iommu/arm-smmu-v3: Disable ECMDQ before the system is suspended

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5TE5L


CVE: NA

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We are currently not doing anything in arm_smmu_suspend(), but ECMDQ may
have executed some commands. In arm_smmu_device_reset(), we assume that
the index value of prod and cons are zero. Therefore, when ecmdq is
enabled again, the index values of prod and cons are inconsistent. As a
result, the hardware mistakenly considers that there are commands in the
queue and executes them and reports invalid commands.

On the other hand, when we disable ecmdq, we need to wait for ENACK to
become 0 before writing cons.

Disable ECMDQ in arm_smmu_suspend() to save energy.

Fixes: 4b009f70 ("iommu/arm-smmu-v3: Add suspend and resume support")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Tested-by: Liyan Liu <liuliyan6@h-partners.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>