ioat2,3: put channel hardware in known state at init

Put the ioat2 and ioat3 state machines in the halted state with all
errors cleared.

The ioat1 init path is not disturbed for stability, there are no
reported ioat1 initiaization issues.

Cc: <stable@kernel.org>
Reported-by: Roland Dreier <rdreier@cisco.com>
Tested-by: Roland Dreier <rdreier@cisco.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 52 insertions, 17 deletions

diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index 8f1f7f05deaa..5f7a500e18d0 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -239,20 +239,50 @@ void __ioat2_restart_chan(struct ioat2_dma_chan *ioat)
 		__ioat2_start_null_desc(ioat);
 }
 
-static void ioat2_restart_channel(struct ioat2_dma_chan *ioat)
+int ioat2_quiesce(struct ioat_chan_common *chan, unsigned long tmo)
 {
-	struct ioat_chan_common *chan = &ioat->base;
-	unsigned long phys_complete;
+	unsigned long end = jiffies + tmo;
+	int err = 0;
 	u32 status;
 
 	status = ioat_chansts(chan);
 	if (is_ioat_active(status) || is_ioat_idle(status))
 		ioat_suspend(chan);
 	while (is_ioat_active(status) || is_ioat_idle(status)) {
+		if (end && time_after(jiffies, end)) {
+			err = -ETIMEDOUT;
+			break;
+		}
 		status = ioat_chansts(chan);
 		cpu_relax();
 	}
 
+	return err;
+}
+
+int ioat2_reset_sync(struct ioat_chan_common *chan, unsigned long tmo)
+{
+	unsigned long end = jiffies + tmo;
+	int err = 0;
+
+	ioat_reset(chan);
+	while (ioat_reset_pending(chan)) {
+		if (end && time_after(jiffies, end)) {
+			err = -ETIMEDOUT;
+			break;
+		}
+		cpu_relax();
+	}
+
+	return err;
+}
+
+static void ioat2_restart_channel(struct ioat2_dma_chan *ioat)
+{
+	struct ioat_chan_common *chan = &ioat->base;
+	unsigned long phys_complete;
+
+	ioat2_quiesce(chan, 0);
 	if (ioat_cleanup_preamble(chan, &phys_complete))
 		__cleanup(ioat, phys_complete);
 
@@ -318,6 +348,19 @@ void ioat2_timer_event(unsigned long data)
 	spin_unlock_bh(&chan->cleanup_lock);
 }
 
+static int ioat2_reset_hw(struct ioat_chan_common *chan)
+{
+	/* throw away whatever the channel was doing and get it initialized */
+	u32 chanerr;
+
+	ioat2_quiesce(chan, msecs_to_jiffies(100));
+
+	chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
+	writel(chanerr, chan->reg_base + IOAT_CHANERR_OFFSET);
+
+	return ioat2_reset_sync(chan, msecs_to_jiffies(200));
+}
+
 /**
  * ioat2_enumerate_channels - find and initialize the device's channels
  * @device: the device to be enumerated
@@ -360,6 +403,10 @@ int ioat2_enumerate_channels(struct ioatdma_device *device)
 				  (unsigned long) ioat);
 		ioat->xfercap_log = xfercap_log;
 		spin_lock_init(&ioat->ring_lock);
+		if (device->reset_hw(&ioat->base)) {
+			i = 0;
+			break;
+		}
 	}
 	dma->chancnt = i;
 	return i;
@@ -467,7 +514,6 @@ int ioat2_alloc_chan_resources(struct dma_chan *c)
 	struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
 	struct ioat_chan_common *chan = &ioat->base;
 	struct ioat_ring_ent **ring;
-	u32 chanerr;
 	int order;
 
 	/* have we already been set up? */
@@ -477,12 +523,6 @@ int ioat2_alloc_chan_resources(struct dma_chan *c)
 	/* Setup register to interrupt and write completion status on error */
 	writew(IOAT_CHANCTRL_RUN, chan->reg_base + IOAT_CHANCTRL_OFFSET);
 
-	chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
-	if (chanerr) {
-		dev_err(to_dev(chan), "CHANERR = %x, clearing\n", chanerr);
-		writel(chanerr, chan->reg_base + IOAT_CHANERR_OFFSET);
-	}
-
 	/* allocate a completion writeback area */
 	/* doing 2 32bit writes to mmio since 1 64b write doesn't work */
 	chan->completion = pci_pool_alloc(chan->device->completion_pool,
@@ -746,13 +786,7 @@ void ioat2_free_chan_resources(struct dma_chan *c)
 	tasklet_disable(&chan->cleanup_task);
 	del_timer_sync(&chan->timer);
 	device->cleanup_tasklet((unsigned long) ioat);
-
-	/* Delay 100ms after reset to allow internal DMA logic to quiesce
-	 * before removing DMA descriptor resources.
-	 */
-	writeb(IOAT_CHANCMD_RESET,
-	       chan->reg_base + IOAT_CHANCMD_OFFSET(chan->device->version));
-	mdelay(100);
+	device->reset_hw(chan);
 
 	spin_lock_bh(&ioat->ring_lock);
 	descs = ioat2_ring_space(ioat);
@@ -839,6 +873,7 @@ int __devinit ioat2_dma_probe(struct ioatdma_device *device, int dca)
 	int err;
 
 	device->enumerate_channels = ioat2_enumerate_channels;
+	device->reset_hw = ioat2_reset_hw;
 	device->cleanup_tasklet = ioat2_cleanup_tasklet;
 	device->timer_fn = ioat2_timer_event;
 	device->self_test = ioat_dma_self_test;