On Thu, 7 Apr 2022, Ricardo Martinez wrote:
> From: Haijun Liu <haijun.liu@xxxxxxxxxxxx>
>
> Data Path Modem AP Interface (DPMAIF) HIF layer provides methods
> for initialization, ISR, control and event handling of TX/RX flows.
>
> DPMAIF TX
> Exposes the 'dmpaif_tx_send_skb' function which can be used by the
> network device to transmit packets.
> The uplink data management uses a Descriptor Ring Buffer (DRB).
> First DRB entry is a message type that will be followed by 1 or more
> normal DRB entries. Message type DRB will hold the skb information
> and each normal DRB entry holds a pointer to the skb payload.
>
> DPMAIF RX
> The downlink buffer management uses Buffer Address Table (BAT) and
> Packet Information Table (PIT) rings.
> The BAT ring holds the address of skb data buffer for the HW to use,
> while the PIT contains metadata about a whole network packet including
> a reference to the BAT entry holding the data buffer address.
> The driver reads the PIT and BAT entries written by the modem, when
> reaching a threshold, the driver will reload the PIT and BAT rings.
>
> Signed-off-by: Haijun Liu <haijun.liu@xxxxxxxxxxxx>
> Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>
> Co-developed-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx>
> Signed-off-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx>
>
> >From a WWAN framework perspective:
> Reviewed-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
> + if (txq->tx_skb_head.qlen >= txq->tx_list_max_len)
> + goto report_full_state;
> +
> + skb_cb = T7XX_SKB_CB(skb);
> + skb_cb->txq_number = txq_number;
> + skb_queue_tail(&txq->tx_skb_head, skb);
> + wake_up(&dpmaif_ctrl->tx_wq);
> + return 0;
> +
> +report_full_state:
> + callbacks = dpmaif_ctrl->callbacks;
> + callbacks->state_notify(dpmaif_ctrl->t7xx_dev, DMPAIF_TXQ_STATE_FULL, txq_number>
> + return -EBUSY;
> +}
Should this actually report full earlier so that the queue can be stopped
before NETDEV_TX_BUSY has to be returned (by the callers in 09/13)?
(see Documentation/networking/driver.rst)
> + /* Wait for active Tx to be doneg */
doneg -> done
> +struct dpmaif_drb {
> + __le32 header;
> + union {
> + struct {
> + __le32 data_addr_l;
> + __le32 data_addr_h;
> + __le32 reserved;
> + } pd;
> + struct {
> + __le32 msg_hdr;
> + __le32 reserved1;
> + __le32 reserved2;
> + } msg;
> + };
> +};
"reserved" and "reserved2" could be placed outside of the union
as they have the same offset.
--
i.
