linux-kernel - Re: [PATCH v10 4/5] tpm: Add a driver for Loongson TPM device

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Message-ID: <afaeb91a-afb4-428a-2c17-3ea5f098da22@loongson.cn>
Date: Wed, 28 May 2025 16:42:05 +0800
From: Qunqin Zhao <zhaoqunqin@...ngson.cn>
To: Stefano Garzarella <sgarzare@...hat.com>
Cc: lee@...nel.org, herbert@...dor.apana.org.au, jarkko@...nel.org,
 linux-kernel@...r.kernel.org, loongarch@...ts.linux.dev,
 davem@...emloft.net, linux-crypto@...r.kernel.org, peterhuewe@....de,
 jgg@...pe.ca, linux-integrity@...r.kernel.org,
 Yinggang Gu <guyinggang@...ngson.cn>, Huacai Chen <chenhuacai@...ngson.cn>
Subject: Re: [PATCH v10 4/5] tpm: Add a driver for Loongson TPM device


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 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.

Thanks,

Qunqin.

>
> BTW, I think I should touch also this driver in the next version of my 
> series that I'll send after the merge window:
> https://lore.kernel.org/linux-integrity/20250514134630.137621-1-sgarzare@redhat.com/ 
>
>
> The rest LGTM!
>
> Thanks,
> Stefano