[PATCH v4 13/14] gunyah: rsc_mgr: Add auxiliary devices for console

[Greg Kroah-Hartman]

On Wed, Sep 28, 2022 at 12:56:32PM -0700, Elliot Berman wrote:
> Gunyah resource manager exposes a concrete functionalities which
> complicate a single resource manager driver.

I am sorry, but I do not understand this sentance.  What is so
complicated about individual devices being created?  Where are they
created?  What bus?

Use auxiliary bus
> to help split high level functions for the resource manager and keep the
> primary resource manager driver focused on the RPC with RM itself.
> Delegate Resource Manager's console functionality to the auxiliary bus.
> 
> Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
> ---
>  drivers/virt/gunyah/Kconfig   |  1 +
>  drivers/virt/gunyah/rsc_mgr.c | 21 +++++++++++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> index 78deed3c4562..610c8586005b 100644
> --- a/drivers/virt/gunyah/Kconfig
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -17,6 +17,7 @@ config GUNYAH_RESORUCE_MANAGER
>  	tristate "Gunyah Resource Manager"
>  	select MAILBOX
>  	select GUNYAH_MESSAGE_QUEUES
> +	select AUXILIARY_BUS
>  	default y
>  	help
>  	  The resource manager (RM) is a privileged application VM supporting
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> index 7f7e89a6436b..435fe0149915 100644
> --- a/drivers/virt/gunyah/rsc_mgr.c
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -16,6 +16,7 @@
>  #include <linux/notifier.h>
>  #include <linux/workqueue.h>
>  #include <linux/completion.h>
> +#include <linux/auxiliary_bus.h>
>  #include <linux/gunyah_rsc_mgr.h>
>  #include <linux/platform_device.h>
>  
> @@ -98,6 +99,8 @@ struct gh_rsc_mgr {
>  	struct mutex send_lock;
>  
>  	struct work_struct recv_work;
> +
> +	struct auxiliary_device console_adev;
>  };
>  
>  static struct gh_rsc_mgr *__rsc_mgr;
> @@ -573,13 +576,31 @@ static int gh_rm_drv_probe(struct platform_device *pdev)
>  
>  	__rsc_mgr = rsc_mgr;
>  
> +	rsc_mgr->console_adev.dev.parent = &pdev->dev;
> +	rsc_mgr->console_adev.name = "console";
> +	ret = auxiliary_device_init(&rsc_mgr->console_adev);
> +	if (ret)
> +		goto err_msgq;
> +	ret = auxiliary_device_add(&rsc_mgr->console_adev);
> +	if (ret)
> +		goto err_console_adev_uninit;
> +
>  	return 0;
> +
> +err_console_adev_uninit:
> +	auxiliary_device_uninit(&rsc_mgr->console_adev);
> +err_msgq:
> +	gunyah_msgq_remove(&rsc_mgr->msgq);
> +	return ret;
>  }

Why can't you just have individual platform devices for the individual
devices your hypervisor exposes?

You control the platform devices, why force them to be shared like this?

thanks,

greg k-h