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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Sat, 26 Jan 2019 17:05:52 +0100
Message-ID: <CAK8P3a2NX_SNZPfqE4fnVcnxmSfAEzWMODce3L-g6JJ0NSTuBw@mail.gmail.com>
Subject: Re: [PATCH 01/15] habanalabs: add skeleton driver
To:     Oded Gabbay <oded.gabbay@gmail.com>
Cc:     gregkh <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        ogabbay@habana.ai
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On Wed, Jan 23, 2019 at 1:01 AM Oded Gabbay <oded.gabbay@gmail.com> wrote:

> diff --git a/drivers/misc/habanalabs/include/habanalabs_device_if.h b/drivers/misc/habanalabs/include/habanalabs_device_if.h
> new file mode 100644
> index 000000000000..9dbb7077eabd
> --- /dev/null
> +++ b/drivers/misc/habanalabs/include/habanalabs_device_if.h

Since this is a apparently a user space ABI, the file should be in
include/uapi/linux/,
not in the driver directory.

> +/* must be aligned to 4 bytes */
> +struct armcp_info {
> +       struct armcp_sensor sensors[ARMCP_MAX_SENSORS];
> +       __u8 kernel_version[VERSION_MAX_LEN];
> +       __u32 reserved[3];
> +       __u32 cpld_version;
> +       __u32 infineon_version;
> +       __u8 fuse_version[VERSION_MAX_LEN];
> +       __u8 thermal_version[VERSION_MAX_LEN];
> +       __u8 armcp_version[VERSION_MAX_LEN];
> +       __u64 dram_size;
> +};

The compiler will align this to 8 bytes on most architectures, and
add another padding field before dram_size. Better remove the
'reserved' fields, or make them an even number.

       Arnd