MLK-9769-8 Add a test for the Freescale CAAM Random Number Generator

Freescale's 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@freescale.com>

diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig
index 64bf302..83c1bb8 100644 (file)
--- a/drivers/crypto/caam/Kconfig
+++ b/drivers/crypto/caam/Kconfig
@@ -128,6 +128,16 @@ config CRYPTO_DEV_FSL_CAAM_IMX
        def_bool SOC_IMX6 || SOC_IMX7D
        depends on CRYPTO_DEV_FSL_CAAM
 
+
+config CRYPTO_DEV_FSL_CAAM_RNG_TEST
+       boolean "Test caam rng"
+       depends on CRYPTO_DEV_FSL_CAAM_RNG_API
+       default n
+       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.
+
 config CRYPTO_DEV_FSL_CAAM_DEBUG
        bool "Enable debug output in CAAM driver"
        depends on CRYPTO_DEV_FSL_CAAM

diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c
index 9b92af2..601381c 100644 (file)
--- a/drivers/crypto/caam/caamrng.c
+++ b/drivers/crypto/caam/caamrng.c
@@ -256,6 +256,49 @@ static void caam_cleanup(struct hwrng *rng)
        rng_unmap_ctx(rng_ctx);
 }
 
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST
+static inline void test_len(struct hwrng *rng, size_t len, bool wait)
+{
+       u8 *buf;
+       int real_len;
+
+       buf = kzalloc(sizeof(u8) * len, GFP_KERNEL);
+       real_len = rng->read(rng, buf, len, wait);
+       if (real_len == 0 && wait)
+               pr_err("WAITING FAILED\n");
+       pr_info("wanted %d bytes, got %d\n", len, real_len);
+       print_hex_dump(KERN_INFO, "random bytes@: ", DUMP_PREFIX_ADDRESS,
+                      16, 4, buf, real_len, 1);
+       kfree(buf);
+}
+
+static inline void test_mode_once(struct hwrng *rng, bool wait)
+{
+#define TEST_CHUNK (RN_BUF_SIZE / 4)
+
+       test_len(rng, TEST_CHUNK, wait);
+       test_len(rng, RN_BUF_SIZE * 2, wait);
+       test_len(rng, RN_BUF_SIZE * 2 - TEST_CHUNK, wait);
+}
+
+static inline void test_mode(struct hwrng *rng, bool wait)
+{
+#define TEST_PASS 1
+       int i;
+
+       for (i = 0; i < TEST_PASS; i++)
+               test_mode_once(rng, wait);
+}
+
+static void self_test(struct hwrng *rng)
+{
+       pr_info("testing without waiting\n");
+       test_mode(rng, false);
+       pr_info("testing with waiting\n");
+       test_mode(rng, true);
+}
+#endif
+
 static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id)
 {
        struct buf_data *bd = &ctx->bufs[buf_id];
@@ -360,6 +403,10 @@ static int __init caam_rng_init(void)
        if (err)
                goto free_rng_ctx;
 
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST
+       self_test(&caam_rng);
+#endif
+
        dev_info(dev, "registering rng-caam\n");
        return hwrng_register(&caam_rng);