From dd36037d4ae7d66a58ce0ee5ed414d185f9d8652 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Wed, 20 Apr 2022 09:06:01 -0300 Subject: [PATCH] crypto: caam - fix i.MX6SX entropy delay value MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 4ee4cdad368a26de3967f2975806a9ee2fa245df upstream. Since commit 358ba762d9f1 ("crypto: caam - enable prediction resistance in HRWNG") the following CAAM errors can be seen on i.MX6SX: caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error hwrng: no data available This error is due to an incorrect entropy delay for i.MX6SX. Fix it by increasing the minimum entropy delay for i.MX6SX as done in U-Boot: https://patchwork.ozlabs.org/project/uboot/patch/20220415111049.2565744-1-gaurav.jain@nxp.com/ As explained in the U-Boot patch: "RNG self tests are run to determine the correct entropy delay. Such tests are executed with different voltages and temperatures to identify the worst case value for the entropy delay. For i.MX6SX, it was determined that after adding a margin value of 1000 the minimum entropy delay should be at least 12000." Cc: Fixes: 358ba762d9f1 ("crypto: caam - enable prediction resistance in HRWNG") Signed-off-by: Fabio Estevam Reviewed-by: Horia Geantă Reviewed-by: Vabhav Sharma Reviewed-by: Gaurav Jain Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/crypto/caam/ctrl.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index ca0361b..f87aa21 100644 --- a/drivers/crypto/caam/ctrl.c +++ b/drivers/crypto/caam/ctrl.c @@ -609,6 +609,13 @@ static bool check_version(struct fsl_mc_version *mc_version, u32 major, } #endif +static bool needs_entropy_delay_adjustment(void) +{ + if (of_machine_is_compatible("fsl,imx6sx")) + return true; + return false; +} + /* Probe routine for CAAM top (controller) level */ static int caam_probe(struct platform_device *pdev) { @@ -855,6 +862,8 @@ static int caam_probe(struct platform_device *pdev) * Also, if a handle was instantiated, do not change * the TRNG parameters. */ + if (needs_entropy_delay_adjustment()) + ent_delay = 12000; if (!(ctrlpriv->rng4_sh_init || inst_handles)) { dev_info(dev, "Entropy delay = %u\n", @@ -871,6 +880,15 @@ static int caam_probe(struct platform_device *pdev) */ ret = instantiate_rng(dev, inst_handles, gen_sk); + /* + * Entropy delay is determined via TRNG characterization. + * TRNG characterization is run across different voltages + * and temperatures. + * If worst case value for ent_dly is identified, + * the loop can be skipped for that platform. + */ + if (needs_entropy_delay_adjustment()) + break; if (ret == -EAGAIN) /* * if here, the loop will rerun, -- 2.7.4