On Thu, Dec 13, 2018 at 09:31:13AM +0530, Ramalingam C wrote:
> Library functions for endianness are aligned for 16/32/64 bits.
> But hdcp sequence numbers are 24bits(big endian).
> So for their conversion to and from u32 helper functions are developed.
>
> Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
> ---
> include/drm/drm_hdcp.h | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
> index a6de09c5e47f..d8093ecf3ddc 100644
> --- a/include/drm/drm_hdcp.h
> +++ b/include/drm/drm_hdcp.h
> @@ -250,4 +250,22 @@ struct hdcp2_dp_errata_stream_type {
> #define HDCP_2_2_HDMI_RXSTATUS_READY(x) ((x) & BIT(2))
> #define HDCP_2_2_HDMI_RXSTATUS_REAUTH_REQ(x) ((x) & BIT(3))
>
> +/*
> + * Library functions for endianness are aligned for 16/32/64 bits.
> + * But hdcp sequence numbers are 24bits(big endian). So for their conversion
> + * from and to u32 below functions are developed.
Comment is a bit confusing, I'd do a simple:
/*
* Helper functions to convert 24bit big endian hdcp sequence number to
* host format and back
*/
Explaining why we need them exactly isn't terribly interesting.
> + */
> +static inline void
> +drm_hdcp2_seq_num_to_u32(u32 *val, u8 seq_num[HDCP_2_2_SEQ_NUM_LEN])
make u32 val the return value of this function, should be cleaner.
> +{
> + *val = seq_num[2] | seq_num[1] << 8 | seq_num[0] << 16;
> +}
> +
> +static inline void drm_hdcp2_u32_to_seq_num(u8 *seq_num, u32 val)
u8 seq_num[HDCP_2_2_SEQ_NUM_LEN]. Not any different in the actual function
type, just a bit more informative.
> +{
> + seq_num[0] = (val & (0xff << 16)) >> 16;
> + seq_num[1] = (val & (0xff << 8)) >> 8;
Shift alone should be enough, since seq_num[x] is of type u8 the & 0xff is
implied.
With the above comments addressed:
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> + seq_num[2] = val & 0xff;
> +}
> +
> #endif
> --
> 2.7.4
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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