crypto: caam - add Derived Key Protocol (DKP) support

Offload split key generation in CAAM engine, using DKP.
DKP is supported starting with Era 6.

Note that the way assoclen is transmitted from the job descriptor
to the shared descriptor changes - DPOVRD register is used instead
of MATH3 (where available), since DKP protocol thrashes the MATH
registers.

The replacement of MDHA split key generation with DKP has the side
effect of the crypto engine writing the authentication key, and thus
the DMA mapping direction for the buffer holding the key has to change
from DMA_TO_DEVICE to DMA_BIDIRECTIONAL.
There are two cases:
-key is inlined in descriptor - descriptor buffer mapping changes
-key is referenced - key buffer mapping changes

Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/crypto/caam/desc_constr.h b/drivers/crypto/caam/desc_constr.h
index 5b39b7d7a47a..d4256fa4a1d6 100644
--- a/drivers/crypto/caam/desc_constr.h
+++ b/drivers/crypto/caam/desc_constr.h
@@ -496,4 +496,45 @@ static inline int desc_inline_query(unsigned int sd_base_len,
 	return (rem_bytes >= 0) ? 0 : -1;
 }
 
+/**
+ * append_proto_dkp - Derived Key Protocol (DKP): key -> split key
+ * @desc: pointer to buffer used for descriptor construction
+ * @adata: pointer to authentication transform definitions.
+ *         keylen should be the length of initial key, while keylen_pad
+ *         the length of the derived (split) key.
+ *         Valid algorithm values - one of OP_ALG_ALGSEL_{MD5, SHA1, SHA224,
+ *         SHA256, SHA384, SHA512}.
+ */
+static inline void append_proto_dkp(u32 * const desc, struct alginfo *adata)
+{
+	u32 protid;
+
+	/*
+	 * Quick & dirty translation from OP_ALG_ALGSEL_{MD5, SHA*}
+	 * to OP_PCLID_DKP_{MD5, SHA*}
+	 */
+	protid = (adata->algtype & OP_ALG_ALGSEL_SUBMASK) |
+		 (0x20 << OP_ALG_ALGSEL_SHIFT);
+
+	if (adata->key_inline) {
+		int words;
+
+		append_operation(desc, OP_TYPE_UNI_PROTOCOL | protid |
+				 OP_PCL_DKP_SRC_IMM | OP_PCL_DKP_DST_IMM |
+				 adata->keylen);
+		append_data(desc, adata->key_virt, adata->keylen);
+
+		/* Reserve space in descriptor buffer for the derived key */
+		words = (ALIGN(adata->keylen_pad, CAAM_CMD_SZ) -
+			 ALIGN(adata->keylen, CAAM_CMD_SZ)) / CAAM_CMD_SZ;
+		if (words)
+			(*desc) = cpu_to_caam32(caam32_to_cpu(*desc) + words);
+	} else {
+		append_operation(desc, OP_TYPE_UNI_PROTOCOL | protid |
+				 OP_PCL_DKP_SRC_PTR | OP_PCL_DKP_DST_PTR |
+				 adata->keylen);
+		append_ptr(desc, adata->key_dma);
+	}
+}
+
 #endif /* DESC_CONSTR_H */