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Date: Wed, 25 Sep 2013 15:00:39 -0700
From: Jon Mason <jon.mason@...el.com>
To: Dan Williams <dan.j.williams@...el.com>
Cc: Dave Jiang <dave.jiang@...el.com>,
Vinod Koul <vinod.koul@...el.com>, linux-kernel@...r.kernel.org
Subject: [RESEND PATCH] ioat: PM Support
Add power management support in the IOAT driver. Adding this feature
resolves a known issue when attempting to suspend on systems with IOAT
enabled. On those systems, IOAT would experience a DMA channel error
when attempting to resume due to the channels not being suspended
properly. Currently, all channels errors cause panics, thus bringing
the system down.
Unfortunately, a hardware errata needs to be worked around on Xeon IOAT
devices. The channel cannot be suspended or reset if there are active
XOR transactions. To get around this, check to see if XOR is enabled on
the channel and the channel has pending transactions. If so, then grab
the lock and wait for the queue to drain. It might be more elegant to
see if there are any XOR operations pending in the list, but by that
time the queue will have drained anyway.
See BF509S in
http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-c5500-c3500-spec-update.pdf
See BT92 in
http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e5-family-spec-update.pdf
Tested-by: Gary Hade <garyhade@...ibm.com>
Signed-off-by: Jon Mason <jon.mason@...el.com>
---
drivers/dma/ioat/dma.c | 1 +
drivers/dma/ioat/dma.h | 1 +
drivers/dma/ioat/dma_v2.c | 1 +
drivers/dma/ioat/dma_v3.c | 60 ++++++++++++++++++++++++++++++++++++++++++---
drivers/dma/ioat/pci.c | 39 +++++++++++++++++++++++++++++
5 files changed, 99 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 5ff6fc1..eeccfaa 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -1202,6 +1202,7 @@ int ioat1_dma_probe(struct ioatdma_device *device, int dca)
device->self_test = ioat_dma_self_test;
device->timer_fn = ioat1_timer_event;
device->cleanup_fn = ioat1_cleanup_event;
+ device->suspend = ioat_suspend;
dma = &device->common;
dma->device_prep_dma_memcpy = ioat1_dma_prep_memcpy;
dma->device_issue_pending = ioat1_dma_memcpy_issue_pending;
diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index 54fb7b9..1372c8e 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -97,6 +97,7 @@ struct ioatdma_device {
void (*cleanup_fn)(unsigned long data);
void (*timer_fn)(unsigned long data);
int (*self_test)(struct ioatdma_device *device);
+ void (*suspend)(struct ioat_chan_common *chan);
};
struct ioat_chan_common {
diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index b925e1b..bd21dcb 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -890,6 +890,7 @@ int ioat2_dma_probe(struct ioatdma_device *device, int dca)
device->cleanup_fn = ioat2_cleanup_event;
device->timer_fn = ioat2_timer_event;
device->self_test = ioat_dma_self_test;
+ device->suspend = ioat_suspend;
dma = &device->common;
dma->device_prep_dma_memcpy = ioat2_dma_prep_memcpy_lock;
dma->device_issue_pending = ioat2_issue_pending;
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index b642e03..4147561 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -645,12 +645,63 @@ static void ioat3_cleanup_event(unsigned long data)
writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
}
+static inline void ioat3_suspend(struct ioat_chan_common *chan)
+{
+ struct pci_dev *pdev = to_pdev(chan);
+ struct dma_device *dma = &chan->device->common;
+ struct ioat2_dma_chan *ioat = container_of(chan, struct ioat2_dma_chan,
+ base);
+
+ /* Due to HW errata on Xeon, we must make sure to flush the device prior
+ * to suspend or reset of the device if there are any XOR operations
+ * pending. Instead of inspecting the pending operations, just flush it
+ * if the channel supports XOR.
+ */
+ if (is_xeon_cb32(pdev) && dma_has_cap(DMA_XOR, dma->cap_mask) &&
+ is_ioat_active(ioat_chansts(chan))) {
+ unsigned long end = jiffies + msecs_to_jiffies(100);
+
+ spin_lock_bh(&ioat->prep_lock);
+ while (is_ioat_active(ioat_chansts(chan))) {
+ if (time_after(jiffies, end)) {
+ dev_err(&pdev->dev, "Timeout trying to suspend");
+ break;
+ }
+ cpu_relax();
+ }
+ ioat_suspend(chan);
+ spin_unlock_bh(&ioat->prep_lock);
+ } else
+ ioat_suspend(chan);
+}
+
+static int ioat3_quiesce(struct ioat_chan_common *chan, unsigned long tmo)
+{
+ unsigned long end = jiffies + tmo;
+ int err = 0;
+ u32 status;
+
+ status = ioat_chansts(chan);
+ if (is_ioat_active(status) || is_ioat_idle(status))
+ ioat3_suspend(chan);
+ while (is_ioat_active(status) || is_ioat_idle(status)) {
+ if (tmo && time_after(jiffies, end)) {
+ err = -ETIMEDOUT;
+ break;
+ }
+ status = ioat_chansts(chan);
+ cpu_relax();
+ }
+
+ return err;
+}
+
static void ioat3_restart_channel(struct ioat2_dma_chan *ioat)
{
struct ioat_chan_common *chan = &ioat->base;
u64 phys_complete;
- ioat2_quiesce(chan, 0);
+ ioat3_quiesce(chan, 0);
if (ioat3_cleanup_preamble(chan, &phys_complete))
__cleanup(ioat, phys_complete);
@@ -1689,7 +1740,7 @@ static int ioat3_reset_hw(struct ioat_chan_common *chan)
u16 dev_id;
int err;
- ioat2_quiesce(chan, msecs_to_jiffies(100));
+ ioat3_quiesce(chan, msecs_to_jiffies(100));
chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
writel(chanerr, chan->reg_base + IOAT_CHANERR_OFFSET);
@@ -1769,6 +1820,7 @@ int ioat3_dma_probe(struct ioatdma_device *device, int dca)
device->reset_hw = ioat3_reset_hw;
device->self_test = ioat3_dma_self_test;
device->intr_quirk = ioat3_intr_quirk;
+ device->suspend = ioat3_suspend;
dma = &device->common;
dma->device_prep_dma_memcpy = ioat2_dma_prep_memcpy_lock;
dma->device_issue_pending = ioat2_issue_pending;
@@ -1787,8 +1839,10 @@ int ioat3_dma_probe(struct ioatdma_device *device, int dca)
device->cap &= ~(IOAT_CAP_XOR | IOAT_CAP_PQ | IOAT_CAP_RAID16SS);
/* dca is incompatible with raid operations */
- if (dca_en && (device->cap & (IOAT_CAP_XOR|IOAT_CAP_PQ)))
+ if (dca_en && (device->cap & (IOAT_CAP_XOR|IOAT_CAP_PQ))) {
+ pr_info("%s: DCA enabled, disabling XOR\n", __func__);
device->cap &= ~(IOAT_CAP_XOR|IOAT_CAP_PQ);
+ }
if (device->cap & IOAT_CAP_XOR) {
is_raid_device = true;
diff --git a/drivers/dma/ioat/pci.c b/drivers/dma/ioat/pci.c
index 2c8d560..136b10a 100644
--- a/drivers/dma/ioat/pci.c
+++ b/drivers/dma/ioat/pci.c
@@ -126,11 +126,50 @@ struct kmem_cache *ioat2_cache;
#define DRV_NAME "ioatdma"
+#ifdef CONFIG_PM
+static int ioat_pm_suspend(struct device *dev)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct ioatdma_device *device = pci_get_drvdata(pdev);
+ struct dma_device *dma = &device->common;
+ struct dma_chan *chan;
+
+ list_for_each_entry(chan, &dma->channels, device_node) {
+ struct ioat_dma_chan *ioat = to_ioat_chan(chan);
+
+ dev_info(dev, "Suspending Chan %d\n", chan->chan_id);
+ if (device->suspend)
+ device->suspend(&ioat->base);
+ }
+
+ return 0;
+}
+
+static int ioat_pm_resume(struct device *dev)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct ioatdma_device *device = pci_get_drvdata(pdev);
+ struct dma_device *dma = &device->common;
+ struct dma_chan *chan;
+
+ list_for_each_entry(chan, &dma->channels, device_node) {
+ struct ioat_dma_chan *ioat = to_ioat_chan(chan);
+ dev_info(dev, "Starting Chan %d\n", chan->chan_id);
+ ioat_start(&ioat->base);
+ }
+
+ return 0;
+}
+#endif
+
+SIMPLE_DEV_PM_OPS(ioat_pm_ops, ioat_pm_suspend, ioat_pm_resume);
+
static struct pci_driver ioat_pci_driver = {
.name = DRV_NAME,
.id_table = ioat_pci_tbl,
.probe = ioat_pci_probe,
.remove = ioat_remove,
+ .driver.pm = &ioat_pm_ops,
};
static struct ioatdma_device *
--
1.7.9.5
--
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