On Tue, Aug 23, 2016 at 08:05:21PM +0100, Robin Murphy wrote:
> Making S2CRs first-class citizens within the driver with a high-level
> representation of their state offers a neat solution to a few problems:
>
> Firstly, the information about which context a device's stream IDs are
> associated with is already present by necessity in the S2CR. With that
> state easily accessible we can refer directly to it and obviate the need
> to track an IOMMU domain in each device's archdata (its earlier purpose
> of enforcing correct attachment of multi-device groups now being handled
> by the IOMMU core itself).
>
> Secondly, the core API now deprecates explicit domain detach and expects
> domain attach to move devices smoothly from one domain to another; for
> SMMUv2, this notion maps directly to simply rewriting the S2CRs assigned
> to the device. By giving the driver a suitable abstraction of those
> S2CRs to work with, we can massively reduce the overhead of the current
> heavy-handed "detach, free resources, reallocate resources, attach"
> approach.
>
> Thirdly, making the software state hardware-shaped and attached to the
> SMMU instance once again makes suspend/resume of this register group
> that much simpler to implement in future.
>
> Signed-off-by: Robin Murphy <[email protected]>
> ---
> drivers/iommu/arm-smmu.c | 159
> +++++++++++++++++++++++++++--------------------
> 1 file changed, 93 insertions(+), 66 deletions(-)
[...]
> @@ -1145,9 +1198,16 @@ static void arm_smmu_master_free_smes(struct
> arm_smmu_device *smmu,
> static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain,
> struct arm_smmu_master_cfg *cfg)
> {
> - int i, ret;
> + int i, ret = 0;
> struct arm_smmu_device *smmu = smmu_domain->smmu;
> - void __iomem *gr0_base = ARM_SMMU_GR0(smmu);
> + struct arm_smmu_s2cr *s2cr = smmu->s2crs;
> + enum arm_smmu_s2cr_type type = S2CR_TYPE_TRANS;
> + u8 cbndx = smmu_domain->cfg.cbndx;
> +
> + if (cfg->smendx[0] < 0)
Shouldn't that be INVALID_SMENDX?
Will
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