Re: [PATCH v1 3/6] net/can: Add can_dlc2len and can_len2dlc for CAN FD.

[Vikram Garhwal]

On Tue, Jul 14, 2020 at 02:20:16PM +0200, pisa@cmp.felk.cvut.cz wrote:
Hi Pavel,
> From: Jan Charvat <charvj10@fel.cvut.cz>
>
> Signed-off-by: Jan Charvat <charvj10@fel.cvut.cz>
> Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
> ---
>  include/net/can_emu.h |  4 ++++
>  net/can/can_core.c    | 36 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
>
> diff --git a/include/net/can_emu.h b/include/net/can_emu.h
> index c6164dcfb4..7d395fbb9b 100644
> --- a/include/net/can_emu.h
> +++ b/include/net/can_emu.h
> @@ -127,4 +127,8 @@ int can_bus_client_set_filters(CanBusClientState *,
>                                 const struct qemu_can_filter *filters,
>                                 size_t filters_cnt);
>
> +uint8_t can_dlc2len(uint8_t can_dlc);
> +
> +uint8_t can_len2dlc(uint8_t len);
> +
These function are aimed for canfd. Perhaps rename these to canfd_dlc2len and
canfd_len2dlc for better distinction?
Rest of the patch looks good to me.
>  #endif
> diff --git a/net/can/can_core.c b/net/can/can_core.c
> index 90f4d8576a..0115d78794 100644
> --- a/net/can/can_core.c
> +++ b/net/can/can_core.c
> @@ -33,6 +33,42 @@
>  #include "net/can_emu.h"
>  #include "qom/object_interfaces.h"
>
> +/* CAN DLC to real data length conversion helpers */
> +
> +static const uint8_t dlc2len[] = {
> +    0, 1, 2, 3, 4, 5, 6, 7,
> +    8, 12, 16, 20, 24, 32, 48, 64
> +};
> +
> +/* get data length from can_dlc with sanitized can_dlc */
> +uint8_t can_dlc2len(uint8_t can_dlc)
> +{
> +    return dlc2len[can_dlc & 0x0F];
> +}
> +
> +static const uint8_t len2dlc[] = {
> +    0, 1, 2, 3, 4, 5, 6, 7, 8,                              /* 0 - 8 */
> +    9, 9, 9, 9,                                             /* 9 - 12 */
> +    10, 10, 10, 10,                                         /* 13 - 16 */
> +    11, 11, 11, 11,                                         /* 17 - 20 */
> +    12, 12, 12, 12,                                         /* 21 - 24 */
> +    13, 13, 13, 13, 13, 13, 13, 13,                         /* 25 - 32 */
> +    14, 14, 14, 14, 14, 14, 14, 14,                         /* 33 - 40 */
> +    14, 14, 14, 14, 14, 14, 14, 14,                         /* 41 - 48 */
> +    15, 15, 15, 15, 15, 15, 15, 15,                         /* 49 - 56 */
> +    15, 15, 15, 15, 15, 15, 15, 15                          /* 57 - 64 */
> +};
> +
> +/* map the sanitized data length to an appropriate data length code */
> +uint8_t can_len2dlc(uint8_t len)
> +{
> +    if (unlikely(len > 64)) {
> +        return 0xF;
> +    }
> +
> +    return len2dlc[len];
> +}
> +
>  struct CanBusState {
>      Object object;
>
> --
> 2.20.1
>
>