Re: [PATCH v6 5/6] tpm: Add a driver for Loongson TPM device

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Mar 27, 2025 at 10:19:39AM +0800, Qunqin Zhao wrote:
> Loongson security engine supports random number generation, hash,
> symmetric encryption and asymmetric encryption. Based on these
> encryption functions, TPM2 have been implemented in the Loongson
> security engine firmware. This driver is responsible for copying data
> into the memory visible to the firmware and receiving data from the
> firmware.
> 
> Co-developed-by: Yinggang Gu <guyinggang@loongson.cn>
> Signed-off-by: Yinggang Gu <guyinggang@loongson.cn>
> Signed-off-by: Qunqin Zhao <zhaoqunqin@loongson.cn>
> ---
> v6: Replace all "ls6000se" with "loongson"
>     Prefix all with tpm_loongson instead of tpm_lsse.
>     Removed Jarkko's tag cause there are some changes in v6 
> 
> v5: None
> v4: Prefix all with tpm_lsse instead of tpm.
>     Removed MODULE_AUTHOR fields.
> 
> v3: Added reminder about Loongson security engine to git log.
> 
>  drivers/char/tpm/Kconfig        |   9 +++
>  drivers/char/tpm/Makefile       |   1 +
>  drivers/char/tpm/tpm_loongson.c | 103 ++++++++++++++++++++++++++++++++
>  3 files changed, 113 insertions(+)
>  create mode 100644 drivers/char/tpm/tpm_loongson.c
> 
> diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> index 0fc9a510e..5d0e7a1f8 100644
> --- a/drivers/char/tpm/Kconfig
> +++ b/drivers/char/tpm/Kconfig
> @@ -225,5 +225,14 @@ config TCG_FTPM_TEE
>  	help
>  	  This driver proxies for firmware TPM running in TEE.
>  
> +config TCG_LOONGSON
> +	tristate "Loongson TPM Interface"
> +	depends on MFD_LOONGSON_SE
> +	help
> +	  If you want to make Loongson TPM support available, say Yes and
> +	  it will be accessible from within Linux. To compile this
> +	  driver as a module, choose M here; the module will be called
> +	  tpm_loongson.
> +
>  source "drivers/char/tpm/st33zp24/Kconfig"
>  endif # TCG_TPM
> diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
> index 9bb142c75..e84a2f7a9 100644
> --- a/drivers/char/tpm/Makefile
> +++ b/drivers/char/tpm/Makefile
> @@ -44,3 +44,4 @@ obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
>  obj-$(CONFIG_TCG_CRB) += tpm_crb.o
>  obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
>  obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
> +obj-$(CONFIG_TCG_LOONGSON) += tpm_loongson.o
> diff --git a/drivers/char/tpm/tpm_loongson.c b/drivers/char/tpm/tpm_loongson.c
> new file mode 100644
> index 000000000..91e0390c8
> --- /dev/null
> +++ b/drivers/char/tpm/tpm_loongson.c
> @@ -0,0 +1,103 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2025 Loongson Technology Corporation Limited. */
> +
> +#include <linux/device.h>
> +#include <linux/mfd/loongson-se.h>
> +#include <linux/platform_device.h>
> +#include <linux/wait.h>
> +
> +#include "tpm.h"
> +
> +struct tpm_loongson_msg {
> +	u32 cmd;
> +	u32 data_off;
> +	u32 data_len;
> +	u32 info[5];
> +};
> +
> +struct tpm_loongson_dev {
> +	struct lsse_ch *se_ch;
> +	struct completion tpm_loongson_completion;
> +};
> +
> +static void tpm_loongson_complete(struct lsse_ch *ch)
> +{
> +	struct tpm_loongson_dev *td = ch->priv;
> +
> +	complete(&td->tpm_loongson_completion);
> +}
> +
> +static int tpm_loongson_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> +{
> +	struct tpm_loongson_dev *td = dev_get_drvdata(&chip->dev);
> +	struct tpm_loongson_msg *rmsg;
> +	int sig;
> +
> +	sig = wait_for_completion_interruptible(&td->tpm_loongson_completion);
> +	if (sig)
> +		return sig;
> +
> +	rmsg = td->se_ch->rmsg;
> +	memcpy(buf, td->se_ch->data_buffer, rmsg->data_len);
> +
> +	return rmsg->data_len;
> +}
> +
> +static int tpm_loongson_send(struct tpm_chip *chip, u8 *buf, size_t count)
> +{
> +	struct tpm_loongson_dev *td = dev_get_drvdata(&chip->dev);
> +	struct tpm_loongson_msg *smsg = td->se_ch->smsg;
> +
> +	memcpy(td->se_ch->data_buffer, buf, count);
> +	smsg->data_len = count;
> +
> +	return se_send_ch_requeset(td->se_ch);
> +}
> +
> +static const struct tpm_class_ops tpm_loongson_ops = {
> +	.flags = TPM_OPS_AUTO_STARTUP,
> +	.recv = tpm_loongson_recv,
> +	.send = tpm_loongson_send,
> +};
> +
> +static int tpm_loongson_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct tpm_loongson_msg *smsg;
> +	struct tpm_loongson_dev *td;
> +	struct tpm_chip *chip;
> +
> +	td = devm_kzalloc(dev, sizeof(struct tpm_loongson_dev), GFP_KERNEL);
> +	if (!td)
> +		return -ENOMEM;
> +
> +	init_completion(&td->tpm_loongson_completion);
> +	td->se_ch = se_init_ch(dev->parent, SE_CH_TPM, PAGE_SIZE,
> +			       2 * sizeof(struct tpm_loongson_msg), td,
> +			       tpm_loongson_complete);
> +	if (!td->se_ch)
> +		return -ENODEV;
> +	smsg = td->se_ch->smsg;
> +	smsg->cmd = SE_CMD_TPM;
> +	smsg->data_off = td->se_ch->off;
> +
> +	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;
> +	dev_set_drvdata(&chip->dev, td);
> +
> +	return tpm_chip_register(chip);
> +}
> +
> +static struct platform_driver tpm_loongson_driver = {
> +	.probe   = tpm_loongson_probe,
> +	.driver  = {
> +		.name  = "loongson-tpm",
> +	},
> +};
> +module_platform_driver(tpm_loongson_driver);
> +
> +MODULE_ALIAS("platform:loongson-tpm");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Loongson TPM driver");
> -- 
> 2.45.2
> 

Looks good to me.

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko