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 availability.

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: d239b10d ("crypto: caam - add register map changes cf. Era 10")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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)

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