dmaengine: bcm2835: Fix abort of transactions

[mirror_ubuntu-bionic-kernel.git] / drivers / dma / bcm2835-dma.c

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index e5e37583967de7a60d790b954489af7a9a378519..6ba53bbd0e1616d5771dcf44cf068b71a7bcfacd 100644 (file)
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -415,13 +415,11 @@ static void bcm2835_dma_fill_cb_chain_with_sg(
        }
 }
 
-static int bcm2835_dma_abort(void __iomem *chan_base)
+static int bcm2835_dma_abort(struct bcm2835_chan *c)
 {
-       unsigned long cs;
+       void __iomem *chan_base = c->chan_base;
        long int timeout = 10000;
 
-       cs = readl(chan_base + BCM2835_DMA_CS);
-
        /*
         * A zero control block address means the channel is idle.
         * (The ACTIVE flag in the CS register is not a reliable indicator.)
@@ -433,25 +431,16 @@ static int bcm2835_dma_abort(void __iomem *chan_base)
        writel(0, chan_base + BCM2835_DMA_CS);
 
        /* Wait for any current AXI transfer to complete */
-       while ((cs & BCM2835_DMA_ISPAUSED) && --timeout) {
+       while ((readl(chan_base + BCM2835_DMA_CS) &
+               BCM2835_DMA_WAITING_FOR_WRITES) && --timeout)
                cpu_relax();
-               cs = readl(chan_base + BCM2835_DMA_CS);
-       }
 
-       /* We'll un-pause when we set of our next DMA */
+       /* Peripheral might be stuck and fail to signal AXI write responses */
        if (!timeout)
-               return -ETIMEDOUT;
-
-       if (!(cs & BCM2835_DMA_ACTIVE))
-               return 0;
-
-       /* Terminate the control block chain */
-       writel(0, chan_base + BCM2835_DMA_NEXTCB);
-
-       /* Abort the whole DMA */
-       writel(BCM2835_DMA_ABORT | BCM2835_DMA_ACTIVE,
-              chan_base + BCM2835_DMA_CS);
+               dev_err(c->vc.chan.device->dev,
+                       "failed to complete outstanding writes\n");
 
+       writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS);
        return 0;
 }
 
@@ -804,7 +793,6 @@ static int bcm2835_dma_terminate_all(struct dma_chan *chan)
        struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
        struct bcm2835_dmadev *d = to_bcm2835_dma_dev(c->vc.chan.device);
        unsigned long flags;
-       int timeout = 10000;
        LIST_HEAD(head);
 
        spin_lock_irqsave(&c->vc.lock, flags);
@@ -818,18 +806,7 @@ static int bcm2835_dma_terminate_all(struct dma_chan *chan)
        if (c->desc) {
                bcm2835_dma_desc_free(&c->desc->vd);
                c->desc = NULL;
-               bcm2835_dma_abort(c->chan_base);
-
-               /* Wait for stopping */
-               while (--timeout) {
-                       if (!readl(c->chan_base + BCM2835_DMA_ADDR))
-                               break;
-
-                       cpu_relax();
-               }
-
-               if (!timeout)
-                       dev_err(d->ddev.dev, "DMA transfer could not be terminated\n");
+               bcm2835_dma_abort(c);
        }
 
        vchan_get_all_descriptors(&c->vc, &head);