[PATCHv8,10/21] iommu/tegra: smmu: allow duplicate ASID wirte

Submitted by Hiroshi Doyu on May 30, 2014, 11:20 a.m.

Details

Message ID 1401448834-32659-11-git-send-email-hdoyu@nvidia.com
State Superseded, archived
Headers show

Commit Message

Hiroshi Doyu May 30, 2014, 11:20 a.m.
The device, which belongs to the same ASID, can try to enable the same
ASID as the other swgroup devices. This should be allowed but just
skip the actual register write. If the write value is different, it
will return -EINVAL.

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
---
 drivers/iommu/tegra-smmu.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

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diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 1d3f695d3c66..caa531cb1c50 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -417,9 +417,13 @@  static int __smmu_client_set_hwgrp(struct smmu_client *c,
 		offs = HWGRP_ASID_REG(i);
 		val = smmu_read(smmu, offs);
 		if (on) {
-			if (WARN_ON(val & mask))
-				goto err_hw_busy;
-			val |= mask;
+			if (val) {
+				if (WARN_ON(val != mask))
+					return -EINVAL;
+				goto skip;
+			}
+
+			val = mask;
 			memcpy(c->hwgrp, map, sizeof(u64));
 		} else {
 			WARN_ON((val & mask) == mask);
@@ -429,16 +433,8 @@  static int __smmu_client_set_hwgrp(struct smmu_client *c,
 	}
 
 	FLUSH_SMMU_REGS(smmu);
+skip:
 	return 0;
-
-err_hw_busy:
-	for_each_set_bit(i, map, TEGRA_SWGROUP_MAX) {
-		offs = HWGRP_ASID_REG(i);
-		val = smmu_read(smmu, offs);
-		val &= ~mask;
-		smmu_write(smmu, val, offs);
-	}
-	return -EBUSY;
 }
 
 static int smmu_client_set_hwgrp(struct smmu_client *c,