crypto: caam - add a test for the RNG

CAAM includes a Random Number Generator.  This change adds
a kernel configuration option to test the RNG's capabilities via the
hw_random framework.

Signed-off-by: Victoria Milhoan <vicki.milhoan@freescale.com>
Signed-off-by: Dan Douglass <dan.douglass@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Reviewed-by: Gaurav Jain <gaurav.jain@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig
index ec6a9e6..c631f99 100644 (file)
--- a/drivers/crypto/caam/Kconfig
+++ b/drivers/crypto/caam/Kconfig
@@ -162,6 +162,15 @@ config CRYPTO_DEV_FSL_CAAM_PRNG_API
 config CRYPTO_DEV_FSL_CAAM_BLOB_GEN
        bool
 
+config CRYPTO_DEV_FSL_CAAM_RNG_TEST
+       bool "Test caam rng"
+       select CRYPTO_DEV_FSL_CAAM_RNG_API
+       help
+         Selecting this will enable a self-test to run for the
+         caam RNG.
+         This test is several minutes long and executes
+         just before the RNG is registered with the hw_random API.
+
 endif # CRYPTO_DEV_FSL_CAAM_JR
 
 endif # CRYPTO_DEV_FSL_CAAM

diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c
index 50eb55d..b3d14a7 100644 (file)
--- a/drivers/crypto/caam/caamrng.c
+++ b/drivers/crypto/caam/caamrng.c
@@ -172,6 +172,50 @@ static void caam_cleanup(struct hwrng *rng)
        kfifo_free(&ctx->fifo);
 }
 
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST
+static inline void test_len(struct hwrng *rng, size_t len, bool wait)
+{
+       u8 *buf;
+       int read_len;
+       struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
+       struct device *dev = ctx->ctrldev;
+
+       buf = kcalloc(CAAM_RNG_MAX_FIFO_STORE_SIZE, sizeof(u8), GFP_KERNEL);
+
+       while (len > 0) {
+               read_len = rng->read(rng, buf, len, wait);
+
+               if (read_len < 0 || (read_len == 0 && wait)) {
+                       dev_err(dev, "RNG Read FAILED received %d bytes\n",
+                               read_len);
+                       kfree(buf);
+                       return;
+               }
+
+               print_hex_dump_debug("random bytes@: ",
+                       DUMP_PREFIX_ADDRESS, 16, 4,
+                       buf, read_len, 1);
+
+               len = len - read_len;
+       }
+
+       kfree(buf);
+}
+
+static inline void test_mode_once(struct hwrng *rng, bool wait)
+{
+       test_len(rng, 32, wait);
+       test_len(rng, 64, wait);
+       test_len(rng, 128, wait);
+}
+
+static void self_test(struct hwrng *rng)
+{
+       pr_info("Executing RNG SELF-TEST with wait\n");
+       test_mode_once(rng, true);
+}
+#endif
+
 static int caam_init(struct hwrng *rng)
 {
        struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
@@ -258,6 +302,10 @@ int caam_rng_init(struct device *ctrldev)
                return ret;
        }
 
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST
+       self_test(&ctx->rng);
+#endif
+
        devres_close_group(ctrldev, caam_rng_init);
        return 0;
 }