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Date: Thu, 22 Dec 2022 18:50:44 +0000
From: Cristian Marussi <cristian.marussi@....com>
To: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc: sudeep.holla@....com, james.quinlan@...adcom.com,
f.fainelli@...il.com, etienne.carriere@...aro.org,
vincent.guittot@...aro.org, Ludvig.Parsson@...s.com,
cristian.marussi@....com
Subject: [PATCH 4/9] firmware: arm_scmi: Add common notifier helpers
Add a pair of notifier chains and generic empty notifier callbacks: still
currently unused but they will be used to act properly on device request
and creation events.
Signed-off-by: Cristian Marussi <cristian.marussi@....com>
---
drivers/firmware/arm_scmi/bus.c | 6 ++-
drivers/firmware/arm_scmi/common.h | 5 ++
drivers/firmware/arm_scmi/driver.c | 83 +++++++++++++++++++++++++++++-
3 files changed, 92 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 089957f5fb9b..bed566f58029 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -15,6 +15,9 @@
#include "common.h"
+BLOCKING_NOTIFIER_HEAD(scmi_requested_devices_nh);
+EXPORT_SYMBOL_GPL(scmi_requested_devices_nh);
+
static DEFINE_IDA(scmi_bus_id);
static const struct scmi_device_id *
@@ -94,12 +97,13 @@ static void scmi_dev_remove(struct device *dev)
scmi_drv->remove(scmi_dev);
}
-static struct bus_type scmi_bus_type = {
+struct bus_type scmi_bus_type = {
.name = "scmi_protocol",
.match = scmi_dev_match,
.probe = scmi_dev_probe,
.remove = scmi_dev_remove,
};
+EXPORT_SYMBOL_GPL(scmi_bus_type);
int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
const char *mod_name)
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 6a38244494fd..7ddae90eb945 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -105,6 +105,11 @@ void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
int __init scmi_bus_init(void);
void __exit scmi_bus_exit(void);
+extern struct bus_type scmi_bus_type;
+
+#define SCMI_BUS_NOTIFY_DEVICE_REQUEST 0
+#define SCMI_BUS_NOTIFY_DEVICE_UNREQUEST 1
+extern struct blocking_notifier_head scmi_requested_devices_nh;
int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index d1e32ea6d90a..62760bed1645 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -150,6 +150,9 @@ struct scmi_protocol_instance {
* @notify_priv: Pointer to private data structure specific to notifications.
* @node: List head
* @users: Number of users of this instance
+ * @bus_nb: A notifier to listen for device bind/unbind on the scmi bus
+ * @dev_req_nb: A notifier to listen for device request/unrequest on the scmi
+ * bus
*/
struct scmi_info {
struct device *dev;
@@ -169,9 +172,13 @@ struct scmi_info {
void *notify_priv;
struct list_head node;
int users;
+ struct notifier_block bus_nb;
+ struct notifier_block dev_req_nb;
};
#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle)
+#define bus_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, bus_nb)
+#define req_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, dev_req_nb)
static const int scmi_linux_errmap[] = {
/* better than switch case as long as return value is continuous */
@@ -2509,6 +2516,60 @@ static void scmi_cleanup_txrx_channels(struct scmi_info *info)
scmi_cleanup_channels(info, &info->rx_idr);
}
+static int scmi_bus_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct scmi_info *info = bus_nb_to_scmi_info(nb);
+ struct scmi_device *sdev = to_scmi_dev(data);
+
+ /* Skip transport devices and devices of different SCMI instances */
+ if (!strncmp(sdev->name, "__scmi_transport_device", 23) ||
+ sdev->dev.parent != info->dev)
+ return NOTIFY_DONE;
+
+ switch (action) {
+ case BUS_NOTIFY_BIND_DRIVER:
+ break;
+ case BUS_NOTIFY_UNBOUND_DRIVER:
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ dev_dbg(info->dev, "Device %s (%s) is now %s\n", dev_name(&sdev->dev),
+ sdev->name, action == BUS_NOTIFY_BIND_DRIVER ?
+ "about to be BOUND." : "UNBOUND.");
+
+ return NOTIFY_OK;
+}
+
+static int scmi_device_request_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct device_node *np;
+ struct scmi_device_id *id_table = data;
+ struct scmi_info *info = req_nb_to_scmi_info(nb);
+
+ np = idr_find(&info->active_protocols, id_table->protocol_id);
+ if (!np)
+ return NOTIFY_DONE;
+
+ dev_dbg(info->dev, "%sRequested device (%s) for protocol 0x%x\n",
+ action == SCMI_BUS_NOTIFY_DEVICE_REQUEST ? "" : "UN-",
+ id_table->name, id_table->protocol_id);
+
+ switch (action) {
+ case SCMI_BUS_NOTIFY_DEVICE_REQUEST:
+ break;
+ case SCMI_BUS_NOTIFY_DEVICE_UNREQUEST:
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_OK;
+}
+
static int scmi_probe(struct platform_device *pdev)
{
int ret;
@@ -2528,6 +2589,8 @@ static int scmi_probe(struct platform_device *pdev)
info->dev = dev;
info->desc = desc;
+ info->bus_nb.notifier_call = scmi_bus_notifier;
+ info->dev_req_nb.notifier_call = scmi_device_request_notifier;
INIT_LIST_HEAD(&info->node);
idr_init(&info->protocols);
mutex_init(&info->protocols_mtx);
@@ -2563,10 +2626,19 @@ static int scmi_probe(struct platform_device *pdev)
if (ret)
return ret;
- ret = scmi_xfer_info_init(info);
+ ret = bus_register_notifier(&scmi_bus_type, &info->bus_nb);
if (ret)
goto clear_txrx_setup;
+ ret = blocking_notifier_chain_register(&scmi_requested_devices_nh,
+ &info->dev_req_nb);
+ if (ret)
+ goto clear_bus_notifier;
+
+ ret = scmi_xfer_info_init(info);
+ if (ret)
+ goto clear_dev_req_notifier;
+
if (scmi_notification_init(handle))
dev_err(dev, "SCMI Notifications NOT available.\n");
@@ -2624,6 +2696,11 @@ static int scmi_probe(struct platform_device *pdev)
notification_exit:
scmi_notification_exit(&info->handle);
+clear_dev_req_notifier:
+ blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
+ &info->dev_req_nb);
+clear_bus_notifier:
+ bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
clear_txrx_setup:
scmi_cleanup_txrx_channels(info);
return ret;
@@ -2652,6 +2729,10 @@ static int scmi_remove(struct platform_device *pdev)
of_node_put(child);
idr_destroy(&info->active_protocols);
+ blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
+ &info->dev_req_nb);
+ bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
+
/* Safe to free channels since no more users */
scmi_cleanup_txrx_channels(info);
--
2.34.1
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