> Subject: Re: [PATCH V5 5/5] configs: imx8qm: add configuration files
> 
> On 22.09.20 08:45, Alice Guo wrote:
> > +           .platform_info = {
> > +                   /*
> > +                    * .pci_mmconfig_base is fixed; if you change it,
> > +                    * update the value in mach.h
> > +                    * (PCI_CFG_BASE) and regenerate the inmate library
> > +                    */
> > +                   .pci_mmconfig_base = 0xfd700000,
> > +                   .pci_mmconfig_end_bus = 0x0,
> > +                   .pci_is_virtual = 1,
> > +                   .pci_domain = 0,
> > +
> > +                   .iommu_units = {
> > +                           {
> > +                                   .type = JAILHOUSE_IOMMU_ARM_MMU500,
> > +                                   .base = 0x51400000,
> > +                                   .size = 0x40000,
> > +                                   .arm_mmu500.sid_mask = 0x7f80,
> 
> How is the sid_mask of a platform retrieved? Can this be derived from
> information in a normal device tree?

This could be get from device tree, to i.MX8QM,
iommus = <&smmu 0x12 0x7f80>;
0x12 is sid, 0x7f80 is sid mask.

Sid mask is use to get the extract the exact sid from SOC internal BUS,
You could think as below:
Bus signal & 0x7f80 = 0x12

Regards,
Peng.

> 
> Or is this coming from here:
> 
> /* ID0 */
> id = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_ID0); [...]
> /* Max. number of entries we have for stream matching/indexing */ if
> (smmu->version == ARM_SMMU_V2 && id & ARM_SMMU_ID0_EXIDS) {
>          smmu->features |= ARM_SMMU_FEAT_EXIDS;
>          size = 1 << 16;
> } else {
>          size = 1 << FIELD_GET(ARM_SMMU_ID0_NUMSIDB, id); }
> smmu->streamid_mask = size - 1;
> 
> If it were so simple, I would actually say do the same in Jailhouse and drop 
> the
> configurable. We may even demand ARM_SMMU_ID0_EXIDS if that is
> practically the only case in the field by now.
> 
> But I'm lacking a full picture yet.
> 
> Jan
> 
> --
> Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate
> Competence Center Embedded Linux

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