linux-kernel - [PATCH 3/3] crypto: caam: read entropy delay from device tree

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Date:   Mon, 30 May 2022 23:39:24 +0530
From:   Vabhav Sharma <vabhav.sharma@....com>
To:     horia.geanta@....com, gaurav.jain@....com, pankaj.gupta@....com,
        herbert@...dor.apana.org.au, davem@...emloft.net,
        shawnguo@...nel.org, robh+dt@...nel.org
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        NXP Linux Team <linux-imx@....com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        silvano.dininno@....com, V.Sethi@....com
Subject: [PATCH 3/3] crypto: caam: read entropy delay from device tree

Read entropy-delay property from device tree for
TRNG configuration.

update the value if entry is missing in DT.

Signed-off-by: Vabhav Sharma <vabhav.sharma@....com>
Reviewed-by: Gaurav Jain <gaurav.jain@....com>
Reviewed-by: Horia Geanta <horia.geanta@....com>
---
 drivers/crypto/caam/ctrl.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index 32253a064d0f..5ffab99d831c 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -619,7 +619,7 @@ static bool needs_entropy_delay_adjustment(void)
 /* 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, gen_sk;
 	u64 caam_id;
 	const struct soc_device_attribute *imx_soc_match;
 	struct device *dev;
@@ -627,7 +627,7 @@ static int caam_probe(struct platform_device *pdev)
 	struct caam_ctrl __iomem *ctrl;
 	struct caam_drv_private *ctrlpriv;
 	struct dentry *dfs_root;
-	u32 scfgr, comp_params;
+	u32 scfgr, comp_params, ent_delay = RTSDCTL_ENT_DLY_MIN;
 	u8 rng_vid;
 	int pg_size;
 	int BLOCK_OFFSET = 0;
@@ -847,6 +847,16 @@ static int caam_probe(struct platform_device *pdev)
 			(rd_reg32(&ctrl->vreg.aesa) & CHA_VER_MISC_AES_NUM_MASK);
 	}
 
+	/*
+	 * Read entropy-delay property from device tree. If property is not
+	 * available or missing, update the entropy delay value only for imx6sx.
+	 */
+	if (device_property_read_u32(dev, "entropy-delay", &ent_delay)) {
+		dev_dbg(dev, "entropy-delay property missing in DT\n");
+		if (needs_entropy_delay_adjustment())
+			ent_delay = 12000;
+	}
+
 	/*
 	 * If SEC has RNG version >= 4 and RNG state handle has not been
 	 * already instantiated, do RNG instantiation
@@ -875,8 +885,6 @@ 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",
-- 
2.25.1