Re: [PATCH v2 2/7] drivers/soc: Add Aspeed XDMA Engine Driver

[Eddie James]

On 5/21/19 7:02 AM, Arnd Bergmann wrote:
> On Mon, May 20, 2019 at 10:19 PM Eddie James <eajames@xxxxxxxxxxxxx> wrote:
> > diff --git a/include/uapi/linux/aspeed-xdma.h b/include/uapi/linux/aspeed-xdma.h
> > new file mode 100644
> > index 0000000..2a4bd13
> > --- /dev/null
> > +++ b/include/uapi/linux/aspeed-xdma.h
> > @@ -0,0 +1,26 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/* Copyright IBM Corp 2019 */
> > +
> > +#ifndef _UAPI_LINUX_ASPEED_XDMA_H_
> > +#define _UAPI_LINUX_ASPEED_XDMA_H_
> > +
> > +#include <linux/types.h>
> > +
> > +/*
> > + * aspeed_xdma_op
> > + *
> > + * upstream: boolean indicating the direction of the DMA operation; upstream
> > + *           means a transfer from the BMC to the host
> > + *
> > + * host_addr: the DMA address on the host side, typically configured by PCI
> > + *            subsystem
> > + *
> > + * len: the size of the transfer in bytes; it should be a multiple of 16 bytes
> > + */
> > +struct aspeed_xdma_op {
> > +       __u32 upstream;
> > +       __u64 host_addr;
> > +       __u32 len;
> > +};
> > +
> > +#endif /* _UAPI_LINUX_ASPEED_XDMA_H_ */
> If this is a user space interface, please remove the holes in the
> data structure.


Surely it's 4-byte aligned and there won't be holes??


> I don't see how this is actually used in this patch, maybe you meant
> the definition to be part of another patch?


The structure is used in this patch as an argument to aspeed_xdma_start().


Thanks,

Eddie


>      Arnd