mailbox: mtk-cmdq: Add cmdq private data to cmdq_pkt for generating instruction

Add the cmdq_mbox_priv structure to store the private data of GCE,
such as the shift bits of the physical address. Then, include the
cmdq_mbox_priv structure within the cmdq_pkt structure.

This allows CMDQ users to utilize the private data in cmdq_pkt to
generate GCE instructions when needed. Additionally, having
cmdq_mbox_priv makes it easier to expand and reference other GCE
private data in the future.

Add cmdq_get_mbox_priv() for CMDQ users to get all the private data
into the cmdq_mbox_priv of the cmdq_pkt.

Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Author: Jason-JH Lin

drivers/mailbox/mtk-cmdq-mailbox.c

@@ -104,6 +104,14 @@ static inline dma_addr_t cmdq_revert_gce_addr(u32 addr, const struct gce_plat *p
 	return (dma_addr_t)addr << pdata->shift;
 }
 
+void cmdq_get_mbox_priv(struct mbox_chan *chan, struct cmdq_mbox_priv *priv)
+{
+	struct cmdq *cmdq = container_of(chan->mbox, struct cmdq, mbox);
+
+	priv->shift_pa = cmdq->pdata->shift;
+}
+EXPORT_SYMBOL(cmdq_get_mbox_priv);
+
 u8 cmdq_get_shift_pa(struct mbox_chan *chan)
 {
 	struct cmdq *cmdq = container_of(chan->mbox, struct cmdq, mbox);

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

@@ -70,13 +70,31 @@ struct cmdq_cb_data {
 	struct cmdq_pkt		*pkt;
 };
 
+struct cmdq_mbox_priv {
+	u8 shift_pa;
+};
+
 struct cmdq_pkt {
 	void			*va_base;
 	dma_addr_t		pa_base;
 	size_t			cmd_buf_size; /* command occupied size */
 	size_t			buf_size; /* real buffer size */
+	struct cmdq_mbox_priv	priv; /* for generating instruction */
 };
 
+/**
+ * cmdq_get_mbox_priv() - get the private data of mailbox channel
+ * @chan: mailbox channel
+ * @priv: pointer to store the private data of mailbox channel
+ *
+ * While generating the GCE instruction to command buffer, the private data
+ * of GCE hardware may need to be referenced, such as the shift bits of
+ * physical address.
+ *
+ * This function should be called before generating the GCE instruction.
+ */
+void cmdq_get_mbox_priv(struct mbox_chan *chan, struct cmdq_mbox_priv *priv);
+
 /**
  * cmdq_get_shift_pa() - get the shift bits of physical address
  * @chan: mailbox channel