linux-kernel - [PATCH] crypto: caam: disable pkc for non-E SoCs

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Message-Id: <20210915220307.3079917-1-michael@walle.cc>
Date:   Thu, 16 Sep 2021 00:03:07 +0200
From:   Michael Walle <michael@...le.cc>
To:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Horia Geantă <horia.geanta@....com>,
        Pankaj Gupta <pankaj.gupta@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>,
        Michael Walle <michael@...le.cc>
Subject: [PATCH] crypto: caam: disable pkc for non-E SoCs

On newer CAAM versions, not all accelerators are disabled if the SoC is
a non-E variant. While the driver checks most of the modules for
availability, there is one - PKHA - which sticks out. On non-E variants
it is still reported as available, that is the number of instances is
non-zero, but it has limited functionality. In particular it doesn't
support encryption and decryption, but just signing and verifying. This
is indicated by a bit in the PKHA_MISC field. Take this bit into account
if we are checking for availablitly.

This will the following error:
[    8.167817] caam_jr 8020000.jr: 20000b0f: CCB: desc idx 11: : Invalid CHA selected.

Tested on an NXP LS1028A (non-E) SoC.

Fixes: d239b10d4ceb ("crypto: caam - add register map changes cf. Era 10")
Signed-off-by: Michael Walle <michael@...le.cc>
---
 drivers/crypto/caam/caampkc.c | 19 +++++++++++++++----
 drivers/crypto/caam/regs.h    |  3 +++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/caampkc.c b/drivers/crypto/caam/caampkc.c
index e313233ec6de..bf6275ffc4aa 100644
--- a/drivers/crypto/caam/caampkc.c
+++ b/drivers/crypto/caam/caampkc.c
@@ -1153,16 +1153,27 @@ static struct caam_akcipher_alg caam_rsa = {
 int caam_pkc_init(struct device *ctrldev)
 {
 	struct caam_drv_private *priv = dev_get_drvdata(ctrldev);
-	u32 pk_inst;
+	u32 pk_inst, pkha;
 	int err;
 	init_done = false;
 
 	/* Determine public key hardware accelerator presence. */
-	if (priv->era < 10)
+	if (priv->era < 10) {
 		pk_inst = (rd_reg32(&priv->ctrl->perfmon.cha_num_ls) &
 			   CHA_ID_LS_PK_MASK) >> CHA_ID_LS_PK_SHIFT;
-	else
-		pk_inst = rd_reg32(&priv->ctrl->vreg.pkha) & CHA_VER_NUM_MASK;
+	} else {
+		pkha = rd_reg32(&priv->ctrl->vreg.pkha);
+		pk_inst = pkha & CHA_VER_NUM_MASK;
+
+		/*
+		 * Newer CAAMs support partially disabled functionality. If this is the
+		 * case, the number is non-zero, but this bit is set to indicate that
+		 * no encryption or decryption is supported. Only signing and verifying
+		 * is supported.
+		 */
+		if (pkha & CHA_VER_MISC_PKHA_NO_CRYPT)
+			pk_inst = 0;
+	}
 
 	/* Do not register algorithms if PKHA is not present. */
 	if (!pk_inst)
diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h
index af61f3a2c0d4..3738625c0250 100644
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -322,6 +322,9 @@ struct version_regs {
 /* CHA Miscellaneous Information - AESA_MISC specific */
 #define CHA_VER_MISC_AES_GCM	BIT(1 + CHA_VER_MISC_SHIFT)
 
+/* CHA Miscellaneous Information - PKHA_MISC specific */
+#define CHA_VER_MISC_PKHA_NO_CRYPT	BIT(7 + CHA_VER_MISC_SHIFT)
+
 /*
  * caam_perfmon - Performance Monitor/Secure Memory Status/
  *                CAAM Global Status/Component Version IDs
-- 
2.30.2