Re: [PATCH v2 02/16] rpmsg: add RPMsg control API to register service

Arnaud POULIQUEN
2021-01-05T16:54:25Z

On 1/5/21 1:34 AM, Bjorn Andersson wrote:
> On Tue 22 Dec 04:57 CST 2020, Arnaud Pouliquen wrote:
>
>> Add API to register a RPMsg service to the control device.
>> The rpmsg_drv_ctrl_info structure links a service to its driver.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> ---
>> drivers/rpmsg/rpmsg_ctrl.c | 57 ++++++++++++++++++++++++++++++++++++++
>> include/linux/rpmsg.h | 31 +++++++++++++++++++++
>> include/uapi/linux/rpmsg.h | 14 ++++++++++
>> 3 files changed, 102 insertions(+)
>>
>> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
>> index 425c3e32ada4..065e2e304019 100644
>> --- a/drivers/rpmsg/rpmsg_ctrl.c
>> +++ b/drivers/rpmsg/rpmsg_ctrl.c
>> @@ -27,6 +27,20 @@ struct rpmsg_ctrl_dev {
>> struct device dev;
>> };
>>
>> +/**
>> + * struct rpmsg_ctl_info - control info list node
>> + * @ctrl: control driver info
>> + * @node: list node
>> + *
>> + * This structure is used by rpmsg_ctl to list the registered drivers services
>> + */
>> +struct rpmsg_ctl_info {
>> + const struct rpmsg_drv_ctrl_info *ctrl;
>> + struct list_head node;
>> +};
>> +
>> +static LIST_HEAD(rpmsg_drv_list);
>> +
>> static DEFINE_IDA(rpmsg_ctrl_ida);
>> static DEFINE_IDA(rpmsg_minor_ida);
>>
>> @@ -175,6 +189,49 @@ static struct rpmsg_driver rpmsg_ctrl_driver = {
>> .remove = rpmsg_ctrl_remove,
>> };
>>
>> +/**
>> + * rpmsg_ctrl_register_ctl() -register control for the associated service
>> + * @ctrl: rpmsg driver information
>> + *
>> + * This function is called by the rpmsg driver to register a service that will
>> + * be exposed to be instantiate by the application.
>> + */
>> +int rpmsg_ctrl_register_ctl(const struct rpmsg_drv_ctrl_info *ctrl)
>> +{
>> + struct rpmsg_ctl_info *drv_info;
>> +
>> + drv_info = kzalloc(sizeof(*drv_info), GFP_KERNEL);
>> + if (!drv_info)
>> + return -ENOMEM;
>> +
>> + drv_info->ctrl = ctrl;
>> +
>> + list_add_tail(&drv_info->node, &rpmsg_drv_list);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(rpmsg_ctrl_register_ctl);
>> +
>> +/**
>> + * rpmsg_ctrl_unregister_ctl() -unregister control for the associated service
>> + * @ctrl: the rpmsg control information
>> + *
>> + * This function is called by the rpmsg driver to unregister the associated
>> + * service.
>> + */
>> +void rpmsg_ctrl_unregister_ctl(const struct rpmsg_drv_ctrl_info *ctrl)
>> +{
>> + struct rpmsg_ctl_info *drv_info, *tmp;
>> +
>> + list_for_each_entry_safe(drv_info, tmp, &rpmsg_drv_list, node) {
>> + if (drv_info->ctrl == ctrl) {
>> + list_del(&drv_info->node);
>> + kfree(drv_info);
>> + }
>> + }
>> +}
>> +EXPORT_SYMBOL(rpmsg_ctrl_unregister_ctl);
>> +
>> static int rpmsg_ctrl_init(void)
>> {
>> int ret;
>> diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
>> index a5db828b2420..5d64704c2346 100644
>> --- a/include/linux/rpmsg.h
>> +++ b/include/linux/rpmsg.h
>> @@ -26,6 +26,19 @@ struct rpmsg_endpoint;
>> struct rpmsg_device_ops;
>> struct rpmsg_endpoint_ops;
>>
>> +/**
>> + * struct rpmsg_drv_ctrl_info - rpmsg ctrl structure
>> + * @drv_name: name of the associated driver
>> + * @service: the associated rpmsg service listed in @rpmsg_services
>> + *
>> + * This structure is used by rpmsg_ctl to link the endpoint creation to the
>> + * service rpmsg driver.
>> + */
>> +struct rpmsg_drv_ctrl_info {
>> + const char *drv_name;
>> + u32 service;
>> +};
>> +
>> /**
>> * struct rpmsg_channel_info - channel info representation
>> * @name: name of service
>> @@ -315,4 +328,22 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
>> module_driver(__rpmsg_driver, register_rpmsg_driver, \
>> unregister_rpmsg_driver)
>>
>> +#if IS_ENABLED(CONFIG_RPMSG_CTRL)
>> +
>> +int rpmsg_ctrl_register_ctl(const struct rpmsg_drv_ctrl_info *ctrl);
>> +void rpmsg_ctrl_unregister_ctl(const struct rpmsg_drv_ctrl_info *ctrl);
>> +
>> +#else
>> +
>> +static inline int rpmsg_ctrl_register_ctl(const struct rpmsg_drv_ctrl_info *ctrl)
>> +{
>> + return 0;
>> +}
>> +
>> +static inline void rpmsg_ctrl_unregister_ctl(const struct rpmsg_drv_ctrl_info *ctrl)
>> +{
>> +}
>> +
>> +#endif /* IS_ENABLED(CONFIG_RPMSG_CTRL) */
>> +
>> #endif /* _LINUX_RPMSG_H */
>> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
>> index e14c6dab4223..0b0cb028e0b3 100644
>> --- a/include/uapi/linux/rpmsg.h
>> +++ b/include/uapi/linux/rpmsg.h
>> @@ -9,6 +9,20 @@
>> #include <linux/ioctl.h>
>> #include <linux/types.h>
>>
>> +/**
>> + * enum rpmsg_services - list of supported RPMsg services
>> + *
>> + * @RPMSG_RAW_SERVICE: char device RPMSG service
>> + * @RPMSG_START_PRIVATE_SERVICES: private services have to be declared after.
>> + */
>> +enum rpmsg_services {
>> + /* Reserved services */
>> + RPMSG_RAW_SERVICE = 0,
>> +
>
> What kind of things do you envision this list to contain in a year from
> now?

The next one is the TTY, and perhaps the RPMsg I2C that allows to share a I2C
bus between the main and a remote processor.

Please notice that this field will also has to be added in a second step to the
rpmsg_endpoint_info struct, to allow the applications to select the expected
service.

Regards
Arnaud

>
> Regards,
> Bjorn
>
>> + /* Private services */
>> + RPMSG_START_PRIVATE_SERVICES = 1024,
>> +};
>> +
>> /**
>> * struct rpmsg_endpoint_info - endpoint info representation
>> * @name: name of service
>> --
>> 2.17.1
>>