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

[Eddie James <eajames@linux.vnet.ibm.com>]

On 5/21/19 7:02 AM, Arnd Bergmann wrote:
> On Mon, May 20, 2019 at 10:19 PM Eddie James <eajames@linux.ibm.com> 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
>