soc: mediatek: cmdq: add read_s function

Add read_s function in cmdq helper functions which support read value from
register or dma physical address into gce internal register.
Signed-off-by: Dennis YC Hsieh <dennis-yc.hsieh@mediatek.com>
Link: https://lore.kernel.org/r/1594136714-11650-5-git-send-email-dennis-yc.hsieh@mediatek.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

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

@@ -227,6 +227,21 @@ int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u8 subsys,
 }
 EXPORT_SYMBOL(cmdq_pkt_write_mask);
 
+int cmdq_pkt_read_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx, u16 addr_low,
+		    u16 reg_idx)
+{
+	struct cmdq_instruction inst = {};
+
+	inst.op = CMDQ_CODE_READ_S;
+	inst.dst_t = CMDQ_REG_TYPE;
+	inst.sop = high_addr_reg_idx;
+	inst.reg_dst = reg_idx;
+	inst.src_reg = addr_low;
+
+	return cmdq_pkt_append_command(pkt, inst);
+}
+EXPORT_SYMBOL(cmdq_pkt_read_s);
+
 int cmdq_pkt_write_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx,
 		     u16 addr_low, u16 src_reg_idx)
 {

include/linux/mailbox/mtk-cmdq-mailbox.h

@@ -60,6 +60,7 @@ enum cmdq_code {
 	CMDQ_CODE_JUMP = 0x10,
 	CMDQ_CODE_WFE = 0x20,
 	CMDQ_CODE_EOC = 0x40,
+	CMDQ_CODE_READ_S = 0x80,
 	CMDQ_CODE_WRITE_S = 0x90,
 	CMDQ_CODE_WRITE_S_MASK = 0x91,
 	CMDQ_CODE_LOGIC = 0xa0,

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

@@ -104,6 +104,18 @@ int cmdq_pkt_write(struct cmdq_pkt *pkt, u8 subsys, u16 offset, u32 value);
 int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u8 subsys,
 			u16 offset, u32 value, u32 mask);
 
+/*
+ * cmdq_pkt_read_s() - append read_s command to the CMDQ packet
+ * @pkt:	the CMDQ packet
+ * @high_addr_reg_idx:	internal register ID which contains high address of pa
+ * @addr_low:	low address of pa
+ * @reg_idx:	the CMDQ internal register ID to cache read data
+ *
+ * Return: 0 for success; else the error code is returned
+ */
+int cmdq_pkt_read_s(struct cmdq_pkt *pkt, u16 high_addr_reg_idx, u16 addr_low,
+		    u16 reg_idx);
+
 /**
  * cmdq_pkt_write_s() - append write_s command to the CMDQ packet
  * @pkt:	the CMDQ packet