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Groups > linux.kernel > #1632036
| From | sunil.kovvuri@gmail.com |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively |
| Date | 2017-04-27 13:20 +0200 |
| Message-ID | <tAPCN-8aG-9@gated-at.bofh.it> (permalink) |
| Organization | linux.* mail to news gateway |
From: Sunil Goutham <sgoutham@cavium.com>
Modified polling on CMDQ consumer similar to how polling is done for TLB SYNC
completion in SMMUv2 driver. Code changes are done with reference to
8513c8930069 iommu/arm-smmu: Poll for TLB sync completion more effectively
Poll timeout has been increased which addresses issue of 100us timeout not
sufficient, when command queue is full with TLB invalidation commands.
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: Geetha <gakula@cavium.com>
---
drivers/iommu/arm-smmu-v3.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index d412bdd..34599d4 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -379,6 +379,9 @@
#define CMDQ_SYNC_0_CS_NONE (0UL << CMDQ_SYNC_0_CS_SHIFT)
#define CMDQ_SYNC_0_CS_SEV (2UL << CMDQ_SYNC_0_CS_SHIFT)
+#define CMDQ_DRAIN_TIMEOUT_US 1000
+#define CMDQ_SPIN_COUNT 10
+
/* Event queue */
#define EVTQ_ENT_DWORDS 4
#define EVTQ_MAX_SZ_SHIFT 7
@@ -737,7 +740,8 @@ static void queue_inc_prod(struct arm_smmu_queue *q)
*/
static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe)
{
- ktime_t timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US);
+ ktime_t timeout = ktime_add_us(ktime_get(), CMDQ_DRAIN_TIMEOUT_US);
+ unsigned int spin_cnt, delay = 1;
while (queue_sync_cons(q), (drain ? !queue_empty(q) : queue_full(q))) {
if (ktime_compare(ktime_get(), timeout) > 0)
@@ -746,8 +750,13 @@ static int queue_poll_cons(struct arm_smmu_queue *q, bool drain, bool wfe)
if (wfe) {
wfe();
} else {
- cpu_relax();
- udelay(1);
+ for (spin_cnt = 0;
+ spin_cnt < CMDQ_SPIN_COUNT; spin_cnt++) {
+ cpu_relax();
+ continue;
+ }
+ udelay(delay);
+ delay *= 2;
}
}
--
2.7.4
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[PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively sunil.kovvuri@gmail.com - 2017-04-27 13:20 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-05-03 15:20 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Will Deacon <will.deacon@arm.com> - 2017-05-03 17:40 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-05-03 18:00 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Will Deacon <will.deacon@arm.com> - 2017-05-03 18:00 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-05-03 18:30 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Robin Murphy <robin.murphy@arm.com> - 2017-05-03 17:40 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Will Deacon <will.deacon@arm.com> - 2017-05-03 17:50 +0200
Re: [PATCH] iommu/arm-smmu-v3: Poll for CMDQ drain completion more effectively Sunil Kovvuri <sunil.kovvuri@gmail.com> - 2017-05-03 18:30 +0200
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