soc: mediatek: cmdq: Refine cmdq_pkt_create() and cmdq_pkt_destroy()

cmdq_pkt_create() and cmdq_pkt_destroy() is not suitable for
client drivers so each client driver has implement its own
function. This refinement would pass struct cmdq_pkt pointer into
cmdq_pkt_create(). In addition, client driver has the struct
cmdq_client information, so it's not necessary to store this
information in struct cmdq_pkt. After this refinement, client
drivers could use these helper funciton instead of implementing
its own version.

Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Link: https://lore.kernel.org/r/20240222154120.16959-8-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

@@ -106,47 +106,37 @@ void cmdq_mbox_destroy(struct cmdq_client *client)
 }
 EXPORT_SYMBOL(cmdq_mbox_destroy);
 
-struct cmdq_pkt *cmdq_pkt_create(struct cmdq_client *client, size_t size)
+int cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt *pkt, size_t size)
 {
-	struct cmdq_pkt *pkt;
 	struct device *dev;
 	dma_addr_t dma_addr;
 
-	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
-	if (!pkt)
-		return ERR_PTR(-ENOMEM);
 	pkt->va_base = kzalloc(size, GFP_KERNEL);
-	if (!pkt->va_base) {
-		kfree(pkt);
-		return ERR_PTR(-ENOMEM);
-	}
+	if (!pkt->va_base)
+		return -ENOMEM;
+
 	pkt->buf_size = size;
-	pkt->cl = (void *)client;
 
 	dev = client->chan->mbox->dev;
 	dma_addr = dma_map_single(dev, pkt->va_base, pkt->buf_size,
 				  DMA_TO_DEVICE);
 	if (dma_mapping_error(dev, dma_addr)) {
 		dev_err(dev, "dma map failed, size=%u\n", (u32)(u64)size);
 		kfree(pkt->va_base);
-		kfree(pkt);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	pkt->pa_base = dma_addr;
 
-	return pkt;
+	return 0;
 }
 EXPORT_SYMBOL(cmdq_pkt_create);
 
-void cmdq_pkt_destroy(struct cmdq_pkt *pkt)
+void cmdq_pkt_destroy(struct cmdq_client *client, struct cmdq_pkt *pkt)
 {
-	struct cmdq_client *client = (struct cmdq_client *)pkt->cl;
-
 	dma_unmap_single(client->chan->mbox->dev, pkt->pa_base, pkt->buf_size,
 			 DMA_TO_DEVICE);
 	kfree(pkt->va_base);
-	kfree(pkt);
 }
 EXPORT_SYMBOL(cmdq_pkt_destroy);
 

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

@@ -62,17 +62,19 @@ void cmdq_mbox_destroy(struct cmdq_client *client);
 /**
  * cmdq_pkt_create() - create a CMDQ packet
  * @client:	the CMDQ mailbox client
+ * @pkt:	the CMDQ packet
  * @size:	required CMDQ buffer size
  *
- * Return: CMDQ packet pointer
+ * Return: 0 for success; else the error code is returned
  */
-struct cmdq_pkt *cmdq_pkt_create(struct cmdq_client *client, size_t size);
+int cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt *pkt, size_t size);
 
 /**
  * cmdq_pkt_destroy() - destroy the CMDQ packet
+ * @client:	the CMDQ mailbox client
  * @pkt:	the CMDQ packet
  */
-void cmdq_pkt_destroy(struct cmdq_pkt *pkt);
+void cmdq_pkt_destroy(struct cmdq_client *client, struct cmdq_pkt *pkt);
 
 /**
  * cmdq_pkt_write() - append write command to the CMDQ packet
@@ -318,12 +320,12 @@ static inline struct cmdq_client *cmdq_mbox_create(struct device *dev, int index
 
 static inline void cmdq_mbox_destroy(struct cmdq_client *client) { }
 
-static inline  struct cmdq_pkt *cmdq_pkt_create(struct cmdq_client *client, size_t size)
+static inline int cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt *pkt, size_t size)
 {
-	return ERR_PTR(-EINVAL);
+	return -EINVAL;
 }
 
-static inline void cmdq_pkt_destroy(struct cmdq_pkt *pkt) { }
+static inline void cmdq_pkt_destroy(struct cmdq_client *client, struct cmdq_pkt *pkt) { }
 
 static inline int cmdq_pkt_write(struct cmdq_pkt *pkt, u8 subsys, u16 offset, u32 value)
 {