On 2021-03-23 14:19, Daejun Park wrote:

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On 2021-03-23 13:37, Daejun Park wrote:

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On 2021-03-23 12:22, Can Guo wrote:

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On 2021-03-22 17:11, Bean Huo wrote:

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On Mon, 2021-03-22 at 15:54 +0900, Daejun Park wrote:

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+       switch (rsp_field->hpb_op) {

+       case HPB_RSP_REQ_REGION_UPDATE:

+               if (data_seg_len != DEV_DATA_SEG_LEN)

+                       dev_warn(&hpb->sdev_ufs_lu->sdev_dev,

+                                "%s: data seg length is not
same.\n",

+                                __func__);

+               ufshpb_rsp_req_region_update(hpb, rsp_field);

+               break;

+       case HPB_RSP_DEV_RESET:

+               dev_warn(&hpb->sdev_ufs_lu->sdev_dev,

+                        "UFS device lost HPB information during
PM.\n");

+               break;

Hi Deajun,
This series looks good to me. Just here I have one question. You
didn't
handle HPB_RSP_DEV_RESET, just a warning.  Based on your SS UFS, 
how
to
handle HPB_RSP_DEV_RESET from the host side? Do you think we shoud
reset host side HPB entry as well or what else?


Bean

Same question here - I am still collecting feedbacks from flash
vendors
about
what is recommanded host behavior on reception of HPB Op code 0x2,
since it
is not cleared defined in HPB2.0 specs.

Can Guo.

I think the question should be asked in the HPB2.0 patch, since in
HPB1.0 device
control mode, a HPB reset in device side does not impact anything in
host side -
host is not writing back any HPB entries to device anyways and HPB
Read
cmd with
invalid HPB entries shall be treated as normal Read(10) cmd without
any
problems.

Yes, UFS device will process read command even the HPB entries are
valid or
not. So it is warning about read performance drop by dev reset.

Yeah, but still I am 100% sure about what should host do in case of
HPB2.0
when it receives HPB Op code 0x2, I am waiting for feedbacks.

I think the host has two choices when it receives 0x2.
One is nothing on host.
The other is discarding all HPB entries in the host.

In the JEDEC HPB spec, it as follows:
When the device is powered off by the host, the device may restore L2P 
map
data upon power up or build from the host’s HPB READ command.

If some UFS builds L2P map data from the host's HPB READ commands, we 
don't
have to discard HPB entries in the host.

So I thinks there is nothing to do when it receives 0x2.

But in HPB2.0, if we do nothing to active regions in host side, host can 
write
HPB entries (which host thinks valid, but actually invalid in device 
side since
reset happened) back to device through HPB Write Buffer cmds (BUFFER ID 
= 0x2).
My question is that are all UFSs OK with this?

Yes, it must be OK.

Please refer the following the HPB 2.0 spec:

If the HPB Entries sent by HPB WRITE BUFFER are removed by the device,
for example, because they are not consumed for a long enough period of time,
then the HPB READ command for the removed HPB entries shall be handled as a
normal READ command.

Thanks,
Daejun

Thanks,
Can Guo.

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Thanks,
Daejun

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Thanks,
Can Guo.

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Thanks,
Daejun

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Please correct me if I am wrong.

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Thanks,
Can Guo.