diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c
index 8668dad790b6..d3c2319e2fad 100644
--- a/drivers/dma/plx_dma.c
+++ b/drivers/dma/plx_dma.c
@@ -18,13 +18,103 @@ MODULE_VERSION("0.1");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Logan Gunthorpe");
 
+#define PLX_REG_DESC_RING_ADDR			0x214
+#define PLX_REG_DESC_RING_ADDR_HI		0x218
+#define PLX_REG_DESC_RING_NEXT_ADDR		0x21C
+#define PLX_REG_DESC_RING_COUNT			0x220
+#define PLX_REG_DESC_RING_LAST_ADDR		0x224
+#define PLX_REG_DESC_RING_LAST_SIZE		0x228
+#define PLX_REG_PREF_LIMIT			0x234
+#define PLX_REG_CTRL				0x238
+#define PLX_REG_CTRL2				0x23A
+#define PLX_REG_INTR_CTRL			0x23C
+#define PLX_REG_INTR_STATUS			0x23E
+
+#define PLX_REG_PREF_LIMIT_PREF_FOUR		8
+
+#define PLX_REG_CTRL_GRACEFUL_PAUSE		BIT(0)
+#define PLX_REG_CTRL_ABORT			BIT(1)
+#define PLX_REG_CTRL_WRITE_BACK_EN		BIT(2)
+#define PLX_REG_CTRL_START			BIT(3)
+#define PLX_REG_CTRL_RING_STOP_MODE		BIT(4)
+#define PLX_REG_CTRL_DESC_MODE_BLOCK		(0 << 5)
+#define PLX_REG_CTRL_DESC_MODE_ON_CHIP		(1 << 5)
+#define PLX_REG_CTRL_DESC_MODE_OFF_CHIP		(2 << 5)
+#define PLX_REG_CTRL_DESC_INVALID		BIT(8)
+#define PLX_REG_CTRL_GRACEFUL_PAUSE_DONE	BIT(9)
+#define PLX_REG_CTRL_ABORT_DONE			BIT(10)
+#define PLX_REG_CTRL_IMM_PAUSE_DONE		BIT(12)
+#define PLX_REG_CTRL_IN_PROGRESS		BIT(30)
+
+#define PLX_REG_CTRL_RESET_VAL	(PLX_REG_CTRL_DESC_INVALID | \
+				 PLX_REG_CTRL_GRACEFUL_PAUSE_DONE | \
+				 PLX_REG_CTRL_ABORT_DONE | \
+				 PLX_REG_CTRL_IMM_PAUSE_DONE)
+
+#define PLX_REG_CTRL_START_VAL	(PLX_REG_CTRL_WRITE_BACK_EN | \
+				 PLX_REG_CTRL_DESC_MODE_OFF_CHIP | \
+				 PLX_REG_CTRL_START | \
+				 PLX_REG_CTRL_RESET_VAL)
+
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_64B		0
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_128B	1
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_256B	2
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_512B	3
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_1KB		4
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_2KB		5
+#define PLX_REG_CTRL2_MAX_TXFR_SIZE_4B		7
+
+#define PLX_REG_INTR_CRTL_ERROR_EN		BIT(0)
+#define PLX_REG_INTR_CRTL_INV_DESC_EN		BIT(1)
+#define PLX_REG_INTR_CRTL_ABORT_DONE_EN		BIT(3)
+#define PLX_REG_INTR_CRTL_PAUSE_DONE_EN		BIT(4)
+#define PLX_REG_INTR_CRTL_IMM_PAUSE_DONE_EN	BIT(5)
+
+#define PLX_REG_INTR_STATUS_ERROR		BIT(0)
+#define PLX_REG_INTR_STATUS_INV_DESC		BIT(1)
+#define PLX_REG_INTR_STATUS_DESC_DONE		BIT(2)
+#define PLX_REG_INTR_CRTL_ABORT_DONE		BIT(3)
+
+struct plx_dma_hw_std_desc {
+	__le32 flags_and_size;
+	__le16 dst_addr_hi;
+	__le16 src_addr_hi;
+	__le32 dst_addr_lo;
+	__le32 src_addr_lo;
+};
+
+#define PLX_DESC_SIZE_MASK		0x7ffffff
+#define PLX_DESC_FLAG_VALID		BIT(31)
+#define PLX_DESC_FLAG_INT_WHEN_DONE	BIT(30)
+
+#define PLX_DESC_WB_SUCCESS		BIT(30)
+#define PLX_DESC_WB_RD_FAIL		BIT(29)
+#define PLX_DESC_WB_WR_FAIL		BIT(28)
+
+#define PLX_DMA_RING_COUNT		2048
+
+struct plx_dma_desc {
+	struct dma_async_tx_descriptor txd;
+	struct plx_dma_hw_std_desc *hw;
+	u32 orig_size;
+};
+
 struct plx_dma_dev {
 	struct dma_device dma_dev;
 	struct dma_chan dma_chan;
+	struct pci_dev __rcu *pdev;
 	void __iomem *bar;
 
 	struct kref ref;
 	struct work_struct release_work;
+	struct tasklet_struct desc_task;
+
+	spinlock_t ring_lock;
+	bool ring_active;
+	int head;
+	int tail;
+	struct plx_dma_hw_std_desc *hw_ring;
+	struct plx_dma_desc **desc_ring;
 };
 
 static struct plx_dma_dev *chan_to_plx_dma_dev(struct dma_chan *c)
@@ -32,8 +122,143 @@ static struct plx_dma_dev *chan_to_plx_dma_dev(struct dma_chan *c)
 	return container_of(c, struct plx_dma_dev, dma_chan);
 }
 
+static struct plx_dma_desc *plx_dma_get_desc(struct plx_dma_dev *plxdev, int i)
+{
+	return plxdev->desc_ring[i & (PLX_DMA_RING_COUNT - 1)];
+}
+
+static void plx_dma_process_desc(struct plx_dma_dev *plxdev)
+{
+	struct dmaengine_result res;
+	struct plx_dma_desc *desc;
+	u32 flags;
+
+	spin_lock_bh(&plxdev->ring_lock);
+
+	while (plxdev->tail != plxdev->head) {
+		desc = plx_dma_get_desc(plxdev, plxdev->tail);
+
+		flags = le32_to_cpu(READ_ONCE(desc->hw->flags_and_size));
+
+		if (flags & PLX_DESC_FLAG_VALID)
+			break;
+
+		res.residue = desc->orig_size - (flags & PLX_DESC_SIZE_MASK);
+
+		if (flags & PLX_DESC_WB_SUCCESS)
+			res.result = DMA_TRANS_NOERROR;
+		else if (flags & PLX_DESC_WB_WR_FAIL)
+			res.result = DMA_TRANS_WRITE_FAILED;
+		else
+			res.result = DMA_TRANS_READ_FAILED;
+
+		dma_cookie_complete(&desc->txd);
+		dma_descriptor_unmap(&desc->txd);
+		dmaengine_desc_get_callback_invoke(&desc->txd, &res);
+		desc->txd.callback = NULL;
+		desc->txd.callback_result = NULL;
+
+		plxdev->tail++;
+	}
+
+	spin_unlock_bh(&plxdev->ring_lock);
+}
+
+static void plx_dma_abort_desc(struct plx_dma_dev *plxdev)
+{
+	struct dmaengine_result res;
+	struct plx_dma_desc *desc;
+
+	plx_dma_process_desc(plxdev);
+
+	spin_lock_bh(&plxdev->ring_lock);
+
+	while (plxdev->tail != plxdev->head) {
+		desc = plx_dma_get_desc(plxdev, plxdev->tail);
+
+		res.residue = desc->orig_size;
+		res.result = DMA_TRANS_ABORTED;
+
+		dma_cookie_complete(&desc->txd);
+		dma_descriptor_unmap(&desc->txd);
+		dmaengine_desc_get_callback_invoke(&desc->txd, &res);
+		desc->txd.callback = NULL;
+		desc->txd.callback_result = NULL;
+
+		plxdev->tail++;
+	}
+
+	spin_unlock_bh(&plxdev->ring_lock);
+}
+
+static void __plx_dma_stop(struct plx_dma_dev *plxdev)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+	u32 val;
+
+	val = readl(plxdev->bar + PLX_REG_CTRL);
+	if (!(val & ~PLX_REG_CTRL_GRACEFUL_PAUSE))
+		return;
+
+	writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE,
+	       plxdev->bar + PLX_REG_CTRL);
+
+	while (!time_after(jiffies, timeout)) {
+		val = readl(plxdev->bar + PLX_REG_CTRL);
+		if (val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE)
+			break;
+
+		cpu_relax();
+	}
+
+	if (!(val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE))
+		dev_err(plxdev->dma_dev.dev,
+			"Timeout waiting for graceful pause!\n");
+
+	writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE,
+	       plxdev->bar + PLX_REG_CTRL);
+
+	writel(0, plxdev->bar + PLX_REG_DESC_RING_COUNT);
+	writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR);
+	writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR_HI);
+	writel(0, plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR);
+}
+
+static void plx_dma_stop(struct plx_dma_dev *plxdev)
+{
+	rcu_read_lock();
+	if (!rcu_dereference(plxdev->pdev)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	__plx_dma_stop(plxdev);
+
+	rcu_read_unlock();
+}
+
+static void plx_dma_desc_task(unsigned long data)
+{
+	struct plx_dma_dev *plxdev = (void *)data;
+
+	plx_dma_process_desc(plxdev);
+}
+
 static irqreturn_t plx_dma_isr(int irq, void *devid)
 {
+	struct plx_dma_dev *plxdev = devid;
+	u32 status;
+
+	status = readw(plxdev->bar + PLX_REG_INTR_STATUS);
+
+	if (!status)
+		return IRQ_NONE;
+
+	if (status & PLX_REG_INTR_STATUS_DESC_DONE && plxdev->ring_active)
+		tasklet_schedule(&plxdev->desc_task);
+
+	writew(status, plxdev->bar + PLX_REG_INTR_STATUS);
+
 	return IRQ_HANDLED;
 }
 
@@ -66,18 +291,109 @@ static void plx_dma_put(struct plx_dma_dev *plxdev)
 	kref_put(&plxdev->ref, plx_dma_release);
 }
 
+static int plx_dma_alloc_desc(struct plx_dma_dev *plxdev)
+{
+	struct plx_dma_desc *desc;
+	int i;
+
+	plxdev->desc_ring = kcalloc(PLX_DMA_RING_COUNT,
+				    sizeof(*plxdev->desc_ring), GFP_KERNEL);
+	if (!plxdev->desc_ring)
+		return -ENOMEM;
+
+	for (i = 0; i < PLX_DMA_RING_COUNT; i++) {
+		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+		if (!desc)
+			goto free_and_exit;
+
+		dma_async_tx_descriptor_init(&desc->txd, &plxdev->dma_chan);
+		desc->hw = &plxdev->hw_ring[i];
+		plxdev->desc_ring[i] = desc;
+	}
+
+	return 0;
+
+free_and_exit:
+	for (i = 0; i < PLX_DMA_RING_COUNT; i++)
+		kfree(plxdev->desc_ring[i]);
+	kfree(plxdev->desc_ring);
+	return -ENOMEM;
+}
+
 static int plx_dma_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
+	size_t ring_sz = PLX_DMA_RING_COUNT * sizeof(*plxdev->hw_ring);
+	dma_addr_t dma_addr;
+	int rc;
+
+	rcu_read_lock();
+	if (!rcu_dereference(plxdev->pdev)) {
+		rcu_read_unlock();
+		return -ENODEV;
+	}
 
 	kref_get(&plxdev->ref);
 
-	return 0;
+	writel(PLX_REG_CTRL_RESET_VAL, plxdev->bar + PLX_REG_CTRL);
+
+	plxdev->hw_ring = dmam_alloc_coherent(plxdev->dma_dev.dev, ring_sz,
+					      &dma_addr, GFP_KERNEL);
+	if (!plxdev->hw_ring) {
+		rcu_read_unlock();
+		return -ENOMEM;
+	}
+
+	plxdev->head = plxdev->tail = 0;
+
+	rc = plx_dma_alloc_desc(plxdev);
+	if (rc) {
+		plx_dma_put(plxdev);
+		rcu_read_unlock();
+		return rc;
+	}
+
+	writel(lower_32_bits(dma_addr), plxdev->bar + PLX_REG_DESC_RING_ADDR);
+	writel(upper_32_bits(dma_addr),
+	       plxdev->bar + PLX_REG_DESC_RING_ADDR_HI);
+	writel(lower_32_bits(dma_addr),
+	       plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR);
+	writel(PLX_DMA_RING_COUNT, plxdev->bar + PLX_REG_DESC_RING_COUNT);
+	writel(PLX_REG_PREF_LIMIT_PREF_FOUR, plxdev->bar + PLX_REG_PREF_LIMIT);
+
+	plxdev->ring_active = true;
+
+	rcu_read_unlock();
+
+	return PLX_DMA_RING_COUNT;
 }
 
 static void plx_dma_free_chan_resources(struct dma_chan *chan)
 {
 	struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
+	struct pci_dev *pdev;
+	int i;
+
+	spin_lock_bh(&plxdev->ring_lock);
+	plxdev->ring_active = false;
+	spin_unlock_bh(&plxdev->ring_lock);
+
+	plx_dma_stop(plxdev);
+
+	rcu_read_lock();
+	pdev = rcu_dereference(plxdev->pdev);
+	if (pdev)
+		synchronize_irq(pci_irq_vector(pdev, 0));
+	rcu_read_unlock();
+
+	tasklet_kill(&plxdev->desc_task);
+
+	plx_dma_abort_desc(plxdev);
+
+	for (i = 0; i < PLX_DMA_RING_COUNT; i++)
+		kfree(plxdev->desc_ring[i]);
+
+	kfree(plxdev->desc_ring);
 
 	plx_dma_put(plxdev);
 }
@@ -102,7 +418,11 @@ static int plx_dma_create(struct pci_dev *pdev)
 
 	kref_init(&plxdev->ref);
 	INIT_WORK(&plxdev->release_work, plx_dma_release_work);
+	spin_lock_init(&plxdev->ring_lock);
+	tasklet_init(&plxdev->desc_task, plx_dma_desc_task,
+		     (unsigned long)plxdev);
 
+	RCU_INIT_POINTER(plxdev->pdev, pdev);
 	plxdev->bar = pcim_iomap_table(pdev)[0];
 
 	dma = &plxdev->dma_dev;
@@ -181,6 +501,16 @@ static void plx_dma_remove(struct pci_dev *pdev)
 
 	free_irq(pci_irq_vector(pdev, 0),  plxdev);
 
+	rcu_assign_pointer(plxdev->pdev, NULL);
+	synchronize_rcu();
+
+	spin_lock_bh(&plxdev->ring_lock);
+	plxdev->ring_active = false;
+	spin_unlock_bh(&plxdev->ring_lock);
+
+	__plx_dma_stop(plxdev);
+	plx_dma_abort_desc(plxdev);
+
 	plxdev->bar = NULL;
 	plx_dma_put(plxdev);
 
