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firmware: arm_scmi: virtio: Rework transport probe sequence

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Use the new per-instance transport handles helpers to synchronize and
optionally defer the core SCMI driver probe up until the transport driver
has completely been initialized and it is fully operational as a supplier.

Introduce proper module init/exit routines while removing the ugly trick of
registering a driver from within the probe sequence of another one, just to
avoid to have to deal with probe deferrals.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://patch.msgid.link/20260510160527.3537474-4-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
This commit is contained in:
Cristian Marussi 2026-05-10 17:05:26 +01:00 committed by Sudeep Holla
parent ab6eb28a47
commit c08051901a
1 changed files with 43 additions and 9 deletions
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52
drivers/firmware/arm_scmi/transports/virtio.c
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@ -4,7 +4,7 @@
* (SCMI).
*
* Copyright (C) 2020-2022 OpenSynergy.
* Copyright (C) 2021-2024 ARM Ltd.
* Copyright (C) 2021-2026 ARM Ltd.
*/
/**
@ -116,6 +116,8 @@ static struct scmi_transport_core_operations *core;
/* Only one SCMI VirtIO device can possibly exist */
static struct virtio_device *scmi_vdev;
static DEFINE_SCMI_TRANSPORT_SUPPLIER(scmi_virtio_supplier);
static void scmi_vio_channel_ready(struct scmi_vio_channel *vioch,
struct scmi_chan_info *cinfo)
{
@ -394,6 +396,10 @@ static bool virtio_chan_available(struct device_node *of_node, int idx)
return false;
}
dev_dbg(&scmi_vdev->dev, "%s Channel %sAVAILABLE on SCMI Virtio device.\n",
idx == VIRTIO_SCMI_VQ_TX ? "TX" : "RX",
(vioch && !vioch->cinfo) ? "" : "NOT ");
return vioch && !vioch->cinfo;
}
@ -410,7 +416,7 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
int i;
if (!scmi_vdev)
return -EPROBE_DEFER;
return -EINVAL;
vioch = &((struct scmi_vio_channel *)scmi_vdev->priv)[index];
@ -460,6 +466,9 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
scmi_vio_channel_ready(vioch, cinfo);
dev_dbg(&scmi_vdev->dev, "%s Channel SETUP on SCMI Virtio device.\n",
tx ? "TX" : "RX");
return 0;
}
@ -801,7 +810,7 @@ static struct scmi_desc scmi_virtio_desc = {
};
static const struct of_device_id scmi_of_match[] = {
{ .compatible = "arm,scmi-virtio" },
{ .compatible = "arm,scmi-virtio", .data = &scmi_virtio_supplier.th},
{ /* Sentinel */ },
};
@ -864,33 +873,33 @@ static int scmi_vio_probe(struct virtio_device *vdev)
sz = MSG_TOKEN_MAX;
}
channels[i].max_msg = sz;
dev_dbg(dev, "VQ%d initialized with max_msg: %d\n", i, sz);
}
vdev->priv = channels;
/* Ensure initialized scmi_vdev is visible */
smp_store_mb(scmi_vdev, vdev);
/* Set device ready */
virtio_device_ready(vdev);
ret = platform_driver_register(&scmi_virtio_driver);
ret = scmi_transport_supplier_put(&scmi_virtio_supplier.th, &vdev->dev);
if (ret) {
virtio_reset_device(vdev);
vdev->priv = NULL;
vdev->config->del_vqs(vdev);
/* Ensure NULLified scmi_vdev is visible */
smp_store_mb(scmi_vdev, NULL);
return ret;
}
dev_dbg(dev, "Probed and initialized SCMI Virtio device.\n");
return 0;
}
static void scmi_vio_remove(struct virtio_device *vdev)
{
platform_driver_unregister(&scmi_virtio_driver);
/*
* Once we get here, virtio_chan_free() will have already been called by
* the SCMI core for any existing channel and, as a consequence, all the
@ -900,8 +909,10 @@ static void scmi_vio_remove(struct virtio_device *vdev)
*/
virtio_reset_device(vdev);
vdev->config->del_vqs(vdev);
/* Ensure scmi_vdev is visible as NULL */
smp_store_mb(scmi_vdev, NULL);
scmi_transport_supplier_put(&scmi_virtio_supplier.th, &vdev->dev);
}
static int scmi_vio_validate(struct virtio_device *vdev)
@ -936,7 +947,30 @@ static struct virtio_driver virtio_scmi_driver = {
.validate = scmi_vio_validate,
};
module_virtio_driver(virtio_scmi_driver);
static int __init scmi_transport_virtio_init(void)
{
int ret;
ret = register_virtio_driver(&virtio_scmi_driver);
if (ret)
return ret;
ret = platform_driver_register(&scmi_virtio_driver);
if (ret) {
unregister_virtio_driver(&virtio_scmi_driver);
return ret;
}
return ret;
}
module_init(scmi_transport_virtio_init);
static void __exit scmi_transport_virtio_exit(void)
{
platform_driver_unregister(&scmi_virtio_driver);
unregister_virtio_driver(&virtio_scmi_driver);
}
module_exit(scmi_transport_virtio_exit);
MODULE_AUTHOR("Igor Skalkin <igor.skalkin@opensynergy.com>");
MODULE_AUTHOR("Peter Hilber <peter.hilber@opensynergy.com>");