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Subject: Re: [PATCH v2 02/16] rpmsg: add RPMsg control API to register service
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
CC:     Ohad Ben-Cohen <ohad@wizery.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Andy Gross <agross@kernel.org>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-msm@vger.kernel.org>
References: <20201222105726.16906-1-arnaud.pouliquen@foss.st.com>
 <20201222105726.16906-3-arnaud.pouliquen@foss.st.com>
 <X/O0JC9z2s9MNRWa@builder.lan>
From:   Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
Message-ID: <f5a30755-cec6-2748-cf3e-bd67cc1613fc@foss.st.com>
Date:   Tue, 5 Jan 2021 17:53:19 +0100
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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
>>