On Tue, Dec 20, 2016 at 12:19:27AM -0600, Jiandi An wrote: > The control area buffer is specified in the TPM2.0 static ACPI table. TPM > CRB driver maps the control area address and reads out cmd and rsp buffer > addresses and maps them. There is no requirement in the TCG TPM ACPI spec > for specifying _CRS to describe the control area buffer. When I rebased > the early prototype for CRB driver ARM64 enablement to the latest kernel, > I hit this issue where I have to specify _CRS method. So in _CRS method > I specify the same control area address that's in the TPM2.0 static ACPI > table. > > I see the _CRS requirement in the CRB driver is for resource synchronization > between the TIS and CRB drivers to support force mode in TIS. Could I get some > background on that so I could be more careful not breaking TIS while making > changes to CRB driver for ARM64 enablement?
At least couple of reasons: - _CRS is required to access locality registers (check my patch set that is waiting for review/testing). - On x86 and PTT _CRS always exists and that's the only platform where this driver has been used so far. /Jarkko
