linux-kernel - Re: [PATCH RFT 03/12] firmware: arm_ffa: Implement the notification bind and unbind interface

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Date:   Tue, 12 Sep 2023 15:23:53 +0200
From:   Jens Wiklander <jens.wiklander@...aro.org>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Lucian Paul-Trifu <lucian.paul-trifu@....com>,
        Marc Bonnici <marc.bonnici@....com>,
        Coboy Chen <coboy.chen@...iatek.com>
Subject: Re: [PATCH RFT 03/12] firmware: arm_ffa: Implement the notification
 bind and unbind interface

On Thu, Aug 03, 2023 at 08:02:07PM +0100, Sudeep Holla wrote:
> A receiver endpoint must bind a notification to any sender endpoint
> before the latter can signal the notification to the former. The receiver
> assigns one or more doorbells to a specific sender. Only the sender can
> ring these doorbells.
> 
> A receiver uses the FFA_NOTIFICATION_BIND interface to bind one or more
> notifications to the sender. A receiver un-binds a notification from a
> sender endpoint to stop the notification from being signaled. It uses
> the FFA_NOTIFICATION_UNBIND interface to do this.
> 
> Allow the FF-A driver to be able to bind and unbind a given notification
> ID to a specific partition ID. This will be used to register and
> unregister notification callbacks from the FF-A client drivers.
> 
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>  drivers/firmware/arm_ffa/driver.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 022c893c9e06..a76e5d3a2422 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -575,6 +575,35 @@ static int ffa_notification_bitmap_destroy(void)
>  	return 0;
>  }
>  
> +#define NOTIFICATION_LOW_MASK		GENMASK(31, 0)
> +#define NOTIFICATION_HIGH_MASK		GENMASK(63, 32)
> +#define NOTIFICATION_BITMAP_HIGH(x)	\
> +		((u32)(FIELD_GET(NOTIFICATION_HIGH_MASK, (x))))
> +#define NOTIFICATION_BITMAP_LOW(x)	\
> +		((u32)(FIELD_GET(NOTIFICATION_LOW_MASK, (x))))
> +
> +static int ffa_notification_bind_common(u16 dst_id, u64 bitmap,
> +					u32 flags, bool is_bind)
> +{
> +	ffa_value_t ret;
> +	u32 func, src_dst_ids = PACK_TARGET_INFO(dst_id, drv_info->vm_id);
dst_id and drv_info->vm_id should be swapped in the argument to
PACK_TARGET_INFO().

Thanks,
Jens

> +
> +	func = is_bind ? FFA_NOTIFICATION_BIND : FFA_NOTIFICATION_UNBIND;
> +
> +	invoke_ffa_fn((ffa_value_t){
> +		  .a0 = func, .a1 = src_dst_ids, .a2 = flags,
> +		  .a3 = NOTIFICATION_BITMAP_LOW(bitmap),
> +		  .a4 = NOTIFICATION_BITMAP_HIGH(bitmap),
> +		  }, &ret);
> +
> +	if (ret.a0 == FFA_ERROR)
> +		return ffa_to_linux_errno((int)ret.a2);
> +	else if (ret.a0 != FFA_SUCCESS)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static void ffa_set_up_mem_ops_native_flag(void)
>  {
>  	if (!ffa_features(FFA_FN_NATIVE(MEM_LEND), 0, NULL, NULL) ||
> 
> -- 
> 2.41.0
>