diff options
| -rw-r--r-- | drivers/char/hw_random/xilinx-trng.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/char/hw_random/xilinx-trng.c b/drivers/char/hw_random/xilinx-trng.c index f615d5adddde..4a1a168bb46a 100644 --- a/drivers/char/hw_random/xilinx-trng.c +++ b/drivers/char/hw_random/xilinx-trng.c @@ -87,8 +87,8 @@ static void xtrng_softreset(struct xilinx_rng *rng) xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSRST_MASK, 0); } -/* Return no. of bytes read */ -static size_t xtrng_readblock32(void __iomem *rng_base, __be32 *buf, int blocks32, bool wait) +/* Return no. of bytes read or a negative error before any data is read. */ +static int xtrng_readblock32(void __iomem *rng_base, __be32 *buf, int blocks32, bool wait) { int read = 0, ret; int timeout = 1; @@ -103,8 +103,11 @@ static size_t xtrng_readblock32(void __iomem *rng_base, __be32 *buf, int blocks3 ret = readl_poll_timeout(rng_base + TRNG_STATUS_OFFSET, val, (val & TRNG_STATUS_QCNT_MASK) == TRNG_STATUS_QCNT_16_BYTES, !!wait, timeout); - if (ret) + if (ret) { + if (!read) + return ret; break; + } for (idx = 0; idx < TRNG_READ_4_WORD; idx++) { *(buf + read) = cpu_to_be32(ioread32(rng_base + TRNG_CORE_OUTPUT_OFFSET)); @@ -119,27 +122,40 @@ static int xtrng_collect_random_data(struct xilinx_rng *rng, u8 *rand_gen_buf, { u8 randbuf[TRNG_SEC_STRENGTH_BYTES]; int byteleft, blocks, count = 0; + int full_blocks_bytes; int ret; byteleft = no_of_random_bytes & (TRNG_SEC_STRENGTH_BYTES - 1); blocks = no_of_random_bytes >> TRNG_SEC_STRENGTH_SHIFT; + full_blocks_bytes = blocks * TRNG_SEC_STRENGTH_BYTES; xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSTART_MASK, TRNG_CTRL_PRNGSTART_MASK); if (blocks) { ret = xtrng_readblock32(rng->rng_base, (__be32 *)rand_gen_buf, blocks, wait); - if (!ret) - return 0; + if (ret <= 0) { + count = ret; + goto out_stop; + } count += ret; + if (ret < full_blocks_bytes) + goto out_stop; } if (byteleft) { ret = xtrng_readblock32(rng->rng_base, (__be32 *)randbuf, 1, wait); + if (ret < 0) { + if (!count) + count = ret; + goto out_stop; + } if (!ret) - return count; - memcpy(rand_gen_buf + (blocks * TRNG_SEC_STRENGTH_BYTES), randbuf, byteleft); - count += byteleft; + goto out_stop; + ret = min(ret, no_of_random_bytes - count); + memcpy(rand_gen_buf + count, randbuf, ret); + count += ret; } +out_stop: xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGMODE_MASK | TRNG_CTRL_PRNGSTART_MASK, 0U); |