[PATCH v3 08/14] crypto: caam - update rfc4106 sh desc to support zero length input

[Iuliana Prodan]

Update share descriptor for rfc4106 to skip instructions in case
cryptlen is zero. If no instructions are jumped the DECO hangs and a
timeout error is thrown.

Signed-off-by: Iuliana Prodan <iuliana.prodan@xxxxxxx>
---
Changes since v2:
- update shared descriptor with the erratum workaround.
---
 drivers/crypto/caam/caamalg_desc.c | 45 ++++++++++++++++++++++++++------------
 drivers/crypto/caam/caamalg_desc.h |  2 +-
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/drivers/crypto/caam/caamalg_desc.c b/drivers/crypto/caam/caamalg_desc.c
index 7253183..fa8452d 100644
--- a/drivers/crypto/caam/caamalg_desc.c
+++ b/drivers/crypto/caam/caamalg_desc.c
@@ -843,13 +843,16 @@ EXPORT_SYMBOL(cnstr_shdsc_gcm_decap);
  * @ivsize: initialization vector size
  * @icvsize: integrity check value (ICV) size (truncated or full)
  * @is_qi: true when called from caam/qi
+ *
+ * Input sequence: AAD | PTXT
+ * Output sequence: AAD | CTXT | ICV
+ * AAD length (assoclen), which includes the IV length, is available in Math3.
  */
 void cnstr_shdsc_rfc4106_encap(u32 * const desc, struct alginfo *cdata,
 			       unsigned int ivsize, unsigned int icvsize,
 			       const bool is_qi)
 {
-	u32 *key_jump_cmd;
-
+	u32 *key_jump_cmd, *zero_cryptlen_jump_cmd, *skip_instructions;
 	init_sh_desc(desc, HDR_SHARE_SERIAL);
 
 	/* Skip key loading if it is loaded due to sharing */
@@ -892,24 +895,26 @@ void cnstr_shdsc_rfc4106_encap(u32 * const desc, struct alginfo *cdata,
 	append_math_sub_imm_u32(desc, VARSEQINLEN, REG3, IMM, ivsize);
 	append_math_add(desc, VARSEQOUTLEN, ZERO, REG3, CAAM_CMD_SZ);
 
-	/* Read assoc data */
-	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |
-			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_FLUSH1);
+	/* Skip AAD */
+	append_seq_fifo_store(desc, 0, FIFOST_TYPE_SKIP | FIFOLDST_VLF);
 
-	/* Skip IV */
-	append_seq_fifo_load(desc, ivsize, FIFOLD_CLASS_SKIP);
+	/* Read cryptlen and set this value into VARSEQOUTLEN */
+	append_math_sub(desc, VARSEQOUTLEN, SEQINLEN, REG3, CAAM_CMD_SZ);
 
-	/* Will read cryptlen bytes */
-	append_math_sub(desc, VARSEQINLEN, SEQINLEN, REG0, CAAM_CMD_SZ);
+	/* If cryptlen is ZERO jump to AAD command */
+	zero_cryptlen_jump_cmd = append_jump(desc, JUMP_TEST_ALL |
+					    JUMP_COND_MATH_Z);
 
 	/* Workaround for erratum A-005473 (simultaneous SEQ FIFO skips) */
-	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLD_TYPE_MSG);
+	append_seq_fifo_store(desc, 0, FIFOST_TYPE_MESSAGE_DATA);
 
-	/* Skip assoc data */
-	append_seq_fifo_store(desc, 0, FIFOST_TYPE_SKIP | FIFOLDST_VLF);
+	/* Read AAD data */
+	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |
+			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_FLUSH1);
 
-	/* cryptlen = seqoutlen - assoclen */
-	append_math_sub(desc, VARSEQOUTLEN, VARSEQINLEN, REG0, CAAM_CMD_SZ);
+	/* Skip IV */
+	append_seq_fifo_load(desc, ivsize, FIFOLD_CLASS_SKIP);
+	append_math_add(desc, VARSEQINLEN, VARSEQOUTLEN, REG0, CAAM_CMD_SZ);
 
 	/* Write encrypted data */
 	append_seq_fifo_store(desc, 0, FIFOST_TYPE_MESSAGE_DATA | FIFOLDST_VLF);
@@ -918,6 +923,18 @@ void cnstr_shdsc_rfc4106_encap(u32 * const desc, struct alginfo *cdata,
 	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |
 			     FIFOLD_TYPE_MSG | FIFOLD_TYPE_LAST1);
 
+	/* Jump instructions to avoid double reading of AAD */
+	skip_instructions = append_jump(desc, JUMP_TEST_ALL);
+
+	/* There is no input data, cryptlen = 0 */
+	set_jump_tgt_here(desc, zero_cryptlen_jump_cmd);
+
+	/* Read AAD */
+	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |
+			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_LAST1);
+
+	set_jump_tgt_here(desc, skip_instructions);
+
 	/* Write ICV */
 	append_seq_store(desc, icvsize, LDST_CLASS_1_CCB |
 			 LDST_SRCDST_BYTE_CONTEXT);
diff --git a/drivers/crypto/caam/caamalg_desc.h b/drivers/crypto/caam/caamalg_desc.h
index da4a4ee..a6146ea 100644
--- a/drivers/crypto/caam/caamalg_desc.h
+++ b/drivers/crypto/caam/caamalg_desc.h
@@ -31,7 +31,7 @@
 #define DESC_QI_GCM_DEC_LEN		(DESC_GCM_DEC_LEN + 3 * CAAM_CMD_SZ)
 
 #define DESC_RFC4106_BASE		(3 * CAAM_CMD_SZ)
-#define DESC_RFC4106_ENC_LEN		(DESC_RFC4106_BASE + 13 * CAAM_CMD_SZ)
+#define DESC_RFC4106_ENC_LEN		(DESC_RFC4106_BASE + 16 * CAAM_CMD_SZ)
 #define DESC_RFC4106_DEC_LEN		(DESC_RFC4106_BASE + 13 * CAAM_CMD_SZ)
 #define DESC_QI_RFC4106_ENC_LEN		(DESC_RFC4106_ENC_LEN + 5 * CAAM_CMD_SZ)
 #define DESC_QI_RFC4106_DEC_LEN		(DESC_RFC4106_DEC_LEN + 5 * CAAM_CMD_SZ)
-- 
2.1.0