drivers: firmware: scmi: add interface to read hdr message

Introduced an interface to shmem to directly read the current
hdr content without knowing the context of the message

Add api to get shmem message in mailbox driver

Signed-off-by: Yongxu Wang <[email protected]>

Author: yongxu-wang15

drivers/firmware/scmi/mailbox.c

@@ -6,15 +6,39 @@
 
 #include <zephyr/logging/log.h>
 #include "mailbox.h"
+#include <zephyr/drivers/firmware/scmi/protocol.h>
 
 LOG_MODULE_REGISTER(scmi_mbox);
 
+static int scmi_mbox_get_pending_msg(struct scmi_channel *chan,
+				struct scmi_message *msg)
+{
+	uint32_t context;
+	int ret;
+	struct scmi_mbox_channel *mbox_chan = chan->data;
+
+	msg->hdr = 0x0;
+	msg->len = sizeof(uint32_t);
+	msg->content = &context;
+
+	ret = scmi_shmem_read_hdr(mbox_chan->shmem, msg);
+	if (ret < 0) {
+		LOG_ERR("failed to read message to shmem: %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 static void scmi_mbox_tx_reply_cb(const struct device *mbox,
 				mbox_channel_id_t channel_id,
 				void *user_data,
 				struct mbox_msg *data)
 {
 	struct scmi_channel *scmi_chan = user_data;
+	struct scmi_message msg;
+
+	scmi_mbox_get_pending_msg(scmi_chan, &msg);
 
 	if (scmi_chan->cb) {
 		scmi_chan->cb(scmi_chan);
@@ -29,6 +53,9 @@ static void scmi_mbox_rx_notify_cb(const struct device *mbox,
 	struct scmi_channel *scmi_chan = user_data;
 	struct scmi_mbox_channel *mbox_chan = scmi_chan->data;
 	const struct device *shmem = mbox_chan->shmem;
+	struct scmi_message msg;
+
+	scmi_mbox_get_pending_msg(scmi_chan, &msg);
 
 	if (scmi_chan->cb) {
 		scmi_chan->cb(scmi_chan);

drivers/firmware/scmi/shmem.c

@@ -59,6 +59,30 @@ static void scmi_shmem_memcpy(mm_reg_t dst, mm_reg_t src, uint32_t bytes)
 	}
 }
 
+int scmi_shmem_read_hdr(const struct device *shmem, struct scmi_message *msg)
+{
+	struct scmi_shmem_layout *layout;
+	struct scmi_shmem_data *data;
+
+	data = shmem->data;
+	layout = (struct scmi_shmem_layout *)data->regmap;
+
+	/* some sanity checks first */
+	if (!msg) {
+		return -EINVAL;
+	}
+
+	if (scmi_shmem_vendor_read_message(layout) < 0) {
+		LOG_ERR("vendor specific validation failed");
+		return -EINVAL;
+	}
+
+	scmi_shmem_memcpy(POINTER_TO_UINT(&msg->hdr),
+			data->regmap + SCMI_SHMEM_CHAN_MSG_HDR_OFFSET, sizeof(uint32_t));
+
+	return 0;
+}
+
 __weak int scmi_shmem_vendor_read_message(const struct scmi_shmem_layout *layout)
 {
 	return 0;

include/zephyr/drivers/firmware/scmi/shmem.h

@@ -19,6 +19,8 @@
 #define SCMI_SHMEM_CHAN_STATUS_FREE_BIT BIT(0)
 #define SCMI_SHMEM_CHAN_FLAG_IRQ_BIT BIT(0)
 
+#define SCMI_SHMEM_CHAN_MSG_HDR_OFFSET 0x18
+
 struct scmi_shmem_layout {
 	volatile uint32_t res0;
 	volatile uint32_t chan_status;
@@ -100,4 +102,16 @@ int scmi_shmem_vendor_read_message(const struct scmi_shmem_layout *layout);
  */
 void scmi_shmem_clear_channel_status(const struct device *dev);
 
+/**
+ * @brief Read a message header from a SHMEM area
+ *
+ * @param shmem pointer to shmem device
+ * @param msg message to write the data into
+ *
+ * @retval 0 if successful
+ * @retval negative errno if failure
+ */
+
+int scmi_shmem_read_hdr(const struct device *shmem, struct scmi_message *msg);
+
 #endif /* _INCLUDE_ZEPHYR_DRIVERS_FIRMWARE_SCMI_SHMEM_H_ */