[PATCH v4 10/12] soc: mediatek: cmdq: add cmdq_dev_get_subsys function

[Bibby Hsieh <bibby.hsieh@mediatek.com>]

GCE cannot know the register base address, this function
can help cmdq client to get the relationship of subsys
and register base address.

Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
---
 drivers/soc/mediatek/mtk-cmdq-helper.c | 25 +++++++++++++++++++++++++
 include/linux/soc/mediatek/mtk-cmdq.h  | 18 ++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
index 80856b8c2385..d86f800d40dc 100644
--- a/drivers/soc/mediatek/mtk-cmdq-helper.c
+++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
@@ -47,6 +47,31 @@ static void cmdq_pkt_instr_encoder(struct cmdq_pkt *pkt, s16 arg_c, s16 arg_b,
 	pkt->cmd_buf_size += CMDQ_INST_SIZE;
 }
 
+struct cmdq_subsys *cmdq_dev_get_subsys(struct device *dev, int idx)
+{
+	struct cmdq_subsys *subsys;
+	struct of_phandle_args spec;
+
+	subsys = devm_kzalloc(dev, sizeof(*subsys), GFP_KERNEL);
+	if (!subsys)
+		return NULL;
+
+	if (of_parse_phandle_with_args(dev->of_node, "mediatek,gce-client-reg",
+				       "#subsys-cells", idx, &spec)) {
+		dev_err(dev, "can't parse gce-client-reg property");
+
+		return (struct cmdq_subsys *)-ENODEV;
+	}
+
+	subsys->id = spec.args[0];
+	subsys->offset = spec.args[1];
+	subsys->size = spec.args[2];
+	of_node_put(spec.np);
+
+	return subsys;
+}
+EXPORT_SYMBOL(cmdq_dev_get_subsys);
+
 static void cmdq_client_timeout(struct timer_list *t)
 {
 	struct cmdq_client *client = from_timer(client, t, timer);
diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
index 0651a0bffa54..574006c5cd76 100644
--- a/include/linux/soc/mediatek/mtk-cmdq.h
+++ b/include/linux/soc/mediatek/mtk-cmdq.h
@@ -15,6 +15,12 @@
 
 struct cmdq_pkt;
 
+struct cmdq_subsys {
+	u8 id;
+	u16 offset;
+	u16 size;
+};
+
 struct cmdq_client {
 	spinlock_t lock;
 	u32 pkt_cnt;
@@ -142,4 +148,16 @@ int cmdq_pkt_flush_async(struct cmdq_pkt *pkt, cmdq_async_flush_cb cb,
  */
 int cmdq_pkt_flush(struct cmdq_pkt *pkt);
 
+/**
+ * cmdq_dev_get_subsys() - parse sub system from the device node of CMDQ client
+ * @dev:	device of CMDQ mailbox client
+ * @idx:	the index of desired subsys
+ *
+ * Return: CMDQ subsys pointer
+ *
+ * Help CMDQ client pasing the sub system number
+ * from the device node of CMDQ client.
+ */
+struct cmdq_subsys *cmdq_dev_get_subsys(struct device *dev, int idx);
+
 #endif	/* __MTK_CMDQ_H__ */
-- 
2.18.0