static int exynos_read(struct hwrng *rng, void *buf,
size_t max, bool wait)
{
struct exynos_rng *exynos_rng = container_of(rng,
struct exynos_rng, rng);
u32 *data = buf;
int retry = 100;
int ret = 4;
pm_runtime_get_sync(exynos_rng->dev);
exynos_rng_writel(exynos_rng, PRNG_START, 0);
while (!(exynos_rng_readl(exynos_rng,
EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE) && --retry)
cpu_relax();
if (!retry) {
ret = -ETIMEDOUT;
goto out;
}
exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
out:
pm_runtime_mark_last_busy(exynos_rng->dev);
pm_runtime_put_sync_autosuspend(exynos_rng->dev);
return ret;
}
static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
const u8 *seed, unsigned int slen)
{
u32 val;
int i;
/* Round seed length because loop iterates over full register size */
slen = ALIGN_DOWN(slen, 4);
if (slen < EXYNOS_RNG_SEED_SIZE)
return -EINVAL;
for (i = 0; i < slen ; i += 4) {
unsigned int seed_reg = (i / 4) % EXYNOS_RNG_SEED_REGS;
val = seed[i] << 24;
val |= seed[i + 1] << 16;
val |= seed[i + 2] << 8;
val |= seed[i + 3] << 0;
exynos_rng_writel(rng, val, EXYNOS_RNG_SEED(seed_reg));
}
val = exynos_rng_readl(rng, EXYNOS_RNG_STATUS);
if (!(val & EXYNOS_RNG_STATUS_SEED_SETTING_DONE)) {
dev_warn(rng->dev, "Seed setting not finished\n");
return -EIO;
}
rng->last_seeding = jiffies;
rng->bytes_seeding = 0;
return 0;
}
/*
* Start the engine and poll for finish. Then read from output registers
* filling the 'dst' buffer up to 'dlen' bytes or up to size of generated
* random data (EXYNOS_RNG_SEED_SIZE).
*
* On success: return 0 and store number of read bytes under 'read' address.
* On error: return -ERRNO.
*/
static int exynos_rng_get_random(struct exynos_rng_dev *rng,
u8 *dst, unsigned int dlen,
unsigned int *read)
{
int retry = EXYNOS_RNG_WAIT_RETRIES;
if (rng->type == EXYNOS_PRNG_EXYNOS4) {
exynos_rng_writel(rng, EXYNOS_RNG_CONTROL_START,
EXYNOS_RNG_CONTROL);
} else if (rng->type == EXYNOS_PRNG_EXYNOS5) {
exynos_rng_writel(rng, EXYNOS_RNG_GEN_PRNG,
EXYNOS_RNG_SEED_CONF);
}
while (!(exynos_rng_readl(rng,
EXYNOS_RNG_STATUS) & EXYNOS_RNG_STATUS_RNG_DONE) && --retry)
cpu_relax();
if (!retry)
return -ETIMEDOUT;
/* Clear status bit */
exynos_rng_writel(rng, EXYNOS_RNG_STATUS_RNG_DONE,
EXYNOS_RNG_STATUS);
*read = min_t(size_t, dlen, EXYNOS_RNG_SEED_SIZE);
memcpy_fromio(dst, rng->mem + EXYNOS_RNG_OUT_BASE, *read);
rng->bytes_seeding += *read;
return 0;
}
static int exynos_rng_configure(struct exynos_rng *exynos_rng)
{
int i;
int ret = 0;
for (i = 0 ; i < 5 ; i++)
exynos_rng_writel(exynos_rng, jiffies,
EXYNOS_PRNG_SEED_OFFSET + 4*i);
if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
& SEED_SETTING_DONE))
ret = -EIO;
return ret;
}
