Quoting Bjorn Andersson (2019-09-18 17:25:01) > On Tue 17 Sep 02:45 PDT 2019, Sai Prakash Ranjan wrote: > > > From: Vivek Gautam <vivek.gau...@codeaurora.org> > > > > There are other boards such as cheza whose bootloaders don't enable this > > logic. Such boards don't implement callbacks to handle the specific SCM > > call so disabling this logic for such boards will be a no-op. > > [...] > > diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c > > new file mode 100644 > > index 000000000000..24c071c1d8b0 > > --- /dev/null > > +++ b/drivers/iommu/arm-smmu-qcom.c > > @@ -0,0 +1,51 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Copyright (c) 2019, The Linux Foundation. All rights reserved. > > + */ > > + > > +#include <linux/qcom_scm.h> > > + > > +#include "arm-smmu.h" > > + > > +struct qcom_smmu { > > + struct arm_smmu_device smmu; > > +}; > > + > > +static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu) > > +{ > > + int ret; > > + > > + arm_mmu500_reset(smmu); > > + > > + /* > > + * To address performance degradation in non-real time clients, > > + * such as USB and UFS, turn off wait-for-safe on sdm845 based boards, > > + * such as MTP and db845, whose firmwares implement secure monitor > > + * call handlers to turn on/off the wait-for-safe logic. > > + */ > > + ret = qcom_scm_qsmmu500_wait_safe_toggle(0); > > In the transition to this new design we lost the ability to > enable/disable the safe toggle per board, which according to Vivek > would result in some issue with Cheza. > > Can you confirm that this is okay? (Or introduce the DT property for > enabling the safe_toggle logic?) >
I can test this on Cheza. Not sure if anything will happen but it's worth a shot.