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

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Submitter Hiroshi Doyu
Date May 30, 2014, 11:20 a.m.
Message ID <1401448834-32659-11-git-send-email-hdoyu@nvidia.com>
Download mbox | patch
Permalink /patch/354082/
State Superseded, archived
Headers show

Comments

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(-)

Patch

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,