static enum dma_status pxad_tx_status(struct dma_chan *dchan,
		struct pxad_chan *chan = to_pxad_chan(dchan);
		enum dma_status ret;

		if (cookie == chan->bus_error)
		return DMA_ERROR;

		ret = dma_cookie_status(dchan, cookie, txstate);
		if (likely(txstate && (ret != DMA_ERROR)))
		dma_set_residue(txstate, pxad_residue(chan, cookie));

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