drivers: qcom: rpmh: allow requests to be sent asynchronously

Platform drivers that want to send a request but do not want to block
until the RPMH request completes have now a new API -
rpmh_write_async().

The API allocates memory and send the requests and returns the control
back to the platform driver. The tx_done callback from the controller is
handled in the context of the controller's thread and frees the
allocated memory. This API allows RPMH requests from atomic contexts as
well.

Signed-off-by: Lina Iyer <[e-mail]>
Signed-off-by: Raju P.L.S.S.S.N <[e-mail]>
Signed-off-by: Andy Gross <[e-mail]>

drivers/soc/qcom/rpmh-internal.h

···
  * @completion: triggered when request is done
  * @dev: the device making the request
  * @err: err return from the controller
+ * @needs_free: check to free dynamically allocated request object
  */
 struct rpmh_request {
 	struct tcs_request msg;
···
 	struct completion *completion;
 	const struct device *dev;
 	int err;
+	bool needs_free;
 };
 
 /**

drivers/soc/qcom/rpmh.c

···
 		.cmd = { { 0 } },			\
 		.completion = q,			\
 		.dev = dev,				\
+		.needs_free = false,				\
 	}
 
 #define ctrlr_to_drv(ctrlr) container_of(ctrlr, struct rsc_drv, client)
···
 	/* Signal the blocking thread we are done */
 	if (compl)
 		complete(compl);
+
+	if (rpm_msg->needs_free)
+		kfree(rpm_msg);
 }
 
 static struct cache_req *__find_req(struct rpmh_ctrlr *ctrlr, u32 addr)
···
 
 	return ret;
 }
+
+static int __fill_rpmh_msg(struct rpmh_request *req, enum rpmh_state state,
+		const struct tcs_cmd *cmd, u32 n)
+{
+	if (!cmd || !n || n > MAX_RPMH_PAYLOAD)
+		return -EINVAL;
+
+	memcpy(req->cmd, cmd, n * sizeof(*cmd));
+
+	req->msg.state = state;
+	req->msg.cmds = req->cmd;
+	req->msg.num_cmds = n;
+
+	return 0;
+}
+
+/**
+ * rpmh_write_async: Write a set of RPMH commands
+ *
+ * @dev: The device making the request
+ * @state: Active/sleep set
+ * @cmd: The payload data
+ * @n: The number of elements in payload
+ *
+ * Write a set of RPMH commands, the order of commands is maintained
+ * and will be sent as a single shot.
+ */
+int rpmh_write_async(const struct device *dev, enum rpmh_state state,
+		     const struct tcs_cmd *cmd, u32 n)
+{
+	struct rpmh_request *rpm_msg;
+	int ret;
+
+	rpm_msg = kzalloc(sizeof(*rpm_msg), GFP_ATOMIC);
+	if (!rpm_msg)
+		return -ENOMEM;
+	rpm_msg->needs_free = true;
+
+	ret = __fill_rpmh_msg(rpm_msg, state, cmd, n);
+	if (ret) {
+		kfree(rpm_msg);
+		return ret;
+	}
+
+	return __rpmh_write(dev, state, rpm_msg);
+}
+EXPORT_SYMBOL(rpmh_write_async);
 
 /**
  * rpmh_write: Write a set of RPMH commands and block until response

include/soc/qcom/rpmh.h

···
 int rpmh_write(const struct device *dev, enum rpmh_state state,
 	       const struct tcs_cmd *cmd, u32 n);
 
+int rpmh_write_async(const struct device *dev, enum rpmh_state state,
+		     const struct tcs_cmd *cmd, u32 n);
+
 int rpmh_flush(const struct device *dev);
 
 int rpmh_invalidate(const struct device *dev);
···
 			     const struct tcs_cmd *cmd, u32 n)
 { return -ENODEV; }
 
+static inline int rpmh_write_async(const struct device *dev,
+				   enum rpmh_state state,
+				   const struct tcs_cmd *cmd, u32 n)
+{ return -ENODEV; }
 
 static inline int rpmh_flush(const struct device *dev)
 { return -ENODEV; }