Re: [PATCH v6 3/6] crypto: loongson - add Loongson RNG driver support

[Huacai Chen]

Hi, Qunqin,

On Thu, Mar 27, 2025 at 10:17 AM Qunqin Zhao <zhaoqunqin@xxxxxxxxxxx> wrote:
>
> Loongson's Random Number Generator is found inside Loongson security
> engine.
>
> Co-developed-by: Yinggang Gu <guyinggang@xxxxxxxxxxx>
> Signed-off-by: Yinggang Gu <guyinggang@xxxxxxxxxxx>
> Signed-off-by: Qunqin Zhao <zhaoqunqin@xxxxxxxxxxx>
> ---
> v6: Replace all "ls6000se" with "loongson"
> v2-v5: None
>
>  drivers/crypto/Kconfig                 |   1 +
>  drivers/crypto/Makefile                |   1 +
>  drivers/crypto/loongson/Kconfig        |   6 +
>  drivers/crypto/loongson/Makefile       |   2 +
>  drivers/crypto/loongson/loongson-rng.c | 190 +++++++++++++++++++++++++
>  5 files changed, 200 insertions(+)
>  create mode 100644 drivers/crypto/loongson/Kconfig
>  create mode 100644 drivers/crypto/loongson/Makefile
>  create mode 100644 drivers/crypto/loongson/loongson-rng.c
>
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index 19ab145f9..567ed81b0 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -855,5 +855,6 @@ config CRYPTO_DEV_SA2UL
>
>  source "drivers/crypto/aspeed/Kconfig"
>  source "drivers/crypto/starfive/Kconfig"
> +source "drivers/crypto/loongson/Kconfig"
>
>  endif # CRYPTO_HW
> diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
> index fef18ffdb..643c3710b 100644
> --- a/drivers/crypto/Makefile
> +++ b/drivers/crypto/Makefile
> @@ -50,3 +50,4 @@ obj-y += hisilicon/
>  obj-$(CONFIG_CRYPTO_DEV_AMLOGIC_GXL) += amlogic/
>  obj-y += intel/
>  obj-y += starfive/
> +obj-y += loongson/
> diff --git a/drivers/crypto/loongson/Kconfig b/drivers/crypto/loongson/Kconfig
> new file mode 100644
> index 000000000..4368701ad
> --- /dev/null
> +++ b/drivers/crypto/loongson/Kconfig
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config CRYPTO_DEV_LOONGSON_RNG
> +        tristate "Support for Loongson RNG Driver"
> +        depends on MFD_LOONGSON_SE
> +        help
> +          Support for Loongson RNG Driver.
> diff --git a/drivers/crypto/loongson/Makefile b/drivers/crypto/loongson/Makefile
> new file mode 100644
> index 000000000..b8b013c86
> --- /dev/null
> +++ b/drivers/crypto/loongson/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_CRYPTO_DEV_LOONGSON_RNG)  += loongson-rng.o
> diff --git a/drivers/crypto/loongson/loongson-rng.c b/drivers/crypto/loongson/loongson-rng.c
> new file mode 100644
> index 000000000..c80346cf7
> --- /dev/null
> +++ b/drivers/crypto/loongson/loongson-rng.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2019 HiSilicon Limited. */
> +/* Copyright (c) 2025 Loongson Technology Corporation Limited. */
> +
> +#include <linux/crypto.h>
> +#include <linux/err.h>
> +#include <linux/hw_random.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/mfd/loongson-se.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/random.h>
> +#include <crypto/internal/rng.h>
> +
> +struct lsrng_list {
> +       struct mutex lock;
> +       struct list_head list;
> +       int is_init;
> +};
For all data struct and function name, it is better to change the
lsrng_ prefix to loongson_rng_ which matches the file name.


Huacai

> +
> +struct lsrng {
> +       bool is_used;
> +       struct lsse_ch *se_ch;
> +       struct list_head list;
> +       struct completion rng_completion;
> +};
> +
> +struct lsrng_ctx {
> +       struct lsrng *rng;
> +};
> +
> +struct rng_msg {
> +       u32 cmd;
> +       union {
> +               u32 len;
> +               u32 ret;
> +       } u;
> +       u32 resved;
> +       u32 out_off;
> +       u32 pad[4];
> +};
> +
> +static atomic_t rng_active_devs;
> +static struct lsrng_list rng_devices;
> +
> +static void lsrng_complete(struct lsse_ch *ch)
> +{
> +       struct lsrng *rng = (struct lsrng *)ch->priv;
> +
> +       complete(&rng->rng_completion);
> +}
> +
> +static int lsrng_generate(struct crypto_rng *tfm, const u8 *src,
> +                         unsigned int slen, u8 *dstn, unsigned int dlen)
> +{
> +       struct lsrng_ctx *ctx = crypto_rng_ctx(tfm);
> +       struct lsrng *rng = ctx->rng;
> +       struct rng_msg *msg;
> +       int err, len;
> +
> +       do {
> +               len = min(dlen, PAGE_SIZE);
> +               msg = rng->se_ch->smsg;
> +               msg->u.len = len;
> +               err = se_send_ch_requeset(rng->se_ch);
> +               if (err)
> +                       return err;
> +
> +               wait_for_completion_interruptible(&rng->rng_completion);
> +
> +               msg = rng->se_ch->rmsg;
> +               if (msg->u.ret)
> +                       return -EFAULT;
> +
> +               memcpy(dstn, rng->se_ch->data_buffer, len);
> +               dlen -= len;
> +               dstn += len;
> +       } while (dlen > 0);
> +
> +       return 0;
> +}
> +
> +static int lsrng_init(struct crypto_tfm *tfm)
> +{
> +       struct lsrng_ctx *ctx = crypto_tfm_ctx(tfm);
> +       struct lsrng *rng;
> +       int ret = -EBUSY;
> +
> +       mutex_lock(&rng_devices.lock);
> +       list_for_each_entry(rng, &rng_devices.list, list) {
> +               if (!rng->is_used) {
> +                       rng->is_used = true;
> +                       ctx->rng = rng;
> +                       ret = 0;
> +                       break;
> +               }
> +       }
> +       mutex_unlock(&rng_devices.lock);
> +
> +       return ret;
> +}
> +
> +static void lsrng_exit(struct crypto_tfm *tfm)
> +{
> +       struct lsrng_ctx *ctx = crypto_tfm_ctx(tfm);
> +
> +       mutex_lock(&rng_devices.lock);
> +       ctx->rng->is_used = false;
> +       mutex_unlock(&rng_devices.lock);
> +}
> +
> +static int no_seed(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
> +{
> +       return 0;
> +}
> +
> +static struct rng_alg lsrng_alg = {
> +       .generate = lsrng_generate,
> +       .seed = no_seed,
> +       .base = {
> +               .cra_name = "stdrng",
> +               .cra_driver_name = "loongson_stdrng",
> +               .cra_priority = 300,
> +               .cra_ctxsize = sizeof(struct lsrng_ctx),
> +               .cra_module = THIS_MODULE,
> +               .cra_init = lsrng_init,
> +               .cra_exit = lsrng_exit,
> +       },
> +};
> +
> +static void lsrng_add_to_list(struct lsrng *rng)
> +{
> +       mutex_lock(&rng_devices.lock);
> +       list_add_tail(&rng->list, &rng_devices.list);
> +       mutex_unlock(&rng_devices.lock);
> +}
> +
> +static int lsrng_probe(struct platform_device *pdev)
> +{
> +       struct rng_msg *msg;
> +       struct lsrng *rng;
> +       int ret;
> +
> +       rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
> +       if (!rng)
> +               return -ENOMEM;
> +
> +       init_completion(&rng->rng_completion);
> +       rng->se_ch = se_init_ch(pdev->dev.parent, SE_CH_RNG, PAGE_SIZE,
> +                               sizeof(struct rng_msg) * 2, rng, lsrng_complete);
> +       if (!rng->se_ch)
> +               return -ENODEV;
> +       msg = rng->se_ch->smsg;
> +       msg->cmd = SE_CMD_RNG;
> +       msg->out_off = rng->se_ch->off;
> +
> +       if (!rng_devices.is_init) {
> +               ret = crypto_register_rng(&lsrng_alg);
> +               if (ret) {
> +                       dev_err(&pdev->dev, "failed to register crypto(%d)\n", ret);
> +                       return ret;
> +               }
> +               INIT_LIST_HEAD(&rng_devices.list);
> +               mutex_init(&rng_devices.lock);
> +               rng_devices.is_init = true;
> +       }
> +
> +       lsrng_add_to_list(rng);
> +       atomic_inc(&rng_active_devs);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver lsrng_driver = {
> +       .probe          = lsrng_probe,
> +       .driver         = {
> +               .name   = "loongson-rng",
> +       },
> +};
> +module_platform_driver(lsrng_driver);
> +
> +MODULE_ALIAS("platform:loongson-rng");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Yinggang Gu <guyinggang@xxxxxxxxxxx>");
> +MODULE_AUTHOR("Qunqin Zhao <zhaoqunqin@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Loongson random number generator driver");
> --
> 2.45.2
>
>