diff options
Diffstat (limited to 'drivers/crypto/ccp/ccp-dev.c')
| -rw-r--r-- | drivers/crypto/ccp/ccp-dev.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/crypto/ccp/ccp-dev.c b/drivers/crypto/ccp/ccp-dev.c index 9c8cfbb6841f..6b44730ef9d6 100644 --- a/drivers/crypto/ccp/ccp-dev.c +++ b/drivers/crypto/ccp/ccp-dev.c @@ -409,6 +409,34 @@ struct ccp_device *ccp_alloc_struct(struct device *dev) return ccp; } +int ccp_trng_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng); + u32 trng_value; + int len = min_t(int, sizeof(trng_value), max); + + /* Locking is provided by the caller so we can update device + * hwrng-related fields safely + */ + trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG); + if (!trng_value) { + /* Zero is returned if not data is available or if a + * bad-entropy error is present. Assume an error if + * we exceed TRNG_RETRIES reads of zero. + */ + if (ccp->hwrng_retries++ > TRNG_RETRIES) + return -EIO; + + return 0; + } + + /* Reset the counter and save the rng value */ + ccp->hwrng_retries = 0; + memcpy(data, &trng_value, len); + + return len; +} + #ifdef CONFIG_PM bool ccp_queues_suspended(struct ccp_device *ccp) { |