Re: Question about UfsPassThruDxe driver

[Mike M <mike.maslenkin@gmail.com>]

Sorry for the noise. Once I sent this question I understood this code.
I overlooked UTP_TRD and UTP_TR_PRD declarations where lower 32-bit of a
physical address declared as a bitfield...
There are no shifts when HCI programmed via MMIO.


On Sat, Dec 22, 2018 at 1:43 AM Mike M <mike.maslenkin@gmail.com> wrote:

> Dear MdeModulePkg maintainers, I'm a bit baffled about a way
> physical addresses passed to UFS HCI at UfsPassThruDxe driver.
> For example, UFS HCI V.2.1 declares Data Base Address in PRDT structure as
> two 32 bit words,
> where bits 0 and 1 of a physical address are reserved.
> As well UTP Command Descriptor Base Address (UCDBA) shall be aligned to
> 128-byte address,
> i.e. bits [06:00] are reserved.
> In common such reserved bits are being cleared by AND operation
> with appropriate mask, while in UfsPassThruDxe right shift operator is
> used as below:
>     Prdt[PrdtIndex].DbAddr  = (UINT32)RShiftU64 ((UINT64)(UINTN)Remaining,
> 2);
>     Prdt[PrdtIndex].DbAddrU = (UINT32)RShiftU64 ((UINT64)(UINTN)Remaining,
> 32);
> and
>   Trd->UcdBa  = (UINT32)RShiftU64 ((UINT64)CmdDescPhyAddr, 7);
>   Trd->UcdBaU = (UINT32)RShiftU64 ((UINT64)CmdDescPhyAddr, 32);
>
> How does UFS HCI deal with such values?  This doesn't look correct.
> Would you like I prepare a patch replacing RShiftU64 operator with bitwise
> AND operator
> for lower 32-bit of a physical address value?
>