[PATCH v2] crypto: caam - refactor RNG initialization

[meenakshi.aggarwal@nxp.com]

From: Horia GeantA <horia.geanta@nxp.com>

RNG (re-)initialization will be needed on pm resume path,
thus refactor the corresponding code out of the probe callback.

Signed-off-by: Horia GeantA <horia.geanta@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
---
changes in v2:
	Rebased on "page 0" patches
	
NOTE: This patch depends on "page 0" patches, which are under
 review on mailing list.

 drivers/crypto/caam/ctrl.c   | 201 ++++++++++++++++++-----------------
 drivers/crypto/caam/intern.h |   1 +
 2 files changed, 104 insertions(+), 98 deletions(-)

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index 9c5a035e1b96..852d538cfc25 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -342,13 +342,12 @@ static int instantiate_rng(struct device *ctrldev, int state_handle_mask,
 /*
  * kick_trng - sets the various parameters for enabling the initialization
  *	       of the RNG4 block in CAAM
- * @pdev - pointer to the platform device
+ * @dev - pointer to the controller device
  * @ent_delay - Defines the length (in system clocks) of each entropy sample.
  */
-static void kick_trng(struct platform_device *pdev, int ent_delay)
+static void kick_trng(struct device *dev, int ent_delay)
 {
-	struct device *ctrldev = &pdev->dev;
-	struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev);
+	struct caam_drv_private *ctrlpriv = dev_get_drvdata(dev);
 	struct caam_ctrl __iomem *ctrl;
 	struct rng4tst __iomem *r4tst;
 	u32 val;
@@ -589,6 +588,100 @@ static void caam_remove_debugfs(void *root)
 	debugfs_remove_recursive(root);
 }
 
+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 *)&ctrlpriv->jr[0]->perfmon :
+			  (struct caam_perfmon *)&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 (!(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);
+			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;
+}
+
 #ifdef CONFIG_FSL_MC_BUS
 static bool check_version(struct fsl_mc_version *mc_version, u32 major,
 			  u32 minor, u32 revision)
@@ -609,17 +702,10 @@ 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)
 {
-	int ret, ring, gen_sk, ent_delay = RTSDCTL_ENT_DLY_MIN;
+	int ret, ring;
 	u64 caam_id;
 	const struct soc_device_attribute *imx_soc_match;
 	struct device *dev;
@@ -629,10 +715,8 @@ static int caam_probe(struct platform_device *pdev)
 	struct caam_perfmon __iomem *perfmon;
 	struct dentry *dfs_root;
 	u32 scfgr, comp_params;
-	u8 rng_vid;
 	int pg_size;
 	int BLOCK_OFFSET = 0;
-	bool pr_support = false;
 	bool reg_access = true;
 
 	ctrlpriv = devm_kzalloc(&pdev->dev, sizeof(*ctrlpriv), GFP_KERNEL);
@@ -768,7 +852,8 @@ static int caam_probe(struct platform_device *pdev)
 
 		mc_version = fsl_mc_get_version();
 		if (mc_version)
-			pr_support = check_version(mc_version, 10, 20, 0);
+			ctrlpriv->pr_support = check_version(mc_version, 10, 20,
+							     0);
 		else
 			return -EPROBE_DEFER;
 	}
@@ -859,9 +944,6 @@ static int caam_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	if (!reg_access)
-		goto report_live;
-
 	comp_params = rd_reg32(&perfmon->comp_parms_ls);
 	ctrlpriv->blob_present = !!(comp_params & CTPR_LS_BLOB);
 
@@ -871,8 +953,6 @@ static int caam_probe(struct platform_device *pdev)
 	 * check both here.
 	 */
 	if (ctrlpriv->era < 10) {
-		rng_vid = (rd_reg32(&perfmon->cha_id_ls) &
-			   CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT;
 		ctrlpriv->blob_present = ctrlpriv->blob_present &&
 			(rd_reg32(&perfmon->cha_num_ls) & CHA_ID_LS_AES_MASK);
 	} else {
@@ -882,91 +962,16 @@ static int caam_probe(struct platform_device *pdev)
 			(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;
 		ctrlpriv->blob_present = ctrlpriv->blob_present &&
 			(rd_reg32(&vreg->aesa) & CHA_VER_MISC_AES_NUM_MASK);
 	}
 
-	/*
-	 * 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 && 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(pdev, 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");
+	if (reg_access) {
+		ret = caam_ctrl_rng_init(dev);
+		if (ret)
 			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);
 	}
 
-report_live:
-	/* NOTE: RTIC detection ought to go here, around Si time */
-
 	caam_id = (u64)rd_reg32(&perfmon->caam_id_ms) << 32 |
 		  (u64)rd_reg32(&perfmon->caam_id_ls);
 
diff --git a/drivers/crypto/caam/intern.h b/drivers/crypto/caam/intern.h
index 86ed1b91c22d..b4f7bf77f487 100644
--- a/drivers/crypto/caam/intern.h
+++ b/drivers/crypto/caam/intern.h
@@ -95,6 +95,7 @@ struct caam_drv_private {
 	u8 blob_present;	/* Nonzero if BLOB support present in device */
 	u8 mc_en;		/* Nonzero if MC f/w is active */
 	u8 optee_en;		/* Nonzero if OP-TEE f/w is active */
+	bool pr_support;        /* RNG prediction resistance available */
 	int secvio_irq;		/* Security violation interrupt number */
 	int virt_en;		/* Virtualization enabled in CAAM */
 	int era;		/* CAAM Era (internal HW revision) */
-- 
2.25.1