Re: [PATCH] Generic WorkQueue Engine (GenWQE) device driver

[Bjorn Helgaas]

On Thu, Jul 25, 2013 at 2:28 AM, Frank Haverkamp <haver@xxxxxxxxxxxx> wrote:
> The GenWQE card provides access to a generic work queue into which the
> work can be put, which should be executed, e.g. compression or
> decompression request, or whatever the card was configured to do.
>
> Each request comes with a set of input data (ASV) and will produce some
> output data (ASIV). The request will also contain a sequence number,
> some timestamps and a command code/subcode plus some fields for hardware-/
> software-interaction.
>
> A request can contain references to blocks of memory. Since the card
> requires DMA-addresses of that memory, the driver provides two ways to
> solve that task:
>   1) The drivers mmap() will allocate some DMAable memory for the user.
>      The driver has a lookup table such that the virtual userspace
>      address can properly be replaced and checked.
>   2) The user allocates memory and the driver will pin/unpin that
>      memory and setup a scatter gatherlist with matching DMA addresses.
>
> Currently work requests are synchronous.
>
> The genwqe driver has a user-space interface described in
> linux/include/genwqe/genwqe_card.h. There are several ioctls which can
> be used to talk to the driver. In addition there are some sysfs
> entries where information can be exchanged with user-space.
>
> Known Restrictions:
>
>  o On my PowerPC testsystem SRIOV did not work.

Does this restriction still apply?  Is there some PCI core issue here?
 We did fix an SR-IOV issue that was reported on PowerPC with
aa914f5ec25, so maybe that's related.  But if there's still a PCI core
issue here, let me know.

Bjorn
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