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From:   Cristian Marussi <cristian.marussi@arm.com>
To:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     sudeep.holla@arm.com, james.quinlan@broadcom.com,
        Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com,
        etienne.carriere@linaro.org, vincent.guittot@linaro.org,
        souvik.chakravarty@arm.com, cristian.marussi@arm.com
Subject: [RFC PATCH 07/10] firmware: arm_scmi: Add is_transport_atomic() handle method
Date:   Sun,  6 Jun 2021 23:12:29 +0100
Message-Id: <20210606221232.33768-8-cristian.marussi@arm.com>
In-Reply-To: <20210606221232.33768-1-cristian.marussi@arm.com>
References: <20210606221232.33768-1-cristian.marussi@arm.com>
Precedence: bulk

Add a method to check if the underlying transport configured for an SCMI
instance is configured to support atomic transaction of SCMI commands.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/driver.c | 16 ++++++++++++++++
 include/linux/scmi_protocol.h      |  8 ++++++++
 2 files changed, 24 insertions(+)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 11bea548947f..c1bf4c4f60d1 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -1062,6 +1062,21 @@ static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id)
 	WARN_ON(ret);
 }
 
+/**
+ * scmi_is_transport_atomic  - Method to check if underlying transport for an
+ * SCMI instance is configured as atomic.
+ *
+ * @handle: A reference to the SCMI platform instance.
+ *
+ * Return: True if transport is configured as atomic
+ */
+static bool scmi_is_transport_atomic(const struct scmi_handle *handle)
+{
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	return info->desc->atomic_capable;
+}
+
 static inline
 struct scmi_handle *scmi_handle_get_from_info_unlocked(struct scmi_info *info)
 {
@@ -1535,6 +1550,7 @@ static int scmi_probe(struct platform_device *pdev)
 	handle->version = &info->version;
 	handle->devm_protocol_get = scmi_devm_protocol_get;
 	handle->devm_protocol_put = scmi_devm_protocol_put;
+	handle->is_transport_atomic = scmi_is_transport_atomic;
 
 	ret = scmi_txrx_setup(info, dev, SCMI_PROTOCOL_BASE);
 	if (ret)
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 79d0a1237e6c..b28eb7c104e7 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -608,6 +608,13 @@ struct scmi_notify_ops {
  * @devm_protocol_get: devres managed method to acquire a protocol and get specific
  *		       operations and a dedicated protocol handler
  * @devm_protocol_put: devres managed method to release a protocol
+ * @is_transport_atomic: method to check if the underlying transport for this
+ *			 instance handle is configured to support atomic
+ *			 transactions for commands.
+ *			 Some users of the SCMI stack in the upper layers could
+ *			 be interested to know if they can assume SCMI
+ *			 command transactions associated to this handle will
+ *			 never sleep and act accordingly.
  * @notify_ops: pointer to set of notifications related operations
  */
 struct scmi_handle {
@@ -618,6 +625,7 @@ struct scmi_handle {
 		(*devm_protocol_get)(struct scmi_device *sdev, u8 proto,
 				     struct scmi_protocol_handle **ph);
 	void (*devm_protocol_put)(struct scmi_device *sdev, u8 proto);
+	bool (*is_transport_atomic)(const struct scmi_handle *handle);
 
 	const struct scmi_notify_ops *notify_ops;
 };
-- 
2.17.1