[RFC PATCH 4/4] firmware: arm_scmi: optee: Rework transport probe sequence
From: Cristian Marussi
Date: Tue Mar 17 2026 - 13:12:35 EST
Use the new per-instance transport handles list to synchronize and
optionally defer the core SCMI probe up until the transport driver has
completely been initialized and is fully operational.
Add also a local xarray to keep track of the association between the
tee_client_device and the per-instance agent for the purpose of resource
cleanup.
Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
drivers/firmware/arm_scmi/transports/optee.c | 137 +++++++++++--------
1 file changed, 79 insertions(+), 58 deletions(-)
diff --git a/drivers/firmware/arm_scmi/transports/optee.c b/drivers/firmware/arm_scmi/transports/optee.c
index ab578152e046..08f7b2b9b9d6 100644
--- a/drivers/firmware/arm_scmi/transports/optee.c
+++ b/drivers/firmware/arm_scmi/transports/optee.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/tee_drv.h>
#include <linux/uuid.h>
+#include <linux/xarray.h>
#include <uapi/linux/tee.h>
#include "../common.h"
@@ -99,6 +100,26 @@ enum scmi_optee_pta_cmd {
#define PTA_SCMI_CAPS_MASK (PTA_SCMI_CAPS_SMT_HEADER | \
PTA_SCMI_CAPS_MSG_HEADER)
+/**
+ * struct scmi_optee_agent - OP-TEE transport private data
+ *
+ * @dev: Device used for communication with TEE
+ * @tee_ctx: TEE context used for communication
+ * @caps: Supported channel capabilities
+ * @mu: Mutex for protection of @channel_list
+ * @channel_list: List of all created channels for the agent
+ * @node: Used to enqueue this agent
+ */
+struct scmi_optee_agent {
+ struct device *dev;
+ struct tee_context *tee_ctx;
+ u32 caps;
+ /* Protect channel_list*/
+ struct mutex mu;
+ struct list_head channel_list;
+ struct list_head node;
+};
+
/**
* struct scmi_optee_channel - Description of an OP-TEE SCMI channel
*
@@ -115,6 +136,7 @@ enum scmi_optee_pta_cmd {
* @io_ops: Transport specific I/O operations
* @tee_shm: TEE shared memory handle @req or NULL if using IOMEM shmem
* @link: Reference in agent's channel list
+ * @agent: Reference to the agent owning this channel
*/
struct scmi_optee_channel {
u32 channel_id;
@@ -130,29 +152,13 @@ struct scmi_optee_channel {
struct scmi_shmem_io_ops *io_ops;
struct tee_shm *tee_shm;
struct list_head link;
-};
-
-/**
- * struct scmi_optee_agent - OP-TEE transport private data
- *
- * @dev: Device used for communication with TEE
- * @tee_ctx: TEE context used for communication
- * @caps: Supported channel capabilities
- * @mu: Mutex for protection of @channel_list
- * @channel_list: List of all created channels for the agent
- */
-struct scmi_optee_agent {
- struct device *dev;
- struct tee_context *tee_ctx;
- u32 caps;
- struct mutex mu;
- struct list_head channel_list;
+ struct scmi_optee_agent *agent;
};
static struct scmi_transport_core_operations *core;
-/* There can be only 1 SCMI service in OP-TEE we connect to */
-static struct scmi_optee_agent *scmi_optee_private;
+static DEFINE_XARRAY(scmi_active_agents);
+static DEFINE_SCMI_TRANSPORT_INSTANCE_QUEUE(scmi_available_agents);
/* Open a session toward SCMI OP-TEE service with REE_KERNEL identity */
static int open_session(struct scmi_optee_agent *agent, u32 *tee_session)
@@ -222,7 +228,7 @@ static int get_capabilities(struct scmi_optee_agent *agent)
static int get_channel(struct scmi_optee_channel *channel)
{
- struct device *dev = scmi_optee_private->dev;
+ struct device *dev = channel->agent->dev;
struct tee_ioctl_invoke_arg arg = { };
struct tee_param param[1] = { };
unsigned int caps = 0;
@@ -241,7 +247,7 @@ static int get_channel(struct scmi_optee_channel *channel)
param[0].u.value.a = channel->channel_id;
param[0].u.value.b = caps;
- ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+ ret = tee_client_invoke_func(channel->agent->tee_ctx, &arg, param);
if (ret || arg.ret) {
dev_err(dev, "Can't get channel with caps %#x: %d / %#x\n", caps, ret, arg.ret);
@@ -268,9 +274,9 @@ static int invoke_process_smt_channel(struct scmi_optee_channel *channel)
param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
param[0].u.value.a = channel->channel_id;
- ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+ ret = tee_client_invoke_func(channel->agent->tee_ctx, &arg, param);
if (ret < 0 || arg.ret) {
- dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
+ dev_err(channel->agent->dev, "Can't invoke channel %u: %d / %#x\n",
channel->channel_id, ret, arg.ret);
return -EIO;
}
@@ -299,9 +305,9 @@ static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t
param[2].u.memref.shm = channel->tee_shm;
param[2].u.memref.size = SCMI_SHMEM_MAX_PAYLOAD_SIZE;
- ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+ ret = tee_client_invoke_func(channel->agent->tee_ctx, &arg, param);
if (ret < 0 || arg.ret) {
- dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
+ dev_err(channel->agent->dev, "Can't invoke channel %u: %d / %#x\n",
channel->channel_id, ret, arg.ret);
return -EIO;
}
@@ -334,7 +340,8 @@ static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *ch
const size_t msg_size = SCMI_SHMEM_MAX_PAYLOAD_SIZE;
void *shbuf;
- channel->tee_shm = tee_shm_alloc_kernel_buf(scmi_optee_private->tee_ctx, msg_size);
+ channel->tee_shm = tee_shm_alloc_kernel_buf(channel->agent->tee_ctx,
+ msg_size);
if (IS_ERR(channel->tee_shm)) {
dev_err(channel->cinfo->dev, "shmem allocation failed\n");
return -ENOMEM;
@@ -390,17 +397,19 @@ static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *de
cinfo->transport_info = channel;
channel->cinfo = cinfo;
channel->channel_id = channel_id;
+ channel->agent = list_entry(hndl, struct scmi_optee_agent, node);
mutex_init(&channel->mu);
ret = setup_shmem(dev, cinfo, channel);
if (ret)
return ret;
- ret = open_session(scmi_optee_private, &channel->tee_session);
+ ret = open_session(channel->agent, &channel->tee_session);
if (ret)
goto err_free_shm;
- ret = tee_client_system_session(scmi_optee_private->tee_ctx, channel->tee_session);
+ ret = tee_client_system_session(channel->agent->tee_ctx,
+ channel->tee_session);
if (ret)
dev_warn(dev, "Could not switch to system session, do best effort\n");
@@ -411,14 +420,14 @@ static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *de
/* Enable polling */
cinfo->no_completion_irq = true;
- mutex_lock(&scmi_optee_private->mu);
- list_add(&channel->link, &scmi_optee_private->channel_list);
- mutex_unlock(&scmi_optee_private->mu);
+ mutex_lock(&channel->agent->mu);
+ list_add(&channel->link, &channel->agent->channel_list);
+ mutex_unlock(&channel->agent->mu);
return 0;
err_close_sess:
- close_session(scmi_optee_private, channel->tee_session);
+ close_session(channel->agent, channel->tee_session);
err_free_shm:
if (channel->tee_shm)
tee_shm_free(channel->tee_shm);
@@ -438,11 +447,11 @@ static int scmi_optee_chan_free(int id, void *p, void *data)
if (!channel)
return 0;
- mutex_lock(&scmi_optee_private->mu);
+ mutex_lock(&channel->agent->mu);
list_del(&channel->link);
- mutex_unlock(&scmi_optee_private->mu);
+ mutex_unlock(&channel->agent->mu);
- close_session(scmi_optee_private, channel->tee_session);
+ close_session(channel->agent, channel->tee_session);
if (channel->tee_shm) {
tee_shm_free(channel->tee_shm);
@@ -524,7 +533,7 @@ static struct scmi_desc scmi_optee_desc = {
};
static const struct of_device_id scmi_of_match[] = {
- { .compatible = "linaro,scmi-optee" },
+ { .compatible = "linaro,scmi-optee", .data = &scmi_available_agents},
{ /* Sentinel */ },
};
@@ -538,12 +547,6 @@ static int scmi_optee_service_probe(struct tee_client_device *scmi_pta)
struct tee_context *tee_ctx;
int ret;
- /* Only one SCMI OP-TEE device allowed */
- if (scmi_optee_private) {
- dev_err(dev, "An SCMI OP-TEE device was already initialized: only one allowed\n");
- return -EBUSY;
- }
-
tee_ctx = tee_client_open_context(NULL, scmi_optee_ctx_match, NULL, NULL);
if (IS_ERR(tee_ctx))
return -ENODEV;
@@ -563,15 +566,14 @@ static int scmi_optee_service_probe(struct tee_client_device *scmi_pta)
if (ret)
goto err;
- /* Ensure agent resources are all visible before scmi_optee_private is */
+ /* Ensure agent resources are visible */
smp_mb();
- scmi_optee_private = agent;
-
- ret = platform_driver_register(&scmi_optee_driver);
- if (ret) {
- scmi_optee_private = NULL;
+ ret = xa_insert(&scmi_active_agents, (unsigned long)scmi_pta, agent,
+ GFP_KERNEL);
+ if (ret)
goto err;
- }
+
+ SCMI_TRANSPORT_INSTANCE_REGISTER(agent->node, scmi_available_agents);
return 0;
@@ -583,19 +585,15 @@ static int scmi_optee_service_probe(struct tee_client_device *scmi_pta)
static void scmi_optee_service_remove(struct tee_client_device *scmi_pta)
{
- struct scmi_optee_agent *agent = scmi_optee_private;
+ struct scmi_optee_agent *agent;
- if (!scmi_optee_private)
+ agent = xa_erase(&scmi_active_agents, (unsigned long)scmi_pta);
+ if (!agent)
return;
- platform_driver_unregister(&scmi_optee_driver);
-
- if (!list_empty(&scmi_optee_private->channel_list))
+ if (!list_empty(&agent->channel_list))
return;
- /* Ensure cleared reference is visible before resources are released */
- smp_store_mb(scmi_optee_private, NULL);
-
tee_client_close_context(agent->tee_ctx);
}
@@ -618,7 +616,30 @@ static struct tee_client_driver scmi_optee_service_driver = {
},
};
-module_tee_client_driver(scmi_optee_service_driver);
+static int __init scmi_transport_optee_init(void)
+{
+ int ret;
+
+ ret = tee_client_driver_register(&scmi_optee_service_driver);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&scmi_optee_driver);
+ if (ret) {
+ tee_client_driver_unregister(&scmi_optee_service_driver);
+ return ret;
+ }
+
+ return ret;
+}
+module_init(scmi_transport_optee_init);
+
+static void __exit scmi_transport_optee_exit(void)
+{
+ platform_driver_unregister(&scmi_optee_driver);
+ tee_client_driver_unregister(&scmi_optee_service_driver);
+}
+module_exit(scmi_transport_optee_exit);
MODULE_AUTHOR("Etienne Carriere <etienne.carriere@xxxxxxxxxxx>");
MODULE_DESCRIPTION("SCMI OPTEE Transport driver");
--
2.53.0