On Wed, May 28, 2025 at 04:42:05PM +0800, Qunqin Zhao wrote:
在 2025/5/28 下午3:57, Stefano Garzarella 写道:
+ chip = tpmm_chip_alloc(dev, &tpm_loongson_ops);
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+ chip->flags = TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_IRQ;
Why setting TPM_CHIP_FLAG_IRQ?
When tpm_engine completes TPM_CC* command,
the hardware will indeed trigger an interrupt to the kernel.
IIUC that is hidden by loongson_se_send_engine_cmd(), that for this
driver is completely synchronous, no?
IIUC this driver is similar to ftpm and svsm where the send is
synchronous so having .status, .cancel, etc. set to 0 should be
enough to call .recv() just after send() in tpm_try_transmit(). See
commit 980a573621ea ("tpm: Make chip->{status,cancel,req_canceled}
opt")
The send callback would wait until the TPM_CC* command complete. We
don't need a poll.
Right, that's what I was saying too, send() is synchronous (as in ftpm
and svsm). The polling in tpm_try_transmit() is already skipped since we
are setting .status = 0, .req_complete_mask = 0, .req_complete_val = 0,
etc. so IMHO this is exactly the same of ftpm and svsm, so we don't need
to set TPM_CHIP_FLAG_IRQ.
Thanks,
Stefano
