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@xxxxxxxxxx> --- v4: This was the part of v3, which isn't used any more. [PATCHv3 10/19] iommu/tegra: smmu: Get "nvidia,swgroups" from DT Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx> --- drivers/iommu/tegra-smmu.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c index fd4479a..2b8a302 100644 --- a/drivers/iommu/tegra-smmu.c +++ b/drivers/iommu/tegra-smmu.c @@ -418,9 +418,13 @@ 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); @@ -430,16 +434,8 @@ 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, -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html