[PATCH 4/9] soc: mediatek: cmdq: Add cmdq_pkt_nop() helper function

[Chun-Kuang Hu <chunkuang.hu@kernel.org>]

cmdq_pkt_nop() append nop command to the packet. nop command ask
GCE to do no operation.

Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
---
 drivers/soc/mediatek/mtk-cmdq-helper.c | 11 +++++++++++
 include/linux/soc/mediatek/mtk-cmdq.h  | 16 ++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
index e982997117c2..1be950b4ec7f 100644
--- a/drivers/soc/mediatek/mtk-cmdq-helper.c
+++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
@@ -369,6 +369,17 @@ int cmdq_pkt_eoc(struct cmdq_pkt *pkt)
 }
 EXPORT_SYMBOL(cmdq_pkt_eoc);
 
+int cmdq_pkt_nop(struct cmdq_pkt *pkt, u8 shift_pa)
+{
+	struct cmdq_instruction inst = { {0} };
+
+	/* Jumping to next instruction is equal to no operation */
+	inst.op = CMDQ_CODE_JUMP;
+	inst.value = CMDQ_INST_SIZE >> shift_pa;
+	return cmdq_pkt_append_command(pkt, inst);
+}
+EXPORT_SYMBOL(cmdq_pkt_nop);
+
 int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
 {
 	struct cmdq_instruction inst = { {0} };
diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
index a67f719dec0b..8179ba5238f9 100644
--- a/include/linux/soc/mediatek/mtk-cmdq.h
+++ b/include/linux/soc/mediatek/mtk-cmdq.h
@@ -255,6 +255,17 @@ int cmdq_pkt_jump(struct cmdq_pkt *pkt, dma_addr_t addr, u8 shift_pa);
  */
 int cmdq_pkt_eoc(struct cmdq_pkt *pkt);
 
+/**
+ * cmdq_pkt_nop() - Append nop command to the CMDQ packet, ask GCE
+ *		    to do no operation.
+ * @pkt:	the CMDQ packet
+ * @shift_pa:	shift bits of physical address in CMDQ instruction. This value
+ *		is got by cmdq_get_shift_pa().
+ *
+ * Return: 0 for success; else the error code is returned
+ */
+int cmdq_pkt_nop(struct cmdq_pkt *pkt, u8 shift_pa);
+
 /**
  * cmdq_pkt_finalize() - Append EOC and jump command to pkt.
  * @pkt:	the CMDQ packet
@@ -361,6 +372,11 @@ static inline int cmdq_pkt_eoc(struct cmdq_pkt *pkt)
 	return -EINVAL;
 }
 
+static inline int cmdq_pkt_nop(struct cmdq_pkt *pkt, u8 shift_pa)
+{
+	return -EINVAL;
+}
+
 static inline int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
 {
 	return -EINVAL;
-- 
2.34.1