Subject: Re: [PATCH v3 1/2] cxl: Add mechanism for delivering AFU driver
 specific events
To: Ian Munsie <imunsie@au1.ibm.com>, Michael Ellerman <michaele@au1.ibm.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Matt Ochs <mrochs@us.ibm.com>, Manoj Kumar <kumarmn@us.ibm.com>
References: <1457401715-26435-1-git-send-email-imunsie@au.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
        Michael Neuling <mikey@neuling.org>
From: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Message-ID: <56DE8656.3040208@au1.ibm.com>
Date: Tue, 8 Mar 2016 18:59:18 +1100
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On 08/03/16 12:48, Ian Munsie wrote:
> From: Ian Munsie <imunsie@au1.ibm.com>
>
> This adds an afu_driver_ops structure with event_pending and
> deliver_event callbacks. An AFU driver such as cxlflash can fill these
> out and associate it with a context to enable passing custom AFU
> specific events to userspace.
>
> The cxl driver will call event_pending() during poll, select, read, etc.
> calls to check if an AFU driver specific event is pending, and will call
> deliver_event() to deliver that event. This way, the cxl driver takes
> care of all the usual locking semantics around these calls and handles
> all the generic cxl events, so that the AFU driver only needs to worry
> about it's own events.
>
> The deliver_event() call is passed a struct cxl_event buffer to fill in.
> The header will already be filled in for an AFU driver event, and the
> AFU driver is expected to expand the header.size as necessary (up to
> max_size, defined by struct cxl_event_afu_driver_reserved) and fill out
> it's own information.
>
> Since AFU drivers provide their own means for userspace to obtain the
> AFU file descriptor (i.e. cxlflash uses an ioctl on their scsi file
> descriptor to obtain the AFU file descriptor) and the generic cxl driver
> will never use this event, the ABI of the event is up to each individual
> AFU driver.
>
> Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>

Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

-- 
Andrew Donnellan              Software Engineer, OzLabs
andrew.donnellan@au1.ibm.com  Australia Development Lab, Canberra
+61 2 6201 8874 (work)        IBM Australia Limited