Re: [RFC PATCH v7 06/16] net: dsa: tag_qca: add define for handling mgmt Ethernet packet

Florian Fainelli
2022-01-26T03:57:15Z

On 1/22/2022 5:33 PM, Ansuel Smith wrote:
> Add all the required define to prepare support for mgmt read/write in
> Ethernet packet. Any packet of this type has to be dropped as the only
> use of these special packet is receive ack for an mgmt write request or
> receive data for an mgmt read request.
> A struct is used that emulates the Ethernet header but is used for a
> different purpose.
>
> Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> ---
> include/linux/dsa/tag_qca.h | 44 +++++++++++++++++++++++++++++++++++++
> net/dsa/tag_qca.c | 13 ++++++++---
> 2 files changed, 54 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/dsa/tag_qca.h b/include/linux/dsa/tag_qca.h
> index c02d2d39ff4a..1a02f695f3a3 100644
> --- a/include/linux/dsa/tag_qca.h
> +++ b/include/linux/dsa/tag_qca.h
> @@ -12,10 +12,54 @@
> #define QCA_HDR_RECV_FRAME_IS_TAGGED BIT(3)
> #define QCA_HDR_RECV_SOURCE_PORT GENMASK(2, 0)
>
> +/* Packet type for recv */
> +#define QCA_HDR_RECV_TYPE_NORMAL 0x0
> +#define QCA_HDR_RECV_TYPE_MIB 0x1
> +#define QCA_HDR_RECV_TYPE_RW_REG_ACK 0x2
> +
> #define QCA_HDR_XMIT_VERSION GENMASK(15, 14)
> #define QCA_HDR_XMIT_PRIORITY GENMASK(13, 11)
> #define QCA_HDR_XMIT_CONTROL GENMASK(10, 8)
> #define QCA_HDR_XMIT_FROM_CPU BIT(7)
> #define QCA_HDR_XMIT_DP_BIT GENMASK(6, 0)
>
> +/* Packet type for xmit */
> +#define QCA_HDR_XMIT_TYPE_NORMAL 0x0
> +#define QCA_HDR_XMIT_TYPE_RW_REG 0x1
> +
> +/* Check code for a valid mgmt packet. Switch will ignore the packet
> + * with this wrong.
> + */
> +#define QCA_HDR_MGMT_CHECK_CODE_VAL 0x5
> +
> +/* Specific define for in-band MDIO read/write with Ethernet packet */
> +#define QCA_HDR_MGMT_SEQ_LEN 4 /* 4 byte for the seq */
> +#define QCA_HDR_MGMT_COMMAND_LEN 4 /* 4 byte for the command */
> +#define QCA_HDR_MGMT_DATA1_LEN 4 /* First 4 byte for the mdio data */
> +#define QCA_HDR_MGMT_HEADER_LEN (QCA_HDR_MGMT_SEQ_LEN + \
> + QCA_HDR_MGMT_COMMAND_LEN + \
> + QCA_HDR_MGMT_DATA1_LEN)
> +
> +#define QCA_HDR_MGMT_DATA2_LEN 12 /* Other 12 byte for the mdio data */
> +#define QCA_HDR_MGMT_PADDING_LEN 34 /* Padding to reach the min Ethernet packet */
> +
> +#define QCA_HDR_MGMT_PKG_LEN (QCA_HDR_MGMT_HEADER_LEN + \
> + QCA_HDR_LEN + \
> + QCA_HDR_MGMT_DATA2_LEN + \
> + QCA_HDR_MGMT_PADDING_LEN)
> +
> +#define QCA_HDR_MGMT_SEQ_NUM GENMASK(31, 0) /* 63, 32 */
> +#define QCA_HDR_MGMT_CHECK_CODE GENMASK(31, 29) /* 31, 29 */
> +#define QCA_HDR_MGMT_CMD BIT(28) /* 28 */
> +#define QCA_HDR_MGMT_LENGTH GENMASK(23, 20) /* 23, 20 */
> +#define QCA_HDR_MGMT_ADDR GENMASK(18, 0) /* 18, 0 */
> +
> +/* Special struct emulating a Ethernet header */
> +struct mgmt_ethhdr {
> + u32 command; /* command bit 31:0 */
> + u32 seq; /* seq 63:32 */
> + u32 mdio_data; /* first 4byte mdio */
> + __be16 hdr; /* qca hdr */
> +} __packed;
> +
> #endif /* __TAG_QCA_H */
> diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
> index f8df49d5956f..c57d6e1a0c0c 100644
> --- a/net/dsa/tag_qca.c
> +++ b/net/dsa/tag_qca.c
> @@ -32,10 +32,10 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
>
> static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
> {
> - u8 ver;
> - u16 hdr;
> - int port;
> + u16 hdr, pk_type;

Should pk_type be u8 since there are only 5 bits for QCA_HDR_RECV_TYPE?

With Vladimir's comments addressed:

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
--
Florian