[PATCH v5 02/16] firmware: scmi: use a protocol's own channel if assigned

[AKASHI Takahiro]

SCMI specification allows any protocol to have its own channel for
the transport. While the current SCMI driver may assign its channel
from a device tree, the core function, devm_scmi_process_msg(), doesn't
use a protocol's channel, but always use an agent's channel.

With this commit, devm_scmi_process_msg() tries to find and use
a protocol's channel. If it doesn't exist, use an agent's.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
v5
* new commit (fixing a potential bug)
---
 drivers/firmware/scmi/mailbox_agent.c     | 5 +++--
 drivers/firmware/scmi/optee_agent.c       | 5 +++--
 drivers/firmware/scmi/scmi_agent-uclass.c | 7 ++++---
 drivers/firmware/scmi/smccc_agent.c       | 5 +++--
 include/scmi_agent-uclass.h               | 8 +++++---
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/scmi/mailbox_agent.c b/drivers/firmware/scmi/mailbox_agent.c
index 8277c1860606..7ad3e8da9f08 100644
--- a/drivers/firmware/scmi/mailbox_agent.c
+++ b/drivers/firmware/scmi/mailbox_agent.c
@@ -94,13 +94,14 @@ static int setup_channel(struct udevice *dev, struct scmi_mbox_channel *chan)
 }
 
 static int scmi_mbox_get_channel(struct udevice *dev,
+				 struct udevice *protocol,
 				 struct scmi_channel **channel)
 {
 	struct scmi_mbox_channel *base_chan = dev_get_plat(dev);
 	struct scmi_mbox_channel *chan;
 	int ret;
 
-	if (!dev_read_prop(dev, "shmem", NULL)) {
+	if (!dev_read_prop(protocol, "shmem", NULL)) {
 		/* Uses agent base channel */
 		*channel = container_of(base_chan, struct scmi_channel, ref);
 
@@ -112,7 +113,7 @@ static int scmi_mbox_get_channel(struct udevice *dev,
 		return -ENOMEM;
 
 	/* Setup a dedicated channel for the protocol */
-	ret = setup_channel(dev, chan);
+	ret = setup_channel(protocol, chan);
 	if (ret) {
 		free(chan);
 		return ret;
diff --git a/drivers/firmware/scmi/optee_agent.c b/drivers/firmware/scmi/optee_agent.c
index db927fb21405..e3e462774045 100644
--- a/drivers/firmware/scmi/optee_agent.c
+++ b/drivers/firmware/scmi/optee_agent.c
@@ -324,6 +324,7 @@ static int setup_channel(struct udevice *dev, struct scmi_optee_channel *chan)
 }
 
 static int scmi_optee_get_channel(struct udevice *dev,
+				  struct udevice *protocol,
 				  struct scmi_channel **channel)
 {
 	struct scmi_optee_channel *base_chan = dev_get_plat(dev);
@@ -331,7 +332,7 @@ static int scmi_optee_get_channel(struct udevice *dev,
 	u32 channel_id;
 	int ret;
 
-	if (dev_read_u32(dev, "linaro,optee-channel-id", &channel_id)) {
+	if (dev_read_u32(protocol, "linaro,optee-channel-id", &channel_id)) {
 		/* Uses agent base channel */
 		*channel = container_of(base_chan, struct scmi_channel, ref);
 
@@ -343,7 +344,7 @@ static int scmi_optee_get_channel(struct udevice *dev,
 	if (!chan)
 		return -ENOMEM;
 
-	ret = setup_channel(dev, chan);
+	ret = setup_channel(protocol, chan);
 	if (ret) {
 		free(chan);
 		return ret;
diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
index ec58ccd2bc5d..a28692f39f4d 100644
--- a/drivers/firmware/scmi/scmi_agent-uclass.c
+++ b/drivers/firmware/scmi/scmi_agent-uclass.c
@@ -144,13 +144,14 @@ static const struct scmi_agent_ops *transport_dev_ops(struct udevice *dev)
  * On return, @channel will be set.
  * Return	0 on success and a negative errno on failure
  */
-static int scmi_of_get_channel(struct udevice *dev, struct scmi_channel **channel)
+static int scmi_of_get_channel(struct udevice *dev, struct udevice *protocol,
+			       struct scmi_channel **channel)
 {
 	const struct scmi_agent_ops *ops;
 
 	ops = transport_dev_ops(dev);
 	if (ops->of_get_channel)
-		return ops->of_get_channel(dev, channel);
+		return ops->of_get_channel(dev, protocol, channel);
 	else
 		return -EPROTONOSUPPORT;
 }
@@ -166,7 +167,7 @@ int devm_scmi_of_get_channel(struct udevice *dev)
 		return -ENODEV;
 
 	priv = dev_get_parent_priv(protocol);
-	ret = scmi_of_get_channel(protocol->parent, &priv->channel);
+	ret = scmi_of_get_channel(protocol->parent, protocol, &priv->channel);
 	if (ret == -EPROTONOSUPPORT) {
 		/* Drivers without a get_channel operator don't need a channel ref */
 		priv->channel = NULL;
diff --git a/drivers/firmware/scmi/smccc_agent.c b/drivers/firmware/scmi/smccc_agent.c
index 6a52cd75d67b..972c6addde21 100644
--- a/drivers/firmware/scmi/smccc_agent.c
+++ b/drivers/firmware/scmi/smccc_agent.c
@@ -81,6 +81,7 @@ static int setup_channel(struct udevice *dev, struct scmi_smccc_channel *chan)
 }
 
 static int scmi_smccc_get_channel(struct udevice *dev,
+				  struct udevice *protocol,
 				  struct scmi_channel **channel)
 {
 	struct scmi_smccc_channel *base_chan = dev_get_plat(dev);
@@ -88,7 +89,7 @@ static int scmi_smccc_get_channel(struct udevice *dev,
 	u32 func_id;
 	int ret;
 
-	if (dev_read_u32(dev, "arm,smc-id", &func_id)) {
+	if (dev_read_u32(protocol, "arm,smc-id", &func_id)) {
 		/* Uses agent base channel */
 		*channel = container_of(base_chan, struct scmi_channel, ref);
 
@@ -100,7 +101,7 @@ static int scmi_smccc_get_channel(struct udevice *dev,
 	if (!chan)
 		return -ENOMEM;
 
-	ret = setup_channel(dev, chan);
+	ret = setup_channel(protocol, chan);
 	if (ret) {
 		free(chan);
 		return ret;
diff --git a/include/scmi_agent-uclass.h b/include/scmi_agent-uclass.h
index b1c93532c0ea..eee46c880a56 100644
--- a/include/scmi_agent-uclass.h
+++ b/include/scmi_agent-uclass.h
@@ -16,16 +16,18 @@ struct scmi_agent_ops {
 	/*
 	 * of_get_channel - Get SCMI channel from SCMI agent device tree node
 	 *
-	 * @dev:		SCMI protocol device using the transport
+	 * @dev:		SCMI agent device using the transport
+	 * @protocol:		SCMI protocol device using the transport
 	 * @channel:		Output reference to SCMI channel upon success
 	 * Return 0 upon success and a negative errno on failure
 	 */
-	int (*of_get_channel)(struct udevice *dev, struct scmi_channel **channel);
+	int (*of_get_channel)(struct udevice *dev, struct udevice *protocol,
+			      struct scmi_channel **channel);
 
 	/*
 	 * process_msg - Request transport to get the SCMI message processed
 	 *
-	 * @dev:		SCMI protocol device using the transport
+	 * @dev:		SCMI agent device using the transport
 	 * @msg:		SCMI message to be transmitted
 	 */
 	int (*process_msg)(struct udevice *dev, struct scmi_channel *channel,
-- 
2.34.1