soc: mediatek: cmdq: Add cmdq_pkt_jump_rel() helper function

cmdq_pkt_jump_rel() append relative jump command to the packet.
Relative jump change PC to the target address with offset from
current PC.

Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240222154120.16959-5-chunkuang.hu@kernel.org
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Author: Chun-Kuang Hu

drivers/soc/mediatek/mtk-cmdq-helper.c

@@ -404,6 +404,16 @@ int cmdq_pkt_jump_abs(struct cmdq_pkt *pkt, dma_addr_t addr, u8 shift_pa)
 }
 EXPORT_SYMBOL(cmdq_pkt_jump_abs);
 
+int cmdq_pkt_jump_rel(struct cmdq_pkt *pkt, s32 offset, u8 shift_pa)
+{
+	struct cmdq_instruction inst = { {0} };
+
+	inst.op = CMDQ_CODE_JUMP;
+	inst.value = (u32)offset >> shift_pa;
+	return cmdq_pkt_append_command(pkt, inst);
+}
+EXPORT_SYMBOL(cmdq_pkt_jump_rel);
+
 int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
 {
 	struct cmdq_instruction inst = { {0} };

include/linux/soc/mediatek/mtk-cmdq.h

@@ -267,6 +267,20 @@ static inline int cmdq_pkt_jump(struct cmdq_pkt *pkt, dma_addr_t addr, u8 shift_
 	return cmdq_pkt_jump_abs(pkt, addr, shift_pa);
 }
 
+/**
+ * cmdq_pkt_jump_rel() - Append jump command to the CMDQ packet, ask GCE
+ *			 to execute an instruction that change current thread
+ *			 PC to a physical address with relative offset. The
+ *			 target address should contains more instruction.
+ * @pkt:	the CMDQ packet
+ * @offset:	relative offset of target instruction buffer from current PC.
+ * @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_jump_rel(struct cmdq_pkt *pkt, s32 offset, u8 shift_pa);
+
 /**
  * cmdq_pkt_finalize() - Append EOC and jump command to pkt.
  * @pkt:	the CMDQ packet
@@ -393,6 +407,11 @@ static inline int cmdq_pkt_jump(struct cmdq_pkt *pkt, dma_addr_t addr, u8 shift_
 	return -EINVAL;
 }
 
+static inline int cmdq_pkt_jump_rel(struct cmdq_pkt *pkt, s32 offset, u8 shift_pa)
+{
+	return -EINVAL;
+}
+
 static inline int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
 {
 	return -EINVAL;