From e093bf60ca498a03b4ea8f5d6cf1d520a68e5d2e Mon Sep 17 00:00:00 2001 From: Robert Jarzmik Date: Mon, 28 Mar 2016 23:32:24 +0200 Subject: [PATCH] dmaengine: pxa: handle bus errors 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 Signed-off-by: Vinod Koul --- drivers/dma/pxa_dma.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c index 77c1c44009d8..6d17dfd67881 100644 --- a/drivers/dma/pxa_dma.c +++ b/drivers/dma/pxa_dma.c @@ -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));