+static int caam_ctrl_rng_init(struct device *dev)
+{
+ struct caam_drv_private *ctrlpriv = dev_get_drvdata(dev);
+ struct caam_ctrl __iomem *ctrl = ctrlpriv->ctrl;
+ int ret, gen_sk, ent_delay = RTSDCTL_ENT_DLY_MIN;
+ u8 rng_vid;
+
+ if (ctrlpriv->era < 10) {
+ struct caam_perfmon __iomem *perfmon;
+
+ perfmon = ctrlpriv->total_jobrs ?
+ (struct caam_perfmon __iomem *)&ctrlpriv->jr[0]->perfmon :
+ (struct caam_perfmon __iomem *)&ctrl->perfmon;
+
+ rng_vid = (rd_reg32(&perfmon->cha_id_ls) &
+ CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT;
+ } else {
+ struct version_regs __iomem *vreg;
+
+ vreg = ctrlpriv->total_jobrs ?
+ (struct version_regs __iomem *)&ctrlpriv->jr[0]->vreg :
+ (struct version_regs __iomem *)&ctrl->vreg;
+
+ rng_vid = (rd_reg32(&vreg->rng) & CHA_VER_VID_MASK) >>
+ CHA_VER_VID_SHIFT;
+ }
+
+ /*
+ * If SEC has RNG version >= 4 and RNG state handle has not been
+ * already instantiated, do RNG instantiation
+ * In case of SoCs with Management Complex, RNG is managed by MC f/w.
+ */
+ if (!(ctrlpriv->mc_en && ctrlpriv->pr_support) && rng_vid >= 4) {
+ ctrlpriv->rng4_sh_init =
+ rd_reg32(&ctrl->r4tst[0].rdsta);
+ /*
+ * If the secure keys (TDKEK, JDKEK, TDSK), were already
+ * generated, signal this to the function that is instantiating
+ * the state handles. An error would occur if RNG4 attempts
+ * to regenerate these keys before the next POR.
+ */
+ gen_sk = ctrlpriv->rng4_sh_init & RDSTA_SKVN ? 0 : 1;
+ ctrlpriv->rng4_sh_init &= RDSTA_MASK;
+ do {
+ int inst_handles =
+ rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_MASK;
+ /*
+ * If either SH were instantiated by somebody else
+ * (e.g. u-boot) then it is assumed that the entropy
+ * parameters are properly set and thus the function
+ * setting these (kick_trng(...)) is skipped.
+ * 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",
+ ent_delay);
+ kick_trng(dev, ent_delay);
+ ent_delay += 400;
+ }
+ /*
+ * if instantiate_rng(...) fails, the loop will rerun
+ * and the kick_trng(...) function will modify the
+ * upper and lower limits of the entropy sampling
+ * interval, leading to a successful initialization of
+ * the RNG.
+ */
+ 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,
+ * so don't hog the CPU
+ */
+ cpu_relax();
+ } while ((ret == -EAGAIN) && (ent_delay < RTSDCTL_ENT_DLY_MAX));
+ if (ret) {
+ dev_err(dev, "failed to instantiate RNG");
+ return ret;
+ }
+ /*
+ * Set handles initialized by this module as the complement of
+ * the already initialized ones
+ */
+ ctrlpriv->rng4_sh_init = ~ctrlpriv->rng4_sh_init & RDSTA_MASK;
+
+ /* Enable RDB bit so that RNG works faster */
+ clrsetbits_32(&ctrl->scfgr, 0, SCFGR_RDBENABLE);
+ }
+
+ return 0;
+}
+