RE: [PATCH v2 3/8] firmware: arm_scmi: Add support for standalone transport drivers

Peng Fan
2024-07-11T12:54:54Z

> Subject: [PATCH v2 3/8] firmware: arm_scmi: Add support for
> standalone transport drivers
>
> Extend the core SCMI stack with structures and methods to allow for
> transports to be split out as standalone drivers, while still supporting
> old style transports, defined as built into the SCMI core stack.
>
> No functional change.
>
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> NOTE: old style transport support will be removed later in this series.
>
> v1 --> v2
> - fixed comit message
> ---
> drivers/firmware/arm_scmi/common.h | 84
> ++++++++++++++++++++++++++++++
> drivers/firmware/arm_scmi/driver.c | 44 +++++++++++++++-
> drivers/firmware/arm_scmi/msg.c | 5 ++
> drivers/firmware/arm_scmi/shmem.c | 5 ++
> 4 files changed, 136 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/common.h
> b/drivers/firmware/arm_scmi/common.h
> index 8e5751aaa600..4af06810eb39 100644
> --- a/drivers/firmware/arm_scmi/common.h
> +++ b/drivers/firmware/arm_scmi/common.h
> @@ -349,6 +349,8 @@ struct scmi_shared_mem_operations {
> bool tx, struct resource *res); };
>
> +const struct scmi_shared_mem_operations
> +*scmi_shared_mem_operations_get(void);
> +
> /* declarations for message passing transports */ struct
> scmi_msg_payld;
>
> @@ -376,6 +378,88 @@ struct scmi_message_operations {
> size_t max_len, struct scmi_xfer
> *xfer); };
>
> +const struct scmi_message_operations
> +*scmi_message_operations_get(void);
> +
> +/**
> + * struct scmi_transport_core_operations - Transpoert core
> operations
> + *
> + * @bad_message_trace: An helper to report a
> malformed/unexpected
> +message
> + * @rx_callback: Callback to report received messages
> + * @shmem: Datagram operations for shared memory based
> transports
> + * @msg: Datagram operations for message based transports */
> struct
> +scmi_transport_core_operations {
> + void (*bad_message_trace)(struct scmi_chan_info *cinfo,
> + u32 msg_hdr, enum scmi_bad_msg
> err);
> + void (*rx_callback)(struct scmi_chan_info *cinfo, u32 msg_hdr,
> + void *priv);
> + const struct scmi_shared_mem_operations *shmem;
> + const struct scmi_message_operations *msg; };
> +
> +/**
> + * struct scmi_transport - A structure representing a configured
> +transport
> + *
> + * @supplier: Device representimng the transport and acting as a
> supplier for
> + * the core SCMI stack
> + * @desc: Transport descriptor
> + * @core_ops: A pointer to a pointer used by the core SCMI stack to
> make the
> + * core transport operations accessible to the transports.
> + */
> +struct scmi_transport {
> + struct device *supplier;
> + const struct scmi_desc *desc;
> + struct scmi_transport_core_operations **core_ops; };
> +
> +#define DEFINE_SCMI_TRANSPORT_DRIVER(__trans, __match_table,
> __core_ptr)\
> +static int __trans##_probe(struct platform_device *pdev) \
> +{
> \
> + struct scmi_transport *scmi_trans;
> \
> + struct platform_device *scmi_pdev;
> \
> + struct device *dev = &pdev->dev; \
> +
> \
> + scmi_trans = devm_kzalloc(dev, sizeof(*scmi_trans),
> GFP_KERNEL);\
> + if (!scmi_trans) \
> + return -ENOMEM;
> \
> +
> \
> + scmi_pdev = devm_kzalloc(dev, sizeof(*scmi_pdev),
> GFP_KERNEL); \
> + if (!scmi_pdev)
> \
> + return -ENOMEM;
> \
> +
> \
> + scmi_trans->supplier = dev;
> \
> + scmi_trans->desc = &__trans##_desc;
> \
> + scmi_trans->core_ops = __core_ptr;
> \
> +
> \
> + scmi_pdev->name = "arm-scmi";
> \
> + scmi_pdev->id = PLATFORM_DEVID_AUTO;
> \
> + scmi_pdev->dev.platform_data = scmi_trans;
> \
> +
> \
> + device_set_of_node_from_dev(&scmi_pdev->dev, dev);
> \
> +
> \
> + dev_set_drvdata(dev, scmi_pdev);
> \
> +
> \
> + return platform_device_register(scmi_pdev);
> \
> +}
> \
> +
> \
> +static void __trans##_remove(struct platform_device *pdev)
> \
> +{
> \
> + struct platform_device *scmi_pdev;
> \
> +
> \
> + scmi_pdev = dev_get_drvdata(&pdev->dev);
> \
> +
> \
> + platform_device_unregister(scmi_pdev);
> \
> +}
> \
> +
> \
> +static struct platform_driver __trans##_driver = { \
> + .driver = {
> \
> + .name = #__trans "_transport", \
> + .of_match_table = __match_table,
> \
> + },
> \
> + .probe = __trans##_probe,
> \
> + .remove_new = __trans##_remove,
> \
> +}
> +
> extern const struct scmi_shared_mem_operations scmi_shmem_ops;
> extern const struct scmi_message_operations scmi_msg_ops;
>
> diff --git a/drivers/firmware/arm_scmi/driver.c
> b/drivers/firmware/arm_scmi/driver.c
> index 6b6957f4743f..a1892d4d8c69 100644
> --- a/drivers/firmware/arm_scmi/driver.c
> +++ b/drivers/firmware/arm_scmi/driver.c
> @@ -194,6 +194,11 @@ struct scmi_info {
> #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 struct scmi_transport_core_operations scmi_trans_core_ops = {
> + .bad_message_trace = scmi_bad_message_trace,
> + .rx_callback = scmi_rx_callback,
> +};
> +
> static unsigned long
> scmi_vendor_protocol_signature(unsigned int protocol_id, char
> *vendor_id,
> char *sub_vendor_id, u32 impl_ver) @@
> -2950,6 +2955,28 @@ static int scmi_debugfs_raw_mode_setup(struct
> scmi_info *info)
> return ret;
> }
>
> +static const struct scmi_desc *scmi_transport_lookup(struct device
> +*dev) {
> + struct scmi_transport *trans;
> +
> + trans = dev_get_platdata(dev);
> + if (!trans || !trans->desc || !trans->supplier || !trans-
> >core_ops)
> + return NULL;
> +
> + if (!device_link_add(dev, trans->supplier,
> DL_FLAG_AUTOREMOVE_CONSUMER)) {

Just wonder why this is needed?

> + dev_err(dev,
> + "Adding link to supplier transport device
> failed\n");
> + return NULL;
> + }
> +
> + /* Provide core transport ops */
> + *trans->core_ops = &scmi_trans_core_ops;
> +
> + dev_info(dev, "Using %s\n", dev_driver_string(trans->supplier));
> +
> + return trans->desc;
> +}
> +
> static int scmi_probe(struct platform_device *pdev) {
> int ret;
> @@ -2962,8 +2989,14 @@ static int scmi_probe(struct
> platform_device *pdev)
> struct device_node *child, *np = dev->of_node;
>
> desc = of_device_get_match_data(dev);
> - if (!desc)
> - return -EINVAL;
> + if (!desc) {
> + desc = scmi_transport_lookup(dev);

from the code, It is not actually a lookup operation.
How about scmi_transport_setup?

Regards,
Peng.