#include <crypto/internal/rng.h>
#include <linux/acpi.h>
#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/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/random.h>
#define HISI_TRNG_REG 0x00F0
#define HISI_TRNG_BYTES 4
#define HISI_TRNG_QUALITY 512
#define HISI_TRNG_VERSION 0x01B8
#define HISI_TRNG_VER_V1 GENMASK(31, 0)
#define SLEEP_US 10
#define TIMEOUT_US 10000
#define SW_DRBG_NUM_SHIFT 2
#define SW_DRBG_KEY_BASE 0x082C
#define SW_DRBG_SEED(n) (SW_DRBG_KEY_BASE - ((n) << SW_DRBG_NUM_SHIFT))
#define SW_DRBG_SEED_REGS_NUM 12
#define SW_DRBG_SEED_SIZE 48
#define SW_DRBG_BLOCKS 0x0830
#define SW_DRBG_INIT 0x0834
#define SW_DRBG_GEN 0x083c
#define SW_DRBG_STATUS 0x0840
#define SW_DRBG_BLOCKS_NUM 4095
#define SW_DRBG_DATA_BASE 0x0850
#define SW_DRBG_DATA_NUM 4
#define SW_DRBG_DATA(n) (SW_DRBG_DATA_BASE - ((n) << SW_DRBG_NUM_SHIFT))
#define SW_DRBG_BYTES 16
#define SW_DRBG_ENABLE_SHIFT 12
#define SEED_SHIFT_24 24
#define SEED_SHIFT_16 16
#define SEED_SHIFT_8 8
#define SW_MAX_RANDOM_BYTES 65520
struct hisi_trng_list {
struct mutex lock;
struct list_head list;
bool is_init;
};
struct hisi_trng {
void __iomem *base;
struct hisi_trng_list *trng_list;
struct list_head list;
struct hwrng rng;
u32 ver;
u32 ctx_num;
u32 random_bytes;
struct mutex lock;
};
struct hisi_trng_ctx {
struct hisi_trng *trng;
};
static atomic_t trng_active_devs;
static struct hisi_trng_list trng_devices;
static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait);
static int hisi_trng_set_seed(struct hisi_trng *trng, const u8 *seed)
{
u32 val, seed_reg, i;
int ret;
writel(0x0, trng->base + SW_DRBG_BLOCKS);
for (i = 0; i < SW_DRBG_SEED_SIZE;
i += SW_DRBG_SEED_SIZE / SW_DRBG_SEED_REGS_NUM) {
val = seed[i] << SEED_SHIFT_24;
val |= seed[i + 1UL] << SEED_SHIFT_16;
val |= seed[i + 2UL] << SEED_SHIFT_8;
val |= seed[i + 3UL];
seed_reg = (i >> SW_DRBG_NUM_SHIFT) % SW_DRBG_SEED_REGS_NUM;
writel(val, trng->base + SW_DRBG_SEED(seed_reg));
}
writel(SW_DRBG_BLOCKS_NUM | (0x1 << SW_DRBG_ENABLE_SHIFT),
trng->base + SW_DRBG_BLOCKS);
writel(0x1, trng->base + SW_DRBG_INIT);
ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
val, val & BIT(0), SLEEP_US, TIMEOUT_US);
if (ret) {
pr_err("failed to init trng(%d)\n", ret);
return -EIO;
}
trng->random_bytes = 0;
return 0;
}
static int hisi_trng_seed(struct crypto_rng *tfm, const u8 *seed,
unsigned int slen)
{
struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
struct hisi_trng *trng = ctx->trng;
int ret;
if (slen < SW_DRBG_SEED_SIZE) {
pr_err("slen(%u) is not matched with trng(%d)\n", slen,
SW_DRBG_SEED_SIZE);
return -EINVAL;
}
mutex_lock(&trng->lock);
ret = hisi_trng_set_seed(trng, seed);
mutex_unlock(&trng->lock);
return ret;
}
static int hisi_trng_reseed(struct hisi_trng *trng)
{
u8 seed[SW_DRBG_SEED_SIZE];
int size;
if (!trng->random_bytes)
return 0;
size = hisi_trng_read(&trng->rng, seed, SW_DRBG_SEED_SIZE, false);
if (size != SW_DRBG_SEED_SIZE)
return -EIO;
return hisi_trng_set_seed(trng, seed);
}
static int hisi_trng_get_bytes(struct hisi_trng *trng, u8 *dstn, unsigned int dlen)
{
u32 data[SW_DRBG_DATA_NUM];
u32 currsize = 0;
u32 val = 0;
int ret;
u32 i;
ret = hisi_trng_reseed(trng);
if (ret)
return ret;
do {
ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
val, val & BIT(1), SLEEP_US, TIMEOUT_US);
if (ret) {
pr_err("failed to generate random number(%d)!\n", ret);
break;
}
for (i = 0; i < SW_DRBG_DATA_NUM; i++)
data[i] = readl(trng->base + SW_DRBG_DATA(i));
if (dlen - currsize >= SW_DRBG_BYTES) {
memcpy(dstn + currsize, data, SW_DRBG_BYTES);
currsize += SW_DRBG_BYTES;
} else {
memcpy(dstn + currsize, data, dlen - currsize);
currsize = dlen;
}
trng->random_bytes += SW_DRBG_BYTES;
writel(0x1, trng->base + SW_DRBG_GEN);
} while (currsize < dlen);
return ret;
}
static int hisi_trng_generate(struct crypto_rng *tfm, const u8 *src,
unsigned int slen, u8 *dstn, unsigned int dlen)
{
struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
struct hisi_trng *trng = ctx->trng;
unsigned int currsize = 0;
unsigned int block_size;
int ret;
if (!dstn || !dlen) {
pr_err("output is error, dlen %u!\n", dlen);
return -EINVAL;
}
do {
block_size = min_t(unsigned int, dlen - currsize, SW_MAX_RANDOM_BYTES);
mutex_lock(&trng->lock);
ret = hisi_trng_get_bytes(trng, dstn + currsize, block_size);
mutex_unlock(&trng->lock);
if (ret)
return ret;
currsize += block_size;
} while (currsize < dlen);
return 0;
}
static int hisi_trng_init(struct crypto_tfm *tfm)
{
struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
struct hisi_trng *trng;
u32 ctx_num = ~0;
mutex_lock(&trng_devices.lock);
list_for_each_entry(trng, &trng_devices.list, list) {
if (trng->ctx_num < ctx_num) {
ctx_num = trng->ctx_num;
ctx->trng = trng;
}
}
ctx->trng->ctx_num++;
mutex_unlock(&trng_devices.lock);
return 0;
}
static void hisi_trng_exit(struct crypto_tfm *tfm)
{
struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
mutex_lock(&trng_devices.lock);
ctx->trng->ctx_num--;
mutex_unlock(&trng_devices.lock);
}
static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
struct hisi_trng *trng;
int currsize = 0;
u32 val = 0;
int ret;
trng = container_of(rng, struct hisi_trng, rng);
do {
ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
val, SLEEP_US, TIMEOUT_US);
if (ret)
return currsize;
if (max - currsize >= HISI_TRNG_BYTES) {
memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
currsize += HISI_TRNG_BYTES;
if (currsize == max)
return currsize;
continue;
}
memcpy(buf + currsize, &val, max - currsize);
currsize = max;
} while (currsize < max);
return currsize;
}
static struct rng_alg hisi_trng_alg = {
.generate = hisi_trng_generate,
.seed = hisi_trng_seed,
.seedsize = SW_DRBG_SEED_SIZE,
.base = {
.cra_name = "stdrng",
.cra_driver_name = "hisi_stdrng",
.cra_priority = 300,
.cra_ctxsize = sizeof(struct hisi_trng_ctx),
.cra_module = THIS_MODULE,
.cra_init = hisi_trng_init,
.cra_exit = hisi_trng_exit,
},
};
static void hisi_trng_add_to_list(struct hisi_trng *trng)
{
mutex_lock(&trng_devices.lock);
list_add_tail(&trng->list, &trng_devices.list);
mutex_unlock(&trng_devices.lock);
}
static int hisi_trng_del_from_list(struct hisi_trng *trng)
{
int ret = -EBUSY;
mutex_lock(&trng_devices.lock);
if (!trng->ctx_num) {
list_del(&trng->list);
ret = 0;
}
mutex_unlock(&trng_devices.lock);
return ret;
}
static int hisi_trng_probe(struct platform_device *pdev)
{
struct hisi_trng *trng;
int ret;
trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
if (!trng)
return -ENOMEM;
platform_set_drvdata(pdev, trng);
trng->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(trng->base))
return PTR_ERR(trng->base);
trng->ctx_num = 0;
trng->random_bytes = SW_MAX_RANDOM_BYTES;
mutex_init(&trng->lock);
trng->ver = readl(trng->base + HISI_TRNG_VERSION);
if (!trng_devices.is_init) {
INIT_LIST_HEAD(&trng_devices.list);
mutex_init(&trng_devices.lock);
trng_devices.is_init = true;
}
hisi_trng_add_to_list(trng);
if (trng->ver != HISI_TRNG_VER_V1 &&
atomic_inc_return(&trng_active_devs) == 1) {
ret = crypto_register_rng(&hisi_trng_alg);
if (ret) {
dev_err(&pdev->dev,
"failed to register crypto(%d)\n", ret);
atomic_dec_return(&trng_active_devs);
goto err_remove_from_list;
}
}
trng->rng.name = pdev->name;
trng->rng.read = hisi_trng_read;
trng->rng.quality = HISI_TRNG_QUALITY;
ret = devm_hwrng_register(&pdev->dev, &trng->rng);
if (ret) {
dev_err(&pdev->dev, "failed to register hwrng: %d!\n", ret);
goto err_crypto_unregister;
}
return ret;
err_crypto_unregister:
if (trng->ver != HISI_TRNG_VER_V1 &&
atomic_dec_return(&trng_active_devs) == 0)
crypto_unregister_rng(&hisi_trng_alg);
err_remove_from_list:
hisi_trng_del_from_list(trng);
return ret;
}
static void hisi_trng_remove(struct platform_device *pdev)
{
struct hisi_trng *trng = platform_get_drvdata(pdev);
while (hisi_trng_del_from_list(trng))
;
if (trng->ver != HISI_TRNG_VER_V1 &&
atomic_dec_return(&trng_active_devs) == 0)
crypto_unregister_rng(&hisi_trng_alg);
}
static const struct acpi_device_id hisi_trng_acpi_match[] = {
{ "HISI02B3", 0 },
{ }
};
MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);
static struct platform_driver hisi_trng_driver = {
.probe = hisi_trng_probe,
.remove = hisi_trng_remove,
.driver = {
.name = "hisi-trng-v2",
.acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
},
};
module_platform_driver(hisi_trng_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");
